Mosaic News

Buy Me A Coffee
News without borders
Friday, 29 May 2026
Mosaic News is free to read — but not free to run. Your (monthly) donation keeps it going. →
Japan·Natural Disaster

Japan issues tsunami warning after 7.4 magnitude earthquake off northern coast[Updated]

Monday, 20 April 2026, 12:03 · 1 min read
Updates
39d

Japan's Meteorological Agency has revised the earthquake's magnitude upward to 7.7, and tsunami warnings across the region were fully lifted by 11:45 p.m. local time, with the largest wave recorded measuring 80 centimetres in Iwate Prefecture. Authorities subsequently issued a "post-quake advisory" — only the second such warning for the region in recent months, following a similar alert after a 7.5-magnitude quake in December — citing a 1% probability of a mega-quake of magnitude 8.0 or greater in the coming week, compared with a baseline chance of 0.1%. The advisory covers 182 towns along the northeastern coast and, while not a prediction, urges residents to confirm evacuation routes, designated shelters, and emergency supplies.

Sources
Original story

A 7.4 magnitude earthquake struck off Iwate Prefecture (a coastal region in northern Honshu, Japan's main island) on Monday afternoon, prompting Japan's Meteorological Agency to issue a tsunami warning for waves of up to three metres and urge residents to move immediately to higher ground. Authorities issued evacuation orders to nearly 177,000 people across five prefectures including Hokkaido, Aomori, Iwate, Miyagi, and Fukushima, while Prime Minister Sanae Takaichi confirmed a crisis management team had been activated and said the government was assessing casualties and damage. The earthquake comes as Japan — which sits atop four tectonic plates along the Pacific 'Ring of Fire' and accounts for roughly 18% of the world's seismic activity — remains on heightened alert following a series of major tremors in recent years, including a deadly 2011 quake and tsunami that killed around 18,500 people.

Sources
EuronewsJapan issues tsunami warning after powerful 7.4 magnitude earthquake ↗︎NHK World5道県 17万6828人に「避難指示」 総務省(20日19時45分時点) ↗︎NHK World北海道・三陸沖後発地震注意情報 “巨大地震の可能性高まる” ↗︎
Also covered by
BBC World · NHK World
This article was automatically compiled by AI from the sources above. It may contain inaccuracies. Always read the original sources for the full context.