Hokkaido, Aomori and Iwate prefectures were under tsunami warnings for several hours.
A television screen shows a news report on Japan Meteorological Agency’s tsunami warning, saying it expected tsunami waves of up to 3m to reach large coastal areas in northern Japan after an earthquake struck off the northeastern coast of Japan, in Tokyo, Japan on Apr 20, 2026. (Photo: Reuters/Issei Kato)
20 Apr 2026 04:06PM (Updated: 20 Apr 2026 09:20PM)
TOKYO: A magnitude 7.7 earthquake struck off northern Japan on Monday (Apr 20), prompting a tsunami alert for several coastal areas where waves of up to 3m were expected.
The Cabinet Office and the Japan Meteorological Agency (JMA) also later flagged a 1 per cent chance for a mega-quake, compared with a 0.1 per cent chance during normal times, in the next week or so following the powerful temblor near the Chishima trough.
Officials said the advisory was not a prediction but urged residents to raise their preparedness while continuing their daily lives.
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