A strong earthquake, registered at magnitude 7.5, shook the north-eastern region of Japan late on December 8, prompting an immediate tsunami alert for the coastal regions of Hokkaido, Aomori, and Iwate prefectures, according to Kyodo News. The Japan Meteorological Agency (JMA) documented the incident at 11:15 pm, originating off the Pacific coastline of Aomori at a depth of 54 kilometres. Although the coastal warning was later rescinded, authorities urged the public to maintain heightened readiness for a minimum of seven days, advising that emergency supplies should be close at hand for swift departure if necessary.

This is a critical reminder of the seismic hazards facing Japan’s north-east, lying along the deep subduction zone where the Pacific plate descends beneath Honshu. This vulnerability necessitates robust national warning systems and constant public vigilance, given the area’s history, including the catastrophic M9.0 quake of 2011.

The JMA noted that this temblor increased the probability of another similar or larger magnitude event striking the same location over the next few days. It marks the first occasion that such an alarm has been activated for Hokkaido’s seaboard and the extensive Sanriku coast. The seismic intensity reached an upper 6 on the Japanese seven-point scale in areas of Aomori, and shaking was perceptible as far as central Tokyo.

The highest sea surge recorded was approximately 70 centimetres in Iwate. The initial tsunami warning was downgraded to an advisory three and a half hours after the main shock, and by 6:20 a.m. Tuesday, the advisory was fully withdrawn. The government reported that nuclear facilities in the affected prefectures, including a fuel reprocessing facility in Aomori, showed no operational disturbances.

Prime Minister Sanae Takaichi and Chief Cabinet Secretary Minoru Kihara confirmed that rescue efforts were the primary focus, while railway operator JR East temporarily suspended Tohoku Shinkansen services between Fukushima and Shin-Aomori stations. Over ten minor injuries were reported across Aomori and Hokkaido, and around 2,700 residences in Aomori lost electric power. Residents described waking to the shaking and seeking safety in sub-zero temperatures.