Magnitude 5.5 earthquake — Mutsu, Japan

A magnitude 5.5 earthquake struck off the north-eastern coast of Japan's Honshu island on 1 August 2026, with the United States Geological Survey (USGS) recording the event at 02:48 UTC (11:48 local time in Japan). The quake was centred approximately 63 kilometres east of Mutsu, a city on the Shimokita Peninsula in Aomori Prefecture, at coordinates 41.33°N, 141.97°E. It struck at an intermediate depth of roughly 75 kilometres beneath the seabed, a factor that typically moderates surface shaking compared with shallower quakes of similar magnitude.

USGS assigned the event a green alert level, its lowest impact category, indicating that little to no damage was expected and reflecting the region's history of frequent seismic activity combined with the earthquake's offshore location and moderate depth. Ground-motion modelling estimated a maximum shaking intensity equivalent to "light" on the Modified Mercalli scale, sufficient to be felt by residents but unlikely to cause structural harm. No tsunami warning was issued in connection with the earthquake. USGS received a small number of "felt" reports from the public shortly after the event, consistent with a moderate, moderately deep offshore tremor in a seismically active part of Japan, and the agency's seismic network — more than 100 stations globally — allowed the event to be located and reviewed with a high degree of confidence.