Geological data shed light on past, future quakes in Sea of Japan
The Noto Peninsula Earthquake, which struck Japan’s north central region on Jan. 1, 2024, registered the maximum seismic intensity of 7 on the Japanese scale and caused the uplift of the coast and ocean floor. Associate Professor Tatsuya Ishiyama of the Earthquake Research Institute’s Research Center for Monitoring Japan Arc explains why a massive earthquake occurred on the Noto Peninsula and what data about geomorphic, geological and crustal structures can tell us about past and future earthquakes in the Sea of Japan region.
Photo of coastal uplift measuring 4.1 meters taken at Igisu fishing port in the city of Wajima, Ishikawa Prefecture, on Jan. 4, 2024.
(Source: Ishiyama, Hirouchi, Matta, Tateishi, and Yasue, 2024*1).
Noto Peninsula in the context of Japan’s geological history
―― What can you tell us about the geomorphology, which describes the landforms — the distinctive, natural features on the land surface — of the Noto Peninsula?
If we compare the coastal landforms before and after the Noto Peninsula Earthquake, we can see that the resulting coastal uplift dried up beaches and fishing ports. We also know that the coastline advanced by several hundred meters in a number of locations. Post-earthquake surveys confirmed that there were about 4-5 meters of uplift at the most extreme points.
The Sea of Japan region, on the western coast of Japan, where Okushiri Island, Sado Island and the Oga and Noto peninsulas are located, is known for its intense crustal and seismic activity. This is especially true for the Noto Peninsula, as it is surrounded by many nearshore active faults. On the peninsula, you can find landforms known as marine terraces that are more than 100 meters above sea level; they depict coastal fe