STRAIN DROP AND APPARENT STRAIN FOR LARGE EARTHQUAKES

被引:17
作者
KIKUCHI, M
机构
[1] Yokohama City University (22-2 Seto, Kanazawa-ku, Yokohama
关键词
D O I
10.1016/0040-1951(92)90054-A
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Two kinds of strains are considered: the strain drop (DELTAsigma-2mu) and the apparent average strain. The latter is given by the ratio between the seismic wave energy and the seismic moment (E(s)/M(o)). These two kinds of strains are related as (E(s)/M(o)) = eta(e)(DELTAsigma/2mu) where eta(e) is a phenomenological constant which coincides with the seismic efficiency if the final stress across a fault plane is equal to zero. Eta(e) is also interpreted in terms of a frictional sliding model. Using the values estimated from the inversion of long-period waves for large earthquakes, a diagram of (E(s)/M(o)) versus (DELTAsigma/2mu) is constructed. It is shown that the value of eta(e) is in general as small as approximately 0.1. A systematic discrepancy can be seen among three groups: (A) shallow inland strike-slip event; (B) ocean-bottom dip-slip event; (C) deep focus event. The value of eta(c) for (C) is smaller than that for (A) and (B), suggesting that deep focus events are associated with a different slip characteristics than shallow events. On the other hand, the strain drop for (B) is smaller than that for (A) and (C), indicating that the strain drop for intra-plate earthquakes is larger than that for inter-plate earthquakes.
引用
收藏
页码:107 / 113
页数:7
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