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

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 squatti...