6:15 PM - 7:30 PM
[HDS25-P06] Distribution of trigger and relationship between trigger and geology of deep-seated landslides
Keywords:deep-seated landslide, trigger, geology, heavy rainfall, strong earthquake
The processes of DSLs induced by two factors and the geological influences on them are summarized as follows. In the Shimanto accretionary complex in the southwest Japan, DSL induced by heavy rainfall is more likely compared with that by earthquake. This is because of the higher precipitation in the relevant area and the convergence of seepage water into the cracks of potential slip surfaces formed by rock creep. Earthquake-induced DSL is unlikely because active faults in this region are few and the mountainous basement is relatively hard. On the other hands, in the Neogene sediments in the northeast Japan, rainfall-induced DSL is unlikely because of the lower precipitation and the divergence of seepage water due to porous media. Earthquake-induced DSL is likely because earthquake stimulates greater ground motion in the Neogene sediments and the mountainous basement is relatively soft.