Seismic Activity in the Ocean near Tokara Islands (near Kodakarajima Island)

In the ocean near Tokara Islands (near Kodakarajima Island) in February 2022, there were 12 earthquakes with seismic intensity 1 or over (maximum seismic intensity: number of earthquakes, 3: 1, 2: 5, 1: 6). The largest seismic intensity was observed at the time of an M3.2 earthquake (maximum seismic intensity 3, ① in the figure) occurring on 20^th at 11:30 (JST). The largest was an M3.5 earthquake (maximum seismic intensity 1, ② in the figure) on 20^th at 00:36 (JST). These events occurred within the continental plate.
For the seismic activity since October 1994, in the vicinity of the recent activity (Area a), there have sometimes been clusters of earthquakes. The most recent is a seismic activity beginning on December 4, 2021 at about 12 o'clock, and till December 31 at 24 o'clock, there occurred 308 earthquakes with maximum seismic intensity 1 or over (maximum seismic intensity: number of earthquakes, 5 Upper: 1, 4: 2, 3: 15, 2: 85, 1: 205). The largest was an M6.1 earthquake (maximum seismic intensity 5 Upper) occurring on 9^th at 11:05 (JST). Although the recent seismic activity caused no human damage nor damage to the house, it caused landslide and so on at Akusekijima Island, Toshima Village, Kagoshima prefecture (as of December 23, 2021, Kagoshima prefecture). Also in April 2021 there was a seismic activity, the largest being M5.3 earthquakes (maximum seismic intensity 4) on 10^th and 12^th, and there occurred 265 earthquakes with seismic intensity 1 or over (including 6 earthquakes with maximum seismic intensity 4). In addition, in a brisk seismic activity in October 2000, a M5.9 earthquake (maximum seismic intensity 5 Upper) on 2^nd caused damage with a water-pipe breakage and so on at Akusekijima Island, Toshima Village, Kagoshima prefecture (Fire and Disaster Management Agency).
For the recent seismic activity and the past major seismic activities, by comparing epicenter distribution diagrams, hypocenter distribution in time and space diagrams, M-T diagrams and cumulative number diagrams in 120 days period, we see that there are various forms of activity and it is difficult to identify the end time of a seismic activity

Japan Meteorological Agency
[Evaluation of Seismic Activities for February 2022 (March 9, 2022)]