2022/09/11 11:09 Weather News
Earthquakes are conspicuous in the northern part of Kanto and the sea near the Tokara Islands. There were two earthquakes with a seismic intensity of 3 or higher. (September 5th to September 10th at 10:00)
Japan: Temporary increase in felt earthquakes in the Tokara Islands
This is the first time in about seven months since February 20, 2018 that an earthquake with a seismic intensity of 3 or higher centered in the sea near the Tokara Islands.
In the waters near the Tokara Islands, the number of felt earthquakes has increased since seismic intensity 1 at 22:30 on the 9th (Friday), and 9 times by the 10th (Saturday). Seismic activity has been in a lull since the afternoon of Saturday 10th.
The area around the epicenter of this time is an area where earthquake swarms have occurred many times in the past. In the activity from December last year, a strong earthquake with a magnitude of 6.1 and a maximum seismic intensity of upper 5 occurred. At this time, it is not clear whether there will be a swarm of earthquakes from now on or whether it will settle down as it is. Be careful of strong tremors for a while.
Japan: Seismic intensity 3 at eastern Kanagawa prefecture
The mechanism of the earthquake is analyzed as a reverse fault type with a pressure axis in the west-northwest-east-southeast direction. This is the first time an earthquake with a seismic intensity of 3 or more with an epicenter in eastern Kanagawa occurred in February this year. The February quake had an epicenter as deep as 100 km, which is the first since the February 2016 magnitude 4.6 earthquake with a depth of 26 km.
At a depth of around 30 km in eastern Kanagawa Prefecture, earthquakes with a magnitude of around 5 occur occasionally. In November 1923, there was an earthquake of magnitude 6.3, which is thought to be an aftershock of the Great Kanto Earthquake or related activity.
The Cabinet Office’s assumption of an earthquake directly hitting the Tokyo metropolitan area includes an earthquake with an epicenter in Kanagawa Prefecture, so it is essential to take countermeasures on a daily basis.
Japan: A series of earthquakes occurred in the Kanto region on the 3rd (Sat)
In addition, at around 16:34, an earthquake estimated to have a magnitude of 3.8 and a depth of about 50 km occurred with an epicenter in the southern part of Ibaraki Prefecture. At 17:39, an earthquake with a magnitude of 3.9 and a depth of about 40 km occurred with an epicenter in Ibaraki Prefecture, and a seismic intensity of 2 was observed in Hitachi City and Takahagi City, Ibaraki Prefecture.
Both occurred in areas with many earthquakes, and it is thought that it was a coincidence that they occurred one after another on the 3rd (Saturday).
There have been earthquakes as large as M6.0 in the past.
Most of the earthquakes are concentrated at a depth of around 10 km even in the depth of the east-west cross section. There are few occurrences at depths of 20 km or more, but there are a few at depths of 100 km or more. Earthquakes that occur near the boundary between the Pacific plate and the Eurasian plate or within the Pacific plate.
Most deep earthquakes are around magnitude 4, but in May 2014, a large earthquake with a magnitude of 6.0 occurred. In this earthquake, a maximum seismic intensity of 5 lower was observed in Chiyoda Ward, Tokyo, and a seismic intensity of 3 to 4 was observed in a wide area of the Kanto region, causing damage such as injuries.
World: M6.6 in Sichuan, China, major damage
Early in the morning of the 5th (Monday) Japan time, an earthquake estimated to have a magnitude of 6.6 and a depth of about 10 km occurred with an epicenter in Sichuan Province, China. The earthquake mechanism is analyzed as strike-slip type.
There were strong tremors near the epicenter, and local reports reported that many buildings were damaged, landslides occurred, and many people died.
Sichuan Province has many earthquakes in China, especially earthquakes accompanying shallow strike-slip faults on the western edge of the Sichuan Basin, which often cause great damage. Recently, a magnitude 6.6 earthquake occurred in 2013 just to the northeast of this epicenter, and in 2008 a magnitude 7.9 earthquake called the “Sichuan Great Earthquake” occurred, causing enormous damage.
M7.6 in Papua New Guinea, world’s largest this year
The mechanism of the earthquake had a large strike-slip component, and because the epicenter was on land, there was no tsunami. A strong tremor of VIII on the revised Mercalli seismic intensity scale is believed to have occurred near the epicenter, and there are concerns about damage caused by the tremor.
Papua New Guinea is located on the boundary between the Pacific plate and the Australian plate, and is a region where large earthquakes occur frequently. In 2019, an earthquake with a magnitude of 7.1 occurred near the epicenter of this earthquake.
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.