Abstract
For the purpose of grasping characteristics of disaster at mountainous district due to earthquake, the circumstances of disaster were adjusted and analyzed about the Kanto, Niigata, and Izu-Oshima-Kinkai Earthquakes. Further, earthquake accelerations at the stricken districts were presumed and it was tried to grasp the relationship between the accelerations put in a correction according to elevation and the disaster. The results are summarized as follows.
(1) Generally, cracks occur by a principal shock and afterward landslides occur by aftershocks or rainfalls.
(2) Especially near a fault landslides are easy to occur.
(3) Landslides increase rapidly with the increment of slope where an angle of inclination of slope is over 30°.
(4) The average depth of landslide is about 1-2m.
(5) Acceleration tends to increase in proportion to elevation and area rate of landslide has the same tendency, too.
(6) The minimum value of acceleration for occurrence of landslide seems to be about 200gal.
(7) A debris flow streams down with passable velocity over 10m/s and oscillation due to earthquake appears to take part in that.
