Overview
- The Japan Meteorological Agency, which reported the offshore quake at 4:53 p.m. Monday near the Sanriku coast at about 10 km depth, put its magnitude at 7.5–7.7.
- Hours after the shaking, officials downgraded tsunami warnings to advisories after waves around 80 cm hit Kuji in Iwate and smaller surges reached other ports.
- Evacuation advisories went out across northern prefectures and rail service, including parts of the Tohoku Shinkansen between Tokyo and Shin-Aomori, was suspended during checks.
- Authorities issued a special advisory that the one-week chance of a magnitude‑8 or larger quake is about 1%, which is higher than normal but still low.
- Operators reported no abnormalities at Fukushima and other nuclear sites, and officials had no confirmed reports of major damage or deaths as inspections continued.