Spatio-temporal evolution characteristics of typical debris flow sources after an earthquake

In the 10 years since the Wenchuan earthquake on May 12, 2008, debris flow disasters have occurred many times in the areas affected by the earthquake. These debris flows are widely distributed, have strong explosive force, and pose a significant hazard. In this work, high-resolution remote sensing image interpretation of 43 gullies along the Duwen Highway over six periods was combined with field investigation and ArcGIS analysis in order to discuss spatio-temporal evolution and distribution characteristics of the source area. The main results are (i) The number, area and volume of landslides decreased rapidly in 5 years after the earthquake, and gradually slowed down after 5 years due to soil consolidation; (ii) A landslide evolution model was proposed to predict that the source of the post-earthquake landslide will return to the pre-earthquake level around 2036; and (iii) The catchment area was positively correlated with source area and attenuation rate, but source area density was negatively correlated. (iv) After the earthquake, the centroid point of the landslide source decreased from year to year. The research results reveal the spatial–temporal evolution and distribution characteristics of landslide source after earthquake, providing reference for the staging and zoning prevention of debris flow landslide in earthquake-prone regions.