[ad_1]
02/28/2021 10:29 AM Weathernews
Last week, the number of earthquakes observed in Japan has been low compared to the previous week. On the other hand, there have been seven earthquakes with a seismic intensity of 3 or more. The number of earthquakes increased in the area from Tohoku to the Pacific side of Hokkaido. (Added from February 22 to 28 at 10:00)
Each of the four earthquakes occurred independently and, with the exception of the two earthquakes off the coast of Fukushima prefecture, there is believed to be little direct relationship.
Examples of earthquakes with a seismic intensity of 3 or more in a short period of time from different epicenters were in the central Nagano prefecture / Hida region in Gifu prefecture, off Fukushima prefecture and in the sea near Amami Oshima on May 19 last year. There are cases that occurred on March 13 in the Noto region of Ishikawa Prefecture, the Ariake Sea and the western part of Shimane Prefecture.
Although it is not possible to say that the frequent occurrence of such earthquakes is related to the expected large earthquakes, it may be a good idea to use it as an opportunity for regular preparations.
In Iyo-nada, earthquakes that occur within the subducting Philippine marine plate occur frequently. Recently, in March 2014, a magnitude 6.2 earthquake occurred slightly northwest of the epicenter, and a seismic intensity of 5 or more was observed in the city of Seiyo.
The same type of earthquake also includes the Geiyo earthquakes that occurred in 2001 and 1905, respectively.
The government headquarters for the promotion of seismic research is in the area from Aki Nada to Iyo Nada and the Bungo Canal, and the probability of an earthquake with a magnitude of 6.7 to 7.4 will occur in the next 30 years is about 40%. If the epicenter occurs close to the ground, there is a risk of a strong earthquake with a seismic intensity of 6 lower than 6 higher, making it an area that requires caution not only for large earthquakes caused by the Nankai Canal but also for such earthquakes.
On Wednesday the 24th Japan time, there was a magnitude 5.6 earthquake with an epicenter on the Reykjanes Peninsula in southwestern Iceland, and earthquakes of magnitude 4 and around have occurred frequently since then. According to the Icelandic Meteorological Office, as of Saturday the 27th, there were 26 earthquakes of magnitude 4 or greater, and more than 150 earthquakes of magnitude 3 or greater.
The epicenter this time occurred near the boundary between the Eurasian plate and the North American plate. The meteorological office has seen movement in the direction of the left lateral shift from analysis of ground movements from satellite images, and this movement is believed to be related to a number of seismic activities. The color code indicating the volcanic activity alert level for aircraft has not changed.
* Information on the epicenter and seismic intensity in Japan comes from the Japan Meteorological Agency, unless otherwise noted. Information on overseas epicenters comes from the United States Geological Survey (USGS) unless otherwise noted. The epicenter information may differ depending on the issuing organization.
