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GPS observations of postseismic deformation for the 1995 Hyogo‐Ken Nanbu Earthquake, Japan
Author(s) -
Nakano Takehide,
Hirahara Kazuro
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl00375
Subject(s) - aftershock , geology , geodesy , deformation (meteorology) , seismology , global positioning system , power law , relaxation (psychology) , exponential function , exponential decay , physics , statistics , mathematics , oceanography , psychology , social psychology , telecommunications , nuclear physics , mathematical analysis , computer science
11‐months of GPS observations, which started within 2 days of the 1995 Hyogo‐ken Nanbu earthquake, detected significant postseismic crustal deformation that reached 20 mm at some stations. A comparison of postseismic and coseismic deformation shows a similar pattern in the direction of displacements. We tried to determine the predominant relaxation mechanism by examining the time dependence of observed postseismic deformation. We considered three models: an exponential, a power‐law, and a logarithmicaly decaying model. However, each of these three time‐dependent models can explain the observed data, equally well. In case of the exponential relaxation model, the relaxation time constant was estimated to be about 50 days. In the power‐law model, the index p was nearly 1.0; this is almost the same as the p value of Omori's decay law of aftershock sequences for this event. This suggests that the mechanism causing postseismic deformation may be related to that producing aftershocks.