Identification and hazard analysis of landslides triggered by earthquakes and rainfall

Abstract

This study aims to utilize the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique and Google Earth optical remote sensing images to analyze the area within 20 ​km around the epicenter of a M 3.9, earthquake that occurred in Tanchang County, Gansu Province, on December 28, 2020. The objective is to identify potential earthquake-induced landslides, assess their scale, and determine their impact range. The study results reveal the successful identification of two potential landslides in the 20 ​km radius around the epicenter. Through time-series deformation analysis, it was observed that these potential landslides were significantly influenced by both the earthquake and rainfall. Further estimation of these potential landslides indicates maximum depths of 7.4 ​m and 14.1 ​m for the failure surfaces, with volumes of 9.02 ​× ​10⁴ ​m³ and 25.5 ​× ​10⁴ ​m³, respectively. Finally, based on the simulation analysis of Massflow software, the maximum thickness of soil accumulation in the final accumulation area after sliding of the potential landslide in Shangyaai is 12 ​m, the area of the final accumulation area is 1.75 ​× ​10⁴ ​m², and the farthest movement distance is 1124 ​m. The maximum thickness of soil accumulation in the final accumulation area after sliding of the potential landslide in Wangshancun is 8 ​m, the area of the final accumulation area is 7.89 ​× ​10⁴ ​m², and the farthest movement distance is 742 ​m.