Was the deep-seated gravitational slope deformation enhanced by an earthquake? Evidence from shaking table tests

A large-scale landslide occurred in Maoxian County, Sichuan Province, on June 24th, 2017, which destroyed Xinmo village and resulted in injuries and the deaths of 83 people. According to earthquake data, earthquakes greater than Ms 7.0 have occurred many times at this location. The importance of taking earthquake factors into consideration during the study of gravity-induced deformation is emphasized in this study. Careful field investigation reveals that macrocracks developed in the source area before landsliding, and there are many gravity-induced (buckling) deformation traces in the landslide area. After a large shaking table test, the deformation failure characteristics of the slope caused by multiple earthquake simulation actions were compared with the practical consequences caused by the Xinmo Landslide. The tension fracture and buckling failure revealed by the test is highly similar to the real phenomena of the Xinmo Landslide in the field, as discovered by historical images. Therefore, undeniably, earthquakes have made important contributions to the Xinmo Landslide, even though the Xinmo Landslide has apparent gravity-induced deformation properties. Furthermore, the influence of earthquakes, gravity, rainfall, and other external factors on landslides is not just supposition. Inter-feedback actions between them gave rise to the landslide event.