Earthquake Offshore East of the Osumi Peninsula on April 2

On April 2, 2025, at 23:03, an M6.1 earthquake (maximum seismic intensity 4) occurred offshore east of the Osumi Peninsula, at a depth of 36 km. The earthquake's focal mechanism (CMT solution) indicated a reverse fault type, with a pressure axis oriented in a west-northwest to east-southeast direction. This seismic event occurred at the boundary between the Philippine Sea Plate and the continental plate. Just a few days earlier on March 29, 2025, an M4.6 earthquake (maximum seismic intensity 3) near its epicenter (Area b)
A review of seismic activity since October 1997 reveals that M5.0 or greater earthquakes have occasionally occurred around the epicenter of this earthquake (Area b). Notably, an M6.0 earthquake (maximum seismic intensity 4) occurred on June 25, 2000.
Furthermore, a review of seismic activities since 1919 shows that earthquakes of M6.0 or greater have occurred seven times around the epicenter of this earthquake (Area c). This includes the M7.3 earthquake on July 13, 1923, which damaged 27 houses in Nakatane Village (present-day Nakatane Town) in Kagoshima Prefecture (according to data from the "Materials for Comprehensive List of Destructive Earthquakes in Japan").

Japan Meteorological Agency
[Evaluation of Seismic Activities for April 2025 (May 13, 2025)]