Assessment of rainfall-generated shallow landslide/debris-flow susceptibility and runout using a GIS-based approach: application to western Southern Alps of New Zealand

摘要: Rainfall-triggered shallow slope failures are very common in the western Southern Alps of New Zealand, causing widespread damage to property and infrastructure, injury loss life. This study develops a geographic information system (GIS)-based approach for landslide/debris-flow susceptibility assessment. Since landslides complex their prediction involves many uncertainties, fuzzy logic is used deal with uncertainties inherent spatial analysis limited knowledge on relationship between conditioning factors instability. A landslide inventory was compiled using data from existing catalogues, satellite imagery field observations. Ten parameters were initially identified as most important rainfall-generated area, memberships established each parameter occurrence based both user-defined functions. Three output maps developed evaluated test area an independent population landslides. The models demonstrated satisfactory performance under curve (AUC) varying 0.708 0.727. Sensitivity analyses showed that six-parameter model angle, lithology, aspect, proximity faults, soil induration, drainage network had highest predictive (AUC = 0.734). runout path distance potential future susceptible areas also modelled multiple flow direction algorithm topographic debris-flow deposits. final map has inform regional-scale land-use planning prioritize where hazard mitigation measures required.