Earthquake Offshore South of Tokaido on October 21

On October 21, 2021 at 17:36 (JST), there was an M5.6 earthquake (maximum seismic intensity 3) at a depth of 356 km, offshore south of Tokaido. This event occurred within the Pacific plate. The focal mechanism (CMT solution) had a compression axis in an NNW-SSE direction.
Seismic intensity 3 was observed in Utsunomiya City, Tochigi prefecture, and seismic intensity 2~1 was observed in Tohoku and Kanto-Kou-Shin-Etsu regions and Wakayama prefecture. Larger shaking was observed in the area far from the epicenter than the vicinity of the epicenter: the phenomena is called as the "Abnormal Seismic Intensity."
For the seismic activity since October 1997, in the vicinity of the recent event (Area b), there have sometimes been earthquakes of M5.0 or over. On January 1, 2012, there was an M7.0 earthquake (maximum seismic intensity 4).
For the seismic activity since 1919, in the area extending from the vicinity of the recent event to offshore west of the Ogasawara Islands, there have sometimes been deep earthquakes of M7.0 or over.

Japan Meteorological Agency
[Evaluation of Seismic Activities for October 2021 (November 10, 2021)]