Weekly Earthquake Information 2023.1.15 Seismic intensity 3 earthquake in western Kanagawa Prefecture Area with many active faults – Weather News

At around 12:19 on the 11th (Wednesday), an earthquake estimated to have a magnitude of 4.1 and a depth of 13 km occurred with an epicenter in western Kanagawa Prefecture. In this earthquake, a maximum seismic intensity of 3 was observed in Sagamihara City, Hadano City, Matsuda Town, etc. in Kanagawa Prefecture, and a seismic intensity of 1 or 2 was observed from Kanagawa Prefecture to Tokyo, Shizuoka Prefecture, and Yamanashi Prefecture.

It was the first time in about two months since November 17 last year that an earthquake with an epicenter in western Kanagawa Prefecture had a seismic intensity of 3 or higher. The earthquake mechanism is analyzed as strike-slip type.

Multiple active faults are distributed in the western part of Kanagawa Prefecture, including the Kozu-Matsuda fault zone, the Hirayama-Matsuda north fault zone, and the Shiozawa fault zone. The epicenter this time was near the Kurokura fault, which extends along the extension of the Shiozawa fault zone.

The government’s Headquarters for Earthquake Research Promotion is evaluating the activity of the Shiozawa fault zone, and the probability of a magnitude 6.8 earthquake occurring within the next 30 years is less than 4%. Among the active faults under evaluation, this group has a high probability of occurrence.

Even with a magnitude 6 earthquake, the epicenter is shallow on land, so there is a risk of strong tremors.

There has been one earthquake with a magnitude of 6 or higher according to US Geological Survey analysis. The largest earthquake was a magnitude 7.6 that occurred off the coast of Indonesia.

An earthquake estimated to have a magnitude of 7.6 and a depth of about 105 km occurred early in the morning of the 10th (Tuesday) Japan time, with an epicenter in the Banda Sea of ​​Indonesia. The mechanism of the earthquake is analyzed as a reverse fault type with a pressure axis in the northeast-southwest direction. It was the first time in about four months since the September 19th earthquake in Mexico last year that an earthquake of magnitude 7.5 or higher occurred.

Since the epicenter was far from the populated island, there were no reports of damage caused by the tremors. Also, because the epicenter was deep, there was no tsunami.

The Banda Sea is a region where the Eurasian plate, Australian plate, Pacific plate, Philippine Sea plate, etc. are all closely packed, and has a very complicated structure.

Many earthquakes in the latter half of the magnitude 7 class have occurred, and in 1963 a huge earthquake of magnitude 8.1 occurred in the immediate vicinity of this epicenter. In addition, shallow earthquakes with a depth of around 10 km often occur, making it one of the areas with many large earthquakes even in Indonesia, which is a seismic country.

*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.