Investigation of the probability of changing fault activity

Sone, Yoshinori*; Hosoda, Hiroshi*; Miwa, Atsushi*; Shimoyama, Masahiro*

JNC TJ7420 2005-011, 104 Pages, 1999/03

It is important study that to seize development, resumption, pause of fault in the future and probability of changing fault activity. As a result, we will be able to presume the stability of geo-environment. In this paper, we study the inversion tectonics, probability of fault's development, and relationship between distribution of active fault and hypocenter distribution.Regional character of tectonic inversion: in the Northeast Japan, tectonic inversion of normal-reverse fault system (stress of normal-reverse fault type) is mainly developed. In the Southwest Japan, strike-slip inversion (stress of lateral fault type) is mostly developed. Probability of fault's development: With the lapse of time from the period before 2Ma to 2-0.5Ma, the number of fault had increased. With the lapse of time from 2-0.5Ma to 0.5-present time, the number of fault has decreased. This result is opposite from present stress status. It is needful to consider probability of fault's development by investigating the past study.