A magnitude 7.6 earthquake struck off the coast of northern Japan on 8 December 2025 and set off an immediate tsunami warning that stretched across Aomori, Iwate and parts of Hokkaido. The epicentre sat roughly eighty kilometres off Aomori at a depth of about fifty kilometres, which was deep enough to spread a long, heavy tremor through towns along the shoreline. Rail services paused while checks were carried out, thousands of homes lost power for a time, and coastal residents were told to move to higher ground as a precaution.
The initial alert warned that waves could reach up to three metres. In the end, the first measured waves were far smaller. Some ports reported heights of around forty centimetres, which is roughly sixteen inches. Even so, officials reminded people to remain in safe zones because later waves sometimes grow in strength. That warning is based on long experience. The Sanriku offshore quake in December 1994 reached magnitude 7.7 and produced a modest but noticeable tsunami, and the huge Kamchatka earthquake in July 2025 sent waves across the region that showed how distant shocks can still affect Japanese shores.
The government has set up an emergency task force to assess the situation and support affected communities. Engineers have begun inspecting structures, and seismologists are watching for aftershocks. People in low lying areas have been asked to wait for the official all clear before returning home. Japan’s coastal regions have lived through many seismic scares, and that collective memory is one reason evacuation drills and safety rules are taken so seriously.
