Tokyo: The powerful earthquake that struck the central Japan prefecture of Ishikawa on New Year’s Day is believed to have created a fourth coastal terrace on the northern side of the Noto Peninsula, researchers have said.

A ground rise of about 4 meters was observed on the northwestern coast in the Ishikawa city of Wajima after the 7.6-magnitude earthquake.

On Saturday, the death toll from the quake in Ishikawa rose to 220, including 13 deaths from indirect causes, while 26 people remained unaccounted for.

According to satellite data analysis by the Geospatial Information Authority of Japan, ground elevation from the latest earthquake caused the coastline to recede toward the sea. The ground rose by up to around 2 meters on the northeastern side of the Noto Peninsula and up to around 4 meters on the northwestern side.

A survey by the National Institute of Advanced Industrial Science and Technology, or AIST, has found that three large coastal terraces on the peninsula may have been created by past major earthquakes.

According to the survey results published in 2020, the height of the three terraces was around 6 meters, 4.9 meters and 3.5 meters, respectively.

Active faults have been found sporadically in the seabed along the northern coast of the peninsula, and the latest and past earthquakes are believed to have occurred there or in nearby faults.

The oldest of the terraces is estimated to have formed about 6,000 years ago or about 3,500 years ago, depending on estimates of past sea levels.

JIJI Press