Changes in seafloor level detected off quake-hit Noto Peninsula, researchers say

Researchers say they have found changes in the level of the seafloor off the coast of Japan's Noto Peninsula that are believed to have been caused by the powerful New Year's Day earthquake in the region.

The researchers are from 13 universities and research organizations, including the Atmosphere and Ocean Research Institute at the University of Tokyo.

They carried out a survey last month in waters in the Sea of Japan in the focal zone of the quake.

They say the changes in the seafloor were found in two locations and the height differences were less than one meter.

One of them was spotted about 2.5 kilometers northwest of the city of Suzu at a depth of 73 meters. Suzu is on the northern tip of the peninsula.

The team says the altered area measures more than 20 meters from northeast to southwest. They think it is likely to have been created within the past few months as there were no living organisms on its vertical surface.

They say it could be an active fault affected by another one called the Suzu-Oki segment, which is thought to have moved when the massive quake occurred.

The other area was found about three kilometers northwest of Wajima City at a depth of 88 meters. The researchers say it is part of the sediment in the area of an active fault, the Saruyama-Oki segment.

The research team will analyze mud, water and other substances collected at the sites.

University of Tokyo Associate Professor Yamaguchi Asuka says even a survey in limited areas has led to the discovery of topographic changes, indicating that the seabed north of the Noto Peninsula has been deformed on a massive scale.

Yamaguchi says he thinks it is rare for such a study to be conducted just after an earthquake, and he hopes it will lead to discoveries about active underwater faults.