Seismically-induced landslide hazard mapping of Aba region, Sichuan Province for future seismic scenarios using LR modelling and probabilistic seismic hazard analysis

Abstract

The purpose of this work is to carry out seismic-induced landslide hazard mapping for future seismic scenarios of Aba region. 9 earthquake events that occurred in Aba prefecture of Sichuan province and neighboring areas are selected, which include a total of 251260 landslide records. We used 13 influencing factors including elevation, slope, aspect, relief, topographic wetness index (TWI), topographic position index (TPI), ground motion, distance to active faults, vegetation coverage, distance to roads, lithology, and annual rainfall to establish the LR modelling. Based on the probabilistic seismic hazard analysis (PSHA), the distribution of predicted seismic motion under four earthquake scenarios are calculated including frequent earthquake, basis earthquake, rare earthquake and very rare earthquake. Using the PGA distribution of the four scenarios as input data, we calculated the occurrence probability of coseismic landslides in the entire Aba area under the action of different ground motions. The result shows that the high-hazard areas are mainly concentrated in the Longmenshan fault zone, and the southern area of Kangding is also a potential high-hazard area for landsliding. Meanwhile, as the probability of exceedance decreases, the probability of corresponding earthquake landslides and the area of high-hazard region also significantly increase. Especially, the Pengguan complex rock mass in the southwest of the Longmenshan fault zone is the potential high-hazard area for coseismic landslides.