Weekly Earthquake Information 2022.12.4 Multiple earthquakes in Noto Peninsula, Ishikawa Prefecture Large earthquake in inland Canada – Weather News

2022/12/04 10:17 Weather News

The number of felt-earthquakes observed in Japan over the past week is at a lower level than the previous week.

Earthquakes are conspicuous in the Kanto region, and there are many earthquakes in the Noto Peninsula of Ishikawa Prefecture. There were two earthquakes with a seismic intensity of 3 or higher. (November 28th to December 4th at 10:00)

Japan: Number of felt earthquakes in Noto Peninsula, Ishikawa Prefecture increased in November

Earthquake in the Noto region of Ishikawa Prefecture

At around 17:07 on November 30 (Wednesday), an earthquake estimated to have a magnitude of 4.4 and a depth of 14 km occurred with an epicenter in the Noto region of Ishikawa Prefecture. This earthquake recorded a maximum seismic intensity of 3 in Suzu City and Noto Town, Ishikawa Prefecture. The mechanism of the earthquake is analyzed as a reverse fault type with a pressure axis in the north-northwest-southeast direction.

The earthquake in the Noto region of Ishikawa Prefecture has continued seismic activity since last spring. There were 15 felt-earthquakes in November, an increase compared to October. An earthquake with a maximum seismic intensity of 4 also occurred on November 14, and the activity is somewhat active.

Although this activity is thought to be related to fluids distributed underground, the detailed mechanism is not clearly understood at this time. There is no tendency for the activity to slow down, so please be careful of strong tremors in Suzu City, which is close to the epicenter.

Epicenters where anomalous seismic regions are likely to appear

Abnormal seismic regions often appear in deep earthquakes off the southeast coast of Mie Prefecture. In many earthquakes, areas with strong shaking are distributed concentrically from the epicenter. On the other hand, in deep earthquakes, strong tremors are transmitted along the subducting plate, and a phenomenon in which the tremors become larger far from the epicenter can be seen, and this is called an “abnormal earthquake zone.”

Other than the southeastern offshore of Mie Prefecture, similar deep earthquakes often occur in the Sea of ​​Okhotsk, the Sea of ​​Japan, the southern offshore of Tokaido, and the sea near Torishima, and once every few years, an earthquake with a magnitude of 6 or more also occurs.

Even if the tremors were small near the epicenter, strong tremors were transmitted far away. Mie Prefecture, which is close to the epicenter, did not have any locations where felt earthquakes were observed, and the maximum seismic intensity of 4 was observed in Ibaraki and Fukushima prefectures. A large-scale earthquake may cause tremors exceeding seismic intensity 5 lower, so caution is required.

Domestic: Ishikawa Prefecture, Noto Peninsula earthquake with seismic intensity 4

At around 22:28 on the 14th (Monday), an earthquake estimated to have a magnitude of 4.2 and a depth of 12 km occurred with an epicenter in the Noto region of Ishikawa Prefecture. This earthquake recorded a maximum seismic intensity of 4 in Suzu City, Ishikawa Prefecture, and a seismic intensity of 2 in Wajima City and Noto Town. The mechanism of the earthquake is analyzed as a reverse fault type with a pressure axis in the northwest-southeast direction.

It was the first time in regarding a month and a half since September 25th that an earthquake with a seismic intensity of 3 or more with an epicenter in the Noto region occurred. However, during that time, felt earthquakes continued to occur, with 8 earthquakes in October and 6 in November before this earthquake.

There are no signs at this time that the activity will subside, and strong tremors may continue in Suzu City, which is close to the epicenter. Please continue to pay attention to seismic activity.

There have been earthquakes as large as M6.0 in the past.

Shallow earthquakes associated with volcanic activity are well known when it comes to earthquakes in the Izu Islands, such as Izu Oshima and Miyakejima. Looking at the hypocenter distribution of the earthquakes that actually occurred around the Izu Islands, most of them occurred in the area from the northwest of Izu Oshima to the Izu Peninsula, and in the area from Miyakejima to Kozushima.

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 little more at depths of 100 km or more. These are 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: Areas with few M5.3 earthquakes in inland Canada

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

There have been no earthquakes of magnitude 6 or higher according to analysis by the United States Geological Survey. The largest earthquake had a magnitude of 5.9 on the Mid-Atlantic Ridge.

On the morning of November 30 (Wednesday) Japan time, an earthquake estimated to have a magnitude of 5.3 and a depth of regarding 10 km occurred in inland Canada. The earthquake mechanism is analyzed as a reverse fault type with a pressure axis in the north-northeast-south-southwest direction. Although it is believed that there was a strong tremor near the epicenter, it was far from the residential area, so there was no particular impact.

Most of the earthquakes that occur in Canada occur on the west coast near the boundary between the Pacific and North American plates. There are very few earthquakes in inland areas, and an earthquake with a magnitude of 4.5 or more that occurred near the epicenter this time goes back to 2015. Earthquakes exceeding magnitude 5 sometimes occur, but it is a region where large-scale earthquakes that cause major damage are unlikely to occur.

M6.1 in northwestern Turkey, area with past major earthquakes

On the morning of the 23rd (Wednesday) Japan time, an earthquake estimated to have a magnitude of 6.1 and a depth of regarding 10km occurred in northwestern Turkey. The earthquake mechanism is analyzed as strike-slip type. In the vicinity of the epicenter, it is believed that there was a maximum shaking of regarding VIII on the revised Mercalli seismic intensity scale.

Turkey is located on a huge bedrock called the Eurasian Plate. It is an area where distortion energy tends to accumulate in the bedrock, such as the boundary between the African plate and the Arabian plate. For this reason, there are many faults in Japan, and the earthquake that occurred on the 23rd is believed to have occurred near the North Anatolian fault.

Turkey, which is located on a plate boundary and is seismically active like Japan, has more than 100 fatal earthquakes since 1900. In 1999, a large earthquake with a magnitude of 7.6 called the “Izmit Earthquake” killed more than 10,000 people.

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.