Investigation of Characteristics of Long Runout Landslides Based on the Multi-source Data Collaboration: A Case Study of the Shuicheng Basalt Landslide in Guizhou, China

On 23rd July 2019, a catastrophic long-runout basalt landslide was triggered by a heavy rainfall in Shuicheng county, Guizhou, China. The sliding mass transformed into a debris avalanche during the runout process traveled approximately 1250 m with an elevation difference of 465 m and finally caused 52 casualties. To improve the ability of risk assessment of such a basalt long-runout landslide, scanning electron microscope (SEM) tests combined with detailed field investigation were conducted to investigate the failure mechanism of the Shuicheng landslide in terms of micro and macro perspectives. The results indicated that the cause of the Shuicheng landslide is the combination of rock mass characteristics (differential weathering and fragmented cataclastic structure), weak tuff intercalation, tectonic structural plane, and human activities, while rainfall is the primary inducing factor. Moreover, a RAMMS simulation and electrical resistivity tomography (ERT) tests were performed to research the disaster-causing behaviors and deposit characteristics of this event. The selected rheological parameters are determined based on multi-source data collaboration. The total duration of the landslide movement was estimated at 60 s with a maximum velocity of approximately 36 m/s, and the final deposit distribution was in good agreement with the ERT test results and seismic signal analysis results. The work conducted in this study is expected to help improve the understanding of the initiation and disaster-causing mechanisms of basalt long-runout landslides and provide valuable information for the prediction of long runout landslides movement distance in the Guizhou, China.