Overview
- An offshore earthquake struck around 11:15 p.m. local time with magnitude estimated at M7.5–7.6, producing a maximum seismic intensity of upper 6 in Aomori’s Hachinohe area.
- Initial tsunami warnings for Pacific coasts in Hokkaido, Aomori and Iwate were later downgraded to advisories as authorities continued coastal monitoring.
- Prime Minister Sanae Takaichi entered the crisis center and directed a life‑first response as the government set up an emergency team and began damage assessment with local officials.
- The Cabinet Office and JMA issued a one‑week aftershock advisory covering 182 municipalities from Hokkaido to Chiba, marking the system’s first use, with experts cautioning that the next 2–3 days carry elevated risk; a magnitude 5.9 aftershock early Dec. 9 produced intensity 3 shaking.
- Initial inspections found no abnormalities at the Higashidori and Onagawa nuclear plants, and Tohoku Shinkansen operations were suspended between Fukushima and Shin‑Aomori following the quake.