| It has been considered that topography, geology and seismic waves gave large impacts on the size and susceptibility of earthquake induced landslide. However, to quantify these effects, we have to analyze landslide maps from a variety of earthquakes, geological settings and topography. Using landslide maps from the epicentral areas of four Japanese earthquakes, Kobe in 1995, western Tottori in 2000, Chuetsu in 2004, and Iwate-Miyagi, 2008, we have investigated the roles of topography, geological settings and seismic waves over the location of earthquake induced landslide. We found that the slope angles, bedrock geology and the distance from fault controlled the landslide susceptibility. Moreover, relationships between the distance from fault and the ratio of landslide area were not different each slope angle and each bedrock geology. It means, the seismological factors related to landslides susceptibility were depended on slope angles. Furthermore, we found that there were large differences in landslide area-frequency relationships. In the epicentral areas of Kobe and western Tottori earthquakes, small shallow landslides were dominant, while in the epicentral areas of Chuetsu and Iwate-Miyagi earthquakes, a number of large scale landslides were occurred. This difference cannot explained by slope angle and the distances to fault break. While, we found that the susceptibility of large scale landslide increased with the increase of relief, indicating that topography is one of main control of seismic landslide size. |
