AN EXPERIMENTAL STUDY ON LANDSLIDE KINEMATICS ON A SUBMARINE SLOPE WITH AN IMPERMEABLE LAYER

Abstract

This paper deals with a laboratory experiment of submarine landslides. In general, submarine landslides can break submarine cable and cause tsunami without any large seismic shaking. It has been thought that tsunami magnitudes by submarine landslides are strongly affected by the velocity of the sliding mass. Based on these backgrounds, our experiments were focusing on their trigger mechanisms due to excess pore water pressure. During the experiments, we measured the displacement and the velocity of the sliding mass. As a result, the experimental landslides were classified into three patterns based on time-profiles of the velocity. A velocity peak characterized patterns 1 and 2 at the initial period during the experiments, and those generated small slides. In contrast, pattern 3 developed into a large slide which behaved like a creep rupture; it slides slowly at the initial stage, reaches a steady-state with the constant velocity at the intermediate period, and slides rapidly at last. In addition, the relationship between the secondary creep velocity and the time to creep rupture can be linearly approximated on a double-logarithmic graph, as in the case of subaerial landslides.