The northern part of Honshu and Hokkaido lie above the convergent plate boundary , where the Pacific Plate is subducting beneath the Okhotsk Plate . The convergence rate across this boundary lies in the range of 7.9 – 9.2 cm per year . The plate interface in the area of the earthquake epicenter shows an abrupt increase in dip from about 5 ° to about 15 ° , 80 km landward of the Japan Trench . This part of the plate boundary has been the location of many powerful historical earthquakes , dating back to the 869 Sanriku earthquake and most recently of the devastating 2011 Tōhoku earthquake . Most of these events relate to rupture along the plate interface , but some , such as the 1933 Sanriku earthquake , involved deformation within the subducting plate . According to the studies of past great earthquakes , a weak seismic coupling is suggested in the offshore Sanriku region . From the distribution of past seismicity , the width of coupling at 40 ° N was assumed to be about 150 km
2011 Tōhoku earthquake
2011 Tōhoku earthquake and tsunami
1994 offshore Sanriku earthquake