ABSTRACT
According to events and studies on landslides of rock slopes due to recent earthquakes mainly in Japan, the author remarks some differences of the characteristics and mechanisms among landslide phenomena. Rockfalls occur by the seismic inertia force on steeper reverse-dip slopes as topples and falls, which consist of loosen rock or jointed rock material in shallow portions. On the other hand, rockslides occur on gentler dip slopes as translational or rotational slide, which develop surface gravitational deformation, consist of mainly bed rock and intercalate sandy, silty or clayey strata of slip plane. Furthermore, rockslides are caused not by the seismic inertia force but by the cyclic shear load which results in both decrease of shear strength and liquefaction with excess pore water pressure of slip plane in earthquake duration.
