Overview
- A magnitude‑7.6 earthquake struck off eastern Aomori around 11:15 p.m. JST on Dec. 8, with shindo 6+ shaking recorded in Aomori’s Hachinohe area.
- The Japan Meteorological Agency issued tsunami warnings for the Hokkaido Pacific coast, Aomori Pacific coast, and Iwate, with observed waves of 50 cm at Kuji and 40 cm at Urakawa and Rokkasho.
- The Cabinet Office and JMA activated the Hokkaido–Sanriku aftershock caution information for the first time, covering 182 municipalities for one week and urging readiness without ordering preemptive evacuations.
- The government set up a crisis response center as JR East suspended the Tohoku Shinkansen between Fukushima and Shin‑Aomori, while Sapporo’s subway saw a full suspension on the Namboku Line and delays on other lines.
- Regulators reported no abnormalities at the Higashidori, Onagawa, and Tomari nuclear plants, with the Rokkasho reprocessing facility’s status still being confirmed.