Plenary: Progress in Landslide Dynamics

Abstract

Landslide Dynamics is a relatively new field in Landslide Science. Reliable scientific knowledge to assess the motion of landslides including hazard area, speed and depth is needed to reduce human loss from landslides. However, the initiation and motion of landslides is not easy to explain quantitatively because of pore-pressure generation during initiation and motion, and continuing changes in grain size, grain shape and water content of the involved soils in the shear zone. An apparatus has been developed to physically simulate the formation of sliding surfaces and the post-failure motion of the involved soils under realistic stresses. It can simulate pore-pressure increase due to rain water infiltration and dynamic loading due to earthquakes in the field, and can monitor pore-pressure generation, and mobilized shear resistance together with shear displacement. The apparatus has evolved from the model DPRI-1 in 1984 through DPRI-2, 3, 4, 5, 6, to the model ICL-1 in 2011 and ICL-2 in 2013. This apparatus which is called the landslide ring-shear simulator is now in use in foreign countries. This paper presents the progress of the landslide ring-shear simulator and its application to earthquake-induced landslides, the 2006 Leyte landslide killing over 1,000 people, the 1792 Unzen Mayuyama landslide killing 15,000 people, and a hypothetical Senoumi (Stone flower sea) submarine megaslide using a cored sample from 190 m below the sea floor. A new integrated computer model (LS-RAPID) simulating the initiation and motion using soil parameters obtained from the landslide ring-shear simulator has been developed in parallel with the development of landslide ring-shear simulator. LS-RAPID was applied to the three earthquake-induced landslide cases mentioned above. The simulations included two triggering factors: pore- water pressure and three-component seismic waves. The combination of landslide ringshear simulator and integrated landslide simulation model provides a new tool for landslide hazard assessment.