Post-earthquake spatiotemporal evolution characteristics of typical landslide sources in the Jiuzhaigou meizoseismal area

Strong earthquakes can trigger mountain landslides, which can produce long-term effects on subsequent landslide activities. Therefore, understanding the spatiotemporal evolution characteristics of post-earthquake landslides is crucial for risk assessment of long-term geological hazards. In light of this, the current study aims to analyze the spatiotemporal evolution law, decay modes, and susceptibility changes of post-earthquake landslides, using the post-hazard condition of the Jiuzhaigou earthquake in 2017 as the reference for research. An integrated monitoring technology known as "space-sky-ground" was utilized to create a comprehensive multi-temporal dataset of post-earthquake typical landslide disasters. The spatiotemporal distribution characteristics of landslides were then analyzed to construct a quantitative predictive model for landslide spatiotemporal evolution and to deduce the long-term spatiotemporal evolution law of landslide disasters in seismic areas. Following this, the typical influencing factors were introduced to construct a coupled post-earthquake landslide susceptibility model (CF + LR), summarizing the spatiotemporal evolution patterns of landslide susceptibility. The results show that post-earthquake landslides gradually transitioned from large and medium-sized to small-scale slides, exhibiting an overall power-law decay pattern, with an estimated recovery to pre-earthquake levels projected by 2033. Additionally, the CF + LR coupled model demonstrated higher accuracy and reliability in identifying the high and extremely high susceptibility areas, with the susceptibility zones showing an evolution trend towards lower altitudes, gentler slopes, windward slopes, and closer proximity to channels. This study provides important guidance for the staging, zoning, and long-term risk assessment and prevention of post-earthquake landslides.