Earthquake Offshore Northeast of Amami-Oshima Island on March 9
The place name of the epicenter used by the JMA's information released about the M5.8 earthquake at 03:54 on March 9 was the "ocean area near Amami-Oshima."
On March 9, 2025, at 03:54 a.m. an M5.8 earthquake (maximum seismic intensity 4, earthquake (1)) occurred offshore northeast of Amami-Oshima Island, at a depth of 14 km (according to CMT solutions). The earthquake's focal mechanism (CMT solution) displayed NW-SE pressure axis. At 08:42 on the same day, about 5 hours after the first earthquake (1), an M5.9 earthquake (maximum seismic intensity of 3, earthquake (2)) occurred at a depth of 23 km (according to the CMT solution). The focal mechanism (CMT solution) revealed a pressure axis oriented in the WNW-ESE direction. Seismic activity near the epicenter (Area a) experienced a slight increase from the 9th to the 11th. By the 31st, a total of 12 earthquakes with a seismic intensity 1 or greater had been recorded (1 earthquake with a seismic intensity 4, 1 event with a seismic intensity 3, 4 events with a seismic intensity 2, and 6 events with a seismic intensity 1). Since then, the number of earthquakes has gradually decreased.
A review of seismic activity since October 1994 reveals that an M5.3 earthquake occurred in Area a on August 13, 2006, followed by an M5.4 earthquake on September 1, 2006. Additionally, two major earthquakes occurred approximately 80 km south-southeast of recent events: an M6.9 earthquake (maximum seismic intensity 5) on October 18, 1995, and an M6.7 earthquake (maximum seismic intensity 5) on October 19, 1995. These earthquakes resulted in one injury and caused partial damage to four houses on Kikaijima Island. Furthermore, they triggered tsunamis along the Pacific coast, stretching from the Kanto region to Okinawa Prefecture, including a 43 cm tsunami (the maximum height above normal tide level) recorded on Nakanoshima Island 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 March 2025 (April 9, 2025)]