Iwate (Japan): A powerful earthquake with a preliminary magnitude of 7.4 struck off the Sanriku coast of northeastern Japan on Monday afternoon, April 20, 2026. The Japan Meteorological Agency (JMA) immediately issued a tsunami warning for the coastal prefectures of Iwate, Aomori, and Hokkaido, with waves predicted to reach as high as 3 metres (approximately 10 feet). Residents in these areas have been urged to evacuate immediately to higher ground or designated evacuation buildings.
The earthquake occurred at a shallow depth of about 10 kilometres below the sea surface. The tremors were felt as far away as Tokyo, hundreds of kilometres to the south, where large buildings were reported to have swayed. In the hardest-hit areas, the quake measured an “upper 5” on Japan’s seismic intensity scale of 7. This level of intensity is strong enough to make it difficult for people to walk and often causes the collapse of unreinforced concrete-block walls.
Key Emergency Details:
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Epicentre: Pacific Ocean off the Sanriku coast (39.8°N, 143.2°E).
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Tsunami Threat: Waves of up to 3 metres are expected to hit the northern shoreline shortly; residents are advised that the first waves could arrive almost immediately.
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Seismic Intensity: Registered an “upper 5” in parts of Aomori and a “lower 5” in Iwate and Miyagi prefectures.
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Government Response: Prime Minister Sanae Takaichi addressed the nation via NHK public television, calling for urgent evacuations and prioritizing human safety as emergency relief teams are mobilized.
Utility companies are currently assessing the status of nuclear power plants in the Tohoku region, including the Onagawa and Higashidori plants, though no immediate reports of abnormalities have surfaced. Local rail services, including sections of the Tohoku Shinkansen, have been suspended for safety checks. This major seismic event comes amid heightened regional anxiety following a string of smaller tremors earlier this month.
