The factors of slope failures triggered by the Noto�]Hanto Earthquake in 2007 were researched in this study. The main factor of the study was four of the following. The influence of the distance from epicenter was limited less than 2km. The influence by the surface earthquake fault was seen in less than 6km range. The area ratio of slope failure was 0.05% in the study area (97.4km2). No significant influence was found on the hangingwall of the earthquake fault. Then, we analyzed the factor using area ratio of slope failure limited by the slope angle more than 30degrees. Area ratio of slope failure in steep slope was high in the low, costal area. Also, the effect by the distance from surface earthquake fault or geological properties evaluated clearly using area ratio of slope failure in steep slope.

Key words�Fearthquake, slope failure, area ratio, steep slope, acceralation