Many in Japan urged to stay ready to evacuate after Aomori quake

Satoshi Harada, director of the Earthquake and Volcanic Engineering Affairs Division at the Japan Meteorological Agency, holds a press conference in Tokyo, Japan on December 9, 2025. Photo: Jiji Press

The Japan Meteorological Agency issued what it calls a subsequent earthquake advisory, warning that a new temblor may occur off the coasts of the Hokkaido and Sanriku regions in northern to northeastern Japan.

The advisory, issued for the first time since its introduction in December 2022, was triggered by Monday’s powerful quake, which registered a seismic intensity of up to upper 6, the second-highest level on the Japanese scale, in Aomori.

The advisory covers 182 municipalities, ranging from Hokkaido in the north to Chiba Prefecture in eastern Japan.

At a joint press conference, the agency and the Cabinet Office urged citizens there to stay prepared to evacuate quickly for a week.

The advisory was developed after the agency found through global seismic statistics that the probability of a quake registering 8 or over on the moment magnitude scale, which correctly reflects the size of the slip in the source fault, occurring stands at 1 pct, or one in 100 events, within a week of a quake with a moment magnitude of 7 or higher.

The probability is far higher than 0.1 pct for a quake with a moment magnitude of 8 or more occurring in normal times in areas along the Chishima-Japan trench system.

In view of this, the agency issued the subsequent quake advisory, aiming to mitigate damage that could be inflicted if a subsequent quake strikes.

Japan experienced a quake with a moment magnitude of 7.3 off Sanriku two days before the Great East Japan Earthquake on March 11, 2011, which unleashed deadly tsunami waves that mainly hit the Tohoku region including Sanriku.

The advisory does not request prior evacuations, transportation service suspensions or temporary school closures.

Citizens are asked to maintain their readiness to evacuate quickly while continuing their daily social and economic activities as usual.

“We expect in the worst case that a quake like the Great East Japan Earthquake will follow,” said Satoshi Harada, director of the agency’s Earthquake and Volcanic Engineering Affairs Division.

The subsequent quake advisory resembles the Nankai Trough quake extra information, which was issued for the first time in August 2024.

Following the issuance of the extra information, fake and false information tended to spread via social media, and moves to stock up on goods were seen.

The Cabinet Office is therefore calling on people not to spread unverified information or stockpile supplies.

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