How size and trigger matter: analyzing rainfall- and earthquake-triggered landslide inventories and their causal relation in the Koshi River basin, central Himalaya

摘要: Abstract. Inventories of landslides caused by different triggering mechanisms, such as earthquakes, extreme rainfall events or anthropogenic activities, may show characteristics in terms distribution, contributing factors and frequency–area relationships. The aim this research is to study differences landslide inventories the effect they have on susceptibility assessment. area is the watershed the transboundary Koshi River central Himalaya, shared by China, Nepal India. Detailed were generated based visual interpretation remote-sensing images field investigation for time periods triggering mechanisms. Maps and images from period 1992 2015 used map 5858 rainfall-triggered landslides, after Gorkha earthquake, an additional 14 127 coseismic mapped. A set topographic, geological land cover employed analyze their correlation with types sizes landslides. frequency–area distributions rainfall- earthquake-triggered (ETLs) a similar cutoff value power-law exponent, although ETLs might larger frequency smaller one. In addition, topographic varied considerably for the two events, with both altitude slope angle showing significantly patterns rainfall-triggered and earthquake-triggered Landslides classified into size groups, combination main mechanism (rainfall- or earthquake-triggered). Susceptibility maps combinations of landslide size generated using logistic regression analysis. triggers data were used validate models. results showed that susceptible areas for small- large-size differed substantially.