Shortening of recurrence interval of Boso slow slip events in Japan

Abstract

A slow slip event occurred off the coast of the Boso peninsula, Japan, from approximately 28 December 2013 to 10 January 2014. The estimated aseismic slip expanded slightly southward and westward over time with a moment magnitude of 6.5, which was the smallest value since 1996. The recurrence interval has decreased from approximately 6.4 to 2.2years from 1996 to 2014. One explanation of this shortening is the change in Coulomb failure stress due to the 2011 Mw9.0 Tohoku earthquake and its afterslip. Another interpretation is related to a scenario observed in several numerical simulation studies, in which the recurrence interval of slow slip becomes shorter as the time nears a large earthquake. This case will constrain the physical processes of a slip cycle. The Boso slow slip events together with the Tohoku earthquake and its afterslip changed the stress state for the anticipated interplate earthquake near the Sagami trough. Key Points Spatial and temporal slow slip process in Boso slow slip, Japan Shortening of the recurrence interval DCFS is increasing after the Tohoku earthquake ©2014. American Geophysical Union. All Rights Reserved.