Volume 14, Issue 1

Seismic method is a major approach for detecting the seismic geological features ahead of the tunnel, understanding the distribution of unfavorable geology, and ensuring the safety of tunnel construction. Observation system is the key for seismic detection, many studies have been conducted to optimize the observation system; however, most of them focused on the surface seismic investigation and numerical simulation rather than in tunnel field environment (limited aperture and full space environment). How to obtain better wavefield information with limited observation aperture is a great challenge. In this study numerical simulation and instrumental techniques (GPR, DC, etc.) were implemented to further check the result of seismic detection at the 1# tailrace tunnel at the Wudongde hydropower station. In the field case, observation detectors were arranged spatially in the tunnel and source points were placed in four ways: linearly along a single side, on the tunnel face, in front of the detectors, and behind the detectors. Then, after data acquisition, the data processing is conducted to carry out the migration results. The imaging results indicate that the observation system with sources and detectors in liner arrangement (with equal interval) helps to suppress artifacts, further supporting the advantages of spatial observation system with liner observation line (detectors). Moreover, the study provides suggestions for geological prospecting in similar tunnel projects.

This research article represents the recompacted dense sand sample behaviour and stress distribution in the direct shear box. In Lithuania, sand is quite common on a construction site, in general about 32%. To reduce the influence of the shear box design on the experimentally determined values of the soil strength parameters, it is necessary to know the regularities of the change of the normal load acting in the shear plane. Three different normal stresses of 50, 100, and 200 kPa were applied to the dense sand in the direct shear boxes during experimental and numerical simulation. The results showed an obvious evidence of non-uniformity of stress for standard and raised specimens. The numerical analysis exhibited that when the sample is loaded only with a vertical load, approximately 75% of that load is transferred to the sample bottom, 84% to the shear plane, and 95% to the top. At the end of the shear test, the vertical force in the shear plane reaches maximum, the normal stress is higher by 13.5% than applied on the sample top. The shear strength of sandy soils were influenced by box size and sample height too. The improved shear box apparatus allows to estimate the vertical load at shear plane.

The present study examines the impact of the tourism industry on rural development and ecological environment after the COVID-19 epidemic from the perspectives of different stakeholders, taking the rural villages of Fujian as an example. The study was conducted using a hybrid study method. 402 valid questionnaires were analyzed using SPSS 22.0 statistical software, statistical and t -test methods, and then the results of the interviews and field surveys were compiled, compared, and examined by multivariate verification. The results found that insufficient parking and recreation, bicycle lanes and commentary facilities, rising prices of land and houses, deteriorating community environment and air quality, inadequate police and security personnel and communication channels for the community, and low awareness of community service among residents have bothered the residents. The poor communication channels in the community, lack of manpower for infrastructure, bicycle lanes, sightseeing indicators, preferential measures, and police and security, poor water quality, and overflow of garbage make tourists feel bad. Different stakeholders have different views on the current development of local society, humanities, environment, and natural ecology.

Paleogeomorphology is the surface morphology formed by the deposition of strata in the basin in historical period, which is greatly affected by the regional tectonic movement; however, the effect of basin paleogeomorphology on reservoir has been underexplored. This study documents the basin paleogeomorphic terrain features and their implications for the depositional processes and oil migration and accumulation in the Jiyuan area of the Ordos Basin. Stratigraphic classification is achieved through well logging data analysis. A seismic fine interpretation of the Triassic–Jurassic paleogeomorphology is conducted. Typical drilling core observations were utilized in a well section analysis of the strata at the top of the Yanchang formation sedimentary facies characteristics. Studies have shown that the Chang 1 subsection on top of the Triassic Yanchang formation in the Jiyuan area was eroded by an ancient Jurassic river, and the residual strata are primarily distributed in the Dingbian and Jiyuan plateaus. The Chang 1 reservoir in the Jiyuan area is dominated by a delta distributary channel sand body. The reservoir is concentrated in a high reservoir sand body structure position, and is controlled by a combination of structural and rock characteristics. This study suggests that the Indosinian movement in the late Triassic caused the entire basin to uplift and denudate, and the strata at the top of the Yanchang formation suffered from weathering and river erosion. The residual strata in the upper part of the Yanchang formation are controlled by the late Triassic–early Jurassic paleogeomorphology.

Changes in hydraulic properties of the flow are reflected in the vertical and/or lateral variation in sedimentary structures. In turbiditic sandstones, common sedimentary structures are grain size grading, planar lamination, and cross-lamination. This research is aimed at applying the advances in non-destructive X-ray fluorescence (XRF) mapping technology to detect various sedimentary structures in sandstones. XRF micro-imaging is able to produce in situ elemental–distribution maps of rock samples. This research applied a statistical technique of discriminant analysis to reduce the dimensionality of the variables in order to determine the key element intensity that can be used as a proxy for the observation of sedimentary structures in turbiditic sandstones. The results suggest that principal component analysis can identify the elements and elemental ratios with high loadings that explain the multivariate data. The sedimentary structures are shown in spatial elemental distribution maps and elemental ratios. The methodology here could be applied to in situ µXRF scans where the observation of sedimentary structures or grain size measurements is inaccessible such as in boreholes.

Soil structure at the basin scale affects the superficial moisture content, heat, salinity balance, and ecological balance of groundwater system. To study the soil particle size fractal characteristics at the basin scale, 188 groups of soil samples were collected over a distance of 258 km in the Ziya River basin of the North China Plain. Particle volume percent was measured using a laser particle size analyzer, and then analyzed by applying the fractal theory to reveal the spatial distribution of soil particle size and soil voids. The results showed that: (1) From the Taihang Mountain piedmont to the coastal area, soil particle-size volume percentages varied in a small range, with the fractal dimension D showing an overall decreasing trend; (2) D showed a significant spatial variation, ranging from 0.13 to 2.188. It was jointly determined by particle uniformity and particle size range; (3) When D ≤ 1, the characteristic fractal size was 30 μm in the basin. When 1 < D ≤ 1.5, the characteristic fractal size was 20 μm and D a was 1.37, and when D > 1.5, the two parameters were 10 μm and 1.77, respectively. The research results indicated that D can effectively quantify the characteristics of soil structure at a large scale.

Vegetation is an important factor that affects the hydrological process of a watershed. In recent years, the vegetation in the hilly and gully regions of the Loess Plateau has undergone significant changes, which have greatly changed the relationship between rainfall and runoff and sediment in the region. A single vegetation cover index cannot represent the important impact of vegetation grade on the effectiveness of soil and water conservation. It is of great scientific significance to deeply study the influence of the vegetation structure change mechanism in the hilly and gully area on the hydrological process of the watershed. In this article, a typical watershed in the loess hilly and gully area is used as the research object, and the method of combining field sampling experiment and remote sensing inversion is used to establish a vegetation index remote sensing model reflecting the vegetation canopy cover and litter. The impact of changes in vegetation structure on hydrological processes is quantitatively assessed. The results show that the more annual precipitation in the basin, the more sensitive the runoff coefficient is to changes in structural vegetation index. The greater the rainfall intensity, the weaker the sensitivity of the sediment yield coefficient to changes in structural vegetation index. The use of remote sensing data to retrieve the underlying surface vegetation still has the problem of the scale effect. It is necessary to further use remote sensing data with a higher spectral resolution to carry out field observations at different scales to improve the applicability of this method in a wider range of watersheds.

Recently, all kinds of geological disasters happen frequently on the earth. In China, there are countless earthquakes every year, which greatly affect the country’s economic level and development as well as the people’s life and health. The analysis of seismic activity is becoming more and more significant. In this article, the spatial distribution of China’s seismic activities was analyzed by using the provincial seismic data from 1970 to 2013. On the basis of spatial autocorrelation analysis theory, Global Moran’s I , Local Moran’s I , and the Local Indicators of Spatial Association are used to measure the geospatial distribution characteristics of China’s seismic activities. The research results show that earthquakes in mainland China have significant global autocorrelation characteristics as a whole, and the global autocorrelation coefficients are all positive. And the Z -value test ( P < 0.05) shows that earthquakes in mainland China present a spatial agglomeration pattern. Furthermore, we observed a reduction trend in disparities of seismic activity among regions in China.

To solve engineering geological problems, including water conservancy, transportation, and mining, it is necessary to obtain information on rock mass structures, such as slopes, foundation pits, and tunnels, in time. The traditional method for obtaining structural information requires manual measurement, which is time consuming and labor intensive. Because geological information is complicated and diverse, it is not practical for general deep learning methods to obtain full-scale structural surface trace images to prepare training samples. Transfer learning can abstract high-level features from low-level features with a small number of training samples, which can automatically express the inherent characteristics of objects. This article proposed a rock mass structural surface trace extraction method based on the transfer learning technique that considers the attention mechanism and shape constraints. For the general test set, the accuracy of rock mass structural surface trace recognition with the proposed method can reach 87.2%. Experimental results showed that the proposed method has advantages in extracting complicated geological structure information and is valuable for providing technical support for the extraction of geological information in the construction of water conservancy, transportation, mining, and related projects.

The protection of water resource has been the significant mission globally. Hydrochemical compositions and recharge source are the critical tools to analyze the water quality. In this study, 18 surface water and 5 groundwater samples were collected along the Xiongqu and Sequ rivers in the northern Longzi county of southern Tibet. The combination of factor analysis, correlation of major ions, geochemical modeling, and D–O–Sr isotopes were employed to clarify the hydrochemical compositions and recharge source. The concentration of major ions followed the abundance order of SO 4 2 − {\text{SO}}_{4}^{2-} > HCO 3 − {\text{HCO}}_{3}^{-} > Cl − for anions and Ca 2+ > Mg 2+ > Na + > K + for cations. Ca–HCO 3 and Ca–SO 4 types were identified for groundwater and surface water. Based on ratios of major ions and geochemical modeling, it is proposed that the dissolutions of gypsum, calcite, and dolomite controlled the hydrochemical compositions. D–O isotopes indicated a meteoric origin for surface water and groundwater, with the recharge elevation of 2,519–3,731 m. The 87 Sr/ 86 Sr ratios of groundwater and surface water were compatible with those of sulfate and carbonate minerals, revealing the main type of minerals interacting with water. The achievements of this study can provide a vital reference for groundwater utilization and protection in the Longzi county and adjacent areas in the Tibet.

Based on natural gas compositions, carbon isotope ratios, and geological analysis, the genesis and origin of gases in the Lower Paleozoic of Ordos basin are discussed. Due to differences in distribution and genesis, the gases in Lower Paleozoic were divided into five types, namely western margin gas, weathered crust gas, pre-salt gas, Ordovician deep gas, and Cambrian gas. The results show that the δ 13 C 1 and δ 13 C 2 of western margin gas range from −35.6 to −38.9‰ and from −27.2 to −35.9‰, respectively, indicating oil-type gas and mainly from the O 1 k and O 2 w marine source rocks. The δ 13 C 1 of weathered crust gas varies from −31.2 to −37.8‰, but δ 13 C 2 is mostly around −25.0‰, which indicates weathered crust gas originates from the Carboniferous–Permian coal-measure source rocks. In contrast, δ 13 C 1 and δ 13 C 2 in the pre-salt strata are mostly less than −30.0‰. Yet its distribution of Δ( δ 13 C 2 – δ 13 C 1 ) is from −1.7 to 13.6‰, and C 1 /C 2 + C 3 is of 6.68–4372.50. These indicate that the pre-salt gas is mainly high-over mature oil cracking gas from the O 1 m marine source rock. The δ 13 C 1 of Ordovician deep gas is averaging −39.4‰, and δ 13 C 2 varies from −25.4 to −33.0‰, which imply coexistence of oil-type and coal-type gas. It is presumed that the C–P coal-type gas may migrate into and accumulate at Ordovician deep reservoirs through unconformity and fault. The δ 13 C 2 and Δ( δ 13 C 2 – δ 13 C 1 ) of Cambrian gas are both the most negative, respectively, averaging −34.9‰ and averaging −3.2‰, indicating over-mature oil-type gas. Formation and evolution of the Qingyang paleo-uplift result in that the Cambrian gas mainly comes from the Cambrian or Ordovician marine source rocks in the southern basin.

The comprehensive benefit evaluation of marine resources developmental model is of great significance to choose the appropriate types of marine resources development and promote the intensive utilization and sustainable development of marine resources. This article examined five types of marine resources development, such as marine protected areas, mariculture, offshore wind power, sewage dumping, and land reclamation, and constructed a three-level evaluation index system for the comprehensive benefits of marine resources development. The projection pursuit clustering model was used to evaluate and analyze the comprehensive benefits and main influencing factors of 15 marine resources development projects in Jiangsu Province, China. It was found that the comprehensive benefit projection values of marine protected areas and offshore wind power are higher. The projection value of comprehensive benefit of land reclamation is the lowest. The main influencing factors include but not limited to the change rate of total output of aquatic products, contradiction between management and marine use, negative impact on residents’ lives, etc. The research results have important guiding significance for promoting the rational development and utilization of marine resources and the high-quality development of the oceans.

In this study, the embedded depths of the rocks of the single-layer placement group and the multilayer riprap group were compared through a self-made test device. Besides, a finite element model of a single layer of regular rocks was developed to probe into the factors that impact the embedded deformation of the rubble-mound foundation of a gravity-type quay wall, including the cohesion and angle of internal friction of foundation soil, as well as the particle size of and the interval between rocks. Research results indicated that it was feasible to replace multilayer randomly dumped rocks with single-layer regularly placed rocks. The embedded depth decreased as the cohesion and angle of internal friction of soil increased. The influence of load on the embedded depth was small when the cohesion was less than 10 kPa or the angle of internal friction was smaller than 40°. When the load was lower than 80 kPa, the impact of the particle size of rocks on the embedded depth would be negligible, and such impact grew along with the load. When the load was below 100 kPa, the interval between rocks exerted relatively minor influence on the embedded depth: under a constant porosity, the embedded depth would decrease as the interval increased, and this correlation became more significant when the load exceeded 800 kPa; under varied porosities, a larger interval would lead to an increased embedded depth but the increase would be limited within a range of 10% of the original depth.

The Ad Damm shear zone (ADSZ) is a major mylonitic right-lateral structure that bounds the Jeddah terrane to the north from the Asir terrane to the south. High-resolution field mapping coupled with petrological and geochemical analyses indicate that Jeddah terrane is characterized by heterogeneous magmatism with extensive meta-basalt intruded by silicic plutons of varying size. South of the ADSZ, Asir terrane is characterized by larger scale granitic batholiths. A younger generation of Eocene–Miocene basaltic dikes cut the mylonitic shear zone at a high angle. Petrographic analyses of the ADSZ mylonitic rocks indicate dynamic recrystallization and grain-size reduction, suggesting high-temperature recrystallization. Field observations also found a lack of low-temperature fault zone rocks (e.g. gouge) except for isolated brittle slickensides. Spider diagrams of Jeddah, Asir terranes, and ADSZ rocks are characterized by an arc-related signature, which related to the amalgamation of Jeddah and Asir terranes and defined ADSZ as Neoproterozoic structure. In contrast, Eocene–Miocene basaltic dikes and southern basaltic flow are represented by a rift-related signature, which associated with the development of the Red Sea rift system. Offshore, south of the ADSZ, the Red Sea rift exhibits well-developed linear magnetic anomalies and large topographic escarpment perpendicular to the rift margin, but they are not present north of it. In addition, recent seismicity recorded along the ADSZ and differences in the crustal thickness and characteristics of Asir and Jeddah terranes, collectively, make ADSZ acted as an active crustal boundary and still influence the ongoing tectonic evolution of the Red Sea rift.

Considering that aeolian sand ripples are formed primarily by creeping particles caused by wind-driven saltation sand particles, we obtain a formulation for determining the height of saturated aeolian sand ripples by incorporating the reptation fluxes with previous experimental results on migration velocities of sand ripples. Based on existing observational results of terrestrial sand ripples on Earth's surface, it estimates that the wavelength of aeolian sand ripples on Mars is generally up to several meters. This implies a possibility that there is another sand ripple on Mars similar in scale to Transverse Aeolian Ridges (TARs) at some time when surface saltation was prevalent. Moreover, perhaps part of the widely observed TARs is the degradation of saltation sand ripples, whose formation is intimately related to saltation and reptation of sand particles. While the other two types of ripple-like morphologies (plain ripples and crater ripples) found by Opportunity Rover are essentially not. Further, we propose that the main factor controlling the scale feature of Martian sand ripples is the intense particle-bed collision process.

In this study, earthquakes with magnitudes above 3.0 on the Richter scale in southwest China from 1900 to 2013 are taken as research objects. The spatio-temporal migration characteristics of seismic activity in the area of concern are studied by using geostatistics method to explore the rules of seismic activity. From the perspective of geostatistics and based on z -value, eight major seismic zones in southwest China were studied zone-wise by using the geostatistics tool ArcGIS and the seismic analysis tool ZMAP to explore the spatial and temporal migration characteristics of earthquakes. It was found that each seismic zone had its own quiet period with relatively inactive seismic activity. Simultaneously, through the study of the time-varying characteristics of the seismic belt, it was found that the time-varying regularity of the seismic frequency of the fault belt with the same or related geological structure background is roughly consistent. In conclusion, the seismic activity in southwest China will still be active in the future.

The Miocene Zhujiang Formation is the key horizon for oil and gas exploration in the Pearl River Mouth basin of northern South China Sea. With the help of core observation, seismic attributes and various analytical data, the sedimentary facies marks, distribution of sedimentary facies and depositional model of forced regression in the Miocene Zhujiang Formation of the Pearl River Mouth basin, northern South China Sea, have been studied. Forced regressive deposits were formed during the period when relative sea level ranged from highstand to lowstand and the sediments were forced to undergo progradation so that five sets of foreset delta deposits are developed in turn. In the early stage of forced regression, the normal delta where the delta plain, delta front and prodelta are not absent mainly developed. In the later stage of forced regression, the shelf edge delta with only the delta front and the prodelta, the longshore bar along the shelf break and the turbidite fan in the deep water of the slope area were developed. The favorable reservoir of forced regressive deposits are located near the upper boundary of the falling stage systems tract and the basal surface of forced regression, and they are the sand bodies of shelf edge delta, longshore bar and turbidite fan. The research results may provide guidance for reservoir prediction.

It is significant to adopt deep learning algorithms and higher-resolution remote sensing images in mapping large-scale and high-precision of aeolian landform. In this study, the western part of Horqin Sandy Land was taken as the study area. Based on the data collected from 2,786 verification points located in sandy land and remote sensing images of high-spectral and spatial resolution Sentinel-1, Sentinel-2, and GDEM (V3), this article made a research on data of large-scale and high-precision mapping classification of this area between 2015 and 2020 by using convolutional neural network deep learning algorithm. The results showed that the types of aeolian sandy landform in the west of Horqin Sandy Land mainly include longitudinal dune, flat sandy land, mild undulating sand land, nest-shaped land, parabolic dune, barchan dune, and dune chain, with an area of 1735.62, 51.32, 251.38, 902.07, 49.57, and 101.63 km 2 . Among them, longitudinal dune, barchan dune, and dune chain have the largest area, while parabolic dunes and flat sand land are smaller. Between 2015 and 2020, the area of aeolian landforms was reduced by 89.27 km 2 and transformed into an oasis from a desert. This study adopted remote sensing data by high-resolution Sentinel and GDEM (V3) and convolutional neural network deep learning algorithm to map the aeolian landforms effectively. The precision of aeolian landform classification and Kappa coefficient in the western part of Horqin Sandy Land is as high as 95.51% and 0.8961. Combined with Sentinel-1, Sentinel-2, and GDEM (V3), the deep learning algorithm based on the convolution neural network can timely and effectively monitor the changes of sand dunes, which can be used for large-scale aeolian landforms.

The Chang 7 Member shale of the Upper Triassic Yanchang formation in the Ordos basin is a hot spot in petroleum geology research. In this study, considering the Chang 7 shale in the Yan’an area as an example, the full-scale pore size characterization of lacustrine shale was realized based on the scanning electron microscopy image gray correction method, nitrogen and carbon dioxide adsorptions, and high-pressure mercury intrusion tests. In addition, the pore structures and oil-bearing properties of the Chang 7 shale were systematically studied. The results show that the Chang 7 shale is rich in organic matter, with an average total organic carbon value of 4.69% and an average R 0 value of 0.9%. It is in the mature-wet gas (crude oil-associated gas) stage. There are certain differences in the development characteristics and pore size distribution of different types of pores in shale. The statistical results showed that the pore diameters of the intergranular pores and intragranular dissolved pores were significantly larger than the intercrystalline pores of clay minerals and the organic pores. The organic pores in solid bitumen are extremely developed, whereas the organic pores in kerogen are relatively underdeveloped. The lower limit of the effective pore size of shale is 20 nm. The network system composed of inorganic pores-microcracks-organic matter-organic pores and siltstone laminae provides important channels and retention spaces for the migration of shale oil and gas within the source. This study found that the proportion of movable oil in sandy layers is relatively high, followed by shale with sandy laminae, whereas pure shale has the lowest proportion of movable oil. Therefore, the degree of sandy laminar development, the abundance of organic matter, and the degree of thermal evolution are the key geological factors that control the porosity and oil-bearing properties of shale oil reservoirs.

Quick clay is found across Scandinavia and is especially prominent in south-eastern and central Norway. Quick clay is prone to failure and can cause landslides with high velocities and large run-outs. The 1978 Rissa landslide is one of the best-known quick clay landslides to have occurred in the last century, both due to its size and the fact that it was captured on film. In this article, we utilise Structure from Motion Multi-View Stereo (SfM-MVS) photogrammetry to process historical aerial photography from 1964 to 1978 and derive the first geodetic volume of the Rissa landslide. We found that the landslide covered a total onshore area of 0.36 km 2 and had a geodetic volume of 2.53 ± 0.52 × 10 6  m 3 with up to 20 m of surface elevation changes. Our estimate differs profusely from previous estimates by 43–56% which can partly be accounted for our analysis not being able to measure the portion of the landslide that occurred underwater, nor account for the material deposited within the landslide area. Given the accuracy and precision of our analyses, we believe that the total volume of the Rissa landslide may have been less than originally reported. The use of modern image processing techniques such as SfM-MVS for processing historical aerial photography is recommended for understanding landscape changes related to landslides, volcanoes, glaciers, or river erosion over large spatial and temporal scales.

The accessibility evaluation between ecological and commercial spaces is important for “production-living-ecological” coordination. This article selects Tongzhou of Beijing as an example. Significance tests showed the commercial facilities in Tongzhou district followed an agglomerated distribution. Further exploration of the relationship between concentrated commercial and ecological spaces show the distribution of ecological space in Tongzhou district is unbalanced, which shows that the northern, western, and central regions of Tongzhou district cover a wide area, whereas the southeast region has a low level of accessibility. The coverage rate of ecological space of each street with 10 min walking is lower than 50% on average. The coverage rate of walking for 20 min varies greatly, and the sub-districts with high coverage rate are basically distributed along the north–south central axis and east–west central axis. Emerging commercial spaces have poor accessibility towards ecological space, which indicates that in the new commercial space, ecological space has not been considered in the planning. It also reflects that in the existing daily ecological management, managers tend to focus on the ecological remediation of the built area and ignore the ecological planning in the community construction stage of commercial space.

The United States Natural Resources Conservation Services Curve Number (NRCS-CN) method uses the CN and rainfall to calculate runoff. However, there are still some uncertainties in the method, such as choosing the most appropriate CN value. Therefore, this study attempts to evaluate the effectiveness of using the NRCS-CN method to estimate the runoff of five catchments in Sudan. For each catchment, CN values were obtained from the number of observed rainfall-runoff events using the NRCS table, arithmetic mean, median, and geometric mean methods. For each method, Nash–Sutcliffe efficiency (NSE) was obtained to evaluate the fit between the observed and runoff, and negative NSE values were found for all methods. Negative values of NSE indicate that the observed runoff and estimated runoff are not well fitted, and the NRCS-CN method is not suitable for runoff calculation in the study areas.

This article considers Xiamen’s two districts as examples to help identify the supply and demand of green services by focusing on the spatial equity of green space in microregions. Based on network and concentration methods, the results show there are great differences in equity enjoyed by residents. The equity value of Tong’an is generally higher than that of Jimei district, and the value of the periphery of the central urban area is generally higher than that of the inner area. Jimei relies more on traffic facilities than Tong’an. This study finds that the carrying capacity of rail transit cannot be ignored in accessibility. By measuring under three travel modes, the distribution density of green space in Jimei and Tong’an is basically similar. The main reason why Jimei’s accessibility perform better than Tong’an district is traffic. Based on the service coverage rate ( C ) and the recreation opportunity index ( R ), this article obtained the regional evenness index, and found the overall characteristics of “high in the south and low in the north.” This study suggests differences in spatial performance at the micro level are often complex, and consideration of different explanatory variables such as population may provide directions for policymaking.

In this article, the integrity of the seismic catalog obtained (1970–2014, M > 2.8) was verified according to the Gutenberg–Richter relation, the appropriate minimum magnitude was determined, and the whole region was divided into five areas according to the geological structure background of the whole research object and the trend of the historical seismic zone. We applied multifractal analysis in each partition. The results showed that although in different geological backgrounds, before major earthquakes, the earthquake time series information dimension had different degrees of growth, and the parameter after the flame had different degrees of decline. To a certain extent, this reflected the seismic energy accumulation and release process. In addition, the variation of fractal parameters in scale-free regions of time series and spatial distribution series also indicated that these two kinds of sequences in different regions show the characteristics of a multifractal structure rather than a single and uniform fractal structure.

Structural lineaments of Southeast Nigeria were delineated using high-resolution aeromagnetic data. Advanced methods such as enhanced horizontal gradient amplitude (EHGA) involving a 3D model and tilt depth method (TDM) were used in this study. The simulated magnetic model involving the EHGA detector positioned peaks over source borders and created sharp and clear edges for magnetic sources. The TDM is a cutting-edge depth determination method revealing the depth of the contacts and thickness of sedimentary bodies that vary from ∼500 to ∼2,500 m and ∼3,000 to ∼5,000 m, respectively. Lineaments of the study area were extracted from the EHGA map. The structural map showed the dominance of short-ranged (∼0.29 to ∼1.48 km) linear magnetic anomalies. In addition, regional geologic structures (∼2.8 to ∼24.5 km) occur at the western flank of the study area. In general, these structures trend in the NE–SW, NNE–SSW, N–S, E–W, and NW–SE directions. They are indicators of subsurface faults, contacts, and tectonic structures of the thermo-tectonic events associated with Santonian Abakaliki Anticlinorium, Tertiary-Recent Ikom-Mamfe Rift, and structural deformations of the basement rocks associated with the Oban Massif.

An edge-based finite element method for the numerical modeling of electromagnetic fields in complex media is presented. We used the analytical solution on an electric field in a homogeneous half space to develop a source correct factor to reduce the influence of source singularity and boundary conditions on the numerical accuracy, so that we can minimize the time required to construct the field source term in the scattered field formula. The modeling domain was discretized using an unstructured tetrahedral mesh. We transformed the complex equations of the electrical field into two real-valued equations by decomposing the field into real and imaginary components. Thereafter, we adopted a block conjugate orthogonal conjugate gradient (BL_COCR) iterative solver with an incomplete LU decomposition preconditioner, which was robust for ill-conditioned systems and efficient for multiple source electromagnetic modeling to solve the real-valued equation systems. Using the analytical solution on an electric field in a homogeneous layer model, we evaluated the accuracy of our numerical forward solution and the results showed that the source correct factor can reduce forward modeling errors associated with boundary effects and source singularities. We also applied the developed algorithm to compute the CSEM responses for typical 3D marine geo-electric models with different number of sources and compared with different iterative solvers, and the results showed that the BL_COCR solver has high computational efficiency when solving multiple right-hand term problems.

The effect of topographic correction (TOC) has a profound influence on the quantitative application of remote sensing image. With regard to the invalid evaluation of the TOC model with such a single topographic correction assessment (TCA) method, we have selected five TCA indexes from five different perspectives: the difference in mean radiance radiometry between sunlit and shaded slopes, the cosine empirical relationship, stability, heterogeneity, and outlier ratio. The entropy weight method was used to assign weight to each TCA indexes, and the comprehensive evaluation value (CEV) of TOC for each band of remote sensing image was obtained by weighted superposition. After that, the weight of each band of the remote sensing image is determined by the entropy weight method, and the CEV of the TOC of the remote sensing image is obtained by weighting and superposition, so as to realize the effect evaluation of the six TOC models of C, SCS + C, VECA, Teillet, Minnaert, and Minnaert + SCS. The results indicate that the proposed method can effectively evaluate the correction effect of the TOC model. Results indicate that the SCS + C model has the best correction effect, while the Minnaert model performs the worst. The results generated from the Minnaert + SCS, Teillet, and Minnaert models typically show inferior quality. The SCS + C, VECA, and C models are better suited for generating images with high spectral fidelity, and these three correction models are recommended for TOCs over mountainous areas.

Under the stress of the global change, rocky desertification has become a serious environmental problem in the Karst Mountain area. At present, few remote sensing monitoring research works on rocky desertification based on feature space model have been conducted and reported. In this study, the Albedo-LST feature space remote sensing monitoring index based on point-point model has been proposed, and subsequently the spatio–temporal evolution pattern and driving mechanism of rocky desertification in Dafang district from 1986 to 2019 were analyzed. The results show that: (1) The point-point Albedo-LST feature space model of rocky desertification has good applicability with the overall accuracy of 90.79%; (2) From 1986 to 2019, the rocky desertification in Dafang district first showed an increasing trend (1986–2005) and then a decreasing trend (2005–2019); (3) The comprehensive evolution frequency of rocky desertification during 2001–2005 was the largest with 7.51% a −1 , which was related to the implementation of the Grain for Green Project; (4) The single factor with the largest contribution rates to rocky desertification are land use type, landform, and temperature. The interactive factors with the largest explanatory power are temperature ∩ land use type and landform ∩ land use type. The research results can provide decision support for the prevention and control of rocky desertification in Southwest China.

Tourism is a highly climate-sensitive sector, and the suitability of climate and weather can be a central motivation for travel. Through the tourism climate index (TCI), this study uses daily data from the period of 1980 to 2014 to identify the spatial and temporal distribution of climatic conditions in Xinjiang of China with regard to its climatic attractiveness for general tourism. The analytical results indicate that the climatic conditions of the most suitable months for tourism in Xinjiang are April, May, September, and October. The best climatic condition (TCI > 80) for tourism activities is found in September in most parts of Xinjiang, except for central Tianshan and Turpan Basins. The climate is not attractive for tourism in Xinjiang during the winter months. The annual average number of climatically suitable days (TCI > 70) are the highest in northwestern Aksu, most parts of Kashgar, and western Hotan. Most parts of northern Xinjiang are favorable for summer travel, with high TCI scores and a high average number of climatically suitable days. By contrast, tourist areas in southern and eastern Xinjiang have favorable climatic conditions during Spring and Autumn. These results can provide useful information to both tourists and the tourism industry.

Balancing the development and protection of national marine parks in a suitable way is of great SIGNIFICANCE for environmental sustainability. Tourism attractiveness is an important indicator for measuring this development. In this study, by searching through online reviews of the national marine parks in the coastal areas of the East China Sea, and by analyzing tourists’ perceptions of them, an indicator system for tourism attraction was established. Natural attributes, supporting facilities, service experience, and tours were taken as secondary indicators. This study combines the analytic hierarchy process with questionnaires to calculate the attractiveness index of national marine parks. The study finds that national marine parks in the coastal areas of the East China Sea have a higher level of tourist satisfaction and attractiveness, but that more attention needs to be paid to supporting facilities, as tourists currently find them insufficient. Among these, natural attributes are an important factor affecting the attractiveness of the marine parks, while special cuisine, customer experience, public transportation, and attitudes are all indicators with higher weight within the attractiveness index. The tourism attractiveness of national marine parks was investigated quantitatively and the indicators affecting the tourism attractiveness index were illustrated clearly.

In China, fresh water resources are scarce, while brackish water resources are abundant. Reasonable utilization of brackish water is one of the important measures to alleviate the contradiction of water shortage. In order to study the effect of brackish water irrigation on water and salt transport in saline-alkali soils, one-dimensional brackish water infiltration experiments of soil columns were conducted. The influence of brackish water with different salinities on water and salt transport in salinized soil was compared and analyzed. The results showed that under brackish water irrigation, the Kostiakov model could better simulate the change in soil infiltration rate with time, the soil infiltration capacity had a positive response to the salinity of irrigation water. There was a good linear relationship between cumulative infiltration and the wetting front distance. Under different salinity conditions, the depth of soil desalination, Na + , and Cl − removal is different, which are inversely proportional to the degree of salinity; with the increase in the salinity of irrigation water, the water salt content and the concentration of Na + and Cl − increased gradually, but the difference in the desalination zone was not obvious. Therefore, brackish water irrigation has a certain effect on the distribution of water and salt in saline soil.

Monitoring rice planting areas and their phenological phases is crucial for yield estimation and informed decision-making. This study proposed a unified method for mapping rice field and rice phenology with a dynamic time wrapping (DTW) distance-based classifier and its variant sub-DTW algorithm using Sentinel-1’s synthetic aperture radar (SAR) VH band. Field samplings were conducted for broad landcover types in one of the areas of interest (AOIs). We implemented a pixel-wise k -nearest neighbor classification model with DTW distance to identify paddy rice pixels. Standard rice phenological profiles of the SAR VH band were defined by ground monitoring of a sample rice field. Based on rice planting maps and the standard phenological profiles, rice phenological phases were estimated by pattern matching strategy with the sub-DTW algorithm. Experiments on six counties in Northeast China presented promising results. The overall producer and user accuracy reached 92.9 and 91.9% for rice mapping, respectively. The mean root mean square error (RMSE) for phenology estimation was 3.5 days. Rice planting and rice phenology maps were generated for the six AOIs. The phenological variances of the AOIs implied the effects of climate and rice cultivars on phenological development.

The spatial distribution of land use at different terrain gradients has been used as an important index for the land management and ecological restoration in the Loess Plateau of China. Based on the land use data surveyed in 2015 and digital elevation model data with a resolution of 30 m from typical village transects in the Loess Plateau area in Yan’an City, Shaanxi Province, this study analyzed the terrain niche index, distribution index, land utilization comprehensive index, and land use equilibrium degree for four village transects. The results demonstrated that the land use types in the four village transects were mainly grassland, forest land, and cropland. Land use types showed obvious differences in respect to topographical gradient with built-up land, traffic land, water bodies, cropland, and orchard distributed in low terrain gradient areas, forest land, and grassland distributed in medium- and high-terrain areas. As terrain gradient increased, the land utilization comprehensive index and land use equilibrium degree showed a generally decreasing trend. These findings may provide a useful reference for land use planning and land resource allocation in the Loess Plateau region.

As the issue of marine waste is emerging around the world, it is urgent to come up with measures to manage marine waste. This study examined the status of the collection project of submerged marine debris (SMD) undertaken to improve the environment of major ports by the central and local governments of Korea. Approximately, 7,174 and 2,817 tons of SMD have been collected at major trade ports and coastal ports, respectively, over the last 7 years (2014–2020). The projects to collect SMD have achieved effectiveness, reducing marine accidents in the port. For example, entanglement accidents caused by floating debris also decreased by 11% in 2018 compared to the previous year. The results of the sediment environment investigation before and after the collection of SMD also showed that the species of benthos and their population density increased, and the concentration of acid volatile sulfides (AVSs) decreased. To reduce marine accidents in ports and improve the benthic environment, it will be necessary to provide policy support, such as investigating the distribution status of SMD regularly, improving the effectiveness of the collection method, identifying the way to recycle collected debris, maintaining the public–private cooperative system, and establishing a specialized agency for the systematic management of marine debris.

After the completion of the Three Gorges Dam, it increases the risk of inducing an earthquake. We use the GRACE Gravity Field Model to analyze the relationship between the operation of the Three Gorges Reservoir and the change of gravity field in western Sichuan. The research results indicate that the reservoir water level and the western Sichuan gravitational field are positively correlated. In the early stage of rising water level, the change of gravity field is not apparent, and the change of gravity field gradually increases with time. Therefore, the change of reservoir water level affects the gravity field in western Sichuan. The dynamic changes of the gravity field can reflect the Earth’s material change and deformation process and are closely related to earthquakes. Consequently, the Three Gorges Dam will indirectly affect the seismicity in western Sichuan by affecting the gravity field. The research provides valuable information for studying regional reservoir earthquake disasters and supports related policy decisions.

The estimation of the Curie point depth (CPD) and heat flow (HF) from magnetic data is useful for geothermal and tectonic studies. However, the methodology of estimating these values is still controversial as numerous studies have used different types of transformed magnetic data. Most studies utilize the total magnetic intensity (TMI) or the reduced to the pole (RTP) data, and since shallow magnetic bodies may affect the final CPD values, low-pass (LP) wavelength filtering has also been used to estimate the CPD. In this study, the two-dimensional radially averaged spectral analysis was applied to the land-based magnetic data from the Sinai Peninsula. TMI and RTP data were both analyzed, using different LP filtered wavelengths, and the final CPD and HF values were compared. The cut-off wavelength parameter was selected in terms of the geologic complexity. The results show that the estimated CPD values are well correlated regardless of whether the magnetic data were either TMI or RTP. The RTP data produced a spatial shift in the CPD smaller than the window size being used. Additionally, the centroid method is primarily dependent on the wavenumber, which varied slightly on applying the RTP. There were slight differences in the estimated CPDs when a short LP filter (e.g., 20 km) was applied, whereas increasing the wavelength (e.g., 40 km) caused the CPD values to increase exceeding the plausible depth limits, and the associated spatial trends varied when compared to the other methods. In areas where the basement rocks were shallow or exposed, a LP filter can be applied with short cut-off wavelength. The estimated CPDs were discussed in the context of seismicity data, gravity-based Moho depths, and HF measurements.

Production-living-ecological space (PLES) reflects the main function of land use types. It is one of the main directions that many scholars researched to evaluate, predict, and optimize the land space from the perspective of PLES. Yunnan Province is affected by such factors as economy, topography, and natural environment. The conflict of PLES is serious, and the problems of spatial planning development are prominent. This study aims at the current status of PLES, based on the establishment of restrictive constraints such as ecological red line, arable land minimum, and natural reserves. Meanwhile, these constraints were combined with the development planning of the Yunnan Province to forecast the quantitative structure change in the PLES in Yunnan Province in 2035 and 2050, coupling Markov and PLUS models to optimize the future space layout. This study can provide a scientific basis for the optimization of land space in Yunnan Province and other areas. The prediction accuracy of the Markov–PLUS model is 98.55%, which can be effectively used to simulate and predict the distribution of PLES in Yunnan in 2035 and 2050. From 2010 to 2015, the disordered layout of PLES in the Yunnan Province was obvious, and the ecological space (ES) seriously occupied the production space (PS) and living space (LS). In 2035 and 2050, the industrial production space (IPS) of Yunnan Province expands and presents distinct regional aggregation. LS and the water ecological space (WES) areas have increased. The layout of PLES in 2035 and 2050 of Yunnan Province mainly centers on PS. The orderly development of IPS promotes the regional economic growth, ensures that the agricultural production space (APS) will not be damaged and allocates the ES reasonably. It will also promote the overall optimization and coordinated development of PLES in Yunnan Province.

The Fuchuan ophiolite, one of the oldest ophiolites in southern China, is located in the northeasternmost segment of the Jiangnan Orogen. It mainly consists of harzburgites, with minor dunites, pyroxenites and gabbro veins. To investigate the origin of the Fuchuan ophiolite and its related chromite ore deposit, bulk-rock major and minor element and platinum-group element (PGE) studies have been carried out. Major and trace element analyses show dual features of mid-ocean ridge basalt (MORB) and supra-subducted zone (SSZ) peridotites and high degrees of partial melting. The chondrite-normalized rare earth element (REE) patterns of the Fuchuan harzburgites are “U” shaped, reflecting the influence of light REE-enriched subducted melts or fluids. The Fuchuan chromitites originate from MORB-like melts and are enriched in IPGE and depleted in PPGE, which are basically consistent with high-Al chromitites worldwide, and the low PGE concentrations of chromitites reflect a lack of sulfur saturation of the parental melts during an early stage of their crystallization. Combining with the tectonic setting of the Jiangnan Orogen, we suggest that the Fuchuan peridotites and chromitites are believed to be formed in a back-arc spreading ridge between the Yangtze and Cathaysia blocks during 860–820 Ma. Graphical Abstract The Fuchuan peridotites have dual features of mid-ocean ridge basalt and supra-subducted zone peridotites and have been experienced high degrees of partial melting; chondrite-normalized “U”-shaped rare earth element (REE) patterns of Fuchuan harzburgites indicate that light REE enriched SSZ melts or fluids have participated in the interaction with peridotites; the Fuchuan chromitites are enriched in IPGE and depleted in PPGE, which are basically consistent with high-Al chromitites worldwide, and the low PGE concentrations of chromitites reflect a lack of sulfur saturation of the parental melts during an early stage of their crystallization; the Fuchuan peridotites and chromitites are believed to be formed in a back-arc spreading ridge between the Yangtze and Cathaysia blocks during 860–820 Ma.

In order to explore the effects of land use change on the contents of total nitrogen and total phosphorus in deep soil, four land use types (cropland, grassland (7 years), grassland (30 years), and Jujube orchard) were selected from the Yuanzegou watershed in the loess hilly region of northern China. Soil samples at 0–10 m depth were collected to measure the contents of soil total nitrogen (STN) and soil total phosphorus (STP), and their stocks were estimated. The results showed that the STN content showed a decreasing trend with the increase in soil depth, and the lowest STN content of grassland (7 years) was 0.09–0.17 g kg −1 . The range of STN content in the watershed was 0.12–0.22 g kg −1 and the coefficient of variation was 10.52–25.90%, which belonged to medium variation. The STP content is stable regionally with the change in soil depth, and does not change much (except for grassland [30 years]). STP content of the watershed is 0.81–1.05 g kg −1 and the coefficient of variation is 9.37–54.69%, which is a high variation. The change trend of STN and STP stocks is consistent with the nitrogen and phosphorus content. The results revealed the dynamic changes in STN and STP after land use change, and estimated the stocks of STN and STP in deep loess, which provided scientific basis for land and soil resource management and sustainable development of the project of returning farmland to forest or grassland in small watershed of loess hilly-gully region.

Due to the characteristics of hyperspectral images (HSIs), such as their high spectral resolution and multiple continuous narrow bands, HSI technology has become widely used in fields such as target recognition, environmental detection, and agroforestry detection. HSIs are subject, for various reasons, to noise in the processes of data acquisition and transmission. Therefore, the denoising of HSIs is very necessary and important. In this article, according to the characteristics of HSIs, an HSI denoising model combining principal component analysis (PCA) and CANDECOMP/PARAFAC decomposition (CP decomposition) is proposed, which is called PCA-TensorDecomp. First, we use PCA to reduce the dimension of HSI signals by obtaining the first K principal components and get the principal composite components. The low-rank part corresponding to the first K principal components is considered the characteristic signal. Then, low-rank CP decomposition is carried out, to denoise the first principal components and the remaining minor components, the secondary composite components, which contain a large amount of noise. Finally, the inverse PCA is then used to restore the HSIs denoised, such that the effect of comprehensive denoising is achieved. To test the effectiveness of the improved algorithm introduced in this article, we compare it with several methods on simulated and real hyperspectral data. The results of the analysis herein indicate that the proposed algorithm possesses a good denoising effect. Graphical abstract

Due to the complex pore structures and strong heterogeneity of fractured reservoirs, it is a hot and difficult point in petroleum geology to identify fractures using logging principles. In this paper, taking the tight sandstone reservoir of the Chang 8 Member in the Huanjiang Oilfield as an example, field outcrops, cores, thin sections, and logging identification methods were used for quantitative description and fine logging evaluation of fractures. The research shows that high-angle, medium-low-angle, near-vertical, and horizontal fractures are developed in the Chang 8 Member of the Huanjiang Oilfield. The main ones are high-angle fractures, followed by horizontal fractures with a low degree of fillings. Under the constraints of core and imaging logging data, three fracture sensitivity logging parameters of acoustic wave time difference, natural gamma, and dual induction-octalateral resistivity were optimized, and a comprehensive fracture probability index was proposed. Seventy-nine fracture development intervals were identified based on log curve characteristics and fracture probability indexes. The coincidence rate of fracture logging identification results with the core observation and imaging logging interpretation is 80.6%. The research results can provide a theoretical basis for the efficient development of fractured continental tight sandstone reservoirs in similar areas.

Petrography, zircon cathodoluminescence, and laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb zircon dating were performed on the Paleoproterozoic khondalite series and the intrusive altered diabase dykes developed in the northeastern Helanshan region were analyzed. The results showed that most of the zircons in the khondalite series were detrital zircons with oscillatory zoning and a high Th/U ratio, with few metamorphic zircons having a low Th/U ratio. The 207 Pb/ 206 Pb age of the detrital zircons ranged from 3131–1980 Ma, which constrained the protolith age of the Helanshan khondalite series to after 1980 Ma. The age of the metamorphic zircons indicated two age groups as follows: 1965–1921 Ma and 1876–1820 Ma. Besides, the age of altered diabase dykes was 1865–1850 Ma. In combination with previous studies, these new metamorphic ages indicated that the metamorphic events in the northeastern Helanshan region involved the collision followed by post-collisional extension and exhumation between the Yinshan Block to the north and the Ordos Block to the south. Moreover, the 1965–1921 Ma group represented the period of the collision between the Yinshan Block and the Ordos Block and the subsequent post-collisional extension event, whereas 1876–1820 Ma indicated the period of the exhumation stage.

The differences in spatial-temporal distribution patterns and dominant driving factors of vegetation evolution among sub-regions during different historical periods were not clear. Therefore, this study introduced the gravity center model and geodetector to analyze the spatial-temporal change characteristics and dominant driving factors of normalized difference vegetation index (NDVI) in China during 1981–2019 from the perspective of geographic divisions. Results showed that (1) during 1981–2019, the average vegetation coverage in China showed an increasing trend and zones with obviously increasing vegetation NDVI were mainly distributed in the middle reaches of the Yellow River basin and the upper reaches of the Yangtze River. (2) During 1981–2019, the gravity center of national vegetation NDVI was mainly concentrated in Yan’an City and Tongchuan City, showing a southward migration trend as a whole, which indicates that the increment and growth rates of the southern part were greater than those of the northern part. (3) The growth of vegetation in southern China was primarily affected by the temperature, while that of northern China was largely influenced by precipitation. (4) During 1981–2019, the dominant interactive factors of vegetation change for all subregions changed greatly: natural factor (climate or terrain) ∩ other factors → landuse ∩ other factors.

This study aims to analyze the impact of attractiveness, satisfaction, and willingness to revisit in the perception of cultural tourism tourists and whether cultural tourism could be a remedy to revitalize rural economic development under the epidemic, using the Hakka settlement in Hukeng town as a case study. In this study, a mixed research method is applied to collect 670 questionnaires by snowball sampling and used SPSS 26.0 statistical software to conduct basic statistical validation and Pearson product-moment correlation coefficient (PPMCC) validation; the semi-structured is also used semi-structured interviews to collect the opinions of six experts and scholars, and the final results were examined by multivariate validation. The researchers found the following dimensions to be attractive for tourists to experience cultural tourism: rural scenery, heritage museums and cultural goods, low spending, use of media marketing, planning for proper tourism information, and public transportation construction effectiveness. However, there is also a need to improve the current situation of rural tourism transportation and transportation facilities, inject young development manpower, improve the knowledge and skills of the elderly to start their businesses, develop business opportunities, and stabilize prices, and improve the quality and satisfaction of tourists to promote the desire to travel. The higher the attractiveness, the higher the satisfaction, and the stronger the willingness to revisit.

Shale rock formed from small clay particles, and shale compaction is an essential factor to estimate shale reserves. The classical Athy’s model has been used to obtain the shale compaction curve to describe the relationship between porosity and depth, an essential input data for basin modelling. But recent studies revealed that burial time, among other factors, should be considered and that geological age is another important factor in some regions. This is because geological and lithological histories are crucially different among geological ages. This study employed the newest data of Thailand shales and confirmed that different geological ages (Cenozoic, Mesozoic, and Paleozoic ages) require different shale compaction curves by estimating numerical geological time with the relationship of velocity and depth in each geological age. We obtained empirical models of the shale compaction curve of each geological age by multi-linear regression. The standard curve of shale compaction with the relationship among porosity, depth, and time, proposed in a previous study, was also re-affirmed with the newly obtained models.

The aim of this study was to identify the impacts of different driving factors on terrestrial ecosystem evolution. The Yellow River Basin was selected as the study area, of which terrestrial ecosystem was deeply affected by climatic change and human activities. We constructed four scenarios (including without any impacts, affected by climate change, by human activities and by both impacts), and the discrepancies between them reflected the impacts of climate change or human activities. Based on this, the future land use simulation model was used to simulate the land use distribution under the four scenarios, and then, the ecosystem services values (ESV) and landscape patterns index were evaluated. The results indicated that affected by climate change during 1995–2015, the Mean Patch Area of the forestland decreased by 0.19% and the landscape patterns became fragmented. Meanwhile, the total ESV decreased by 0.03 billion dollars and the ecosystem regulation services were weakened. Under the influences of human activities, the Contagion index decreased by 1.71% and the landscape patterns became dispersed. Simultaneously, the total ESV increased by 0.56 billion dollars, but the function tends to be unitary. In addition, these effects showed great spatial heterogeneity. This study provides scientific support for ecological protection in the Yellow River Basin.

This article focuses on the study of identifying the quality of tight sandstone reservoirs based on machine learning. The machine learning method – Gradient Boosting Decision Tree (GBDT) algorithm is used to design and classify reservoir quality. First, it is based on logging data, core observation, cast thin section, and reservoir physical statistics. The permeability, porosity, resistivity, mud content, sand-to-ground ratio, and sand thickness were preferred as reservoir evaluation criteria in the area, and the gray correlation method was used to obtain reservoir quality categories and construct training datasets. The machine learning GBDT algorithm is used to train and test the obtained dataset. It is found that the recognition accuracy of the GBDT model is 95% by confusion matrix analysis. In addition, it is compared with four commonly used reservoir prediction methods (Bayesian discriminant method, random forest, support vector machine, and artificial neural network) for verifying the reliability of the GBDT model. Finally, the GBDT model is used to identify the reservoir quality of the study area, and it is well verified in the production data. The research results show that the GBDT model can become an important tool for rapid and real-time tight sandstone reservoir evaluation.

The aeromagnetic anomalies existing in the Deng Deng – Garga Sarali region in Eastern Cameroon were filtered for a structural study of the region’s subsoil. This study presents the results of lineaments and fractures extracted by aeromagnetic image processing methods and compared with scientific data to obtain potential terrain models in the study area. The methodological approach used is based on the filtering of aeromagnetic image by using the analytical signal, the Euler deconvolution, and 2D 3/4 modeling, to establish the maps of the lineaments and faults of the study area and their characteristics, and also to propose three models from three previously chosen profiles. Analytical signal and Euler deconvolution techniques have been applied to aeromagnetic anomalies to highlight the relationship between the depth and the source of magnetic anomalies, two parameters whose importance in geoexploration and modeling of the body is essential. We identified the potential contacts by interpretation of the deep Euler anomalies, these are highlighted on the basis of a certain similarity between the maps of the total magnetic field, the map of the analytical signal, the map of the maxima of the gradient horizontal, and geological map. Euler’s map of solutions correlates well with the edges of certain superficial and deep causative bodies.

The fluid distribution is considerably influenced by the reservoir homogeneity. This study analyzes carbonate reservoir heterogeneity and hydrocarbon accumulation processes in the Khasib reservoirs in AB oilfield in the Middle East to discuss factors controlling the distribution of fluid and the effects of this distribution on the productivity of single wells. The Khasib reservoirs in the AB oilfield show uniform vertical distributions, with a large difference in the longitudinal pore throats, and the upper part of the reservoir is better than the lower one. Because the hydrocarbon accumulation is multiphasic, the heterogeneity of crude oil is based on whether traps are formed in the early or late stage of source rock formation during accumulation. Moreover, the longitudinal physical differences in crude oil properties are mainly attributed to the longitudinal differences in the pore throats. The difference in the pore throat and physical properties of crude oil affords differences in the productivity of horizontal wells in different subzones.

One of the most important parts of disaster management and disaster risk reduction strategies is the special vulnerability of children and the need to increase disaster awareness among them. It is very effective to design and develop awareness-raising tools suitable for children’s learning needs in this process. The main purpose of this study is to contribute to raising awareness of disasters among children in Turkey. With the study, risk maps for forest fire, landslide, flood, earthquake, and avalanche in Turkey were designed, and materials were developed by equipping them with disaster-themed texts. A questionnaire was applied to 165 students in the 10–11 age group with these interesting and entertaining materials. The results indicate that the study increased students’ ability to learn about disasters with maps by an average of 39%.

In recent decades, the bender element (BE) test has been used to estimate the seismic wave velocity in the laboratory due to several advantages; simplicity, versatility, fastness, inexpensiveness, and non-destructive nature. However, even with the advanced usage of BE in the laboratory, there has been little effort to use the BE in the field. In this article, the BE was used on a physical model at a multilayer mixture soils system and using different methods, patterns, and wave path lengths to evaluate the BE technique in the simulated field. The results indicated that the cross-hole pattern was the most suitable pattern to implement the BE test on the simulated field. BE results were highly influenced by the boundary condition when the distance between the sensor and hard boundary is less than 0.3 of the wave path length. BE sensors were able to detect seismic wave velocity at a ratio of the wave path length to sensor length up to 200 times. Graphical abstract

Grassland accounts for 67% of the land area in Qinghai–Tibet Plateau (QTP) to sensitive to climate. This article carried out extensive temporal–spatial variations of grassland water deficit/surplus (GWDS) and net primary productivity (NPP) of QTP grassland using meteorological data of 1981–2018. The results indicate that precipitation’s temporal variations are not related to potential evapotranspiration (PET). The maximum monthly precipitation occurs in July, while the maximum monthly PET appears in June. Precipitation is the second highest in spring when PET is the highest. The water deficit (PET-precipitation) from March to June takes up 51.4% of the total year. Therefore, droughts are more likely to happen in spring and June. This is the most important period for grassland protection. Water deficit is higher in the central and west and the highest in the northwest of QTP grasslands. This indicates the place where the droughts are more likely to occur. The grassland’s annual NPP is high in the southeastern part of QTP and low in the west. This shows the central and western parts of QTP grassland should receive more attention. The specific time and region obtained in this study are important for environmental protection policy-making and reducing grassland degradation in QTP.

High temperature targets (temperature above 500 K), are the special on the surface of the earth such as forest fire, prairie fire, oil well torches, heap coking, volcanic eruptions, significantly different from those of normal surfaces at lower temperatures. Identification of high-temperature targets plays an important role in environmental monitoring, disaster warning, and resource investigation. In remote sensing data, high-temperature target pixels and bands are studied. And they are deemed samples and variables, respectively, in multivariate analysis. And classification of samples for identification of high-temperature targets is necessary. To classify samples, feature analysis of spectrum needs to be done first. In feature analysis of spectrum, feature bands that can be used to distinguish samples need to be selected. Correspondence analysis is the method that can project samples and variables into the same factor space in the meantime. It can realize the classification of samples and variables synchronously, and the results can be interpreted by each other. First, the correspondence analysis is conducted on Landsat8/OLI remote sensing imagery to build the relationship between samples and variables. After that the correspondence relationship between identification results of high-temperature targets and feature bands can be built in the physical theory of remote sensing and factors which have indicative significance on fire are confirmed. Finally, the single band threshold method is adopted to realize high temperature target recognition by using factor scores. In the field confirmation, results suggest that the precision of identification of high-temperature targets reaches 92%. And we also get a consistent result with SWIR temperature inversion.

In order to study the differential diagenesis of sandy conglomerate reservoirs in different tectonic units in eastern Junggar Basin, and establish the differential temporal sequence of burial – diagenesis – hydrocarbon charging – pore evolution, the Upper Permian Wutonggou Formation sandy conglomerate reservoir in the Dongdaohaizi Sag and Baijiahai Uplift, eastern Junggar Basin are studied, based on observation of thin sections under microscope, measurement of scanning electron microscopy (SEM), X-ray diffraction (XRD), physical properties, cathodoluminescence (CL), micro beam fluorescence, and analysis of fluid inclusions, combined with previous research results. The result shows that the reservoir displays a differential diagenetic process as they are situated at different tectonic units of the Dongdaohaizi Sag and the Baijiahai Uplift. The Dongdaohaizi Sag is dominated by continuous subsidence, the reservoir buried in relatively deep depths experienced three stages of hydrocarbon charging, which is more strongly affected by compaction, fracturing, dissolution, and late-stage cementation, the effect of middle-stage cementation is relatively weak. The pore evolution experienced four stages, including decreased porosity by shallow burial compaction, decreased porosity by moderate burial compaction and middle-stage cementation, decreased and increased porosity by moderate to deep burial middle-stage cementation and dissolution, and increased and decreased porosity by deep burial dissolution and late-stage cementation. The diagenetic stage had reached A 2 sub-stage of mesodiagenesis, and the present porosity is relatively low; however, the developed structural fractures in the reservoir has played a good role in improving the reservoir seepage capacity. By contrast, the Baijiahai Uplift is characterized by multi-stage uplift, the reservoir buried in relatively shallow depths experienced two stages of hydrocarbon charging, which is more strongly affected by middle-stage cementation, with relatively weak compaction and dissolution, fracturing, and late-stage cementation was limited. The pore evolution experienced three stages, including decreased porosity by shallow burial compaction, decreased porosity by moderate burial compaction and middle-stage cementation, and decreased and increased porosity by moderate-deep burial middle-stage cementation and dissolution. The diagenetic stage has reached A 1 sub-stage of mesodiagenesis, and the present porosity is relatively high. Two types of favorable reservoirs are developed in the study area. The first one is matrix pore favorable reservoir, which is mainly located in the area of the Baijiahai Uplift of the reservoir with relatively high porosity and permeability. The second one is structural fracture developed favorable reservoir, which is mainly located in the fault development area of the Dongdaohaizi Sag.

Rainfall and surface water infiltration will affect the safety of loess slope. Ecological slope protection can protect and reinforce the surface layer of the slope by using the anchoring effect of plant root. In this study, the prevention and control technology of grass planting on loess slope in the solidified soil was studied. Heavy metal contents in the soil after addition of the stabilizer met the farmland standard at the end of the growth period. A comparison of the biomass data of different groups of solidified soil showed that the biological characteristics of plants had the best response at the mixture ratio of solidified soil of 0.86%. The shear strength of the root–soil composite increased by about 60% compared with that of plain soil at the mixture ratio of 0.86% stabilizer, and the permeability coefficient can be reduced by two orders of magnitude. Through the field engineering application, the ecological restoration test using loess soil solidified by consolid system with grass planting met the engineering requirements, with clear soil and water conservation benefits. Therefore, planting grass in solidified soil can effectively reduce the erosion of soil and improve the stability of the shallow slope.

Indicators and indexes are quantifiable parameters used in scientific disciplines to summarize and communicate complex data in a simple and explanatory manner. In the field of natural hazards, indicators and indexes have been used to characterize natural processes, and the associated risk conditions in terms of impact, vulnerability, exposure, and resilience. In this paper, we formalize indicators at the municipal level to differentiate the Italian territory based on the spatial distribution of landslides. The indicators were combined with other information to define indexes able to better characterize the stability conditions of the municipalities and quantify the possible impact of slope movements on the road network. Indexes were defined only for the Umbria Region (Central Italy), which was chosen as an example. The proposed indicators and indexes show, in a simple way, the severity of the instability on the territory and can be used to support decision-makers to assess, evaluate, and manage landslide mitigation activities and civil protection actions.

The Zhijin phosphorite (P)-bearing rare earth element (REE) deposit in Guizhou Province (China) hosts vast ore resources (P: 1.348 billion tonnes; REE: 1.44 Mt). Up to date, the Zhijin phosphorite resource has not been exploited because of the uncertain occurrence of the associated REEs, which hampers mineral processing and extraction. In this study, the structure, the valence state, and the coordination position of Y in the REE-yttrium-rich bioclastic samples from Zhijin were revealed by means of synchrotron radiation X-ray absorption fine structure analysis. The results show that the Y occurs as Y( iii ) in the samples, and that the form of Y is different from the Y 2 O 3 form in standard xenotime samples. Yttrium in the samples was in a complex coordination position without Y–O–Y bonding, and the Y–O bond lengths range widely without clear patterns. We suggest that Y in the samples is surrounded by organic or macro-molecular compounds, rather than in inorganic ones. Thus, Y in collophanite is unlikely to be in the form of isomorphism.

The response of beaches to typhoons has always been a hot topic at home and abroad. The study of beach changes during typhoons is helpful to deepen the understanding of beach evolution and is important for the coastal ecological environment. Based on the observation results of ten profiles and the sediment samples in Chudao before and after the typhoon Lekima, this article explored the response characteristics of the beach to the typhoon. The results showed that the study area was located on the right side of the typhoon’s forward path, and the double superposition of onshore waves and storm surge resulted in erosion along the beach. In order to alleviate the energy brought by storm waves, the beach was transformed into a more dissipated state. The mean particle size of the beach sediments was coarse on the whole, with poor sorting ability, and that in the wash zone was particularly obvious. The results showed that different profiles responded to Lekima in different ways: while the profiles of N01–N05 in the southwest changed little, those of N06–N10 in the northeast changed from the type of beach shoulder to the type of sandbank as a result of morphological differences in different profiles.

Mixtures of soft rock and sand have been applied extensively in the Mu Us Sandy Land (MUSL, also known as the Mu Us Desert) to limit the loss of top soil by wind erosion. In this study, the efficacy of sand-fixing technology was investigated in a series of experiments. The sand-fixing effect of seven different mixtures (ratios) on soft rock and sand was evaluated in a wind tunnel. The results indicated that the MUSL soils are susceptible to wind erosion, as the textural composition of sand is dominated by coarse particles. MUSL soils dominated by silt and clay particle sizes are more resistant to wind erosion. Each soft rock and sand combination experiences severe wind erosion. However, wind erosion was significantly reduced when soft rock and sand were mixed. An increase in particle size was associated with an increase in the resistance of soft rock and sand mixtures to wind erosion. The ability to resist wind erosion was greatest when the ratio of soft rock and sand was between 1:2 and 1:5. This study provided data to support the approaches to sand-fixing commonly used at present in the MUSL. The results of this study have important practical significance for the improvement of agricultural land potential in dry sandy areas.

The rising energy demands worldwide and difficulty in developing novel clean energy sources have greatly stimulated the exploitation of coalbed methane. Clay minerals are common fractions of coal; thus, understanding their CH 4 adsorption capacities and pore structures is vital. In this study, coal, parting, roof, and floor samples were collected from the Yangquan Mining District. The mineral compositions, CH 4 adsorption capacities, and pore structures of the samples were analyzed using X-ray diffraction, the CH 4 isothermal adsorption method, and the low-temperature N 2 adsorption method, respectively. The results indicated that organic matter had a much higher CH 4 adsorption capacity (33.80 cm 3 /g, 35°C) than that of clay minerals. The CH 4 adsorption capacities of various clay minerals are significantly different, with smectite (18.01 cm 3 /g), kaolinite (5.81 cm 3 /g), mixed-layer illite-smectite (4.47 cm 3 /g), and illite (2.08 cm 3 /g) present in decreasing order. The pore sizes of the samples consisted of sizes <6 nm, and six pore size groups (Groups 1–6) were identified in the PSD patterns. These pore size groups were associated with different clay minerals. We propose that the CH 4 adsorption capacities of clay minerals are mainly influenced by their pore structures, which are in turn associated with their species and formation processes. Furthermore, the conversion of kaolinite to illite, and the illitization of mixed-layer smectite-illite, exerted a negative effect on their CH 4 adsorption capacities.

Since the operation of Xiaolangdi (XLD) Water Conservancy Hub, the reservoir area has witnessed significant changes in eco-environment through the impoundment, and some suggestions can be put forward for the future ecological construction of reservoirs by comparing these changes. This article explores the variation of microclimate, soil erosion, forest and grass coverage, regional animal and plant diversity, and ecotourism resources in the past two decades, and summarizes the contributions of XLD to the following aspects: the eco-environment protection and restoration, the construction of an ecological corridor and a biodiversity conservation network, and the eco-economic development of the Yellow River Basin. On this basis, three suggestions were presented for the ecological construction of XLD in the future: (1) carry out the ecological evaluation of XLD reservoir; (2) implement high-quality afforestation and beautification of the reservoir area; and (3) build a smart ecological monitoring system for XLD.

As global warming continues, extreme precipitation events occur frequently in inland areas, seriously affecting human security and the ecological environment. Spatiotemporal evolution of extreme precipitation as well as response of extreme precipitation to climatic warming and its mechanism were investigated by considering the Weihe river basin in a monsoon transition zone of China as a research object. The results indicate that while the annual average temperature of the Weihe river basin increased with fluctuations from 1966 to 2017, except for the consecutive dry days (CDD) and simple daily intensity index that increased slightly, the other extreme precipitation indices (consecutive wet days, R25, and Rx5day) tended to decrease. Moreover, except for the CDD, the other four indices gradually increased from the northwest to the southeast, showing a similar trend to the temperature. The relationship between the 95th percentile threshold and temperature (hereinafter referred to as the P 95d – T relationship) in the Weihe river basin demonstrates the hook structure and its strength in terms of response is mainly dominated by the super-Clausius–Clapeyron (C–C) and C–C scaling. Furthermore, the peak temperature rises gradually from the northwest to the southeast. The results can provide important reference for the prediction of climate change and future studies of disaster risk in the Weihe river basin.

Xi’an, an inland city in Northwest China, borders the Qinling Mountains to the south and Wei River to the north. This city is rich in biodiversity and occupies a unique position in China. In the past few decades, human activities have led to great changes in land use in Xi’an city, and the ecosystem has experienced an accelerated fragmentation process. This study analyzed the degree of land use change and landscape fragmentation in the region. Land use data in 1990, 2000, 2010, and 2018 were used to evaluate the effects of land use change on the landscape pattern in Xi’an city at different scales using mathematical models and landscape indices. Results show that from 1990 to 2018, built-up land expanded the most, from 7.34 to 13.51%. Cropland decreased the most, from 40.12 to 29.81%. Overall, the fragmentation degree of cropland patches decreased, and the fragmentation degree of built-up land patches increased. The landscape patterns of different districts and counties show different change directions. The results can provide necessary information for land use planning and land resource allocation in inland cities in Northwest China.

Interpolation parameters are the basic elements of an interpolation algorithm in terrain environmental modeling. Different interpolation parameters produce different interpolation precisions, and the differences can be substantial. They are divided into deterministic parameters and uncertainty parameters. The optimization of uncertainty interpolation parameters is studied in this article. First, the methods of cross-validation, correlation analysis, and trend surface analysis are systematically used to identify and determine the optimal interval of interpolation parameters, which is helpful to solve the “black box” problem of parameter selection. Second, the significance degree of different parameters on the interpolation accuracy is given by using analysis of variance, which indicated that the high influence parameters are more helpful to improve the accuracy. This is an innovative conclusion.

The Gangdese batholith, emplaced from the Cretaceous to the Eocene in the southern Lhasa terrane of Tibet, provides critical constraints on the tectonic-magmatic evolution of the Neo-Tethyan Ocean and the India-Asia continental collision. In this article, we report new data for the Laimailang monzogranite in the southern Gangdese, including major and trace element analyses, zircon U–Pb dating, and in situ Hf isotope analyses. In situ zircon U–Pb dating of sample yielded Late Cretaceous ages (ca. 81 Ma). The monzogranite is characterized by relatively high-silica (≥56 wt% SiO 2 ), Na-rich, and high-Al granitoids that are characterized by high Sr, low Y and HREE contents and strongly fractionated REE patterns, with no significant Eu anomaly, indicating that they are consistent with the definition of adakite. These monzogranite have high K 2 O (2.92–6.5%) and negative ε Hf ( t ) (−2.1 to −5.4), suggesting that these rocks were likely derived from the partial melting of the lower continental crust. We conclude that the Laimailang rocks of adakitic affinity were derived due to the melting of the thickened lower continental crust in the late Cretaceous.

The eastern Qinling orogenic belt, located in the conjoint region between the Neo-Tethys tectonic domain and the western Pacific tectonic domain, is key to understanding the tectono-sedimentary evolution of the East Asian interior. Extensive Late Cretaceous–Cenozoic fluvial and lacustrine deposits within the eastern Qinling orogen provide ideal archives of tectono-sedimentary evolution in Fenwei, the eastern Qinling orogen. We present an integrated rock magnetism and anisotropy of magnetic susceptibility (AMS) study of a Middle Eocene–Early Oligocene succession in the Lushi Basin, eastern Qinling region. Our rock magnetic results suggest that hematite and magnetite are the main magnetic carriers of remanence, while χ − T curves, hysteresis loops, and low values of bulk susceptibility indicate that paramagnetic minerals are major contributors to AMS in the Lushi Basin. Nevertheless, the anomalous magnetic fabrics in the Zhangjiacun and Lushi Formations may result from the contribution of the iron-bearing carbonates in deposits. The clustering of the minimum principal axes nearly vertical to the bedding plane and the well-defined NW–SE magnetic lineation almost parallel to the dip of the bounding fault suggest that the AMS of the Dayu Formation is not a sedimentary fabric but an incipient deformation magnetic fabric. The pronounced NW–SE magnetic lineation indicates the NW–SE stretching of the Lushi Basin during the Late Eocene–Earliest Oligocene, which may have been caused by the combined effects of the India–Eurasia collision and the subduction of the western Pacific plate.

Cropland cover datasets is of great significance for research on agricultural monitoring. The existing investigations on the inconsistency of different cropland datasets have mainly focused on first-class cropland and only analyzed the causes of this inconsistency in terms of cartography. To date, investigations have neglected the importance of fine cropland types in studies such as global food security assessment, and a comprehensive analysis of the causes of inconsistency from the perspectives of both cartography and geography is lacking. Moreover, the verification samples of existing studies have primarily been collected based on Google Earth. So, we examined the cropland resources of Cambodia using areal, spatial consistency, elevation classification, and field survey data assessment methods for the Global Food Security-support Analysis Data at 30 m for Southeast Asia, Global Land Cover Fine Surface Cover30-2015, Finer Resolution Observation and Monitoring of Global Land Cover2015, and SERVIR-Mekong datasets and comprehensively investigated the causes of inconsistency in terms of geography and cartography. The results revealed that the consistency of the extracted areas of first-class cropland among the four datasets was high. But, the cropland areas and statistical results from the Food and Agriculture Organization (FAO) of the United Nations are quite different. The overall accuracy (OA) for the first-class cropland of GFSAD30SEACE, GLC_FCS30-2015, and SERVIR-Mekong datasets were >82%. For fine cropland types, however, the OA of the SERVIR-Mekong dataset was relatively high, at 74.87%, while the accuracy levels of the global-scale GLC_FCS30-2015 and FROM_GLC2015 datasets were <50% due to the influence of scale size on mapping accuracy. In addition, in the eastern and northern portions of Cambodia with elevations of 50–200 m, the spatial consistency of the four datasets was low due to the serious confusion between cropland and forest, grassland, and shrub types. Therefore, land cover producers should adopt a zonal stratification strategy, focusing on remote sensing extraction techniques for confusing types in areas with high inconsistency to improve the accuracy of cropland.

Studying the distribution law and influencing factors of coseismic landslides has important scientific significance and engineering value for understanding the mechanism of seismic landslides and predicting the occurrence of seismic landslides. After a hundred years, these large- and medium-scale landslides induced by the 1920 Haiyuan earthquake are still well-preserved and have extremely high academic research value. About 620 loess seismic landslides induced by the Haiyuan earthquake in 1920 were investigated on site. On this basis, the shape differences between seismic landslides and gravity landslides were summarized; 605 landslides were identified by satellite images, and the Haiyuan earthquake-induced loess landslide database containing seismic information and landslide information was established. The distribution law and morphological characteristics of large- and medium-sized landslides induced by the Haiyuan earthquake were systematically counted according to the conditions of the landslide-intensive area, intensity, and fault upper and lower plates. The influencing factors of loess earthquake landslides were summarized, and the following conclusions were obtained: (1) 1,225 large- and medium-sized landslides were induced by the Haiyuan earthquake in 1920. These landslides have the characteristics of long sliding distance, large single scale, and strong disaster-causing. They are mainly distributed in three concentrated areas of Xiji, Haiyuan, and Pengyang. The landslide morphological characteristics of the three landslide-intensive areas are different because the landslide sliding mechanism caused by topography and lithology is different. (2) The landslide distribution has obvious clustering, zonation, and directivity, and has an obvious river distance effect and fault hanging wall effect. (3) The internal influencing factors such as stratum lithology, topography, fault location, and direction, and the role of water control the occurrence location and scale of landslide. The external factor of an earthquake is an important incentive and control factor for landslide occurrence.

Increasing rain levels can easily destabilize and destroy particulate matter in mountainous areas, which can cause natural disasters, such as debris flow and landslides. Constitutive equations and numerical simulation are the theoretical bases for understanding the behavior of these disasters. Thus, this study aimed to investigate the impact of the debris flow and its entrainment behavior on gully bed sediments. We adopted a coupled analysis method based on elastic–plastic constitutive equations by considering the elasto-plasticity of slurry and the elastic characteristics of debris materials. The coupled method consisted of smooth particle hydrodynamic (SPH), discrete element method (DEM), and finite element method (FEM) (SPH–DEM–FEM). SPH particles represented fluid, DEM particles denoted solid immersed in fluid, and FEM elements represented the terrain and structures. The coupling analysis model was used to simulate the coupling contact of solid, liquid, and structures and to describe the entrainment behavior between solid and liquid phases. The model feasibility was verified by comparing the basic simulation results with experimental values of the dam break model and the rotating cylindrical tank model. The coupled model was then combined with the data management and modeling of geographic information system to simulate the 2010 Yohutagawa debris flow event. Finally, we explored the influence of debris shape-related parameters on the debris flow erosion entrainment process.

Taking into consideration the difficulties in predicting the properties of liquid production and evaluating the irreducible water saturation of low-porosity and ultra-low-permeability sandstone reservoirs, the relationships between the irreducible water saturation and logging reservoir evaluation parameters are explored based on a large number of core mercury injection experiment. When the permeability cumulative contribution value reaches 99.9%, the lower limit of pore throat radius is determined as 0.025 μm and the corresponding irreducible water saturation is more accurate. The experimental results of 77 samples in the research area showed that the irreducible water saturation has a good correlation with the median pore throat radius which has a good correlation with the porosity. The irreducible water saturation is consistent with the nuclear magnetic experiment results. Therefore, a new method to determine the irreducible water saturation based on logging data is established. The application results of this method in tight sandstone reservoirs in the Keshen area show that the fluid types identified by the relationship between the calculated irreducible water saturation and total water saturation are consistent with the actual test results, which confirms the accuracy and feasibility of this method. This method solves the problem of irreducible water saturation evaluation in low-porosity and ultra-low-permeability sandstone reservoirs. In the field or other situations where core testing is lacking, accurate irreducible water saturation can be obtained based on only porosity. It also lays a foundation for further improving the prediction accuracy of fluid properties, which has broad application prospects.

In recent years, the geochemical characteristics, genesis and sources of natural gas in the Upper Triassic Xujiahe Formation in the Sichuan Basin have received extensive attention, but their genesis and sources are still controversial. In this study, taking the natural gas from the Xujiahe Formation in the Sichuan Basin as an example, the source and genesis of the natural gas have been systematically analyzed. The results show that the natural gas of the Xujiahe Formation in the Sichuan Basin is dominated by methane, followed by a small amount of CO 2 and N 2 ; only the southern Sichuan area contains a small amount of H 2 S, which comes from the supply of the underlying carbonate source rocks. Except for the western Sichuan Basin, the drying coefficient of the natural gas is generally less than 0.95 (wet gas). Furthermore, the composition of the natural gas is mainly controlled by the maturity of source rocks. The carbon isotope of ethane in natural gas ranges from −33.9 to −21.5‰, and the hydrogen isotope of methane ranges from −188‰ to −151‰. The carbon and hydrogen isotope values are higher in the western Sichuan Basin than in the central, northeastern and southern Sichuan Basin. The identification of the origin of natural gas and the comparison of gas sources show that the natural gas in the Xujiahe Formation is mainly coal-derived gas from its own coal-measure source rocks; the natural gas in the northern part of the southern Sichuan Basin is oil-derived gas originating from the Changxing Formation and the Silurian marine source rocks; however, the natural gas in the northeastern Sichuan Basin is a mixture of coal-derived and oil-derived gases. In addition, the carbon and hydrogen isotopes in some natural gas samples from the Xujiahe Formation have inversions of δ 13 C 1 > δ 13 C 2 , δ 13 C 2 > δ 13 C 3 , δ 13 C 3 > δ 13 C 4 , and δD 2 > δD 3 , and the magnitude of the inversions is small. It is considered to be caused by the mixing of gases from the same source, as well as the mixing of coal-derived and oil-derived gases.

Peridotite xenoliths of wehrlite composition, scarcely known in Adamawa plateau, Cameroon, were sampled by Mio-Pliocene basanites from Hosséré Do Guessa volcano. Their origins are discussed and elucidated trough petrography and mineral chemistry. Studied wehrlites exhibit poikilitic or protogranular textures and are composed of four main mantle phases (high Mg-olivine, augite, enstatite and Al-spinel). Petrographic and microprobe (Camebax SX100) chemical data (Fo90.8-91.4 olivine, Wo39.4-42.0 augite, En90.5-91.1 enstatite and Al-spinel) suggest a mantle origin for the Hosséré Do Guessa wehrlites. Hence, these rocks could not be considered cumulate. They have been equilibrated between 1,140 and 1,220°C, at pressures of 1.5–2.0 GPa, at 50–66 km deep, below the crust-mantle boundary. Wehrlites might result in reactions with carbonate/carbonatite melt, accompanying CO 2 degassing and metasomatism by fluid phases. They suffered transpressional tectonics, during movement at Tertiary times of Pan-African strike-slip-faults, after solid-state tectonic relaxation. Graphical abstract

The Manas River Basin is located in the inland arid area of China. It has a unique natural environment that contains a mountain, oasis, and desert complex ecosystem. Changes in land use type have had significant impacts on the social, economic, and ecological environment in the basin. Based on the remote sensing interpretation data of land use types from 1980 to 2020 in the Manas River Basin, using ArcGIS 10.2 and Fragstats 4.2 and other software to study the temporal and spatial evolution of land use, landscape pattern, and ecological service value (ESV) in the Manas River Basin, several key results were obtained. (1) Unused land accounted for the largest proportion of the total area at about 44%, and the smallest proportion was construction land at 1%, the construction land and farmland areas increased significantly to 82.16 and 34.87%, while the woodland and grassland area decreased to 15.06 and 14.34%, respectively. (2) Between 1980 and 2020, the inflows and outflows of the quantitative transfer tracks for farmland, grassland, and unused land were highly dominant, but the frequent conversion among various types of land led to the transfer tracks becoming more diversified. (3) From 1980 to 2020 the complexity and fragmentation of landscape in the basin decreased, and the heterogeneity, differences, and connectivity of the landscape increased. (4) The ESV of the Manas River Basin had a tendency to initially decrease and then increase, which increased from 237.27 × 10 8 yuan in 1980 to 238.10 × 10 8 yuan in 2020. The above research results can not only provide a basis for the ecological improvement of the Manas River Basin but also provide a reference for the study of other basins/regions in arid areas.

Point settlement selection is one of the critical tasks in map generalization, which should consider spatial distribution, spatial conflict, proximity to objects, and other factors. By analyzing the current research, spatial structure-preserving and conflict-avoiding methods are proposed in this article for point settlement selection. On the one hand, in view of the shortcomings of the Voronoi diagram in measuring settlement density and spatial distribution, a spatial conflict-avoiding strategy is proposed, which utilizes the minimum distance between adjacent settlements to weight the Voronoi diagram area to avoid local conflicts. On the other hand, in order to solve the problem of excessive temporary solidification of adjacent settlements, an adaptive temporary solidification strategy considering local spatial characteristics is proposed, with an improved novel distance-constrained Voronoi diagram model suggested and employed. Comparative experiments and related quantitative analysis on the National Land Survey of Finland Topographic Database confirm that the above methods have good effect. The conflict-avoiding strategy can effectively prioritize map readability and legibility, while the adaptive temporary solidification method can better deal with the boundary effect of settlement groups.

The mechanism of hydrolysis and extension diffusion of heavy metal pollution elements infiltrated into rock is analyzed by the theory of ion hydrolysis displacement. The hydrolysis properties of typical elements such as cadmium, zinc, lead, and copper are verified by convective dispersion model, and the diffusion law and fission characteristics of heavy metal with different hydrolysis constant are discussed. A three-dimensional constitutive relation model of rock extension diffusion surface is established by combining viscoelastic monomer model with a damage monomer model. Considering the influence of diffusion coefficient, hydrolysis constant, deformation factor, and other parameters, the rationality of the test results and model fitting results of heavy metal invading rock are verified. The results show that the replacement rate of colloidal mineral elements in rock varies with different hydrolysis constant, when the hydrolysis constant is large, the extension diffusion rate in rock is large; otherwise, the extension diffusion rate is small. Constitutive relation curves of polluted rock with different lithologies are in good agreement with the fitting results of the combination model under the influence of the same test conditions and the same parameters.

Cretaceous formation in the western Tabei Uplift is significant petroleum pay zone in the Tarim Basin, NW China. For the complex relationship between tectonic movement and depositional environment, sequence stratigraphic filling model of the whole Cretaceous formation has not been established yet. Using well logs and seismic data in this article, sequence stratigraphic evolution process and filling model of the Cretaceous are interpreted involving paleo-uplift, sedimentary and water-level. As a first-order sequence, the Cretaceous is subdivided into three second-order sequences, Shushanhe, Baxigai and Bashijiqike Formation. Shushanhe Formation is subdivided into three third-order sequences, KSQ1, KSQ2 and KSQ3 upwards; Baxigai Formation is considered as one single third-order sequence, KSQ4; Bashijiqike Formation is subdivided into three third-order sequences, KSQ5, KSQ6 and KSQ7 upwards. In the early KSQ1, paleo-uplift was aquatic. From KSQ1 to KSQ3, water-level raised and paleo-uplift moved upwards gradually; and water-level raising was faster than paleo-uplift ascending. The accommodations of these three sequences increased. Lacustrine facies mudstones and siltstones were onlap filling sequences towards Xiqiu Paleo-uplift. In the end of KSQ3, the whole region was subaqueous. The water-level and paleo-uplift in KSQ4 were easy steady, and the accommodation in KSQ4 was sustained. Delta depositional system began to prograde from depocenter to distal slope of paleo-uplift. In the high of Xiqiu Paleo-uplift, dominated sediments were fine grains for the sedimentary dynamic force. From KSQ5 to KSQ7 in the Bashijiqike Formation, water turned regression, paleo-uplift raised slowly and the accommodation reduced continually. Because of the progradation deltaic sandstones, downlap sequences were developed towards the Xiqiu Paleo-uplift. Exposed in the Early Paleogene, KSQ7 and part KSQ6 were truncated to form top unconformable boundaries. Established sequence filling model of the Cretaceous in the western Tabei Uplift provides important insights on the stratigraphic characteristics and in turn on the exploration potential of petroleum systems.

The Luanchuan polymetallic mining district (LPMD) covers many major deposits of the East Qinling metallogenic belt in Henan Province, central China. It has attracted much attention because of its various types of minerals, abundant mineral reserves and huge metallogenic potential. Systematic research on the geology of LPMD has been carried out previously, and it is concluded that the formation of the ore deposits is dominantly controlled by fault structure. However, there are few reports on the quantitative characterization of fault structure and spatial distribution of deposits and the coupling relationship between them. This study applies fractal theory to the illustration of the characteristics of inter-relationship between fault structure and spatial distribution of the ore deposits in LPMD, which then may serve as a basis for further ore exploration. Our results indicate that the capacity dimension (CPDs) of integrated fault structure, NW-trend fault and NE-trend fault for the area investigated are 1.7206, 1.6539 and 1.2145, respectively; while the information dimension (IND) of which is 1.7143, 1.6559 and 1.2222, respectively. The studied area has superior geological environment for potential ore deposits, with major contribution from the NW-trend fault. Spatial distribution dimension value of metallic ore is 0.8873. Quantity fractal dimension and Density fractal dimension values of the metallic deposits are 1.1154 and 1.115, respectively. Quantitatively, the main ore deposits discovered in this area mainly fall on either CPD ≥ 1.49, IND ≥ 1.38 or 1.49 > CPD ≥ 1.00, 1.38 > IND ≥ 1.00. Qualitatively, conditions that facilitate ore deposits require higher fractal dimension values. Among the areas studied, we found that Rank I area is the most ideal region that fulfilled the quantitative and qualitative conditions, which is consistent with the actual location of the ore deposits discovered.

Comprehensive management of the ecological environment and sustainable ecological development, such as the gully control and land consolidation (GCLC) project, may affect surface vegetation. The normalized difference vegetation index (NDVI) is a sensitive indicator of vegetation dynamics; however, an in-depth study that continually monitors the spatial and temporal variation of regional vegetation before and after the implementation of the GCLC project is still scarce. To address this issue, we analyzed the spatial and temporal variations of Landsat surface reflectance-derived NDVI data in the Jiulongquan watershed in Yan’an City, China, from 2010 to 2019, and examined the main driving factors for these variations. Results showed high overall vegetation coverage in the evaluated watershed. The NDVI was spatially varied and tended to be low in the gully area and high on the slope. From 2010 to 2019, the NDVI values exhibited an increasing trend, and the most evident changes were concentrated in the gully areas. The changes in NDVI were mainly driven by human activities rather than the evaluated climatic factors. This work indicates that the GCLC project had positive effects on the ecological and agricultural environment at a regional scale.

Various socio-historical and cultural influences that have permeated the territory of Serbia have created a specific cultural heritage composed of interesting architecture, spatial and environmental units, folklore, gastronomy, lifestyle, and other specifics, which are usually under protection and are significantly visited by tourists. The value of resources and the state of development determine the overall tourist potential of the area. In this research, two methods were used to assess the tourist potential for six spatial, cultural, and historical units in Serbia: the analytical hierarchical process and the mathematical model, which is based on the du Cros method. The aim of the research is to determine the validity of the obtained results through their comparison and to record the shortcomings. The same indicators and sub-indicators were used in both methodologies, while the weighting coefficients differed according to the methodology. The importance of the research is reflected in the confirmation of the fact that there is a need to develop new methods that would eliminate all the shortcomings and increase the level of objectivity in the assessment of tourism potential.

Remote sensing technology has shown its irreplaceable advantages in the identification of urban black and odorous water body. However, the universality of the remote sensing recognition algorithm for the black and odorous water body is not clear in different regions. Thus, two typical cities, Shenyang and Nanjing, were selected from northern and southern China as the study areas. Four forms of recognition models of the black and odorous water body are built based on Gaofen-2 images, including the single-band model, difference model, ratio model, and water quality parameter model. Combined with the remote sensing interpretation marks of black and odorous water body, the recognition precision of black and odorous water body is analyzed by the methods of the confusion matrix and Kappa coefficient. The results show that the overall accuracy of the normalized difference black-odorous water index (NDBWI) model is higher than 80% in the northern and southern cities of China, with good consistency of spatial distribution. The accuracy of the black and odorous water index model and G model is higher than 75% only in the special areas of Nanjing or Shenyang. The accuracy of other models is generally low. Research show that the NDBWI model has better universality in the identification of urban black and odorous water body, and it is suitable for promotion and application. The remote sensing interpretation marks of black and odorous water body have shown a good auxiliary identification function. The research provides a technical foundation for large-scale and rapid identification of urban black and odorous water body.

Early Cretaceous granitic rocks are widely distributed in the Great Xing’an Range, northeast China. However, their precise age and tectonic evolution remain controversial. This study presents new zircon U–Pb, Lu–Hf, and whole-rock geochemical data for the granitic plutons in the Yili area, Xing’an Massif, northern Great Xing’an Range. The aim of this study was to decipher the tectono-thermal history and obtain further understanding of the geodynamic setting of the large-scale Late Mesozoic magmatism in the Great Xing’an Range. Zircon U–Pb age dating indicated that the plutons were emplaced during the Early Cretaceous, with ages of 132.2–130.1 Ma. The plutons showed similar geochemical features, characterized by high concentrations of SiO 2 and Na 2 O + K 2 O and low concentrations of P 2 O 5 , CaO, MgO, and TFe 2 O 3 . The plutons were enriched in light rare earth elements and large ion lithophile elements and depleted in heavy earth elements and high-field-strength elements. Such features indicate that the plutons are highly fractionated with I-type granite affinity. These findings, combined with pluton ε Hf ( t ) values of + 5.25 to + 8.28 and two-stage model ages ( t DM2 ) of 661–855 Ma, indicate that the primary magmas originated from partial melting of juvenile basaltic crustal material accreted during the Neoproterozoic. These results combined with regional geological evolution indicated that the generation of Early Cretaceous plutons in the northern Great Xing’an Range might be closely related to the post-collisional gravitational collapse and subsequent extension resulting from the closure of the Mongolia-Okhotsk Ocean. Their generation also superimposed the back-arc extension resulting from retraction of the Paleo-Pacific subduction plate.

The phenomenon of urbanization has led to an increase in residential land and other economic activities that resulted in the conversion of undeveloped land into developed and settled lands. Thus, it has an impact on limited water absorption, and eventually, a flood occurs when extreme rainfall happens. The Kedurus watershed is a flood-prone area where floods consistently occur with a depth of up to 1 m. However, the Kedurus watershed is an area that has a vital function in the economic development of the city of Surabaya. From the previous research, three instruments were declared effective in reducing flooding. By using the positivistic approach, the purpose of this study is a spatial planning concept for flood reduction in the Kedurus River Basin. The results will be presented as spatial modeling of the flood with the existing conditions resulting in a flood inundation area of 228.88 ha. The stages of the formulation of the spatial planning concept for flood reduction resulted in several proposals, namely, the allocation of green open space for all the land assets of the Surabaya City government and the provision of a maximum requirement of 60% development for space allocation on existing nondeveloped land.

Discovery of the Siah Diq porphyry (Cu–Au) prospect in the foothill of Dam Koh volcano is a recent exploration success story of mineralization buried under a 46 m alluvium cover in an exploratory mature Chagai belt. Acquisition of geophysical data followed by drilling and logging was key in the discovery. Integrated magnetics and induced polarization (IP) surveys in an area of 7.5 km 2 , pointed out magnetic-low, IP-high, and resistivity-low anomalies corresponding to porphyry Cu–Au type sulfide mineralization. Three bore holes were drilled to test the geophysical anomalies. After careful observation and geoscientific logging of core, porphyry style Cu–Au mineralization was revealed. The porphyry prospect was further characterized based on host rock lithology, petrography, alteration mineralogy, ore vein characterization, and Cu/Au geochemical assays based on core samples. Rocks hosting the mineralization include andesite, granodiorite, coarse, as well as fine grained diorite and pink granite, all highly altered, mineralized and porphyritic. Propylitic alteration was dominant in all the three bore holes and developed earlier followed by phyllic, potassic, and argillic alterations. Sulfide mineralization is present as cross-cutting stockwork veins and disseminations. Average copper and gold assays of drill core are 0.17% Cu and 0.78 ppm Au, respectively. Economically insignificant values of molybdenum and silver have been noted in some samples.

We investigate the possibility of using Differential interferometric synthetic aperture radar (DInSAR) to develop models of vertical crustal movements (VCMs). We determined VCM using the DInSAR method in the locations of four Polish GNSS stations: Borowa Góra, Borowiec, Lamkówko, and Józefosław. They are included in the International GNSS service and EUREF permanent GNSS networks. All Sentinel-1A and 1B satellite data were from 2020, and the time intervals of the created interferograms are 12 days, 24 days, and 336 days for each of the orbits: ascending and descending. We verified the calculated results of VCM based on GNSS data recorded by individual stations. We developed reference data with the precise point positioning (PPP) method. We confronted them with the Nevada Geodetic Laboratory service. The GNSS data covered larger time intervals than the synthetic aperture radar (SAR) data. To calculate daily positions with the PPP method we used GipsyX software. The obtained results of the directions of displacement are convergent between SAR and GNSS data. The values differ from each other, both between the types of orbits and GNSS data. The obtained results allow us to assume that SAR data developed using the DInSAR method may provide additional support in the development of VCM models in the Polish area, but they cannot be the only source of such results.

The article presents a novel computation technique for predicting the settlement of reinforcement concrete (R.C) raft foundations based on total station and precise leveling measurements. Modified inverse distance weight (MIDW) and principal component analysis (PCA) are developed to predict the nonmeasurable settlement of raft foundations and are compared to regression techniques. Wall measurements are used to verify the proposed interpolation methods. Six observation epochs were carried out over 3 years for the R.C raft foundation of a multistory building in Baltim, Egypt, which rests on clay soil, to monitor and predict the foundation settlement. The obtained results show that PCA and MIDW models outperform other models in interpolating nonmeasurable (invisible) points, while the accuracy of MIDW is the best. The developed techniques can be used to interpolate nonmeasurable (invisible) points to understand the actual behavior of foundation settlement. The monitoring building showed that the slope of the foundation in the X direction is 7.9 and 14.5% after 5 and 26 months, respectively.

Pliocene-aged carbonaceous rocks of varying thicknesses, alternating with siliciclastic and carbonate rock units, are located on the northern border of the Çameli-Acıpayam basin (in southwestern Turkey), which is filled with thick Neogene sediments. Organic and inorganic geochemical properties of carbonaceous rocks were examined to evaluate their hydrocarbon production potential and paleo-depositional conditions (provenance, paleoclimate, paleosalinity, paleoredox, weathering, heavy metal contents, etc.). Based on organic geochemical analysis, carbonaceous rocks show good to excellent source rock potential and have gas production potential. Organic substances are mostly of allochthonous origin, and their thermal maturity degree is quite low. Carbonaceous rocks have a high amount of inorganic substance (minerals) composed of quartz, clay + mica minerals (mostly illite and a lesser amount of smectite, chlorite, and kaolinite), feldspar, and opaque minerals (pyrite and ilmenite). Although carbonaceous rocks have similar major oxide and trace element concentrations, they show clear differences in terms of Fe 2 O 3 , MgO, and some heavy metals (such as Ni, Cr, Co, V, and Sc). The major oxide, trace element concentrations, various element ratios of carbonaceous rocks bear the characteristics of mafic/ultramafic magmatic rocks formed on the active continental margin. In addition, carbonaceous rocks were precipitated in a brackish water environment under oxic conditions. The sediments, which were rapidly stored without recycling in the deposition environment where hot/humid climatic conditions are effective, did not undergo intense decomposition in the source area.

Considering that many hydrological analysis methods compare and analyze the runoff before and after the construction of the reservoir, without restoring the measured data of the hydrological station, in this case, when the length of the measured data series is short, the evaluation results will be affected. In this article, based on the runoff reduction of stations affected by water conservancy projects, an improved range of variability approach (RVA) which can be applied to 1-year hydrological change analysis is proposed by coupling the hydrological variation index with the appropriate upper and lower limit theory of RVA. As Jialing river watershed is selected as the research area, the runoff depth of Beibei station is reduced, and then the improved RVA is employed to analyze the degree of change in river water regime. It is concluded that the change degree of overall hydrological index in Beibei station is high, and the prediction of variation of water regime of Beibei station can be made with the aid of simulating the operation of cascade reservoirs, with the inflow of Beibei station in flood season to reduce, and the inflow in dry season to increase. The example verifies the effectiveness of the improved RVA method, and the analysis results can provide a reference for the adjustment of the operation mode of upstream cascade reservoirs.

In recent years, the proliferation of coronavirus disease has profoundly affected the world. The vitality of urban space is difficult to recover in the short term. Therefore, in the early stage of human-to-human transmission of the epidemic, we need to determine the potential urban agglomeration space as soon as possible, the timely find of hidden danger areas, and carry out spatial optimization to prevent the further spread of the epidemic. This becomes the urgent problem at the moment. Jinan is the capital city of Shandong Province, and the mega-city of China. The study is focused on the main urban area within the bypass. This study used spatial data methods such as spatial grammar and GIS technology. First, we analyzed the spatial topological properties of urban road network during the epidemic. Then, we carried out spatial autocorrelation analysis on the topological attributes to get the shape of urban spatial clustering layout during the epidemic. Finally, the thesis crawled through various types of infrastructure points-of-interest and conducted nuclear density analysis to get the dynamic trend of urban space in Jinan. The research results showed that there is significant space for agglomeration in the main urban area of Jinan. The areas with strong agglomeration are basically located in tourism areas, school areas, business areas, living circle areas of residential communities in Licheng and Lixia districts, transportation hub areas in Tianqiao District, and high-tech industrial areas in Lixia District. Topography, water body, greening, and parks could effectively reduce the concentration of human flow, and are important areas to relieve the potential abnormal epidemic. This study provided a new method for detecting epidemic prevention and control areas, optimizing urban space layout and formulating prevention and control strategies in the early stage of human-to-human epidemic transmission and lack of case surveillance data and control measures.

The Zhujiang Formation in the Baiyun Sag, Pearl River Mouth Basin, China, is formed primarily in a deep-water continental slope environment. Its chronostratigraphic framework is based on biostratigraphy and sequence stratigraphy, and its geological dating is based on micropaleontological data. This makes it difficult to obtain precise absolute ages for various geological events. In this study, gamma ray (GR) well log data from Wells Y1, Y2, and Y3 were used as paleoclimate proxies, and spectral and wavelet analyses were used to conduct cyclostratigraphic research. The results show that the Milankovitch cycles were preserved in the Zhujiang Formation in the Baiyun Sag. Stratigraphic cycles controlled by 405 and 95 ka orbital eccentricity, 40.4 ka orbital obliquity, and 23.5 ka orbital precession cycles can be identified; the signal of stratigraphic cycles controlled by the 405 ka long eccentricity cycle is the strongest. The floating astronomical time scale is constructed based on 405 ka orbital eccentricity cycle tuning of the GR series. The precise durations of the Zhujiang Formation in Wells Y1, Y2, and Y3 are 7.13, 6.93, and 7.18 Ma, and the average deposition rates are 4.68, 5.91, and 5.33 cm/ka, respectively. The Zhujiang Formation was divided into 17 fourth-, 76 fifth-, and 174 sixth-order cycles using the 405, 95, and 40.4 ka orbital periods as the dividing scales, respectively. This study provides a quantitative method for high-precision isochronous stratigraphic division and correlation in deep-water sedimentary systems.

With the increasing demand for filling engineering construction in the Loess Plateau, the engineering problems related to saturated loess caused by rainfall and irrigation are also increasingly prominent. This work studied the shear characteristics of saturated compacted loess by experiments, and qualitatively and quantitatively explained the meso-mechanism of the effect of compaction degree on the shear characteristics combined with the meso-pore characteristic parameters. The study shows that the stress–strain curve of saturated loess under 80 and 85% compaction degree is strain softening, it is strain weak softening under 90% compaction degree, and strain hardening under 95% compaction degree. The failure strength and pore water pressure have a good fitting linear relationship with compaction degree, and the fitting correlation coefficients are more than 0.97. Under 95% compaction degree, the pore water pressure increases with the development of axial strain, then decreases after the peak, and may appear negative. With the increase in compaction degree, the micro and small pore content of the saturated loess soil increases, the medium, large and super large pore content decreases, the proportion of pore area decreases, the pore shape becomes uniform and smooth, the complexity of pore shape decreases, the pore arrangement tends to be regular and neat, and the directionality increases. The research results can provide references for engineering design, construction, and numerical calculation of filling engineering in loess area.

Extracting spatial objects and their key points from remote sensing images has attracted great attention of worldwide researchers in intelligent machine perception of the Earth’s surface. However, the key points of spatial objects (KPSOs) extracted by the conventional mask region-convolution neural network model are difficult to be sorted reasonably, which is a key obstacle to enhance the ability of machine intelligent perception of spatial objects. The widely distributed artificial structures with stable morphological and spectral characteristics, such as sports fields, cross-river bridges, and urban intersections, are selected to study how to extract their key points with a multihot cross-entropy loss function. First, the location point in KPSOs is selected as one category individually to distinguish morphological feature points. Then, the two categories of key points are arranged in order while maintaining internal disorder, and the mapping relationship between KPSOs and the prediction heat map is improved to one category rather than a single key point. Therefore, the predicted heat map of each category can predict all the corresponding key points at one time. The experimental results demonstrate that the prediction accuracy of KPSOs extracted by the new method is 80.6%, taking part area of Huai’an City for example. It is reasonable to believe that this method will greatly promote the development of intelligent machine perception of the Earth’s surface.

Various climate and watershed characteristics determine the runoff coefficient (RC), and their interactions are complicated. Understanding the driving factors of the RC is important for understanding the long-term water balance and how it might change. Using the upper reaches of the Huaihe River Basin as the study area, remote sensing data were used to produce a RC map. The geographical detector was selected to quantify the individual and interactive influences of 13 driving factors on the RC. The results revealed that moderate resolution imaging spectroradiometer evapotranspiration (ET) data can be used to produce a mean average RC map based on the water balance equation. The dominant factors influencing the RC were found to vary at different scales. Precipitation had the largest correlation coefficient with the RC at the watershed scale. For the pixel scale, results from the geographical detector indicated that actual evapotranspiration (AET) and precipitation had the highest explanatory rate for the RC in the small watershed region and the whole study area (0.785 and 0.248, respectively). Climate factors, elevation, and normalized difference vegetation index had a substantial influence on the RC. Any two factors exhibited bilinear or nonlinear enhanced relationships in their interactions. The largest interactions between the factors were AET and precipitation, which exceeded 0.900. This study serves to better understand and explain runoff’s complex interrelationships.

Urban expansion caused numerous geological hazards, particularly in the mountainous areas. In this article, the unsaturated soil mechanics combined with a numerical method is applied to build the rainfall thresholds for the Xiangmi Lake slope in early warning. The drainage mechanism in soil slope under different rainfall conditions has been studied. Then, the actual rainfall data collected in the rainy season are taken as the rainfall condition to simulate the actual rainfall situation. The corresponding safety factor of the slope under the rainfall has been calculated and compared with the improved deformation tangential angle criterion for the slope safety prediction. The tangent angle can be used as the judgment basis to classify the early warning levels of a rainstorm, which helps to establish the early warning model of slope rainfall and guide the landslide early warning.

Mineralized indicator minerals are an important geological and mineral exploration indicator. Rapid extraction of mineralized indicator minerals from hyperspectral remote sensing images using ensemble learning model has important geological significance for mineral resources exploration. In this study, two mineralized indicator minerals, limonite and chlorite, exposed at the surface of Qinghai Gouli area were used as the research objects. Sparrow search algorithm (SSA) was combined with random forest (RF) and gradient boosting decision tree (GBDT) ensemble learning models, respectively, to construct hyperspectral mineralized indicative mineral information extraction models in the study area. Youden index (YD) and ore deposit coincidence (ODC) were applied to evaluate the performance of different models in the mineral information extraction. The results indicate that the optimization of SSA parameter algorithm is obvious, and the accuracy of both the integrated learning models after parameter search has been improved substantially, among which the SSA-GBDT model has the best performance, and the YD and the ODC can reach 0.661 and 0.727, respectively. Compared with traditional machine learning model, integrated learning model has higher reliability and stronger generalization performance in hyperspectral mineral information extraction and application, with YD greater than 0.6. In addition, the distribution of mineralized indicative minerals extracted by the ensemble learning model after parameter optimization is basically consistent with the distribution pattern of the fracture tectonic spreading characteristics and known deposits (points) in the area, which is in line with the geological characteristics of mineralization in the study area. Therefore, the classification and extraction model of minerals based on hyperspectral remote sensing technology, combined with the SSA optimization algorithm and ensemble learning model, is an efficient mineral exploration method.

The identification of formations in anisotropic reservoirs using seismic reflection data and logging data may lead to misrepresentations of the actual formations. Lithofacies discrimination intrinsically has ambiguity, and the depositional sequences of the study area comprise shales, fine-grained sands, and silts. So it needs to reduce the uncertainty of the lithofacies discrimination using anisotropic parameters. This study proposes an approach involving seismic anisotropic parameters to discriminate between different lithofacies. We calculate four anisotropic parameters ( ε, δ, γ, η ) from logging data ( V p , V s , and density) and then employ these for lithofacies discrimination. We compared our results to lithofacies discrimination based on traditional parameters such as V p / V s ratio, clay volume, and water saturation. Using field data from Muglad Basin in South Sudan, we show how the suggested parameters could be used to identify eleven zones with distinct lithofacies. According to the anisotropic parameters, the lithofacies discrimination results are similar to other logging data, and it is easier to separate the lithofacies than petrophysical data. Furthermore, we introduce a new parameter, i.e., the difference between the normalized anisotropic δ parameter and clay volume, which can be used as a possible indicator for heavy oil reservoirs. The new parameter matches well with water saturation in the field data application.

Loose layers are the locus of human activities. The high-quality 3D modeling of loose layers has essential research significance and applicability in engineering geology, hydraulic and hydroelectric engineering, and urban underground space design. To address the shortcomings of traditional 3D loose-layer modeling based on borehole data, such as the lack of bedrock surface constraints, simple strata pinch-out processing, and the higher fitting error of the strata surface, a 3D loose-layer modeling method based on the stratum development law is proposed. The method mainly uses three different virtual boreholes, bedrock-boundary virtual boreholes, pinch-out virtual boreholes, and densified virtual boreholes, to control the stratigraphic distribution. Case studies demonstrate the effectiveness of this 3D loose-layer modeling method in the Qinhuai District of Nanjing and Hangkonggang District of Zhengzhou. Compared to the previous methods that interpolated stratigraphic surfaces with elevation information, the method proposed in this article interpolates the stratum thickness based on stacking, which could improve the interpolation accuracy. In the area where the loose layers and exposed bedrock are alternately distributed, stratigraphic thickness errors’ mean and standard deviation decreased by 2.11 and 2.13 m. In the pure loose-layer area, they dropped by 0.96 and 0.33 m. In addition, the proposed approach allows us to infer the different stratigraphic distribution patterns accurately and complete 3D loose-layer model construction with higher accuracy and a good visualization effect.

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants of global concern, mainly originating from industrial activities, biomass combustion, and vehicle emissions. With the acceleration of industrialization, the surrounding environment of the industrial area may have potential health effects on the population. Therefore, we focused on the occurrence, source, and health risk assessment of PAHs in soil, plants, and water near industrial areas in southern Xinjiang, China. The occurrence of PAHs in different soil layers (0–10, 10–30, and 30–50 cm) was studied, with PAHs mainly concentrated in the topsoil (11.50–34.68 ng/g). In plants, PAHs varied from 56.63 to 597.28 ng/g, with the highest concentrations in reed (267.29–597.28 ng/g). Total PAHs in water ranged from 4183.85 to 24803.45 ng/L, with an average of 10,240 ng/L. 3-ring PAHs were the dominant species in soil, plants, and water with 55, 69, and 59%, respectively. PAHs isomer ratio results indicated that PAHs in soil, plants, and water mainly came from fossil fuels and biomass combustion. Incremental lifetime cancer risk estimation results demonstrated that adults might face higher potential health risks than children. Adults’ dermal contact was the dominant route of exposure, while oral ingestion was the dominant exposure pathway for children. The total carcinogenic risk value of corn is much higher than that of walnuts and red dates, indicating that PAHs pollution in corn must be taken seriously. The results can clarify the local pollution situation, and provide suggestions for improving pollution prevention and control measures. Graphical abstract

As an important tributary of the Yangtze River basin, the Jialing River Basin (JRB) has a variable topography and fragile ecological environment. Under the influence of climate warming and human activities, the runoff and vegetation cover of the area are undergoing significant changes. For evaluating the impact of different factors on vegetation and streamflow variation in the JRB, the univariate linear regression method was employed to analyze the variation trend of streamflow and vegetation, and a heuristic segmentation algorithm was applied for identifying the mutation year of streamflow and NDVI time-series data in the JRB. Then, the influence degree of different factors on streamflow variation in the JRB was calculated by the Budyko equation and elastic coefficient method. Finally, the contribution rates of different factors to vegetation variation in the JRB were calculated by the multiple linear regression method. The results indicated that the mutation year of streamflow and NDVI time series data were 1985 and 2006, respectively. The contribution rates of climate factors and human activities to streamflow change in the JRB were 42.7 and 57.3%, respectively. The contribution rates to vegetation change were 28.89 and 71.11%, respectively. In general, human activities are the main driving force leading to runoff and vegetation changes in the JRB. This study can provide a theoretical basis for the ecological environment protection and water resources management of the JRB.

Since the 21st century, China’s urban construction land has been growing rapidly, piquing academic interest. However, mountainous counties account for the majority in China, previous studies have concentrated on the horizontal expansion characteristics of construction land, leaving a gap in the vertical expansion. This study used datasets for urban construction land and digital elevation model to analyze the spatiotemporal evolution characteristics of construction land slope in 2670 China’s counties, by exploratory spatial data analysis. Furtherly, we explored the slope relationship between ground and construction land using regression analysis. The findings indicate what follows: (1) The average slope of construction land had a spatial pattern of “high in the south and low in the north,” with significant spatial agglomeration characteristics. And it had increased with the urban expansion, shifting the slope-weighted mean center toward the southeast while enhancing spatial agglomeration. (2) There was a significant and steadily rising linear association between the urban construction land slope and ground slope, due to spatial heterogeneity; the most affected counties were primarily located near the Sichuan basin. According to the results, we provided suggestions for the rational use and sustainable development of land in cities, especially for mountainous regions in a period of rapid urbanization.

Some commonly used empirical formulas (e.g., Soviet CHиПII57-75, Ikeno-Tanaka, Führböter-Sparboom, and Stanczak) for estimating plunging breaker wave slamming pressure on sea dike surface do not take into account the comprehensive influence of the wave steepness, slope angle, and breaker height and depth on the loads, and the Yang formula eliminates the drawback. The Yang formula is derived based on an analysis of the impulse in the breaking wave tongue and the kinetic and potential energy in the wave tongue. But the limited range of the Yang formula is 0.5 ≤ ξ ≤ 3.3 and 0.01 ≤ tan  α ≤ 0.44; otherwise, its prediction error will greatly increase. In addition, some parameters in the Yang formula need to be optimized. The aim of this project is to revise the Yang formula for improving its performance and making it suitable for a wider range of hydraulic conditions and bottom slope conditions. A constant term in the Yang formula is replaced by the function obtained by analysis, and the calculation method of breaking wave height in the formula is also changed. The resulting formula is of interest because the comparison of the formula with some measurements is done well.

Scientific evaluation of the development efficiency of the regional tourism industry has important practical significance in promoting the high-quality development of the industry. This study calculated the county tourism efficiency and total factor productivity (TFP) for 86 counties and cities in Xinjiang, China, from 2011 to 2019 based on the SBM-data envelopment analysis model and the Malmquist productivity index model, which determines the respective temporal changes and spatial differences. The factors affecting the evolution of the spatial–temporal pattern of the tourism industry efficiency were also analyzed using the geographic detector model. The results show that: (1) The average tourism efficiency of Xinjiang county from 2011 to 2019 was at a low level of 0.382. During the study period, the evolution trend of the tourism efficiency fluctuated. There was a positive spatial autocorrelation in the tourism efficiency. The difference between cold and hot spots was evident by “hot-in-the-north and cold-in-the-South” characteristics. (2) The TFP maintained an upward trend during the research period, with an average annual growth rate of 28.7%. The number of counties and cities with an increased TFP was much higher than those with a decreased TFP, and its growth was mainly attributed to the progress of technical efficiency. (3) The county tourism efficiency was mainly affected by the level of economic development, tourism resource endowment, market scale, and government policies. There were large differences in the intensity and space among various influencing factors. During the research period, the influence of the economic development level and market scale gradually weakened, and the influence of tourism resource endowment and government policies continuously strengthened.

Soil temperature (ST) is an important land surface factor as a predictor of regional climate change. Based on the ST data from 30 climate stations in Northwest China (NWC) during the period 1960–2000, the trends and distribution of STs at 0, 80, 160, and 320 cm depths were investigated, together with observed atmospheric variables, such as air temperature (AT) and precipitation. The differences between the annual average AT and ST at each layer (0, 80, 160, and 320 cm) in each station was no more than 6°C. In different seasons, the differences were even more remarkable than annual values. Trends in some stations varied during the period 1961–2000, with warming trends appearing at some stations after the mid-1980s. Few warming trends appeared in the west part of NWC, while most warming trends appeared in the east part. There were more warming trends at annual time scales than in season timescales. The fewest warming trends were found in winter, but they had the largest magnitude of increase (1.1°C/decade) for surface ST; the largest magnitudes of increase for 80 and 160 cm ST were in summer, with increase of 0.95 and 0.88°C/decade, respectively. The correlation coefficients between ST and AT were positive and statistically significant at the 95% confidence level in most stations except in winter. The correlation values between ST and precipitation were different at different time scales.

Vietnam’s economy with agriculture and aquaculture still account for roughly 26% of the country’s gross domestic product, and nearly 70% of the Vietnamese population lives in rural areas; therefore, agriculture and aquaculture land use play a crucial role in the development process of Vietnam. Rapidly increasing population and infrastructure in rural areas and industrial zones lead to these land-use changes. Hence, these land-use change predictions are crucial for local authorities and the local people to make land-resource funds and set up planning. This article suggests support vector regression (SVR), artificial neural network (ANN), and seasonal autoregressive integrated moving average (SARIMA) methods to predict land-use change. By comparing the three models, the results indicate that almost all of the SVR models improve the accurate performance more than ANN and SARIMA in Quangtri, ThuThienHue, Danang, and Quảngnam provinces. Furthermore, the ANN model indicates more accurate forecasting than the SVR and SARIMA models in Quan Binh province. The result may be support for the Ministry of Natural Resources and Environment to conduct the land-use inventory and upgrade agriculture and aquaculture land-use change maps every 5 years. Afterward, the Department of Natural Resources and Environment’s provinces use the estimating database and update it manually.

Plant color was an important landscape of the urban green space, and quantitative analysis of its characteristics could provide a basis for plant color configuration. The leaf color attributes of 80 colored-leaf plants were studied and the Scenic Beauty Estimates (SBE) was used to evaluate their beauty. The data of leaves color were obtained by MATLAB software and scanner under the hue–saturation–brightness (HSB) system and then were further analyzed to determine the relationship between the SBE and color attributes (HSB). Results showed that the leaf colors of 80 plants contained 13 hues in total, which belonged to six color systems. The species contained in different color systems, from most to least, were yellow–green series (27 species) > orange series (19 species) > red series (18 species) > yellow series (10 species) > blue-green (four species) > purple (two species). There were fewer blue and purple series species. The brightness and saturation of color were mainly distributed in the middle (26–50%), middle and high (51–75%) stages, and those of the yellow–green system belonged to the medium and high stages and were significantly higher than other color systems. There is a significant positive correlation between the brightness and saturation of color and the value of SBE, and an SBE evaluation model was established based on the color attributes. The results are helpful to select plants with higher beauty and create a rich plant color landscape.

Landslides are frequent geological hazards, mainly in the rainy season along road corridors worldwide. In the present study, we have comparatively analyzed landslide susceptibility by employing integrated geospatial approaches, i.e., data-driven, knowledge-driven, and machine learning (ML), along the main road corridors of the Muzaffarabad district. The landslide inventory of three road corridors is developed to evaluate landslide susceptibility, and eleven landslide causative factors (LCFs) were analyzed. After statistical significance analysis, these eleven LCFs generated susceptibility models using WoE, AHP, LR, and RF. Distance from roads, landcover, lithological units, and slopes are considered more influential LCFs. The performance matrix of different LSMs is evaluated through the area under the curve (AUC-ROC), overall accuracy, Kappa index, F 1 score, Mean Absolute Error, and Root Mean Square Error. The AUC-ROC for WoE, AHP, LR, and RF techniques along Neelum road is 0.86, 0.82, 0.91, and 0.97, respectively, along Jhelum Valley road is 0.83, 0.81, 0.93, and 0.95, respectively, while along Kohala road is 0.89, 0.88, 0.89, and 0.92, respectively. The produced LSMs through ML (i.e., RF and LR) showed better prediction accuracies than WoE and AHP along these three road corridors. The LSMs are categorized into very high, high, moderate, and low susceptible zones along these roads. The LSM generated through hybrid models can facilitate the concerned local agencies to implement landslide mitigation policies for the landslide-prone zones along road corridors.

The timing of the onset of Taiwan sediment input to the northern South China Sea (SCS) is still controversial even though many provenance proxies had been used. To analyze the change of Taiwan input since the Late Miocene (11.63–0 Ma), we applied the major-element-based proxies R AK and R KCN , combined with the published clay mineral and Sr–Nd isotope data, to study the sediment provenance near the northern SCS slope. The results show that significant Taiwan sediment input began at ∼6.5 Ma in the Late Miocene, consistent with the timing of Taiwan uplift. Moreover, Pearl River input increased after ∼3.6 Ma, corresponding to the sea level fall caused by the ice sheet expansion in the Northern Hemisphere. The Taiwan input increased during the Mid-Pleistocene Transition (MPT, 1.25–0.7 Ma) because of the Northern Pacific Intermediate Water expansion. After the MPT, the Pearl River input re-increased in response to the lowered sea level in glacials. In general, tectonic activities such as the Taiwan uplift control the sediment provenance in the northern SCS from 6.5 to 3.6 Ma. After 3.6 Ma, as the weathering regime of Taiwan sediment became more stable, climate change became a more important factor in influencing sediment provenance.

This study explores drones’ applications and proposes a cost-effective drone monitoring system for both palm trees and street lighting networks. The planned drone technical system has two monitoring sections. First, a model is developed to examine the health of date palm trees, in which drone photos are used to determine whether palm trees are suffering from diseases such as black scorch and sudden decline syndrome. These images are transferred into a central computer to stimulate normalized difference vegetation index (NDVI) models using AgiSoft software. The simulated NDVI models indicated that there are no health issues with date palm trees, which has resulted in the positive feedback in terms of the economic growth. Second, drone technology is utilized to detect the technical faults in the lighting network to ensure proper maintenance and social security. Twelve images of street lights are captured to demonstrate the working condition and the operational status of the street lights. These images are processed in MATLAB software, and a stimulated image processing model is implemented to enhance the monitoring of the street lighting network. The simulation findings indicate that the light in one of the images is not functioning, and ArcGIS Pro is utilized to locate it.

On March 23, 2021 (21:14 universal time coordinated), an Mw 5.3 earthquake occurred in Baicheng County in Xinjiang, northwestern China, according to the United States Geological Survey. The earthquake produced a 4-km-long surface rupture at the epicenter, which is generally rare for earthquakes of magnitude 5.3. Thus, investigating the Baicheng earthquake is crucial for understanding the seismogenic structure of the region. We obtained the interferometric synthetic aperture radar deformation field and inverted the slip distribution of the Baicheng earthquake using Sentinel-1A satellite data and surface rupture data. The results indicate that the surface deformation area was elliptical, with long and short axes of approximately 20 and 10 km, respectively. The seismogenic structure is a left-lateral strike-slip fault with a small dip-slip component and strike and dip angles of 248° and 70°, respectively. Two other slip centers were also observed at 2 and 8 km beneath the surface in the dip direction. The maximum slip at 2 km was 0.45 m. Shear deformation between the Tarim Basin and Southern Tianshan Mountains was responsible for the strike-slip features of the Baicheng earthquake.

Visual features play a key role in indoor positioning and navigation services as the main semantic information to help people understand the environment. However, insufficient semantic constraint information and mismatching localization without building map have hindered the ubiquitous application services. To address the problem, we propose a smartphone indoor scene features recognition localization method with building map semantic constraints. First, based on Geographic Information System and Building Information Modeling techniques, a geocoded entity library of building Map Location Anchor (MLA) is constructed, which is able to provide users with “immersive” meta-building-map and semantic anchor constraints for mobile phone positioning when map matching. Second, using the MYOLOv5s deep learning model improved on indoor location scenario, the nine types of ubiquitous anchor features in building scenes are recognized in real time by acquiring video frames from the smartphone camera. Lastly, the spatial locations of the ubiquitous indoor facilities obtained using smartphone video recognition are matched with the MLA P3P algorithm to achieve real-time positioning and navigation. The experimental results show that the MLA recognition accuracy of the improved MYOLOv5s is 97.2%, and the maximum localization error is within the range of 0.775 m and confined to the interval of 0.5 m after applying the Building Information Modeling based Positioning and Navigation road network step node constraint, which can effectively achieve high positioning accuracy in the building indoor scenarios with adequate MLA and road network constraint.

In order to reflect the creep characteristics of unsaturated silty clay, a triaxial compression consolidation drainage creep test was conducted under the condition of controlling the matric suction. According to the results of the creep test, combined with the empirical models, Mesri model and Log-modified model, the relationship between the initial tangent modulus and the matric suction was established, and two empirical models of unsaturated soil creep considering the effect of matric suction were constructed. The study confirmed the stress–strain through the ε/D–ε relationship curve, and determined the parameters F and n through power function. The methods for determining the strain–time relationship parameters of the two improved models are different. The improved Mesri model was obtained by fitting the ln  ε– ln  t relationship, while the improved Log-modified model was solved by the BFGS algorithm and the general global optimization method. By comparing the two improved models of unsaturated soil creep tests, it was found that the improved Mesri model can more accurately describe the creep characteristics of unsaturated soils, which confirms the rationality and feasibility of this model and method.

Remotely piloted aircrafts (RPAs) are becoming well-known for monitoring forest restoration (FR). Canopy cover percentage on a restoration site is a major indicator for the early phases of FR. We present a protocol to evaluate canopy cover using low-cost RPA and a friendly computational environment. We tested the protocol in six FR projects in the Brazilian Atlantic Forest. After processing the images automatically to generate the digital surface model and the digital terrain model, the canopy cover is measured in QGIS by considering height thresholds in the canopy height model. The results had F 1 values higher than 0.9, which confirms a robust methodology that does not require specific computer science or remote sensing skills. Thus, low-cost RPA proved to be accurate and user-friendly in measuring the canopy cover, which improves monitoring during most FR stages. Such finding plays an important role in FR policies and future works must study a user-friendly protocol for measuring tree height via low-cost drones.

The size of the texture extraction window impacts image tree species classification, and the determination of the optimal texture extraction window requires the supervision of a specific classifier for accuracy. Therefore, it is necessary to analyse which kind of classifier is more suitable and should be to choose. In this study, we extracted eight types of textures, namely mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment and correlation, changed the window size by gradient increase and used maximum likelihood classification (MLC) and random forest (RF) to supervise and determine their optimal extraction windows, respectively. Finally, the optimised time consumption and classification accuracy for tree species classification was identified. The time consumption of MLC was significantly less than that of RF; however, neither was very long; for most textures, the optimal texture extraction window determined by MLC supervision was larger than that determined by RF supervision; in the classification of most feature sets, the overall accuracy obtained by MLC was less than that of RF. Because the time consumption of the texture extraction was much greater than that of the image classification, the comprehensive trade-off indicates that using RF supervision to determine the optimal window for texture extraction was more conducive to tree species recognition.

Mt. Stara Planina is located in the eastern part of the Republic of Serbia and represents the westernmost part of the large mountain massif of the Balkans. Both endogenous and exogenous forces created interesting geomorphological and hydrological features for geotourism development in this area. This article proposes a preliminary list of geomorphological and hydrological sites and analyses them to reveal which geosite possesses geotourism potential. This research was carried out by applying the modified geosite assessment model. In this article, ten geosites were singled out based on the degree of their attractiveness for geotourism development. The results reveal information about the key fields of improvement for each evaluated geosite, and identify which areas require more attention and better management in the upcoming period for Mt. Stara Planina to become a well-known geotourism destination that would attract a large number of tourists in the future.

The main goal of this study is to emphasise the geotourism potential and the values of geoethics as drivers of rural development in the territory of the Knjaževac municipality, which is one of the richest areas in Serbia in terms of geoheritage. Numerous objects of geomorphological and hydrological heritage stand out in an area of 1,202 km 2 . Despite this richness in geoheritage, the potential of geotourism development has been ignored by many stakeholders, and the geoheritage of this area has not been sufficiently explored and proposed for tourism purposes. This study makes an inventory of geosites in the municipality of Knjaževac. The selected sites were evaluated by applying the Modified Geosite Assessment Model to discover the most suitable geosites for future geotourism development, in order to select the geosite that possesses the greatest geotourism potential to support rural development. The results uncover information about the major areas of improvement for each evaluated geosite. Moreover, areas that demand more attention and better management in the upcoming period to become recognisable geotourism destinations were identified. It is pointed out that geoethical implications in geosite management can contribute to sustainable geoconservation in Eastern Serbia.

Serbian spas, with their abundant geothermal springs and air qualities, are a significant natural resource for the country. Nowadays, tourism industry has become a predominant beneficiary attracting both leisure- and health-related visits. Nonetheless, the literature on current consumer behavior is devoid of a model that incorporates both motivating and constraining factors in the spa and wellness industry’s decision-making process. Serbia’s spa industry is still adjusting to the needs of the modern wellness visitor as a result of the country’s unique transitional path. The purpose of this study is to ascertain the role of incentive and restrictions in the destination selection process of spa visitors in Serbia, to gain insight into the development of wellness tourism in a particular sociocultural environment. The analytical hierarchy process was used to determine the relative relevance of the consumer behavior elements evaluated. The findings indicate that non-medical motivations are becoming more important, implying that demand is finally shifting toward the wellness idea, which was initially disrupted by the country’s delayed transformation. The findings have administrative ramifications, the most significant of which were price strategies and product diversification.