Seismic Activity offshore Sanriku beginning on February 17 (2)

b. Focal mechanism.
The focal mechanisms (CMT solutions) of earthquakes in the recent seismic activity showed a reverse fault type with compression axis in almost WNW-ESE direction.

c. Past seismic activity.
For the seismic activity since January 1923, in the area around the recent event (Area b), there have often been sequences of earthquakes of maximum M7 class.
In addition, in the region around the Area b, there were the 1968 Tokachi-Oki Earthquake (M7.9, maximum seismic intensity 5) and the 1994 Sanriku-Harukaoki Earthquake (M7.6, maximum seismic intensity 6), wich caused damage.

Japan Meteorological Agency
[Evaluation of Seismic Activities for February 2015 (March 10, 2015)]