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	<title>landslide susceptibility &#8211; Science</title>
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	<title>landslide susceptibility &#8211; Science</title>
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		<title>Decade of Satellite Images Reveals Accelerating Landslide Crisis in Eastern Congo Highlands</title>
		<link>https://scienmag.com/decade-of-satellite-images-reveals-accelerating-landslide-crisis-in-eastern-congo-highlands/</link>
		
		<dc:creator><![CDATA[Sloane Callahan]]></dc:creator>
		<pubDate>Wed, 23 Sep 2026 09:36:25 +0000</pubDate>
				<category><![CDATA[Climate]]></category>
		<category><![CDATA[Albertine Rift]]></category>
		<category><![CDATA[Climate impact on landslides in Albertine Rift]]></category>
		<category><![CDATA[Data scarcity and conflict impact on natural hazard research]]></category>
		<category><![CDATA[Decade-long landslide analysis in South Kivu]]></category>
		<category><![CDATA[deep-seated landslides]]></category>
		<category><![CDATA[deforestation]]></category>
		<category><![CDATA[Deforestation and slope failure in Congo Highlands]]></category>
		<category><![CDATA[Democratic Republic of Congo]]></category>
		<category><![CDATA[Environmental challenges of Congo mountain regions]]></category>
		<category><![CDATA[Google Earth Pro]]></category>
		<category><![CDATA[land cover]]></category>
		<category><![CDATA[Landslide crisis in eastern Congo]]></category>
		<category><![CDATA[Landslide frequency and land surface change]]></category>
		<category><![CDATA[landslide susceptibility]]></category>
		<category><![CDATA[landslides]]></category>
		<category><![CDATA[Mountainous terrain landslide vulnerability]]></category>
		<category><![CDATA[Natural hazard assessment in conflict zones]]></category>
		<category><![CDATA[remote sensing]]></category>
		<category><![CDATA[Remote sensing for disaster risk management]]></category>
		<category><![CDATA[Satellite imagery for landslide monitoring]]></category>
		<category><![CDATA[shallow landslides]]></category>
		<category><![CDATA[South Kivu]]></category>
		<category><![CDATA[Tropical climate influence on landslide activity]]></category>
		<category><![CDATA[Weight of Evidence]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=210065</guid>

					<description><![CDATA[A ten-year, field-validated satellite inventory documents more than 2,000 landslides and a doubling of landslide-affected land in the mountainous South Kivu highlands of the eastern Democratic Republic of Congo.]]></description>
										<content:encoded><![CDATA[<p>In the steep, densely populated highlands of South Kivu in the eastern Democratic Republic of Congo, the ground is giving way at an accelerating pace. A new ten-year study has produced the most detailed picture yet of landsliding in the Walungu territory and the northeastern part of neighboring Mwenga territory, documenting more than two thousand slope failures between 2015 and 2024 and revealing that the land surface consumed by landslides more than doubled over the decade. The research, published in the journal Environmental Challenges, combines free satellite imagery, local archival records, and demanding fieldwork in a region where armed conflict and chronic data scarcity have long obscured one of the tropics&#8217; most destructive natural hazards.</p>
<p>The study area covers roughly 2,400 square kilometers of mountainous terrain in the Albertine Rift, where altitudes climb from about 810 meters to nearly 3,470 meters from west to east. The climate is tropical with a bimodal rainfall regime: a long rainy season from October to February, a shorter one from March to June, and a dry spell from July to September. Annual rainfall totals between 1,000 and 1,300 millimeters, delivered both by convective storms associated with the Intertropical Convergence Zone and by orographic rain forced upward over the rugged relief. That combination of steep slopes, weathered soils, and intense precipitation makes the landscape inherently unstable, but the researchers emphasize that human activity has dramatically amplified the problem.</p>
<p>Decades of population growth, deforestation for agriculture and fuelwood, artisanal mining, and unregulated rural road construction have stripped hillslopes of their natural protection. Earlier regional studies had already suggested that anthropogenic disturbance interacts with natural controls such as slope gradient, elevation, and rainfall to drive slope failure, but no one had systematically tracked how landslide-affected land actually changed year by year in this part of the rift. The new inventory fills that gap by building a multi-temporal record rather than the single-snapshot surveys that have dominated previous mapping efforts in the eastern Congo.</p>
<p>The team&#8217;s primary tool was Google Earth Pro, whose free multi-temporal imagery allowed the researchers to digitize landslide scars as polygons and to distinguish newly initiated failures from the progressive widening of older ones. Because dense vegetation can hide landslide morphology from orbit, the satellite interpretation was cross-checked against archival records from local organizations, including the Action de Développement pour les Milieux Ruraux and the Mission Antiérosive, as well as student theses and field reports from the Institut Supérieur Pédagogique de Walungu. Finally, the researchers validated a representative sample of 904 landslide sites in the field, selected to span the full range of altitude, slope, soil type, land cover, and slope aspect across the study area, within the sectors accessible despite security constraints.</p>
<p>The validation exercise produced strikingly strong results. Of 870 landslides confirmed on the ground, 823 had been correctly identified in Google Earth imagery, while 47 were missed and 34 features were falsely flagged as landslides. That translates into a precision of 96 percent and a recall of 95 percent, figures that held almost identically for both shallow and deep-seated failures. The findings demonstrate that freely available virtual globe imagery, when systematically checked against ground truth, can support reliable landslide inventories in regions that cannot afford commercial very-high-resolution satellite data, although the authors caution that small, partially vegetated failures remain the weakest link in any image-based approach.</p>
<p>The inventory itself catalogued 2,088 landslides covering a total of 528 hectares. Shallow failures, predominantly earth flows, utterly dominate the record: 2,051 events, or 98.2 percent of the total, accounting for just over 79 percent of the affected area, with a mean individual footprint of only 0.20 hectares. Deep-seated landslides are rare, just 37 events, but disproportionately destructive, covering 109 hectares thanks to mean areas of nearly 3 hectares and a maximum of almost 24 hectares. Notably, 81 shallow failures occurred along roads and 46 within active artisanal mining perimeters, underscoring the imprint of infrastructure and extraction on slope stability.</p>
<p>To understand why landslides occur where they do, the team applied a Bayesian Weight of Evidence analysis within a geographic information system, testing seven conditioning factors: slope gradient, slope aspect, curvature, elevation, drainage density, land use and land cover, and soil type. A Chi-square test confirmed that every factor is statistically significantly associated with landslide occurrence, with slope degree showing the strongest dependence. The centered weight values reveal a clear threshold: slopes gentler than 20 degrees are consistently stable, with strongly negative weights, while susceptibility jumps sharply between 25 and 30 degrees, where the positive weight peaks at 3.14. Convex and planar curvatures, higher elevations above 1,800 meters, and positions 400 to 600 meters from stream channels, where fluvial incision undercuts steep valley sides, all show strong positive associations with failure.</p>
<p>The land cover results carry perhaps the most consequential message for policy. Forested and woodland terrain shows a strongly negative weight of minus 3.26, reflecting the protective role of dense root networks, rainfall interception, and evapotranspiration in binding soils together. Cropland and herbaceous cover, by contrast, shows a positive weight of 3.15, and built-up or bare soil surfaces a weight of 2.75. Soil type reinforces the pattern, with shallow Leptosols and deeply weathered Ferralsols both highly susceptible. Together, these relationships describe a coupled natural and human system in which terrain establishes the gravitational framework, drainage controls water movement, soils govern material strength, and vegetation removal dismantles the last line of defense.</p>
<p>The temporal record is equally sobering. The number of mapped landslides grew from 967 in 2015 to 2,088 in 2024, with 1,121 newly initiated failures over the decade and a cumulative net land loss of 278 hectares. The affected proportion of the study area rose from 0.104 percent to 0.220 percent. Activity was strikingly episodic rather than steady: quiet years such as 2017 and 2022 saw only about 3 and 2 hectares of new land loss respectively, while 2019, 2021, and 2024 delivered major pulses of 40, 76, and 100 hectares, the last corresponding to annual area growth of more than 23 percent. Importantly, part of the expansion reflects the progressive widening of existing failures, particularly deep-seated ones that continue deforming long after initial failure, meaning the inventory captures ongoing geomorphic adjustment rather than simply counting isolated new events.</p>
<p>The authors are careful to frame their conclusions as a baseline rather than a definitive predictive model. The Weight of Evidence approach quantifies spatial associations but cannot fully resolve interactions among factors, and the study did not quantitatively analyze rainfall triggers, a task the researchers say will require daily rainfall data and the derivation of local triggering thresholds to support early-warning systems. Armed conflict also prevented exhaustive field validation in some sectors, and the results cannot be directly generalized across the whole of eastern Congo. Still, the study delivers something the region has never had: a field-validated, decade-long, annually resolved account of how a tropical rift landscape is unraveling, and a demonstration that with free imagery, local archives, and determined fieldwork, even the world&#8217;s most data-scarce mountains can be brought into the scientific record. As populations keep growing and forests keep receding across the Albertine Rift, that record may prove essential for planning where people can safely build, farm, and live.</p>
<p><strong>Subject of Research:</strong> Landslide inventory, dynamics, and predisposing factors in the tropical highlands of eastern Democratic Republic of Congo</p>
<p><strong>Article Title:</strong> Landslide inventory and dynamics in the tropical highlands of eastern Democratic Republic of Congo</p>
<p><strong>Article References:</strong> Richard, B. C., Jean-Claude, M. M., Léonard, M. K., &amp; Karume, K. (2026). Landslide inventory and dynamics in the tropical highlands of eastern Democratic Republic of Congo. <em>Environmental Challenges, 25</em>, Article 101662. <a href="https://doi.org/10.1016/j.envc.2026.101662" rel="noopener noreferrer">https://doi.org/10.1016/j.envc.2026.101662</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1016/j.envc.2026.101662" rel="noopener noreferrer">10.1016/j.envc.2026.101662</a></p>
<p><strong>Keywords:</strong> landslides, Democratic Republic of Congo, South Kivu, Albertine Rift, Google Earth Pro, remote sensing, landslide susceptibility, Weight of Evidence, deforestation, land cover, shallow landslides, deep-seated landslides</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">210065</post-id>	</item>
		<item>
		<title>Machine Learning Maps Landslide Danger Along Tibet&#8217;s Vital Lhasa–Dingri Highway</title>
		<link>https://scienmag.com/machine-learning-maps-landslide-danger-along-tibets-vital-lhasa-dingri-highway/</link>
		
		<dc:creator><![CDATA[Teresa Odom]]></dc:creator>
		<pubDate>Sun, 13 Sep 2026 02:30:40 +0000</pubDate>
				<category><![CDATA[Social Science]]></category>
		<category><![CDATA[Bayesian optimization]]></category>
		<category><![CDATA[Environmental impact of landslides in Tibet]]></category>
		<category><![CDATA[G318 National Highway]]></category>
		<category><![CDATA[geomorphology]]></category>
		<category><![CDATA[Geotechnical analysis of Tibetan Plateau slopes]]></category>
		<category><![CDATA[Integration of satellite imagery and field data for landslide prediction]]></category>
		<category><![CDATA[Landslide hazard prediction in Tibet]]></category>
		<category><![CDATA[Landslide inventory and mapping in Himalayas]]></category>
		<category><![CDATA[Landslide risk management along Lhasa–Dingri highway]]></category>
		<category><![CDATA[landslide susceptibility]]></category>
		<category><![CDATA[Machine learning]]></category>
		<category><![CDATA[Machine learning for geological risk assessment]]></category>
		<category><![CDATA[Machine learning models for landslide susceptibility]]></category>
		<category><![CDATA[natural hazard prediction using satellite data]]></category>
		<category><![CDATA[natural hazards]]></category>
		<category><![CDATA[Random Forest]]></category>
		<category><![CDATA[remote sensing]]></category>
		<category><![CDATA[Remote sensing and field investigation of landslides]]></category>
		<category><![CDATA[spatial cross-validation]]></category>
		<category><![CDATA[Tibet's G318 highway geological hazards]]></category>
		<category><![CDATA[Tibetan Plateau]]></category>
		<category><![CDATA[topographic controls]]></category>
		<category><![CDATA[Yarlung Tsangpo River]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=200868</guid>

					<description><![CDATA[A new random forest model with spatial cross-validation reveals that slope and topographic relief control landslide hazards along the Lhasa–Dingri highway on the Tibetan Plateau.]]></description>
										<content:encoded><![CDATA[<p>High in the southern Tibetan Plateau, the G318 National Highway between Lhasa and Dingri threads its way through some of the most geologically restless terrain on Earth. This corridor, the lifeline that carries travelers, freight, and supplies toward the Everest region, is under constant threat from landslides that can sever the road without warning and bury entire sections beneath tons of rock and debris. A new study published in the journal Natural Hazards has now delivered both a sharper scientific explanation of why these slopes fail and a more honest method for predicting where the next failure is most likely to occur.</p>
<p>The research, led by Lei Li and Zhiqing Li of the State Key Laboratory of Lithospheric and Environmental Coevolution at the Institute of Geology and Geophysics, Chinese Academy of Sciences, together with colleagues from Zhejiang Jiuhe Geological Ecological Environment Planning and Design and China University of Mining and Technology, began with an exhaustive inventory of the region&#8217;s slope failures. Combining satellite remote sensing interpretation with painstaking field investigation, the team documented 439 landslides covering a total area of 16.85 square kilometers along the Lhasa–Dingri section of the highway. That catalog is more than a tally of past disasters; it is the training ground on which any predictive model must learn, and its quality determines whether the resulting maps can be trusted.</p>
<p>With the inventory in hand, the researchers turned to the question that has long puzzled geoscientists working in this region: which factors actually control where landslides occur? The answer, the study finds, is written in the topography. Slope angle and local topographic relief emerged as the dominant controls on landslide distribution, outweighing other candidate variables. This is no accident of local geography but the signature of a continent-scale tug of war. The Indo-Eurasian collision continues to push the Tibetan Plateau upward, while the Yarlung Tsangpo River and its tributaries cut downward with equal ferocity, carving deeply incised valleys and steepening hillsides faster than erosion can mellow them. The result is a landscape primed for failure, where the steepest slopes and the greatest local relief concentrate landslide activity along the very corridors engineers have carved out for roads.</p>
<p>Understanding those causal mechanisms is only half the battle. The other half is building a model that predicts susceptibility without fooling itself, and this is where the study makes its most consequential methodological contribution. Landslide susceptibility mapping has become a showcase application for machine learning, with random forests, support vector machines, and neural networks routinely churning out impressive-looking hazard maps. Yet the team identified a systemic flaw in how these models are typically evaluated. Most studies split their data into training and testing sets at random, which sounds neutral but is quietly misleading in a spatial setting.</p>
<p>The problem is spatial autocorrelation. Landslides cluster: a slope that failed once is surrounded by neighbors with nearly identical elevation, aspect, lithology, and drainage, and those neighbors are likely to fail too. When a random split places some of these near-duplicate points in the training set and their twins in the test set, the model is effectively being quizzed on answers it has already memorized. The resulting performance scores are over-optimistic, flattering the algorithm while overstating its true ability to generalize to unfamiliar terrain. For a highway engineer deciding which slopes to reinforce, that flattery can be dangerous.</p>
<p>To break this circularity, the researchers built their random forest framework around a rigorous sixfold spatial cross-validation scheme. Instead of shuffling individual points, the study area is partitioned into spatially distinct blocks, and the model is trained on some blocks and tested on entirely separate ones. Each fold therefore simulates the real-world challenge the model will face: predicting hazard in terrain it has never seen. The team paired this validation strategy with Bayesian hyperparameter optimization, using Gaussian-process-based search to efficiently tune the random forest&#8217;s settings rather than relying on default values or brute-force grid searches. The combination yields a model whose reported accuracy reflects genuine predictive skill rather than geographic leakage.</p>
<p>The payoff was clear in the final susceptibility maps. The spatially cross-validated model demonstrated superior generalization compared with conventional approaches, producing hazard estimates that held up when confronted with new territory. The maps reveal that sections of the G318 corridor passing through deeply incised valleys, steep slopes, and areas of high local relief carry the highest landslide susceptibility, and the authors flag these segments as requiring the most attention from maintenance and protection programs. In a region where a single road-blocking landslide can isolate communities and disrupt a strategic artery, knowing precisely which kilometers of highway deserve priority investment is a matter of practical consequence, not academic refinement.</p>
<p>The study&#8217;s implications reach well beyond one highway. Susceptibility models are now standard tools in hazard zoning and land use planning worldwide, and the over-optimism problem the team documented is endemic to the field. By demonstrating that spatial cross-validation changes the picture of model reliability, the researchers add weight to a growing consensus that validation design, not just algorithm choice, determines whether a susceptibility map is science or decoration. Their framework, which couples a carefully constructed landslide inventory with Bayesian-tuned random forests and block-based validation, offers a template that other teams working along the Himalayan arc, the Sichuan–Tibet corridor, and other tectonically active mountain belts can adapt directly.</p>
<p>There is also a deeper geoscience lesson embedded in the results. The finding that slope and local relief dominate landslide occurrence ties the modern hazard map to the long-term evolution of the plateau itself, where tectonic uplift and fluvial incision jointly set the tempo of erosion. In that sense, the machine learning model is not merely a predictive device but a diagnostic instrument, revealing in statistical form the geomorphic engine that has been shaping the southern Tibetan margin for millions of years. As climate change alters precipitation patterns and infrastructure expansion pushes roads into ever more precarious terrain, tools of this kind, honest about their own uncertainty and grounded in the physical mechanisms of failure, will become indispensable for keeping mountain lifelines open.</p>
<p><strong>Subject of Research:</strong> Landslide susceptibility mapping along the Lhasa–Dingri highway corridor on the Tibetan Plateau using spatially cross-validated random forest modeling</p>
<p><strong>Article Title:</strong> Optimizing landslide susceptibility mapping using spatially cross-validated random forest: Lhasa–Dingri corridor, Tibetan Plateau</p>
<p><strong>Article References:</strong> Li, L., Li, Z., Qi, Z., Su, W., Sun, K., Wang, S., Kong, Y., &amp; Hu, R. (2026). Optimizing landslide susceptibility mapping using spatially cross-validated random forest: Lhasa–Dingri corridor, Tibetan Plateau. <em>Natural Hazards, 122</em>(19), Article 635. <a href="https://doi.org/10.1007/s11069-026-08374-5" rel="noopener noreferrer">https://doi.org/10.1007/s11069-026-08374-5</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1007/s11069-026-08374-5" rel="noopener noreferrer">10.1007/s11069-026-08374-5</a></p>
<p><strong>Keywords:</strong> landslide susceptibility, random forest, spatial cross-validation, Tibetan Plateau, machine learning, G318 National Highway, topographic controls, remote sensing, Bayesian optimization, geomorphology, natural hazards, Yarlung Tsangpo River</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">200868</post-id>	</item>
		<item>
		<title>Scientists Map How Climate-Driven River Erosion Could Trigger Future Landslides</title>
		<link>https://scienmag.com/scientists-map-how-climate-driven-river-erosion-could-trigger-future-landslides/</link>
		
		<dc:creator><![CDATA[Violet Maxwell]]></dc:creator>
		<pubDate>Sat, 12 Sep 2026 22:40:29 +0000</pubDate>
				<category><![CDATA[Earth Science]]></category>
		<category><![CDATA[bathymetry]]></category>
		<category><![CDATA[climate change]]></category>
		<category><![CDATA[climate change and flood regime alterations]]></category>
		<category><![CDATA[Climate-driven river erosion]]></category>
		<category><![CDATA[environmental impact of climate change]]></category>
		<category><![CDATA[fluvial erosion and slope stability]]></category>
		<category><![CDATA[future landslide prediction]]></category>
		<category><![CDATA[geotechnical hazard mapping]]></category>
		<category><![CDATA[geotechnical risk]]></category>
		<category><![CDATA[Göta River]]></category>
		<category><![CDATA[hydrodynamic modelling]]></category>
		<category><![CDATA[hydropower regulation]]></category>
		<category><![CDATA[landslide risk assessment]]></category>
		<category><![CDATA[landslide susceptibility]]></category>
		<category><![CDATA[long-term geological hazard modeling]]></category>
		<category><![CDATA[morphodynamics]]></category>
		<category><![CDATA[probabilistic geotechnical analysis]]></category>
		<category><![CDATA[river erosion]]></category>
		<category><![CDATA[riverbank stability]]></category>
		<category><![CDATA[sediment transport and erosion]]></category>
		<category><![CDATA[sediment transport.]]></category>
		<category><![CDATA[slope stability]]></category>
		<category><![CDATA[Sweden]]></category>
		<category><![CDATA[Swedish river studies]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=199352</guid>

					<description><![CDATA[A synthesis of five Swedish river studies presents a transferable workflow for projecting climate-induced erosion to 2100 and integrating it into probabilistic landslide risk assessment.]]></description>
										<content:encoded><![CDATA[<p>Rivers do not simply carry water. Over decades, they carve away their own beds and banks, quietly undermining the slopes that rise above them. When climate change intensifies floods and alters flow regimes, that slow carving can accelerate into a genuine hazard. A new study published in Environmental Earth Sciences synthesizes more than a decade of work by the Swedish Geotechnical Institute, drawing on five large-scale investigations along four Swedish rivers to show how climate-induced river erosion can be projected forward to the year 2100 and folded directly into landslide risk assessments.</p>
<p>The research, led by Gunnel Göransson and colleagues at the Swedish Geotechnical Institute, examines the Göta River, the Nors River, the Säve River and the Ångerman River, all of which flow through fine-grained or mixed sediments where landslide susceptibility is high. The five case studies, conducted between 2009 and 2022, were carried out within a national programme for assessing and mapping future landslide hazards along watercourses. Together they form one of the most sustained efforts anywhere in the world to connect climate-driven fluvial erosion with probabilistic geotechnical slope-stability analysis.</p>
<p>The methodological framework that emerged was iterative, refined case by case, but consistently followed seven steps: compiling previous studies and measurements, conducting hydroacoustic surveys and sediment investigations, running hydrodynamic models to derive erosion parameters, selecting future flow scenarios, modelling erosion, validating results and assessing uncertainty, and finally integrating erosion forecasts into geotechnical stability analyses. Multibeam echosounder surveys mapped bathymetry, side-scan sonar characterized bedforms, backscatter analysis classified sediments, and physical sampling determined how erodible the riverbed materials actually were.</p>
<p>Hydrodynamic modelling sat at the heart of each assessment. The teams used two-dimensional models, including Delft3D, TELEMAC-2D, MIKE 21 C and MIKE 21 FM, to simulate water levels, flow velocities and bed shear stresses under a range of hydrological conditions. Two-dimensional modelling was deliberately chosen as the best balance between computational demand, data requirements and accuracy; three-dimensional simulation, while more detailed, was not considered justified given the uncertainties inherent in forecasting erosion over nearly a century. Erosion estimates rested on the relationship between calculated bed shear stresses, critical shear-stress thresholds and sediment erodibility coefficients, with cohesive sediments handled through the Partheniades formulation within a GIS framework.</p>
<p>The choice of erosion model depended on the geology. In clay-dominated systems such as the Göta, Nors and Säve rivers, the GIS-based analyses were supplemented with the Bank Stability and Toe Erosion Model, known as BSTEM, which explicitly couples hydraulic toe erosion with geotechnical bank-failure mechanisms. The Ångerman River, by contrast, is dominated by frictional sediments such as silt, sand and gravel, so the team adopted a full morphodynamic approach using the MIKE 21 C multi-fraction model, representing sediment transport and channel evolution explicitly. Future flows were derived from downscaled RCP climate projections supplied by the Swedish Meteorological and Hydrological Institute, alongside alternative hydropower regulation strategies.</p>
<p>The erosion projections were then translated into future channel cross-sections that served as direct input to slope-stability calculations performed with Slope/W, following Swedish geotechnical practice. Both present-day and year-2100 conditions were analysed, accounting for projected changes in groundwater, pore-water pressures and erosion-modified slope geometry. To capture uncertainty, the team applied the Point Estimate Method, a computationally efficient alternative to Monte Carlo simulation, deriving failure probabilities from statistical distributions of shear strength, unit weight, pore pressure and geometry. These probabilities were classified into five classes and combined with consequence classes in a GIS-based risk matrix to produce landslide risk maps sensitive to climate change.</p>
<p>Among the most striking findings is the role of hydropower regulation. In heavily regulated rivers, erosion driven by operational flow management can exceed that caused by climate-related changes in discharge, potentially obscuring the climate signal altogether. On the Ångerman River, short-term regulation generated rapid fluctuations in water level and flow velocity that dwarfed projected climate-driven hydrological changes. The study also revealed that the temporal resolution of discharge data matters enormously: simulations based on 14-day averaged flows suggested reduced future erosion, while high-resolution data capturing short-duration flow peaks indicated the opposite, because those peaks contribute disproportionately to bed shear stress but vanish when flows are averaged.</p>
<p>The synthesis also clarified how erosion interacts with inherent susceptibility. In areas already highly prone to landslides, even minor erosion can significantly raise the probability of a catastrophic failure, whereas in stable terrain substantial erosion is needed before risk begins to climb. Sediment composition determines which climate-related driver dominates: in cohesive clay valleys such as those of the Göta, Nors and Säve rivers, fluvial erosion is the dominant climate-related trigger of slope instability, while in the coarser deposits of the Ångerman valley, changes in groundwater and pore-water pressure are likely to matter more.</p>
<p>The authors are candid about uncertainty. Scarcity of sediment-transport measurements, limited repeated bathymetric surveys, positional inaccuracies on steep underwater slopes and the sheer difficulty of simulating long-term fluvial geomorphology all constrain quantitative precision. Their response is a call for recurrent, systematic monitoring, particularly comprehensive bathymetric surveys, and for assessments that are treated as living documents, updated regularly and immediately after any landslide occurs, since such an event would fundamentally reshape river morphology. The projections are best read as semi-quantitative tools for identifying erosion-prone areas and prioritizing detailed investigations rather than as precise predictions.</p>
<p>Perhaps the most valuable export of the study is its transferable workflow. Because it is grounded in fundamental principles of hydrology, hydraulics, sediment transport and erosion, the framework can be adapted beyond Sweden by adjusting the hydrological forcing, whether the driver is monsoon rainfall, tropical cyclones, drought or rapid glacier retreat. The authors emphasize that success depends on interdisciplinary collaboration across geomorphology, hydrology, sediment transport, hydraulics and geotechnics, and on adaptive rather than static management. As extreme precipitation intensifies worldwide, the lesson from the Swedish rivers is clear: the ground beneath riverside communities is being reshaped now, and the only responsible way to plan for it is to model, monitor and adapt continuously.</p>
<p><strong>Subject of Research:</strong> Projecting climate-induced river erosion to assess future landslide susceptibility in Swedish river valleys</p>
<p><strong>Article Title:</strong> Projecting climate-induced river erosion for assessing future landslide susceptibility: methodological insights and lessons learned from five Swedish cases</p>
<p><strong>Article References:</strong> Göransson, G., Odén, K., Bergdahl, K., &amp; Bolin, P. (2026). Projecting climate-induced river erosion for assessing future landslide susceptibility: methodological insights and lessons learned from five Swedish cases. <em>Environmental Earth Sciences, 85</em>(15), Article 396. <a href="https://doi.org/10.1007/s12665-026-13128-4" rel="noopener noreferrer">https://doi.org/10.1007/s12665-026-13128-4</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1007/s12665-026-13128-4" rel="noopener noreferrer">10.1007/s12665-026-13128-4</a></p>
<p><strong>Keywords:</strong> river erosion, landslide susceptibility, climate change, slope stability, hydrodynamic modelling, sediment transport, bathymetry, hydropower regulation, geotechnical risk, Sweden, Göta River, morphodynamics</p>
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		<post-id xmlns="com-wordpress:feed-additions:1">199352</post-id>	</item>
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		<title>Simple Statistical Model Outperforms Expert Judgment in Mapping Deadly Landslide Risk in Northern Pakistan</title>
		<link>https://scienmag.com/simple-statistical-model-outperforms-expert-judgment-in-mapping-deadly-landslide-risk-in-northern-pakistan/</link>
		
		<dc:creator><![CDATA[Violet Maxwell]]></dc:creator>
		<pubDate>Fri, 11 Sep 2026 02:01:05 +0000</pubDate>
				<category><![CDATA[Earth Science]]></category>
		<category><![CDATA[AHP]]></category>
		<category><![CDATA[corridor-scale landslide risk analysis]]></category>
		<category><![CDATA[earthquake and snowmelt landslide triggers]]></category>
		<category><![CDATA[frequency ratio]]></category>
		<category><![CDATA[geohazard mapping]]></category>
		<category><![CDATA[geoscience mapping techniques]]></category>
		<category><![CDATA[GIS]]></category>
		<category><![CDATA[hazard prediction in Hindu Kush and Karakoram]]></category>
		<category><![CDATA[Hindu Kush]]></category>
		<category><![CDATA[landslide forecasting accuracy]]></category>
		<category><![CDATA[Landslide risk mapping in Pakistan]]></category>
		<category><![CDATA[landslide susceptibility]]></category>
		<category><![CDATA[landslide susceptibility models]]></category>
		<category><![CDATA[monsoon-induced slope failures]]></category>
		<category><![CDATA[Pakistan]]></category>
		<category><![CDATA[remote area infrastructure safety]]></category>
		<category><![CDATA[remote mountain terrain hazard assessment]]></category>
		<category><![CDATA[remote sensing]]></category>
		<category><![CDATA[road infrastructure]]></category>
		<category><![CDATA[ROC–AUC]]></category>
		<category><![CDATA[simple statistical models in disaster risk management]]></category>
		<category><![CDATA[statistical index]]></category>
		<category><![CDATA[statistical vs expert judgment in hazard prediction]]></category>
		<category><![CDATA[Upper Dir]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=192184</guid>

					<description><![CDATA[A new comparative study of the Sheringal–Kumrat Road in Upper Dir, Pakistan, shows a simple statistical index model outperforming expert-based AHP in mapping landslide susceptibility along a vital mountain corridor.]]></description>
										<content:encoded><![CDATA[<p>Along the Sheringal–Kumrat Road in Upper Dir District, one of the most remote corners of northwestern Pakistan, the mountains are quietly telling a story of instability. Steep valley walls of fractured volcanic rock and slate hang above a narrow ribbon of asphalt that is the only reliable link between dozens of communities and the outside world. Every year, during intense monsoon rains and spring snowmelt, slopes give way, burying sections of the road, severing access, and occasionally claiming lives. Now, a team of researchers led by Sulaiman Khan of Tianjin University has produced one of the first corridor-scale landslide susceptibility maps for this treacherous route, and their results, published in Discover Geoscience, carry a striking message: a simple statistical technique beat expert judgment at predicting where the next slope failure is most likely to occur.</p>
<p>The study set out to answer a question that has long frustrated geoscientists working in the Hindu Kush and Karakoram regions: when data are scarce and terrain is extreme, which mapping approach best identifies dangerous ground? The researchers compared three widely used techniques—the Analytical Hierarchy Process (AHP), a knowledge-driven method that translates expert judgment into numerical weights; and two bivariate statistical models, the Frequency Ratio (FR) and the Statistical Index (SI), which derive weights empirically from the observed relationship between past landslides and terrain characteristics. What makes their comparison unusually rigorous is the experimental design. Rather than allowing each method to use its own data or assumptions, the team forced all three models to work from the same landslide inventory, the same eight conditioning factors, the same 12.5-meter spatial resolution, the same training and testing split, and a common validation dataset.</p>
<p>Building the foundation for this comparison was itself a substantial undertaking. Between 2017 and 2025, the researchers compiled a multi-temporal inventory of 90 landslides along the corridor, combining satellite image interpretation, documentary records, and repeated field visits to verify each mapped failure. The fieldwork documented a sobering variety of slope failures: rotational slides with well-defined scarps, shallow translational slides, debris slides accumulating talus at their bases, and rockfall debris piling up against the road at the toes of fractured rock faces. The geology of the region—part of the Kohistan Island Arc, squeezed between the Main Mantle Thrust and Main Karakoram Thrust—provides ample raw material for instability, with tectonically disturbed volcanic, metavolcanic, metasedimentary, and intrusive rocks all represented along the route.</p>
<p>With the inventory in hand, the team prepared eight landslide-conditioning factors from a 12.5-meter digital elevation model and geological mapping: slope angle, elevation, aspect, curvature, profile curvature, lithology, drainage density, and relative relief. Before modeling, they tested the factors for redundancy using Spearman&#8217;s rank correlation and the Variance Inflation Factor, a standard diagnostic for multicollinearity. The results were reassuring: VIF values ranged from just 1.01 to 2.43, far below the conventional threshold of 10, meaning no factor was duplicating the information carried by the others. Lithology showed the highest VIF at 2.43, followed by slope at 2.12, but all eight variables could be retained without concern that overlapping signals would distort the model weights.</p>
<p>The pattern of empirical associations that emerged from the data reads like a field guide to slope failure in the region. Slope angle showed one of the clearest relationships, with the 30–45 degree class recording the highest frequency ratio of 1.712, and slopes steeper than 45 degrees registering the highest statistical index value. Drainage density proved even more potent: the highest class, 0.309 to 0.5, returned both the highest FR (2.433) and the highest SI (1.673), reflecting how dense stream networks concentrate runoff, undercut slope toes, and raise pore-water pressures during rainfall. Relative relief—the local difference between maximum and minimum elevation—showed a similarly strong association, with the 2097–2277 meter class reaching an FR of 2.059. These relationships are geomorphologically intuitive: steep, deeply dissected terrain provides the gravitational energy and the water pathways that slope failures require.</p>
<p>Lithology added its own decisive fingerprint. The Barawal Banda Slate, a fine-grained, foliated slate and phyllite unit with pervasive cleavage, showed the strongest association with mapped landslides among the well-behaved comparisons, with an FR of 1.457. The rock&#8217;s low intact strength and well-developed anisotropic failure surfaces parallel to its foliation make it a natural candidate for instability, and the data confirmed that intuition. West- and southwest-facing slopes also showed elevated susceptibility, plausibly reflecting stronger afternoon solar heating, repeated thermal stress on fractured rock, and differences in moisture retention and vegetation. Convex profile curvature classes, where flow accelerates and lateral support diminishes, added a further local concentration of risk. No single factor told the whole story; the danger zones emerged where multiple unfavorable conditions stacked on top of one another.</p>
<p>When the three models were run and their outputs classified into five susceptibility levels from very low to very high, all three converged on the same broad geography: the northwestern sector of the corridor is the principal hotspot, where steep, highly dissected terrain, dense drainage, high relative relief, and weak lithological units coincide. But the models differed in how sharply they discriminated. In the AHP implementation, slope angle received the highest expert weight at 32.1 percent, followed by drainage density at 21.7 percent and relative relief at 20.1 percent, with a consistency ratio of 0.0737 confirming internally coherent expert judgments. The FR and SI models, by contrast, let the landslide inventory itself speak, assigning each factor class a weight based purely on its observed association with past failures.</p>
<p>Independent validation on the withheld 25 percent testing subset delivered the study&#8217;s headline result. The Statistical Index model achieved the highest area under the receiver operating characteristic curve, an ROC–AUC of 0.903—considered excellent discrimination—followed by the Frequency Ratio model at 0.881 and the expert-based AHP at 0.847. In other words, the simplest, purely empirical approach outperformed structured expert judgment in this setting. The SI model also proved remarkably efficient in its spatial allocation: it classified only 12.2 percent of the study area as very high susceptibility while capturing 57.7 percent of the mapped landslides within that class, precisely the kind of concentrated warning that road managers need. The authors are careful, however, to note that without confidence intervals or formal pairwise significance tests, SI should be described as the best performer in this experiment rather than as statistically proven superior.</p>
<p>The practical implications extend well beyond an academic comparison of methods. The maps give engineers and disaster-management authorities in Upper Dir a defensible, reproducible screening tool for prioritizing slope monitoring, drainage improvement, detailed geotechnical investigation, and road-maintenance budgets along a corridor where alternative access routes are scarce and every closure carries real consequences for isolated communities. Sections of road crossing contiguous high and very high susceptibility cells should be first in line for inspection and stabilization, particularly after major rainfall or snowmelt episodes. The authors also stress the limits of the analysis: with only 90 mapped events, no rainfall or seismic predictors, and no temporal validation, the maps indicate where failures are likely, not when or how large. Still, the framework—three interpretable models tested on identical data—offers a template that other data-poor mountain regions, from the Himalaya to the Andes, can adapt. In an era when climate change is intensifying the rainfall that triggers landslides across high-mountain Asia, knowing precisely which kilometers of road to watch first may prove to be the cheapest insurance available.</p>
<p>The distinction between susceptibility and hazard is worth emphasizing for readers encountering these maps. Susceptibility, as produced here, is a purely spatial statement: given the terrain and geological conditions observed today, which locations possess the combination of attributes most conducive to failure. It deliberately excludes timing, magnitude, and runout, which would require rainfall thresholds, seismic triggers, and dynamic runout modeling that the current inventory cannot support. This is why the authors frame their product as a screening tool rather than a forecast, and why they caution against reading the very high class as a prediction of imminent failure.</p>
<p>The statistical logic underlying the two bivariate models also merits brief explanation. Both FR and SI operate class by class: each factor class receives a weight reflecting the proportion of landslide pixels it contains relative to its share of the study area. The Frequency Ratio expresses this as a simple ratio, while the Statistical Index takes its logarithm, which compresses extreme values and can stabilize model behavior when class areas vary widely. Because both models treat each factor independently, they cannot capture interactions—for instance, a steep slope may be far more dangerous under one lithology than another—a limitation that machine-learning approaches address at the cost of greater data demands and reduced transparency.</p>
<p>The regional geological setting amplifies the value of such screening. The Kohistan Island Arc records the collisional history between the Indian and Eurasian plates, and the rocks it preserves—slates, volcanics, and batholithic intrusions—have been repeatedly sheared, fractured, and altered. Tectonic fabrics such as cleavage and foliation create planes of weakness that orient failure surfaces, meaning geology and topography interact rather than act independently. In corridors like Sheringal–Kumrat, where road cuts expose these weakened materials directly to weathering and infiltration, even modest increases in seasonal precipitation can translate into measurable slope instability, reinforcing the case for targeted, map-guided maintenance.</p>
<p><strong>Subject of Research:</strong> Landslide susceptibility assessment along the Sheringal–Kumrat Road corridor in Upper Dir, northern Pakistan, comparing AHP and bivariate statistical models</p>
<p><strong>Article Title:</strong> Landslide susceptibility assessment along Sheringal Road, Upper Dir Northern Pakistan using AHP and bivariate statistical models</p>
<p><strong>Article References:</strong> Khan, S., Anjum, N., Bibi, H., Rauf, M., Ullah, W., Khan, A., Jadoon, H. K., &amp; Yaqoob, A. (2026). Landslide susceptibility assessment along Sheringal Road, Upper Dir Northern Pakistan using AHP and bivariate statistical models. <em>Discover Geoscience, 4</em>(1), Article 353. <a href="https://doi.org/10.1007/s44288-026-00725-w" rel="noopener noreferrer">https://doi.org/10.1007/s44288-026-00725-w</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1007/s44288-026-00725-w" rel="noopener noreferrer">10.1007/s44288-026-00725-w</a></p>
<p><strong>Keywords:</strong> landslide susceptibility, AHP, frequency ratio, statistical index, GIS, remote sensing, Upper Dir, Pakistan, Hindu Kush, ROC–AUC, road infrastructure, geohazard mapping</p>
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