Evidence that a complete stress release may have contributed to the 2011 Tohoku earthquake that broke records. Both sedimentary formations above and below the plate boundary fault lie in the stress state of normal faults in which vertical stress is greater than maximum horizontal stress. The new data show good consistency with previous results above the fault — at the boundary between the North American plate and the subducting Pacific plate — suggesting that combining geophysical data and core samples to comprehensively investigate stress states is effective.