Upper 6 quake hits Aomori Prefecture, no tsunami damage; follow-up alert withheld

2026-06-25

A quake with a maximum seismic intensity of upper 6 struck Aomori Prefecture at around 7:30 a.m. on the 25th. According to the Japan Meteorological Agency, the epicentre was off the coast of Iwate Prefecture, the depth was 44 kilometres, and the magnitude, which indicates the scale of the quake, was estimated at 7.2. The agency said there is a slight risk of sea level changes along Japan's coast, but no tsunami damage is feared.

Follow-up quake alert falls short of threshold

At a morning news conference the same day, the JMA said the 'Hokkaido-Sanriku offshore follow-up earthquake advisory', issued when the chance of a larger-than-normal quake rises, did not meet the release criteria. It also urged people to remain alert for quakes of around upper 6 intensity for roughly the next week.

The JMA said strong shaking in some areas poses a risk of house collapse and landslides, and called for caution over future quakes and rain. After examining the size of the quake, it said the moment magnitude used to judge the advisory was 6.8, below the 7.0 or higher threshold for issuing it.

No major disruptions to transport or nuclear plants

According to the Nuclear Regulation Authority, no abnormalities caused by the quake were confirmed at Tohoku Electric Power's Higashidori nuclear plant, the Onagawa nuclear plant that is in operation, or Nippon Nuclear Fuel's reprocessing plant. Tokyo Electric Power said there were no abnormalities at the Fukushima No. 1 and No. 2 nuclear plants.

JR East temporarily suspended Tohoku Shinkansen services between Tokyo and Shin-Aomori, but resumed operations between Tokyo and Sendai shortly after 9:30 a.m. Services between Sendai and Shin-Aomori remain suspended because track equipment inspections are needed between Mizusawa-Esashi and Shin-Aomori.

School closures and long-period ground motion

According to the Hachinohe Town Board of Education in Aomori Prefecture, five municipal elementary and junior high schools in the town, where upper 6 shaking was observed, were temporarily closed. In Hachinohe City, where lower 6 shaking was recorded, 65 municipal elementary and junior high schools were also temporarily closed.

The JMA also issued observation information on long-period ground motion, which causes upper floors of buildings to sway slowly. Class 2 long-period ground motion was observed in areas including Mutsu and Aomori cities in Aomori Prefecture, Kuji and Oshu cities in Iwate Prefecture, Obihiro in Hokkaido and Tome in Miyagi Prefecture. Class 2 is considered a level at which people feel it is difficult to walk unless they hold onto something.

The government set up a response office at the Prime Minister's Office crisis management centre, and relevant ministries and agencies are working together in response. This is the first time Aomori Prefecture has recorded upper 6 shaking since Dec. 8, 2025.

The main seismic intensities recorded in various locations were as follows. Upper 6 = Hashikami, Aomori Prefecture ▽ Lower 6 = Hachinohe, the same prefecture ▽ Upper 5 = Sannohe, the same prefecture; Morioka, Ninohe, Hachimantai, Fudai and Karumai in Iwate Prefecture

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