• Noto Peninsula Earthquake

Land on the Noto Peninsula Dramatically Relocated by Quake; Land in Wajima Rose 1.1 Meters, Shifted 1.2 Meters West

The Yomiuri Shimbun
Toshihiro Shimoyama, a senior coordinator for seismological information of the Japan Meteorological Agency, speaks at a press conference in Minato Ward, Tokyo, on Monday.

In Monday’s earthquake centered in the Noto region of Ishikawa Prefecture, major crustal movements were observed, centering around the Noto Peninsula, with the land in the city of Wajima on the peninsula shifting as much as about 1.2 meters westward and rising about 1.1 meters, the Geospatial Information Authority of Japan (GSI) said Tuesday.

The GSI, based in Tsukuba, Ibaraki Prefecture, analyzed land deformations at observation points in the region, using the Global Positioning System. It found that the greatest deformation occurred in Wajima. At the same time, the land in Suzu, near the epicenter, shifted about 90 centimeters westward and rose by the same amount.

The observation point in the town of Anamizu showed that the land moved about 90 centimeters westward, and rose about 3 centimeters, while land on Noto Island in the city of Nanao on the peninsula moved about 70 centimeters northwestward, and sank about 30 centimeters.

Also, in the neighboring prefectures of Toyama and Niigata, deformations occurred by up to 10 centimeters, while in the prefectures of Nagano, Gifu, Gunma and Tochigi, movements by up to several centimeters northwestward were observed.

The GSI said, “Since these are provisional figures, we will conduct further analysis in the days ahead.”

The authority also noted, “The values of changes are large and the changes are widely distributed, indicating that this was indeed a large-scale earthquake.”

Crustal movements were observed in past major earthquakes, too.

In the 2011 Great East Japan Earthquake, horizontal crustal movements of up to about 5.4 meters were observed on the Oshika Peninsula in Ishinomaki, Miyagi Prefecture, with a subsidence of about 1.1 meters. In the 2016 Kumamoto Earthquake, the village of Minamiaso in Kumamoto Prefecture moved horizontally by about 1 meter and rose by about 20 centimeters.