The fault that triggered a major earthquake in central Japan on New Year’s Day may stretch for around 150 kilometers under the Noto Peninsula and associated seismic activity is likely to continue for the time being, a government panel of experts said Tuesday.
At the end of its meeting in Tokyo, the panel said it believes the magnitude-7.6 quake was caused by a reverse fault, when the upper hanging wall of a fault is displaced upward away from the footwall.
The area of tectonic activity has been expanding in and around the region and residents should remain alert for further quakes that register the highest level of 7 on Japan’s seismic intensity scale, the panel said.
Strong seismic activity has been detected in the northern area of the peninsula, located in Ishikawa Prefecture on the Sea of Japan coast, since December 2020, according to the panel. The area experienced a quake with a magnitude of 5.4 in June 2022 and one with a magnitude of 6.5 in May 2023.
The magnitude 7.6 quake measured 7 on the seismic intensity scale in the prefectural town of Shika on Monday afternoon, and the peninsula and its vicinity have since experienced strong aftershocks, including quakes measuring upper 5.
Naoshi Hirata, professor emeritus at the University of Tokyo who heads the panel, told reporters the latest quake is believed to be part of the ongoing seismic activity but “it is not known at this point exactly what part of the fault moved.”