Earthquake Off-shore East of the Chishima Islands [Off-shore of the Chishima Islands] on January 16
On January 16, 2009, at 02:49 (JST) there was a M7.4 earthquake off-shore east of the Chishima Islands (Moment magnitude from a global CMT analysis is also Mw7.4; maximum seismic intensity 2 in Japan.). The focal mechanism (Global CMT analysis) showed a reverse fault with a compression axis in a WNW-ESE direction. It is thought that this event occurred within the Pacific plate. Associated with this event, small tsunamis were seen on Chichijima.
To the southwest of this event (near the trench axis), there was a Mw8.1 earthquake on January 13, 2007 (Magnitude determined by Japan Meteorological Agency is Mj8.2). In addition, on the northwest side of the trench axis, there was a Mw8.3 event on November 15, 2006 (Magnitude determined by Japan Meteorological Agency is Mj7.9).
Japan Meteorological Agency
[Seismic Activity for January 2009 (February 9, 2009)]