Earthquake Under the Ocean Area near Miyakojima Island on October 16

On October 16, 2023 at 19:42 (JST), there was an M6.0 earthquake (maximum seismic intensity 4) at a depth of 17 km (due to CMT solution) under the ocean area near Miyakojima Island. The focal mechanism (CMT solution) showed a strike-slip fault with a tension axis in an NE-SW direction. This event occurred within the continental plate. In the vicinity of the recent event, till 31^st there occurred 6 earthquakes (maximum seismic intensity: number of earthquakes, 4: 1, 2: 2, 1: 3) with seismic intensity 1 observed. In the vicinity of the recent event (Area a), seismic activity became high temporally after the earthquake on October 16, 2023.
For the seismic activity since July 2000, there have sometimes been earthquakes of M5.0 or over. In the area around the recent event (Area b), there was an M6.4 earthquake (maximum seismic intensity 3) on August 18, 2001. Also, there was an M6.1 earthquake (maximum seismic intensity 4) on December 26, 2021.
For the seismic activity since 1919, in the region around the recent event (Area c), there have sometimes been earthquakes of M6.0 or over. Among them, an M7.2 earthquake (maximum seismic intensity 4) on June 10, 1938 caused tsunami of 1.5 m height witnessed at Hirara Port, Miyakojima Island and damage with outflow of piers and so on. Also, an M7.2 earthquake (maximum seismic intensity 5) on March 11, 1958 caused damage with 2 fatalities, 4 injured persons, damaged houses and so on in the Sakishima Islands (damage: Materials for Comprehensive List of Destructive Earthquakes in Japan).

Japan Meteorological Agency
[Evaluation of Seismic Activities for October 2023 (November 10, 2023)]