Weekly information about earthquakes 2023.1.1 Seismic activity is relatively quiet at the end of the year, seismic intensity 3 in East Kochi Prefecture – Weather News

At around 1:47 am on December 29 (Thursday), an earthquake with a magnitude of 4.4 and a depth of 35 km occurred with its epicenter in eastern Kochi prefecture. In this earthquake, a maximum seismic intensity of 3 was observed in Kochi City, Konan City, Kami City, Kochi Prefecture, Mima City, Tokushima Prefecture and Miyoshi City.

It was the first time in about 19 years since August 2003 that an earthquake with a seismic intensity of 3 or greater was concentrated in eastern Kochi prefecture. The earthquake mechanism is analyzed as a reverse fault type with a pressure axis in the northeast-southwest direction.

Most of the earthquake damage in Kochi Prefecture is caused by massive earthquakes along the Nankai Trough. Although there is believed to be a northeast-extending fault zone near the epicenter of this earthquake, the detailed activity is unknown. There are no records of major damage from earth quakes like this in Kochi Prefecture.

There was an earthquake measuring 6 or greater according to analysis by the US Geological Survey. The largest earthquake was a magnitude 6.0 off the coast of Vanuatu.

In the early hours of Thursday, December 29 (Japan time), an earthquake with an estimated magnitude of 6.0 and a depth of approximately 10 km occurred in the South Pacific Ocean near Vanuatu. The seismic mechanism is analyzed as strike-slip. As the epicenter was far from the island, there was no impact from the shaking.

Various types of earthquakes occur in the sea near Vanuatu because the boundary between the Pacific Plate and the Australian Plate is complicated. The epicenter of this time is a bit away from the region where earthquakes are concentrated at the plate boundary, so it appears that the earthquake is caused by rupture within the plate.

*Information on earthquake sources and seismic intensity in Japan is from the Japan Meteorological Agency unless otherwise specified. Overseas epicenter information is from the United States Geological Survey (USGS) unless otherwise noted. There may be differences in hypocenter information depending on the publishing organization.