Publication Date:
1989-01-01
Description:
Transient deformation resulting from postseismic stress relaxation in underlying viscoelastic layers is examined. The main purpose of the present study is to understand spatial and temporal modes of postseismic deformation especially due to strike-slip faulting with a realistic geometry. The fault size as well as the viscoelastic structure of the earth proved to have large effects on the amount of postseismic deformation. Therefore, it should be taken into serious consideration in modeling the faulting. It is noteworthy that the concentration of shear strain into the near field continues long after the faulting. This strain concentration is similar to the preseismic strain accumulation and is contrary to the coseismic strain release. The viscoelastic structure of the earth, however, is hard to determine solely by the surface measurements performed at long time intervals. Crustal movements in the Inner Zone of Southwest Japan, in particular, those associated with the 1927 Tango earthquake of M=7.5, are then investigated in connection with postseismic stress relaxation. The discrepancies between the observed and calculated postseismic deformations can be reduced if the effect of tectonic stress is added to the calculated deformation field. © 1989, The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan. All rights reserved.
Print ISSN:
0022-3743
Electronic ISSN:
1884-2305
Topics:
Geosciences
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