A major earthquake registered by the Japan Meteorological Agency (JMA) and USGS as M7.6 struck off the east coast of Aomori Prefecture, Japan, at 14:15 UTC (23:15 JST) on December 8, 2025. Both agencies are reporting a depth of 50 km (31 miles). According to the Pacific Tsunami Warning Center (PTWC), hazardous tsunami waves are possible within 1 000 km (620 miles) of the epicenter.
Epicenter of M7.6 earthquake off the east coast of Aomori Prefecture, Japan on December 8, 2025. Credit: TW/SAM, Google
The epicenter was located 84 km (52 miles) ENE of Misawa (population 42 800), 77 km (48 miles) NE of Hachinohe (population 239 050), 89 km (55 miles) ESE of Mutsu (population 52 250), and 123 km (77 miles) E of Aomori (population 298 400), Aomori, Japan.
According to the Pacific Tsunami Warning Center (PTWC), hazardous tsunami waves are possible within 1 000 km (620 miles) of the epicenter. The threat includes the coastal areas of Japan and Russia.
The initial tsunami waves were expected to reach coastal areas within minutes of the earthquake. Estimated times of arrival (UTC) included 14:44 for Hachinohe, 14:58 for Kushiro, and 15:32 for Katsuura, Japan. Urup Island in Russia was expected around 15:43 UTC, followed by Hachijo-jima at 15:50 and Sapporo at 16:28 UTC.
Subsequent waves were forecast to reach Niigata at 16:48, Vladivostok at 17:04, and Shimane at 17:47 UTC. The Russian ports of Gastello and Vanino were forecast to see initial tsunami activity around 18:04 and 18:06 UTC, respectively.
PTWC reminded that actual arrival times may differ and that the first wave may not be the largest. Tsunami waves can occur in a series, with intervals ranging from five minutes to one hour.
Epicenter of M7.6 earthquake off the east coast of Aomori Prefecture, Japan on December 8, 2025. Credit: TW/SAM, Google According to USGS estimates, about 303 000 people experienced very strong shaking, 1 289 000 strong, 6 257 000 moderate, and 4 795 000 light shaking.
The USGS issued a Green alert for shaking-related fatalities and a Yellow alert for economic losses. There is a low likelihood of casualties. Some damage is possible and the impact should be relatively localized. Estimated economic losses are less than 1% of Japan’s GDP. Past events with this alert level have required a local or regional level response.
Overall, the population in this region resides in structures that are resistant to earthquake shaking, though vulnerable structures exist. The predominant vulnerable building types are adobe block and unreinforced brick with mud construction.
Recent earthquakes in this area have caused secondary hazards such as tsunamis, landslides, and fires that might have contributed to losses.
Liquefaction triggered by this earthquake is estimated to be significant in severity and/or spatial extent. The number of people living near areas that could have produced liquefaction in this earthquake is significant. Landslides triggered by this earthquake are estimated to be limited in number and/or spatial extent.
Estimated population exposure to earthquake shaking Image credit: USGS Selected cities exposed Regional seismicity Image credit: EMSC References:
1 M7.6 earthquake off the east coast of Aomori Prefecture, Japan — USGS — December 8, 2025
2 M7.5 earthquake Hokkaido, Japan region — EMSC — December 8, 2025
3 M7.6 earthquake off the east coast of Aomori Prefecture, Japan – NWS/PTWC – December 8, 2025
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Teo Blašković
I’m a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.