Spatial predictive modelling of rainfall- and earthquake-induced landslide susceptibility in the Himalaya region of Uttarakhand, India

摘要

Rainfall and earthquakes are the most frequent landslide-triggering parameters throughout the Indian Himalayan region. This region is susceptible to both rainfall- and earthquake-induced landslides. Therefore, landslide susceptibility zonation (LSZ) based on the individual triggering parameter is insufficient for this region. The primary aim of this work is to assess the combined effect of rainfall- and earthquake-triggering parameters on LSZ using a GIS-based relative frequency ratio (RFR) approach. Consequently, the objective is to develop rainfall- and earthquake-induced LSZ maps for the study area. In this paper, the study area considered is a part of Chamoli district in the Uttarakhand state of India. For this study, the landslide inventories were derived from the pre- and post-Chamoli earthquake (1999). Landslide inventory includes 220 landslides that occurred before the Chamoli earthquake, considered as rainfall-induced landslides (RIL) and 56 earthquake-induced landslides (EIL). The variation between landslides' spatial distribution and controlling parameters for both cases, i.e. RIL and EIL, are assessed and compared. Then, rainfall- and earthquake-induced LSZ maps in the same study area are produced and compared.