An earthquake with a preliminary magnitude of 7.5 shook northeastern Japan on Monday at 16:53 local time, with its epicenter off the coast of Sanriku, in the Iwate prefecture, and immediately triggered tsunami alerts for several regions of the country.
The Japan Meteorological Agency (JMA) issued a tsunami alert with expected waves of up to three meters for the coasts of Iwate, Aomori, and Hokkaido, along with yellow level alerts of up to one meter for Fukushima and northeastern Hokkaido.
The epicenter was located approximately 100 km east of the city of Miyako, at a depth of 10 kilometers, according to data from JMA.
The initial observations confirmed the arrival of waves: a wave measuring between 80 cm and one meter was recorded at the port of Kuji and 40 cm at the port of Miyako, both located in Iwate Prefecture.
Tsunami activity was also detected about 50 km off the coast of Aomori.
The intensity of the earthquake reached level 5 on the Japanese seismic scale, which ranges from 1 to 7, indicating strong tremors with falling objects and difficulty moving without support.
The Prime Minister Sanae Takaichi activated an emergency team and urged the population to evacuate to higher ground immediately.
As preventive measures, the bullet train service (Shinkansen) was suspended in Aomori and ships were ordered to leave the ports in Hokkaido and Hachinohe.
The nuclear plants in the area did not report any initial impacts, and in the first news reports, no casualties or significant material damages were confirmed.
Some sources reported the preliminary magnitude as 7.4; the final figure may be revised by the JMA in the coming hours.
The Sanriku region is one of the most seismically active areas on the planet, located over the subduction of the Pacific plate beneath the Amur plate.
It is the same area that was devastated on March 11, 2011 by a magnitude 9.0 earthquake that generated a tsunami with waves of up to 40 meters, resulting in more than 22,000 deaths and disappearances and causing the Fukushima nuclear accident.
Japan has recorded a series of significant seismic events in recent months: on December 8, 2025, a magnitude 7.6 earthquake off the coast of Aomori generated waves of up to 70 cm in Kuji, and on November 9, 2025, a magnitude 6.7 earthquake off Iwate triggered tsunami warnings of up to one meter along the same coast.
Authorities have kept evacuation alerts active while the JMA monitors the development of the phenomenon and the potential arrival of new waves to the affected coasts.
Filed under: