“Recent Earthquake Trends in Japan and Around the World: Up-to-Date News and Information”

2023-05-28 01:27:00

2023/05/28 10:27 Weather News

The number of felt-earthquakes observed in Japan over the past week has increased significantly compared to last week.

Most of the earthquakes occurred in the waters near the Tokara Islands and the Izu Islands, and earthquakes around the Boso Peninsula are also noticeable. There were 11 earthquakes with a seismic intensity of 3 or higher, two of which had a seismic intensity of lower 5. (Tally from May 22nd to May 28th at 10:00)

Japan: An earthquake off the eastern coast of Chiba prefecture with a seismic intensity of 5 lower occurred near the plate boundary

Earthquake off the east coast of Chiba Prefecture

At around 19:03 on the 26th (Friday), an earthquake estimated to have a magnitude of 6.2 and a depth of 50 km 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. A seismic intensity 3 shaking was observed over a wide area in the south.

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

A magnitude 6-class 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 lower 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.

What is the seismic trend in southern Chiba Prefecture so far?

Underneath the southern part of Chiba Prefecture, the North American plate, the Philippine Sea plate, and the Pacific plate intertwine, creating a complex structure. Looking at the distribution of hypocenters since 2001, we can see that the areas with many earthquakes are roughly divided into areas with a depth of 10 to 20 km, around 40 km, which is the same as this time, and around 70 km.

The 5.2-magnitude earthquake that occurred in July 2012 occurred near the southern end of the Boso Peninsula, and was of a slightly deeper type with a depth of 88 km. Magnitude 5.2 in August 2007 is a shallow type with a depth of 20 km.

In this area, there are cases where strong earthquakes occur in the sea areas off the southeast of Chiba Prefecture and off the east of Chiba Prefecture, rather than land areas, so it is essential to be prepared on a regular basis.

Japan: The earthquake near Niijima and Kozushima also has a seismic intensity of lower 5

Earthquake near Niijima and Kozushima

At around 16:42 on the 22nd (Monday), an earthquake estimated to have a magnitude of 5.3 and a depth of 11 km 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 strike-slip fault type with a tension axis in the northeast-southwest direction, and is thought to have occurred within the crust.

Earthquake swarms frequently occur in the sea near Niijima and Kozushima. Recently, there was active seismic activity in 2020, and an earthquake with a magnitude of 5.0 and a maximum seismic intensity of lower 5 occurred on December 18. Two weeks later, on January 1 of the following year, an earthquake with a magnitude of 4.7 and a maximum seismic intensity of 4 occurred. In addition, in 2000, 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 in the two days from 22nd (Monday) to 23rd (Tuesday). Since then, the activity has calmed down, but as of the 27th (Saturday), there are still many earthquakes, so it is necessary to pay attention to strong tremors for the time being.

Japan: A strong earthquake in January this year with a seismic intensity of 4 in Hyuga Nada

World: M6.5 near the border of Panama and Colombia

Earthquakes of M4.5 or higher around the world (quoted from USGS website/processed by Weathernews)

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

Around noon on the 25th (Thursday) Japan time, an earthquake estimated to have a magnitude of 6.5 and a depth of about 13 km occurred with an epicenter in the Caribbean Sea near the border of Panama and Colombia. The earthquake mechanism is analyzed as a reverse fault type 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 a little more than this time.

world:

Reference materials, etc.

*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 specified. There may be differences in hypocenter information depending on the publishing organization.

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