Japan warns of bigger quake risk after 7.7 offshore event

A magnitude-7.7 offshore earthquake near Iwate prompted Japan’s Meteorological Agency to issue a rare “subsequent quake advisory” covering about 182 municipalities from Hokkaido to Chiba, telling residents to be ready to evacuate as the chance of a larger quake (and a follow-on tsunami) remains higher than normal—about 1% for an 8+ event. The advisory is valid until April 27 at 5 p.m. Tsunami waves reached up to 80 cm in places, with about 172,000 people evacuated or urged to review plans. There were a few injuries, some train services resumed, and no abnormalities were reported at nuclear plants, with officials stressing continued vigilance in the days ahead.