Overview

• A magnitude-8.8 undersea earthquake struck July 30 at a depth of 12 miles, centered about 78 miles southeast of Petropavlovsk-Kamchatsky.
• Tsunami waves of 3–4 meters inundated sections of the Kamchatka coast, while 1–1.3-meter surges were recorded in Hokkaido and Severo-Kurilsk.
• Authorities ordered mass evacuations from Kamchatka to Hawaii and along Japan’s eastern Pacific coast, and all personnel at Fukushima Daiichi were evacuated as a precaution with no abnormalities detected.
• By July 31, most tsunami warnings in Japan and the U.S. Pacific were lifted or downgraded, though advisories remain for northern California and parts of South America’s Pacific shoreline.
• Seismic networks and tsunami centers across the Pacific basin are tracking aftershocks and sea-level fluctuations to guard against potential secondary waves.