Abstract
This paper examined a prediction method of location, falling direction and falling distance of rock falls caused by horizontal earthquake motion in granite area. Many rock falls took place on mountain ridges and near convex break of slope where earthquake motion was probably amplified. Earthquake damages were bigger in ccomparatively fresh and fracture-poor granite than in strong-disintegrated or fracture-rich one. Then dominant movement types of earthquake-induced rock falls were of toppling and tumbling of large granite boulders on mountain ridges, jumping of large jointed blocks from fresh granite-outcropped scarps near convex break of slope and jumping of weak-disintegrated blocks from strong-disintegrated granite cliff near the top of road-cuts. The falling direction tends to orient perpendicular to the seismic faults. The distance of free falling from road-cuts tends to be come equal about to height of falling position. On the basis of these features this paper has proposed a tool for selection of location of earthquake-induced rock falls in granite area.
