Earthquake sets off brief tsunami alert and a megaquake advisory in northern Japan

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TOKYO (AP) — A 7.7 magnitude earthquake Monday off northern Japan sparked a short-lived tsunami alert and an advisory of a slightly higher risk of a possible megaquake for its coastal areas.

The Cabinet Office and the Japan Meteorological Agency said there was a 1% chance for a megaquake, compared to a 0.1% chance during normal times, in the next week or so following the quake near the Chishima and Japan trenches.

Officials said the advisory was not a prediction but urged residents in 182 towns along the northeastern coasts to raise their preparedness while continuing their daily lives.

Prime Minister Sanae Takaichi urged residents to confirm their designated shelters and evacuation routes and to check emergency food and grab bags so they can run immediately when a megaquake hits. “The government will do our utmost in case of an emergency,” she told reporters.

It was the second such advisory for the region in recent months. One was issued following a 7.5-magnitude quake in December but no megaquake occurred.

Still, Monday's earthquake and tsunami were a reminder to the quake-prone area of the March 2011 disaster that ravaged large swaths of the northern coast, triggering a nuclear crisis in Fukushima.

NHK television footage showed hanging objects swaying and people squatting at a shopping center in Aomori, as authorities told people to seek higher ground and avoid coastal areas.

The Fire and Disaster Management Agency said two people, one in Aomori and another in Iwate, were injured after falling.

Shinkansen bullet trains connecting Tokyo and northern Japan were temporarily suspended, leaving passengers in cars and on platforms waiting for service to resume.

The quake occurred off the coast of Sanriku at around 4:53 p.m. and was about 19 kilometers (11 miles) deep, JMA said. The U.S. Geological Survey measured the quake's strength as 7.4 magnitude.

A tsunami of about 80 centimeters (2.6 feet) was detected at the Kuji port and a smaller tsunami of 40 centimeters (1.3 feet) was recorded at another port, both in Iwate prefecture, before Japan lifted all tsunami alert and advisories.

The Nuclear Regulation Authority said nuclear power plants and related facilities in the region were intact and no abnormalities were detected.

It's been 15 years since a magnitude 9.0 earthquake and massive tsunami on March 11, 2011, ravaged parts of northern Japan, causing more than 22,000 deaths and forcing nearly half a million people to flee their homes.