TOKYO — A strong earthquake with a magnitude of 7.7 struck off the northern coast of Japan on Monday afternoon, prompting authorities to issue a tsunami warning for parts of the country’s Pacific coastline, officials said.
The quake occurred at around 4:53 p.m. local time off the Sanriku coast in northeastern Japan at a shallow depth, according to the Japan Meteorological Agency (JMA). The agency warned that tsunami waves of up to about 3 meters could reach coastal areas in Iwate, Aomori and Hokkaido, urging residents to evacuate to higher ground immediately.
“Tsunami waves will strike repeatedly. Please do not enter the sea or approach coastal areas,” the JMA said in an emergency alert broadcast shortly after the quake.
Initial observations showed smaller waves, with some coastal locations recording heights of less than 1 meter, public broadcaster reports indicated. Authorities later downgraded parts of the warning to an advisory as more data became available, government officials said.
There were no immediate reports of significant casualties or major structural damage, Chief Cabinet Secretary Minoru Kihara said, adding that the government was assessing the situation.
Evacuation advisories were issued for more than 100,000 residents across several northern prefectures, with local governments opening shelters and directing people away from coastal and low-lying areas. Transportation was disrupted, including temporary suspensions of some Shinkansen bullet train services and highway closures for safety checks, according to transport authorities.
Prime Minister Sanae Takaichi instructed officials to prioritize public safety and ensure timely information dissemination, according to government statements. Emergency response teams were mobilized, and inspections were conducted at infrastructure facilities, including nuclear plants, where no abnormalities were reported, regulators said.
Japan, located along the seismically active Pacific “Ring of Fire,” frequently experiences earthquakes. The affected Sanriku region was heavily impacted by the 2011 earthquake and tsunami disaster.
As of late Monday, tsunami warnings had been downgraded in many areas, and authorities said monitoring would continue for aftershocks and any further sea level changes. Details on the full extent of damage remain unclear.
