Search Results (537)

The Jinsha River Basin on the eastern margin of the Qinghai–Xizang (Tibetan) Plateau is one of the most landslide-prone regions globally. The Batang reach (from Suwalong Township to Changbo Township) lies in the core of the Jinsha River Suture Zone, characterized by complex geological conditions and frequent landslide disasters. To address the limitations of traditional monitoring methods—including difficulty in full-area coverage, high costs, and low efficiency in mountainous canyon terrain—a systematic study of landslide monitoring was conducted using Sentinel-1A SAR data and Interferometric Synthetic Aperture Radar (InSAR) technology. The results demonstrate that SBAS-InSAR, via short-baseline combinations, achieves a monitoring point density of 697 points/km² (6.28 times that of PS-InSAR), offering significant advantages in mountainous canyon areas with dense vegetation and fragmented rock masses. Using this technical framework, a total of 38 active landslides were identified in the study area, including 5 newly detected rapidly deforming hazards, 17 with river blockage risk, and 10 with the potential to bury buildings. The maximum downslope deformation rate reaches −89.56 mm/yr for the landslide near Suwalong Hydropower Station. Landslides are concentrated within 500 m of faults, in weak rock zones, on steep slopes with gradients greater than 30°, and near road-cutting projects. Temporally, landslide deformation shows an evident correlation with rainfall; approximately 70% of annual cumulative deformation occurs within the rainy season. Engineering activities including hydropower station impoundment appear to be associated with elevated deformation rates of local landslides. This study provides a scientific basis for the safety of major infrastructure corridors (e.g., the Sichuan–Tibet Railway) and regional disaster prevention and mitigation. Full article

Traditional villages serve as the material carriers of traditional Chinese culture. Their cultural spaces, as concentrated reflections of rural humanistic spirit, face multiple crises, including the rupture of intergenerational transmission, functional decline, and spatial isolation. In mountainous counties, where the terrain is complex, resources are scattered, and locations are peripheral, the challenges of protecting and revitalizing cultural spaces are especially acute, yet holistic understanding at the county scale remains insufficient. Focusing on the 25 nationally listed traditional villages in Suichang County, Zhejiang Province, this study selected four representative villages as case studies: Hengkeng (steep-slope mountain), Caihe (gentle-slope hilly), Dushan (mountain-enclosed valley), and Changlian (river-valley plain). We established a comprehensive framework integrating a qualitative “text–space mutual corroboration” interpretation with space-syntax accessibility and isovist-based visibility analysis. The results demonstrate that cultural space nodes exhibit systematically higher accessibility and visibility than ordinary residences, and the coupling between the two dimensions differs sharply by type. Specifically, lineage culture spaces display high–high synergy; religious belief spaces show a low-accessibility–high-visibility mismatch; ritual education spaces occupy a moderate-accessibility–low-visibility position; meanwhile, basic livelihood and daily life spaces are accessibility-dominated. Furthermore, geographical type governs the coupling mode, shifting from linear mismatch on steep slopes, through axial synergy on gentle hills and centripetal aggregation in valleys, to axial serialization on plains. Based on these findings, four adaptive-reuse strategies are distilled. Complemented by a baseline information database and a prospective intelligent-evaluation framework, they provide transferable methodological guidance for planning and revitalizing the cultural spaces of traditional villages in mountainous counties. Full article

This study aims to spatially analyze the potential soil loss rates of the Özkonak Watershed, located within Nevşehir Province, using the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information Systems (GIS) and Remote Sensing (RS) technologies. In the 149.9 km² watershed, the main parameters triggering erosion—rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), land cover and management (C), and support practices (P)—were modeled in a GIS environment. According to the spatial analysis results, 85.8% of the watershed area falls within the “very low” and “low” erosion susceptibility classes. Nevertheless, erosion increases markedly in the northern areas with high slope gradients and in areas where agricultural activities are concentrated. The mean soil loss across the watershed was calculated as 2.75 t ha⁻¹ yr⁻¹. The eroded and transported material was determined to constitute a threat to the dam. The findings indicate that conservation plans, including afforestation in the upper watershed, adjustment of land use to natural land capability, and construction of check dams, should be implemented to ensure sustainable management of the watershed. From a soil and sediment remediation perspective, the identification of erosion-source areas and sediment-transport pathways provides a scientific basis for source-control measures aimed at reducing sediment delivery and associated water-quality deterioration in the Bayramhacılı Dam reservoir. Full article

A high-resolution unstructured-grid ocean model was used to investigate the generation, propagation, and dissipation of M₂ internal tides in the Luzon Strait and northeastern South China Sea, with the aim of clarifying how energy evolves across contrasting topographic regimes. Wave decomposition, harmonic and modal analyses, energy-budget diagnostics, and along-path tracking were applied to quantify the spatial distribution and modal evolution of internal-tide energy. The results show that the Luzon Strait double-ridge system is the primary source region, contributing approximately 4.826 GW of barotropic-to-baroclinic energy conversion, with the Lanyu Ridge (3.080 GW) exhibiting stronger conversion than the Hengchun Ridge (1.643 GW). The generated low-mode internal tides radiate mainly westward into the northeastern South China Sea, with energy progressively attenuated over the deep basin and continental slope. Energy-budget analyses indicate that the ridge region dominates generation, the Luzon Trough mainly supports transmission, and the deep basin and slope are associated with enhanced dissipation and scattering. Along-path energetic diagnostics quantitatively reveal a sequential depletion of mode 1 internal-tide energy in the vicinities of steep topography and internal-tide steepening zones, concomitant with a marked augmentation of mode 2 energy and intensified cross-frequency energy transfer. Specifically, within the deep basin of the South China Sea, the fractional contribution of mode 1 energy declines from 78.3% to 73.8% as the internal tide propagates from the abyssal to the shallower shelf-slope region, whereas that of mode 2 increases correspondingly from 18.2% to 24.3%. Moreover, pronounced internal-tide steepening is observed in the deep basin, and the spectrally integrated cross-frequency transfer coefficient reaches 0.32 in this area, substantially exceeding that in other regions. These findings suggest that topographic scattering, modal redistribution, and nonlinear interactions contribute substantially to regional internal-tide dissipation. Full article

Steep rock slopes are widely distributed in the karst mountainous regions of southwestern China, where structurally controlled rockfalls frequently threaten transportation infrastructure and human safety. Accurate identification of unstable rock blocks (URs) and quantitative assessment of their post-failure hazards remain major challenges because of complex discontinuity networks and fragmentation during rockfall motion. Taking the Zuojiaying steep rock slope in Guizhou Province as a representative case, this study integrates high-resolution UAV photogrammetry, automatic discontinuity identification, unstable rock block detection, and three-dimensional rockfall simulation to investigate the formation mechanisms and hazard characteristics of discontinuity-controlled rockfalls. A high-resolution three-dimensional terrain model was reconstructed from UAV imagery, and six dominant discontinuity sets were automatically identified using the I-MinPts-constrained DBSCAN algorithm. Combined with the Rock Occurrence Kinematic Analysis (ROKA) algorithm and Block Theory, 54 unstable rock blocks were identified, with wedge failure and toppling failure representing the dominant instability modes. The results indicate that discontinuity combinations govern both rock mass segmentation and unstable rock block geometry. Specifically, discontinuity sets J1, J3, and J5 mainly control wedge-shaped blocks, and J2 and J4 dominate columnar toppling blocks, whereas J6 further promotes the formation of isolated unstable rock blocks. Three-dimensional RockGIS simulations considering fragmentation reproduced the complete rockfall process from detachment to final deposition. The maximum travel distance, kinetic energy, and bounce height reached 395 m, 748.5 kJ, and 40.1 m, respectively. Fragmentation increased the number of rock blocks from 54 to 1013, substantially enlarging the potential impact area. A raster-based Rockfall Hazard Index (RHI) further revealed that the middle–lower slope and slope toe constitute the principal high-hazard zones, and under extreme scenarios, high-energy fragments may reach the G246 National Highway and adjacent infrastructure. This study revealed the formation mechanisms and hazard characteristics of unstable rock blocks controlled by discontinuity combinations in the study area, providing a case reference for rockfall hazard identification and mitigation on similar high-steep rock slopes in karst mountainous regions. Full article

Continuous Global Navigation Satellite System (GNSS) monitoring is essential for characterizing surface subsidence in underground coal-mining areas. However, monitoring-station site selection remains strongly dependent on empirical judgment. Furthermore, steep deformation gradients can cause interferometric synthetic aperture radar (InSAR) decorrelation, phase-unwrapping failure, and data gaps in areas where ground-based monitoring is most needed. This study develops a quantitative, multi-source remote-sensing-assisted framework for GNSS monitoring-station site selection under a short-baseline real-time kinematic (RTK) configuration. Sentinel-1A, Sentinel-2C, unmanned aerial vehicle (UAV) photogrammetric products, and road-network data were integrated to construct eight evaluation factors: normalized difference vegetation index (NDVI), slope, terrain ruggedness index, deformation intensity, cumulative subsidence, InSAR coverage, distance to the subsidence edge, and distance to roads. An analytic hierarchy process (AHP) was used as the primary suitability assessment framework, while a random forest (RF) model was introduced with a limited weight to provide auxiliary information only in InSAR data-sparse areas. Grid-level aggregation, three-component Gaussian mixture model (GMM) screening, minimum-distance thinning, field reconnaissance, and monitoring-network review were subsequently combined to convert the continuous suitability surface into deployable station candidates. The resulting high-suitability areas were concentrated mainly along subsidence margins and near InSAR coverage gaps, reflecting the combined effects of deformation representativeness, supplementary monitoring demand, observation conditions, and engineering accessibility. Sixteen candidate stations were identified, of which S12, S3, and S10 were finally recommended to improve the northern, southwestern, and southeastern coverage of the existing monitoring network, respectively. Sensitivity analyses confirmed that the overall suitability pattern and recommended-station rankings remained stable under moderate parameter perturbations. Comparison with two existing GNSS stations further showed that the station with the higher suitability score exhibited a higher fitted subsidence rate (0.438 versus 0.320 mm day⁻¹). Given the two-station and two-month validation dataset, this agreement represents preliminary consistency evidence rather than statistical proof of general effectiveness. The proposed framework links regional remote-sensing assessment with site-scale engineering review and monitoring-network optimization, providing practical decision support for GNSS deployment in underground mining-subsidence areas. Full article

Ferdinandea Island, part of a shallow-water submarine volcanic field, emerged in the Sicily Channel between Italy and Tunisia in July 1831 and was eroded below sea level within months; its submerged remnant forms the shallowest water depth region of Graham Bank. Here, we review nearly two centuries of historical accounts, geological interpretations and geomorphological data analysis and reassess them against high-resolution multibeam bathymetry, sub-bottom profiles (CHIRP) and published multichannel seismic data. The field comprises six volcanic edifices (V1–V6), 100–170 m high, located along structural trends characteristic of the Sicily Channel Rift. V3, the shallowest edifice, is the remnant of Ferdinandea Island formed during the 1831 Surtseyan eruption. Its flat summit, wave-reworked terrace and steep flanks record rapid post-eruptive modification. Historical observations and hydrographic surveys document the destruction of the emergent island and a further ~6 m lowering of its shallowest point between 1883 and 2012–2015; the separate contributions of wave erosion, subsidence and gravitational adjustment cannot be resolved from the available data. The same regional structural framework appears to have governed the distribution of the other volcanic centres, pockmarks, erosional escarpments and mass-transport deposits of the study area. Seventeen pockmarks, up to ~540 m wide and 22 m deep, occur as isolated, clustered and locally aligned depressions; they are associated with subsurface concave-upward reflectors and local water-column acoustic anomalies, consistent with focused fluid escape. Failures of volcanic and sedimentary slopes are widespread, with the largest debris-avalanche deposit covering ~2.2 km². Taken together, these observations indicate that tectonics, volcanism, fluid migration, wave- and bottom-current reworking, and gravitational instability have operated over different timescales to shape Graham Bank. Ferdinandea thus offers a rare historical and geological reference for investigating the rapid construction, degradation and long-term evolution of shallow-water volcanic edifices and highlights the still-open questions regarding the evolution and fate of ephemeral volcanic islands. Full article

Maternal capital (e.g., anthropometrics, hormones, bioactives) enables investment in infant somatic growth during lactation. We draw from the maternal capital hypothesis to contextualize the associations between human milk cortisol variation and infant height-for-age z-score (HAZ) and weight-for-height z-score (WHZ). We hypothesize stable conditions (e.g., low perceived stress, high socioeconomic status/SES including income and education attained) will be associated with greater milk cortisol declines (i.e., steeper slopes), signaling increased capital to invest in larger infant anthropometrics, while stressful conditions (e.g., illness within the dyad, low SES, poor maternal sleep quality) may be associated with flatter slopes and subsequent reduced investment. We measured milk cortisol (N = 110) in U.S. mother–infant dyads using enzyme immunoassay. We collected milk 30–45 min after waking and at the last evening infant feeding, and provided questionnaires (e.g., demographics, perceived stress, Pittsburgh sleep quality index) for mothers to complete. We calculated milk cortisol slope (%Δ) (AM-PM/AM) to assess variation between collections. Larger %Δ indicated steeper slopes; smaller %Δ indicated flatter slopes. We employed an information-theoretic approach to estimate associations between maternal stress and %Δ, and %Δ and infant anthropometrics using multivariable linear regressions. The %Δ best-fit model suggested maternal postgraduate education and poor sleep quality was associated with steep %Δ. The HAZ best-fit model suggested the combined effect of steeper %Δ and milk intake was associated with increased HAZ. Additionally, the combined effect of steeper %Δ and infant milk intake was associated with increased HAZ among mothers with postgraduate degrees and who woke up three or more times to night-feed. %Δ was not associated with WHZ. We speculate %Δ exposure calibrates infant development to their shared environment, with implications for lifelong fitness. Full article

The Shangri-La region in northwest Yunnan preserves extensive glacial moraines, which provide abundant loose material for landslides and debris flows. Mapping these moraines is therefore critical for susceptibility assessment. In this study, we used remote sensing interpretation to extract the spatial distribution of moraines. We then applied the Analytic Hierarchy Process (AHP) to eight factors—elevation, slope, curvature, vegetation cover, lithology, moraine distribution, rainfall, and human activities—and built a susceptibility model within a GIS framework. A Monte Carlo simulation was also conducted to test the sensitivity of the factor weights to potential uncertainties in expert judgments. The results show that moraines cover about 186.7 km² of the study area. Rainfall intensity and moraine distribution emerged as the two most influential factors. The simulation gave weights that differ from the standard AHP by less than 1.6%, suggesting the results are stable. The resulting susceptibility map divides the area into four zones: non-susceptible, low, moderate, and high susceptibility. The high-susceptibility zone covers 1656.48 km² (14.26% of the total area), mainly in high-altitude, steep terrain where moraines are present. The model performed reasonably well in validation, with an ROC curve AUC of 0.807. These findings could support local hazard prevention and land-use planning. Full article

Karst hillslope land systems are characterized by strong microtopographic heterogeneity, exposed rock–soil patches, and management-related disturbance, resulting in pronounced fine-scale variation in ecological responses. This study investigated three contrasting karst hillslopes within the Guanling–Zhenfeng Huajiang Rocky Desertification Comprehensive Control Demonstration Area in Guizhou Province, China, designated as High, Medium, and Natural sites according to their observed land cover and management characteristics, using UAV multispectral imagery and LiDAR-derived DEM data. A terrain–ecology coupling strength indicator (TECSI) framework was developed to assess the spatially transferable predictability of ecological response patterns by terrain variables. At the 5 m block scale, FVC, OSAVI, NDRE750, rock–soil exposure index (REI), and GLCM contrast were linked with LiDAR-derived microtopographic predictors using generalized additive models, residual Moran’s I, random cross-validation, and spatial block cross-validation. FVC, OSAVI, NDRE750, and GLCM contrast differed significantly among the three sites (p < 0.001), whereas REI mainly reflected patchy non-vegetated rock–soil substrate exposure within hillslopes. Across the 15 site–indicator models, deviance explained ranged from 5.5% to 35.8%. Under 25 m spatial block cross-validation, integrated TECSI ranked Medium (0.143) > High (0.086) > Natural (0.036), and this ranking remained stable across sensitivity analyses. Steep-slope units at or above 25° in the High and Medium sites were associated with poorer vegetation condition and increased substrate exposure. TECSI provides a reproducible spatial validation framework for identifying terrain-sensitive ecological response units and supporting fine-scale monitoring, soil–water conservation screening, and vulnerable land unit management in karst hillslopes. Full article

The Miocene Sanya, Meishan, and Huangliu formations in the Qiongdongnan Basin (QDNB) record a complete evolutionary history of submarine fan systems, yet a continuous Miocene-scale depositional framework has not been established for the Northern Lingshui Sag. Using 3D seismic data, this study investigates the paleogeomorphological reconstruction, channel system architecture, channel-sink correspondence, and controlling factors of Miocene submarine fans within the Northern Lingshui Sag, QDNB. Paleogeomorphological reconstruction reveals three fundamentally different slope configurations. The Sanya Formation is characterized by a gentle ramp-like slope (1–2°) with high accommodation. The Meishan Formation exhibits a steep structurally partitioned slope (eastern part ~9°, western part 8° decreasing to 2°) with a confined trough in the east. The Huangliu Formation shows a mature moderate slope (3–4°) with reduced structural confinement. Channel system architecture shows fifteen NW-SE oriented channels in the Sanya, six N-S oriented channels in the Meishan, and seven bidirectional channels in the Huangliu. Channel-sink correspondence is strong in the Sanya, localized in the Meishan, and weak in the Huangliu. Fan evolution was driven by three controlling factors: relative sea-level fluctuations, sediment supply and provenance, and paleogeomorphology. Global eustatic falls at 23.0 Ma (T60), 15.5 Ma (T50), and 10.5 Ma (T40) facilitated fan development within lowstand systems tracts. The Ningyuan River supplied sand-rich sediment to the Sanya, the Lingshui River supplied mud-rich sediment to the Meishan, and dual Ningyuan and Lingshui rivers supplied low-flux mud-dominated sediment to the Huangliu. Two major transitions are identified: the Sanya-to-Meishan transition (ca. 15.5 Ma) represents channel reorientation from NW-SE to N-S, reduction from fifteen to six channels, and shift from sand-rich to mud-rich supply; the Meishan-to-Huangliu transition (ca. 10.5 Ma) represents channel reorientation from N-S to bidirectional, increase from six to seven channels, and shift from mud-rich to low-flux mud-dominated supply. Full article

Rainfall variability plays a significant role in modulating both aquatic and socioeconomic systems in the Eastern Himalayas. Among the longitudinal ranges of the Himalayas, the Greater Himalaya is considered the most vulnerable due to its high climatic sensitivity and steep topography. Given this importance, the present study investigates the spatial patterns of temperature and precipitation, their trends, and the occurrence of extreme events over Eastern Greater Himalaya (EGH) during 1981–2025. High-resolution gridded datasets for temperature (0.1° × 0.1°) from ERA5-Land and precipitation (0.05° × 0.05°) from CHIRPS are used. The significance and magnitude of trends are quantified using the Mann–Kendall test and Sen’s slope, respectively. The temperature in EGH is increasing at ~0.27 °C per decade, with the most pronounced increase during winter (>0.4–0.5 °C per decade). Temperature extremes show a clear shift toward warmer conditions, with an increasing frequency of warm days and nights (TX90p: ~0.29; TN90p: ~0.64), along with rising intensity (TXx: ~0.007 °C/year; TNn: ~0.04 °C/year) and a decline in cold extremes. Precipitation exhibits high spatial variability (<500 mm to >2000 mm) but weak and statistically not significant long-term trends. The monsoon contributes the highest precipitation (~1200–2000 mm), with a shift toward drier conditions after 2010–2015. Extreme precipitation indices show declining trends in daily maximum (RX1day: ~5–140 mm), maximum 5-day (RX5day: ~8.4–240 mm), total (PRCPTOT: ~−0.23 mm/year) and intensity of (SDII: ~−0.041 mm/day) precipitation. This research indicates a significant climate shift in EGH with rapid warming along with uncertain precipitation patterns, which may have implications for water resources, aquatic systems, and dependent communities. Full article

Mountainous watersheds often suffer from incomplete and spatially biased landslide inventories, which limit the reliability of conventional susceptibility modelling. This study examines whether the erosion coefficient Z of the Gavrilović Erosion Potential Method can provide a process-oriented indicator of slope-instability predisposition in the Portaikos watershed, Central Greece. The Z coefficient was derived from geospatial layers representing vegetation protection, lithological erodibility, erosion-process expression and slope gradient, using Copernicus land-cover products, tree-cover density data, Sentinel-2 imagery, FABDEM and national soil–geological information. A landslide inventory of 46 mapped occurrences from the Hellenic Survey of Geology and Mineral Exploration was then used as an independent reference layer. Erosion severity was classified into five classes and compared with the landslide distribution through Frequency Ratio analysis. Most of the basin was assigned to moderate, very slight and slight erosion classes, covering 34.7%, 30.1% and 28.2% of the area, respectively. By contrast, severe and excessive erosion occupied only 6.7% and 0.4% of the watershed, but contained a much larger proportion of the mapped landslides: 58.7% and 10.9%, respectively. This disproportion was also reflected in the Frequency Ratio analysis. When the severe and excessive classes were considered together, they occupied approximately 7.1% of the watershed but contained 69.6% of the mapped landslides, corresponding to an FR value of 9.79. The separate excessive class showed the highest FR, but it was interpreted cautiously because of its very limited spatial extent and small landslide count. These results indicate that high Z values coincide with terrain sectors where lithological weakness, steep slopes, reduced surface protection and erosion-related sediment-source conditions jointly favour slope instability. The Gavrilović Z coefficient should therefore not be interpreted as a substitute for rainfall-threshold analysis or inventory-based predictive models. Rather, it may serve as a useful first-order screening layer for field verification, spatial prioritization and ecosystem-based mitigation planning in data-scarce Mediterranean mountain watersheds. Full article

Landslides and collapses seriously threaten the safety of residents in Xiangtan County, Hunan Province, southern China. Local human engineering activities, dominated by slope cutting for housing construction, create steep artificial free faces, greatly weakening slope stability and becoming the key anthropogenic driver aggravating geological hazard risks, while targeted quantitative susceptibility assessment for residential slope units is still lacking for precise disaster prevention. To fill this gap and support proactive geohazard mitigation, this study selects Xiangtan County as the research object. A total of 166 landslide and collapse hazard points and 869 moderately and highly susceptible residential slope units were collected, and 12 conditioning factors, such as relative height difference, average slope and engineering rock mass group, were subsequently screened. Three hybrid intelligence models, namely PSO-BP, PSO-RF and PSO-SVM, were established to map residential slope unit susceptibility across the whole study area. The ROC-AUC and Kappa coefficient were adopted to quantify and compare the predictive performance of each model, and the Jenks natural breakpoint method combined with field survey data was used to classify all 7257 residential slope units into three susceptibility grades. The evaluation results show that the PSO-RF model performs best with an AUC of 0.913 and a Kappa coefficient of 0.64, representing strong predictive reliability. Under this optimal model, moderate-susceptibility units account for 12.94% (939 units) and high-susceptibility units account for 0.69% (50 units), both of which are concentrated in the southwest, southeast and partially northern zones of the county where intensive human slope-cutting activities prevail. This research provides a feasible technical framework for identifying high-risk residential slopes and delivers clear data support for local geohazard risk control and disaster reduction. In summary, the PSO-RF hybrid model is proven suitable for fine-scale susceptibility assessment of residential slopes in hilly regions with frequent small-sized slope failures. Full article

To address the insufficient representation of terrain constraints and surface resistance in traditional path planning for off-road environments, this study proposes an improved A* path planning method for unmanned ground vehicles. First, an off-road environment model is constructed using Digital Elevation Model (DEM) and land cover data, and environment–vehicle traversability is evaluated by integrating geometric and support-based traversability analyses. Geometric constraints are determined using slope thresholds, minimum ground clearance, and approach/departure angles, while support-based traversability is quantified through a surface velocity influence coefficient to reflect traversal-efficiency differences under various surface conditions. These terrain and surface constraints are incorporated into the actual cost function of the A* algorithm, and a direction-corrected heuristic function is designed to enhance goal-directed search. Experiments conducted in Jiancaoping District, Taiyuan, show that, compared with the traditional A* algorithm, the proposed method reduces cumulative travel time, maximum path slope, and expanded nodes by 15.3%, 22.9%, and 47.8%, respectively, with only a 2.4% increase in path length. The results demonstrate that the proposed method effectively avoids steep and high-resistance areas while achieving coordinated optimization of path length, traversal efficiency, and terrain safety. Full article