The probability of coseismic landslides in different peak ground accelerations: a case of 1927 Gulang M8.0 event

Abstract

A catastrophic Ms 8.0 earthquake struck Gulang County, Gansu Province on May 23, 1927, and triggered numerous coseismic landslides. Based on a high-resolution remote sensing image from Google Earth Platform, we delineated 936 coseismic landslides with an area of 58.6 km2. Further, ten factors were selected as the impact factors for earthquake-triggered landslide hazard mapping of the earthquake. We propose a sampling method that selects the sliding and nonsliding samples established on the ratio of the study area to the landslide area based on the Bayesian theory, and a total of 247080 samples are selected. We establish a multi-factor impact model for landslide probabilities using the logistic regression (LR) model, calculate the regression coefficients based on LR models, and obtain the occurrence probability of coseismic landslides. The model is then applied to calculate the probability of earthquake landslides under different PGAs. The study areas are divided into extremely high-risk, high-risk, medium-risk, low-risk, and extremely low-risk areas. The results of this study provide scientific references for mitigating earthquake-related landslides in earthquake-prone areas.