Possibility of recovery of slip deficit rate between the North American plate and the Pacific plate off Sanriku, northeast Japan

Abstract

The analysis of global positioning system (GPS) data shows an increase in the westward ground velocity in Iwate, northeast Japan, from around 2003, after a period of roughly constant crustal deformation rate. The spatiotemporal study of time series of displacements reveals that the westward slip deficit rate increased slightly from 2001 to 2003 at the deeper part of the source region of the 1994 Sanriku-oki earthquake. The increase has been considerable since January 2003, and the area of increased slip deficit rate has expanded, and now covers the source region of the 1994 Sanriku-oki earthquake. This indicates that the restoration of the slip deficit rate, which was affected by the 1994 earthquake, was not completed in the period from 1994 to 2003. Copyright 2007 by the American Geophysical Union.