A major earthquake struck Colombia on Monday, killing more than 100 people, damaging hundreds of buildings in the country’s west and prompting a frantic search for survivors.

The 7.4-magnitude earthquake was the most powerful recorded in the South American nation in the past decade, the Colombian Geological Survey said.

President Abelardo De La Espriella of Colombia, who had been sworn into office just three days before the quake, declared a state of emergency and said that he would directly lead the disaster response.

Here’s what to know.

Where did the earthquake happen?

The epicenter of the quake, according to the U.S. Geological Survey, was about three miles east of San José del Palmar — a town of about 5,000 people in the Chocó region, one of the poorest parts of Colombia.

The temblor, which struck about 7:34 a.m. local time, rattled much of the country, though the impact was worst in cities and towns in the foothills of the Andes.

Major damage was reported in Cali, the country’s third-largest city, which has about two million residents. The cities of Pereira and Manizales, hubs of Colombia’s coffee-growing region that are each home to about 500,000 people, were also badly hit.

The country’s two largest cities — Bogotá, the capital, and Medellín — appeared to have escaped the worst of the damage. But residents there and across the country reported intense shaking.

The quake was also felt in neighboring countries including Panama, Ecuador and Venezuela, though there were no reports of serious damage.

How many people were killed or injured?

The earthquake killed at least 111 people and injured 87 others, according to Mr. De La Espriella. The death toll was expected to rise as rescuers and residents dug through rubble.

Rescue efforts were underway across western Colombia. In Cali, Mayor Alejando Eder said that emergency workers were focusing on finding people in debris from 10 collapsed buildings. Mayor Carlos Fernando Galán of Bogotá said the city was preparing to send rescue crews to hard-hit cities.

It is unclear how long people can survive trapped in rubble after an earthquake, researchers say. But some experts say that there is a 72-hour “golden” window in which the most lives can be saved.

How severe was the damage?

The quake damaged at least 1,575 homes, 18 health centers and 52 schools, Mr. De La Espriella said.

In Cali, at least 26 buildings collapsed, trapping people inside, according to its mayor. In Calima El Darién, a town north of Cali, a hospital collapsed and another was overwhelmed with victims.

There was also widespread damage, including piles of rubble from collapsed buildings, in Pereira and Manziales. Several airports in western Colombia, including in Pereira and Manziales, were among the structures damaged, according to the Colombian Civil Aviation Authority.

The agency said it had suspended operations at some airports until structural damage could be assessed.

How did Colombia’s new president react?

The earthquake is the first big test for Mr. De La Espriella, a right-wing former lawyer with no previous political experience who was sworn in on Friday after winning the presidential election in June.

He said in a video posted on social media on Monday that he had canceled his travel plans to head to Bogotá, where he said he would “personally assume leadership” of the emergency response.

“You’re not alone,” he wrote, addressing people affected by the disaster. “The state is present and taking action.”