Abstract:
A large number of landslides were triggered by the Ms 6.5 magnitude earthquake that occurred in Ludian, Yunnan Province, on August 3, 2014. Landslides triggered by strong earthquakes exhibit slow post-earthquake recovery, high recovery difficulty, and tend to recur and expand, which can have long-term impacts on roads, water bodies, and ecological environments. Therefore, it is necessary to explore their long-time spatial and temporal variability. Taking the 314km
2 area affected by the earthquake as the study area, post-earthquake landslides were first extracted and a multi-temporal data list was compiled using the ENVI deep learning method. Based on this, the spatial-temporal differentiation analysis was carried out focusing on the spatio-temporal distribution characteristics of landslides, changes in spatio-temporal area, and the evolution of landslide activities. The results show that: (1) following the earthquake, the number and area of landslides increased dramatically, gradually decreasing over the subsequent 8 years. Earthquake-triggered landslides were primarily small-scale, with an area of less than 0.01 km
2, concentrated on both sides of the river valley, and distributed more prominently within 2,000 meters from the epicenter and within seismic intensity IX; (2) over time, the post-earthquake landslide activity rate generally showed a gradual weakening trend, with only 6.08% of the earthquake-triggered landslides still active as of July 2022, indicating a gradual weakening of the earthquake's impact on landslides; (3) the activity evolution of post-earthquake landslides can be divided into three phases: the period of strong landslide activity (August 2014-July 2016), the period of moderate activity (August 2016-August 2021), and the period of weak activity (September 2021-July 2022).