Vegetation damage and recovery characteristics of landslides triggered by earthquake in the Yarlung Zangbo Grand Canyon

Earthquake-induced landslides are a primary driver of surface distribance in alpine canyon regions, exerting long-lasting impacts on vegetation dynamics. This study investigates landslides triggered by the 2017 Ms 6.9 Milin earthquake in the Yarlung Zangbo Grand Canyon. Getis-Ord Gi* analysis was used to delineate the spatial extent of vegetation disturbance, while the Vegetation Damage Area (VDA) and Vegetation Recovery Rate (VRR) indices derived from multi-temporal NDVI data were used to quantify vegetation disturbance intensity and identify the temporal evolution of vegetation recovery. Results indicate that landslide activity persisted for several years post-seismic, with the total number of landslides increasing by 142 and the cumulative landslide area expanding by 21.49 km². Vegetation degradation was not confined to mapped landslide polygons; the most pronounced negative effects extended 20-30 m beyond landslide boundaries, forming a highly sensitive belt of severe vegetation damage. From 2017 to 2023, the VDA consistently accounted for over 50% of the newly triggered landslides areas, peaking at 97.54% in 2017. Although the VRR indicates an overall recovery trend, most affected regions have yet to return to pre-earthquake conditions, with more severely disturbed areas exhibiting significant recovery lags. These findings highlight the prolonged evolution of earthquake-triggered landslides and their sustained influence on alpine ecosystems, providing quantitative evidence to support ecological restoration and long-term geohazard management.