Magnitude-7.5 earthquake triggers tsunami alert in northern Japan
Consensus Summary
A magnitude-7.5 earthquake struck off Japan’s northeastern coast on April 20, 2026, triggering tsunami warnings for Iwate, Aomori, and Hokkaido prefectures, with waves up to 3 meters expected. Tsunami waves of 80 cm were observed at Kuji Port, and authorities urged immediate evacuations, suspending bullet train services and activating emergency task forces. The Japan Meteorological Agency warned of potential aftershocks for up to a week, while nuclear plants in the region reported no abnormalities. The quake, felt as far as Tokyo, follows Japan’s history of seismic activity, including the devastating 2011 magnitude-9.0 earthquake and tsunami that killed nearly 20,000 people. Australia’s Bureau of Meteorology confirmed no tsunami threat to its territories, and live broadcasts showed ships evacuating ports like Hachinohe in anticipation of waves.
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Key details reported by multiple sources:
- A magnitude-7.5 earthquake struck off the east coast of Honshu, Japan, at a depth of 10 km on 20 April 2026 at approximately 16:53 local time (0753 GMT).
- Tsunami warnings were issued for Iwate, Aomori, and Hokkaido prefectures, with waves up to 3 meters (10 feet) expected.
- Tsunami waves of 80 cm were observed at Kuji Port in Iwate Prefecture, and 40 cm at Miyako Port.
- Japan Meteorological Agency (JMA) warned of possible aftershocks of similar magnitude for up to a week.
- No reported abnormalities at nuclear plants in Aomori, Miyagi, or Fukushima Daini, with no radiation changes detected.
- Prime Minister Sanae Takaichi confirmed an emergency task force was set up and urged evacuations.
- Bullet train services between Tokyo and Aomori, as well as local trains in affected regions, were suspended.
- The earthquake was felt in Tokyo, hundreds of kilometers away, with an upper-5 intensity on Japan’s 7-point seismic scale.
Points of Difference
Details reported by only one source:
- Japan lies on four major tectonic plates along the Pacific 'Ring of Fire,' with the Nankai Trough being a key concern for future megaquakes.
- The JMA issued a 'megaquake' advisory in 2024 and December 2025, both lasting a week, triggering panic buying and cancellations.
- A 70 cm tsunami wave was recorded at 17:32 local time before the 80 cm wave at Kuji Port.
- NHK reported live footage from Miyako Port showing 40 cm waves and low visibility as darkness set in.
- The JMA released a map with red zones (tsunami warnings) covering Iwate, central Hokkaido, and Aomori’s Pacific coast, and yellow zones (advisories) in other areas.
- The earthquake initially registered as magnitude 7.4 before being revised to 7.5.
- The 2011 magnitude-9.0 earthquake and tsunami killed nearly 20,000 people and triggered the Fukushima nuclear disaster, with 160,000 evacuating Fukushima due to radiation.
- Australia’s Bureau of Meteorology confirmed no tsunami threat to its mainland, islands, or territories.
- Tohoku Electric Power Co. is checking the impact on its Onagawa nuclear power plant, though no abnormalities were reported at Fukushima Daini.
Contradictions
Conflicting information between sources:
- ABC states the earthquake occurred at 10:20 AM local time (2026-04-20T10:20:43.963921), while Guardian and ABC’s second article place it at 4:53 PM local time (16:53).
- Guardian mentions the earthquake was initially reported as magnitude 7.4 before revision, but ABC does not mention this preliminary figure.
- ABC’s first article mentions a 70 cm wave at 17:32 local time, while Guardian does not reference this specific timing or measurement.
Source Articles
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