Spatiotemporal Evolution Characteristics of Hanyuan Landslide in Sichuan Province, China, on 21 August 2020

Synthetic aperture radar interferometry (InSAR) has the advantages of a wide monitoring range, high density, high accuracy, and is not limited by weather conditions, providing a new technical means for landslide research. On 21 August 2021, a landslide occurred in Zhonghai Village, Hanyuan County, Ya’an City, Sichuan Province, China, resulting in nine deaths. For the research area, the Small Baseline Subsets InSAR (SBAS-InSAR) technique was used to extract the spatiotemporal evolution characteristics before the landslide occurred (from 16 January 2019 to 22 May 2020), and the height difference before and after the landslide occurrence was extracted using unmanned aerial vehicle photogrammetry, high-resolution remote sensing images, and digital elevation model data. By analyzing seismic activity, human activities, and rainfall in the study area, the main causes of landslides were discussed. This study not only reduces the losses caused by landslide disasters but also provides a scientific basis and technical support for local governments’ disaster prevention and mitigation work.