地震危険度解析 (V)

コロンビア・エクアドル・ベネズエラのハザード・マップ

抄録

Seismic risk analyses, which mean here to get regional distributions of maximum earthquake motion and convert them to seismic hazard maps, were made for Colombia, Ecuador and Venezuela, by using the seismic data, attenuation models and the method of extreme value fitting. Attenuation models for peak earthquake motion were put into three categories of maximum acceleration, maximum particle velocity and maximum displacement, and the least upper bound and the greatest lower bound of three categories were examined. In the present paper, Oliveira·McGuire model and Kanai model were used for maximum acceleration and maximum particle velocity, respectively. Colombia and Ecuador were attacked by 79 and 62 earthquakes with damage in the period 1800-1989, severally. The dead in the same period were 111, 855 by 46 events in Colombia and 105, 793 by 27 events in Ecuador. Colombia and Ecuador, therefore, are very intent on making seismic risk analyses and reducing earthquake disasters. Venezuela is located on the northern part of South American plate which make contact with Caribbean plate and seismic activity at the northern part of its territory is very high. During the period 1800-1989, Venezuela was hit by 39 earthquakes with damage and the dead in the period was 93, 834 by 24 events. The above facts have urged Venezuela to making the building code and mitigating earthquake disasters. The regional distributions of maximum earthquake motion and the seismic hazard map, whichwere investigated here for Colombia, Ecuador and Venezuela, will furnish basic data for these countries to make countermeasures against earthquake disasters.