- A 7.5-magnitude earthquake hit northern Japan, injuring 23 and triggering a tsunami.
- The quake struck 50 miles off Aomori's coast, causing a 70 cm tsunami in Kuji.
- Authorities urged caution for aftershocks; 800 homes lost power, and trains were suspended.
TOKYO — A powerful 7.5-magnitude earthquake struck off northern Japan late Monday, injuring more than 20 people and triggering a tsunami of up to 70 centimeters (28 inches) in Pacific coast communities, officials said.
The Japanese government said it was still assessing damages from the tsunami and late-evening quake, which struck at about 11:15 p.m. in the Pacific Ocean around 80 kilometers (50 miles) off the coast of Aomori, the northernmost prefecture of Japan's main Honshu island.
"I've never experienced such a big shaking," convenience store owner Nobuo Yamada told the public broadcaster NHK in the Aomori prefecture town of Hachinohe, adding that "luckily" power lines were still operating in his area.
A tsunami of 70 centimeters was measured in Kuji port in Iwate prefecture, just south of Aomori, and tsunami levels of up to 50 centimeters struck other coastal communities in the region, the agency said.
The Fire and Disaster Management Agency said 23 people were injured, including one seriously. Most of the victims were hit by falling objects, NHK reported, adding that several people were injured in a hotel in Hachinohe and a man in Tohoku was slightly hurt when his car fell into a hole.
The Japan Meteorological Agency reported the quake's magnitude as 7.5, down from its earlier estimate of 7.6. It issued an advisory for potential tsunami surges of up to 3 meters (10 feet) in some areas.
Chief Cabinet Secretary Minoru Kihara urged residents to go to higher ground or seek shelter until advisories were lifted.
Kihara said nuclear power plants in the region were conducting safety checks and that so far no problems were detected. He later told reporters that Shinkansen bullet trains and some local lines were suspended in parts of the region.
About 800 homes were without electricity, he said.
The meteorological agency issued a caution about possible aftershocks in the coming days. It said there is a slight increase in risk of a magnitude 8-level quake and possible tsunami occurring along Japan's northeastern coast from Chiba, just east of Tokyo, to Hokkaido. The agency urged residents in 182 municipalities in the area to monitor their emergency preparedness in the coming week.
Satoshi Kato, a vice principal of a public high school in Hachinohe, told NHK that he was at home when the quake struck, and that glasses and bowls fell and smashed into shards on the floor.
Kato said he drove to the school because it was designated an evacuation center, and on the way, he encountered traffic jams and car accidents as panicked people tried to flee. Nobody had yet come to the school to take shelter, he said.
Prime Minister Sanae Takaichi, in brief comment to reporters, said the government set up an emergency task force to urgently assess the extent of damage. "We are putting people's lives first and doing everything we can," she said.
Later, she urged residents in the region to pay attention to the latest information from local municipalities. "Please be prepared so you can immediately evacuate as soon as you feel a tremor."
The quake struck about 80 kilometers (50 miles) northeast of Hachinohe, and about 50 kilometers (30 miles) below the sea surface, the meteorological agency said.
It was just north of the Japanese coast that suffered the magnitude 9.0 quake and tsunami in 2011 that killed nearly 20,000 people.
