Noto Peninsula Earthquake Exposes 200 Meters of New Coastline

The Yomiuri Shimbun

The Noto Peninsula Earthquake caused ground uplift along the coast, spanning about 85 kilometers through Suzu, Wajima and Shika in Ishikawa Prefecture, leading to 200 meters of new coastline to be exposed, a recent analysis by the Geospatial Information Authority of Japan (GSI) has revealed. The analysis also showed that the tsunami had inundated about 130 hectares in Suzu alone.

The GSI compared data captured by the Japan Aerospace Exploration Agency’s Earth observation satellite, Daichi-2, which irradiated radio waves on the ground surface before and after the earthquake. This revealed that the ground had risen over a wide area of the Noto Peninsula, exposing the seabed in the coastal area on the northern side of the peninsula. The extent of the change, when measured on a map, is about 85 kilometers.

In the area surrounding Minazuki Bay in Wajima, the ground surface rose about 4 meters and 200 meters of new coastline were exposed after the earthquake, while a tsunami observation meter became inactive due to seabed exposure at a fishing port in the Nagahashimachi district of Suzu.

A group from the Association of Japanese Geographers found using GSI aerial photos that the land between Suzu and Wajima cities increased by about 240 hectares along just a 50-kilometer coast.

“There have been several major earthquakes in the area over the past several thousand years that have changed the topography of the area. We believe that a similar major earthquake occurred this time,” Hideaki Goto, associate professor of geography at Hiroshima University and a member of the group said.

GSI’s aerial photo analysis showed that the tsunami had flooded about 130 hectares in Suzu, where many houses were confirmed to have collapsed. The actual affected area could be larger because of cloud cover in the photos.