An earthquake measuring a preliminary 7.5 magnitude struck northeastern Japan on Monday at 4:53 PM local time. The epicenter was located off the coast of Sanriku in Iwate Prefecture, triggering immediate tsunami warnings across several regions.
The Japan Meteorological Agency (JMA) has issued tsunami alerts predicting waves up to three meters high for the shores of Iwate, Aomori, and Hokkaido. Additionally, yellow-level alerts for waves up to one meter have been set for Fukushima and northeastern Hokkaido.
The quake's epicenter was situated approximately 100 kilometers east of Miyako City, at a depth of 10 kilometers, according to JMA data.
Initial wave observations confirm the arrival of tsunami activity: waves between 80 centimeters and one meter hit the port of Kuji, while waves of 40 centimeters were recorded at Miyako port, both located in Iwate Prefecture.
Tsunami activity was also detected about 50 kilometers off the coast of Aomori.
The earthquake's intensity reached the upper 5 level on Japan's seismic scale, which ranges from 1 to 7. Such intensity involves strong tremors that can knock over objects and make it difficult to move without support.
Prime Minister Sanae Takaichi promptly activated an emergency response team and urged residents to evacuate to higher ground without delay.
As precautionary measures, bullet train services (Shinkansen) were halted in Aomori, and ships were ordered to leave ports in Hokkaido and Hachinohe.
Nuclear plants in the affected area reported no initial damage, and early reports indicated no casualties or significant material damage.
Some sources noted the preliminary magnitude as 7.4; the JMA may revise this figure in the upcoming hours.
The Sanriku region is one of the world's most seismically active areas, situated at the subduction zone where the Pacific Plate dives beneath the Amur Plate.
This is the same area that suffered a catastrophic earthquake on March 11, 2011, with a magnitude of 9.0, leading to a tsunami with waves as high as 40 meters, over 22,000 fatalities and missing persons, and the Fukushima nuclear disaster.
Japan has experienced a series of significant seismic events in recent months: on December 8, 2025, a magnitude 7.6 earthquake off Aomori generated waves up to 70 centimeters in Kuji, and on November 9, 2025, a magnitude 6.7 earthquake off Iwate triggered tsunami alerts for waves up to one meter along the same coast.
Authorities continue to enforce evacuation alerts while the JMA closely monitors the situation and the potential arrival of further waves along the affected coastlines.
Understanding Tsunami Warnings and Earthquake Precautions in Japan
What immediate actions should residents take during a tsunami alert in Japan?
Residents should evacuate to higher ground immediately, follow official instructions, and stay tuned to emergency broadcasts for updates.
How does the Japan Meteorological Agency determine earthquake magnitudes?
The JMA calculates earthquake magnitudes based on seismic data collected from various monitoring stations, which may be updated as more data becomes available.
Why is the Sanriku region prone to earthquakes?
The Sanriku region is prone to earthquakes due to its location on a subduction zone where the Pacific Plate is being forced under the Amur Plate.