Earthquake Offshore Southeast of Nemuro Peninsula on January 21

On January 21, 2016 at 06:53 (JST), there was a M5.1 earthquake (maximum seismic intensity 3) at a depth of 50 km offshore southeast of Nemuro peninsula. The focal mechanism (CMT solution) of this event showed a reverse fault type with a compression axis in a WNW-ESE direction.
For the seismic activity since October 2001, in the vicinity of the recent event (Area b), there have sometimes been earthquakes of M5.0 or over; there was a M6.0 earthquake (maximum seismic intensity 4) on August 25, 2002.
For the seismic activity since January 1923, in the area around the recent event (Area c), there was "the Nemuro-Hanto-Oki Earthquake of June 17, 1973" (M7.4, maximum seismic intensity 5) which caused damage with 27 injured persons and about 5,000 collapsed houses. It also caused tsunami with a maximum height of 280 cm from the mean sea-level observed at Hanasaki, Nemuro City (Disaster Records in 1973 and 1974, Hokkaido (1974)).

Japan Meteorological Agency
[Evaluation of Seismic Activities for January 2016 (February 9, 2016)]