Earthquake Offshore Sanriku on December 7 (2)

For the seismic activity since 1923, in the region near Japan Trench offshore Sanriku including the recent event (Area b), there have often been earthquakes of M6 class, and there was a M8.1 earthquake (maximum seismic intensity 5, Showa Sanriku Earthquake) on March 3, 1933. Although damage by seismic ground motion was little in this event, tsunamis caused great damage to coasts from Hokkaido to Sanriku. The maximum height among measured tsunami marks was 28.7 m (height from mean sea level) in Ryori Bay, Iwate prefecture (tsunami height and damage after Comprehensive Bibliography of Destructive Earthquakes in Japan, Latest Edition).

Japan Meteorological Agency
[Evaluation of Seismic Activities for November 2012 (December 11, 2012)]