GROUND MOTION CHARACTERISTICS IN LOCAL CITY IN KANTO AREA, JAPAN ESTIMATED BY MODERATE EARTHQUAKES -FOR SEISMIC DISASTER PREVENTION AT CHOSHI CITY-

摘要

For seismic disaster prevention, it is important to know how differences of ground motion in and around the target area. In this paper, ground motion characteristics at Choshi, that is a local city located in east part of Kanto plain, Japan, were investigated using moderate and small earthquake records. At the site covered over soft soil, it always observes seismograms with big amplitude. And instrumental seismic intensity is larger than the other sites. Going to west part of Choshi, the depth to bedrock increases. And instrumental seismic intensity becomes also larger gradually. But it is difficult to conclude that the different of seismic intensity between west and east part of Choshi is effects of deep understructure condition or not.