Weekly Earthquake Information 2023.5.28 May 5th seismic intensity 5 below or greater M6.2 earthquake off the east coast of Chiba Prefecture – Weather News

At approximately 19:03 on the 26th (Friday), an earthquake estimated to be 6.2 magnitude and 50 km deep occurred off the east coast of Chiba Prefecture. Choshi City, Asahi City, Chiba Prefecture, Kamisu City, Ibaraki Prefecture, and Kamisu City, Ibaraki Prefecture, were affected by this earthquake. Seismic intensity 3 shaking was observed over a wide area in the south.

The mechanism of the earthquake is a type of reverse fault with an east-west axis of pressure, and it is believed to have occurred at the boundary between the Pacific plate and the Philippine Sea plate.

A magnitude 6 earthquake has occurred off the east coast of Chiba Prefecture. Near the epicenter this time, a magnitude 6.0 earthquake occurred on April 21, 2011, and a magnitude 6.1 earthquake occurred on April 11, 2005.

This is the fifth earthquake with a seismic intensity of 5 below or more since the beginning of May, and the number of such earthquakes in a month is the first since April 2016, when the Kumamoto Earthquake occurred, which occurred 22 times.

At approximately 16:42 on the 22nd (Monday), an earthquake estimated to be 5.3 in magnitude and 11 km deep occurred near Niijima and Kozushima. In this earthquake, a maximum seismic intensity of 5 lower was observed in Toshima Village, Tokyo, a seismic intensity of 4 in Niijima Village, and a seismic intensity of 3 in Higashiizu Town and Makinohara City, Shizuoka Prefecture.

The mechanism of the earthquake is a type of strike-slip fault with a tension axis in the northeast-southwest direction, and is believed to have occurred within the crust.

Earthquake swarms occur frequently in the sea near Niijima and Kozushima. Recently, there has been active seismic activity in 2020, and an earthquake with a magnitude of 5.0 and a maximum seismic intensity of 5 lower occurred on December 18. Two weeks later, on January 1 of the following year, an earthquake occurred with a magnitude of 4.7 and a maximum seismic intensity of 4. In addition, in 2000, the activity continued for several months in conjunction with the eruptive activity of Miyakejima.

This time, more than 50 earthquakes that can be felt in the body have occurred during the two days from the 22nd (Monday) to the 23rd (Tuesday). Since then, the activity has calmed down, but as of the 27th (Saturday), there are still many earthquakes, so we need to pay attention to strong tremors for now.

There have been six earthquakes of magnitude 6 or greater according to US Geological Survey analysis. The largest was magnitude 6.5 off the coast of Panama.

Around noon on the 25th (Thursday) Japan time, an earthquake estimated to be 6.5 km in size and about 13 km deep occurred with an epicenter in the Caribbean Sea near the border of Panama and Colombia. The earthquake mechanism is analyzed as a type of reverse fault with a pressure axis in the north-northeast-south-southwest direction.

Three plates, the South American plate, the Caribbean plate, and the Nazca plate, are in contact with each other near the epicenter of this earthquake, making it an area where earthquakes occur frequently. In 1974, a magnitude 7.3 earthquake occurred on land slightly larger than this time.

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