A powerful 6.8 magnitude earthquake struck southwestern Japan on Tuesday afternoon, killing 13 people and injuring dozens of others, damaging buildings and homes, igniting fires and prompting a search for people who may have been trapped in rubble.

Here’s what to know.

Where did the earthquake happen?

The earthquake hit around 4:30 p.m. local time in Kumamoto Prefecture on Kyushu island, the southernmost of Japan’s main islands.

The earthquake’s intensity led to buildings collapsing in the region. Prime Minister Sanae Takaichi of Japan said people were trapped inside some structures. Fires also erupted in Kumamoto City, the regional capital, which has a population of more than 700,000.

The epicenter of the quake was near Uto, a smaller coastal city around 30 miles south of Kumamoto City, according to the U.S. Geological Survey

The U.S. agency had earlier reported a magnitude measurement of 7.1 for the earthquake before it adjusted the figure to 6.8.

Where was the most severe damage?

Ms. Takaichi said on Wednesday morning that the damage was “extensive,” and that officials were working to restore electricity and water to areas affected by outages.

Crews worked overnight to rescue people who may have been trapped when the second floor of a shopping mall collapsed in Kumamoto City on Tuesday. Video footage posted on social media showed debris scattered inside and outside the mall.

“There are still people awaiting rescue, and time is of the essence,” Ms. Takaichi said on Wednesday.

Aerial footage showed a flipped train carriage on tracks in the city and widespread damage to buildings and bridges. Other images recorded by the public broadcaster NHK also captured elevated sections of the Kyushu Expressway that had split into two pieces, as other footage showed a wall that had partly collapsed at Kumamoto Castle, a landmark in the city’s center.

Was anyone killed or injured?

At least 13 people have died in relation to the earthquake, Ms. Takaichi said on Wednesday. One person died in a hospital after being found in a collapsed house in Kumamoto, according to the police.

More than 50 people were being treated for injuries at a hospital in Kumamoto City, and at least 80 people at a hospital in Hikawa, a town to the south of the city, according to NHK.

The last major quake in Japan in 2024, centered on the Noto peninsula farther north, killed hundreds of people, with more succumbing to disaster-linked causes afterward, according to NHK.

In April 2016, the Kumamoto region also experienced days of deadly seismic events that killed at least nine and injured hundreds, according to the U.S. Geological Survey.

What is the status of the area’s nuclear power plant?

The Sendai Nuclear Power Plant appeared to be secure and had no reports of abnormalities, Minoru Kihara, a top Japanese cabinet official, said during a news briefing.

The power plant, which has two reactors and supplies electricity to the Kyushu region, is in Kagoshima, south of Kumamoto.