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Response of seismicity to static and dynamic stress changes induced by the 2011 M9.0 Tohoku-Oki earthquake

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Abstract

[1] A growing body of evidence indicates that many earthquakes are triggered by static and dynamic stress changes following large earthquakes. However, it has been difficult to differentiate the roles of static and dynamic stress transfer on earthquake triggering. Here we focus on two adjacent seismic clusters aligned E-W beneath the Hida Mountain Range, central Japan, where spatially uniform static and dynamic stress changes resulted from the Tohoku-Oki earthquake. The rate of seismicity in the western cluster, detected by the matched filter technique, showed a slight increase after the mainshock, which can be explained by static stress transfer. In contrast, seismicity in the eastern cluster showed a marked increase due to dynamic stress change. The difference in the number of triggered events between these clusters indicates that dynamic stress change is more important than the static one in terms of remote triggering, provided that large-sized potential earthquake-nucleation patches are close to failure.

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