Earthquake Offshore Iwate Prefecture on February 17

On February 17, 2015 at 13:46 (JST), there was a M5.7 earthquake (maximum seismic intensity 5 Upper) at a depth of 50 km (near the boundary between the Pacific and the continental plates), offshore Iwate prefecture. The focal mechanism (CMT solution) showed a reverse fault type with a compression axis in an NW-SE direction.
For the seismic activity since October 1997, in the vicinity of the recent event (Area b), seismic activity is high after "the 2011 off the Pacific Coast of Tohoku Earthquake."
For the seismic activity since January 1923, in the area around the recent event (Area c), there have sometimes been earthquakes of M6.0 or over before "the 2011 off the Pacific Coast of Tohoku Earthquake."

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