Deformation of the northeastern Japan arc inferred from rheology of rocks and minerals

Abstract

Rheology profiles created by recent results on rock mechanics and geophysical observations predict the current lithospheric deformation of the NE Japan arc. The lateral variation in the lithospheric strength well explains the current geodetic strain accumulation and shallow seismicity. The various mechanisms likely operated in the lithosphere (e.g. partial melting and grain size reduction) reduce viscosity significantly at deeper parts of the lithosphere. The strain localization along such weak zones may explain the estimates of viscosity by post-seismic creep and cause reactivation of pre-existing faults.