2D resistivity model around the rupture area of the 2011 Tohoku-oki earthquake (Mw 9.0)

Abstract The 2011 Tohoku-oki earthquake ( M w 9.0) was characterized by a huge fault slip on the shallowest part of plate interface, where behavior had been believed to be aseismic. In this study, we modeled two-dimensional resistivity distribution across area based ocean-bottom electromagnetic measurements understand physical properties around interface controlling rupture processes. optimal 2D model showed conductive coseismic observed, whereas deeper nucleated relatively more resistive. interpreted have high pore seawater fraction, as dry area. These findings are consistent with hypothesis that aseismic frictional conditions changed enhancing when propagated wet, clay-rich also revealed under outer-rise Pacific Plate. This finding supports existence hydrated oceanic crust supplied aqueous water subduction zone, including Graphical