Seismic Activity in Northern Wakayama Prefecture Since October 23
In northern Wakayama Prefecture, there were rather concentrated seismic activities since around 7:00 on October 23, including 12 earthquakes with seismic intensity 1 or over (maximum seismic intensity: number of earthquakes, 3: 1, 2: 4, 1: 7) from October 23 to 31. The largest of these earthquakes was an M4.0 earthquake (maximum seismic intensity 3) at 7:08 am on October 23. The earthquake occurred in the crust. The focal mechanism of this earthquake was of the type with a compression axis in the WNW-ESE direction. The number of earthquakes has been decreasing over time.
For the seismic activity since October 1997, the area around the current seismic activity (Area a) is an area of constant seismic activity. Recently, seismic activity became active in February 2021, and 25 earthquakes of seismic intensity 1 or over were observed from February 15 to 28. The largest of these earthquakes was an M4.0 earthquake (maximum seismic intensity 4) on February 15.
For the seismic activity since 1919, earthquakes exceeding M5.0 have sometimes occurred near the current earthquake activity (Area b). Among these, the M6.7 earthquake on June 15, 1948 caused 2 deaths, 33 injuries, and 60 houses collapsed (damage data: according to the "Materials for Comprehensive List of Destructive Earthquakes in Japan").
Japan Meteorological Agency
[Evaluation of Seismic Activities for October 2024 (November 12, 2024)]