The powerful quake, centered near the Pacific Coast in Oaxaca, was felt hundreds of miles away.
A strong earthquake shook southern Mexico on Tuesday, killing at least four people, causing buildings to shake hundreds of miles away and prompting residents to flee homes and offices to seek safety on the streets under open sky.
The earthquake’s magnitude was 7.5, according to Mexico’s national seismological service, and it was centered in the Pacific Ocean, about 14 miles off the coast, south of Crucecita, a beach town in the southern state of Oaxaca that has been popular with tourists. It struck at 10:29 a.m. local time.
The U.S. Geological Survey, however, estimated the magnitude at 7.4; it is not unusual for preliminary measurements to vary.
Another quake, estimated by the U.S.G.S. at 4.9 magnitude, struck the same region Monday night. By early afternoon on Tuesday, President Andrés Manuel López Obrador said, there had been 147 aftershocks to the larger quake, and officials warned that more were expected.
At least four people died, but early reports indicated that damage was not extensive.
Four people have been confirmed killed in the earthquake, according to the governor of Oaxaca, Alejandro Murat, and David León, Mexico’s national coordinator of civil protection.
Information on the toll trickled in throughout the day, and local news reports showed rubble from some damaged buildings in Oaxaca.
“Fortunately there was no major damage,” President Andrés Manuel López Obrador said in a Twitter video posted early in the afternoon, one of a series he posted, relaying updates from Mr. León and others. A phone pressed to his ear, the president said, “collapses, some broken glass, signage fell, walls, but nothing serious.”
Mr. López Obrador urged everyone to remain attentive to further seismic warnings and to stay calm. “I hope and I wish with all my soul that there will be no more damaging aftershocks,” he said.
The area closest to the epicenter is largely rural, and the nearest sizable city is Oaxaca, the state capital, more than 90 miles away.
Buildings swayed in Mexico City, more than 300 miles to the northwest, but local news reports showed little damage beyond debris that had fallen away from some building facades. The mayor of Mexico City, Claudia Sheinbaum, said neither the city’s security command center nor officials conducting overflights of the municipality had reported any “serious” impacts from the earthquake.
Flora Pedro Mora, the administrator of Mansiones Cruz del Mar, a condo-hotel complex near Crucecita, described the earthquake as “horrible.”
“It was like one of those movies,” she said, audibly shuddering.
But she added that, apart from some roof tiles that were knocked loose and fell to the ground, the property suffered no serious damage. Though some hotels and resort properties in the area, commonly known as Huatulco, had begun to reopen in the past week after an extended shutdown in response to the pandemic, Mansiones Cruz del Mar was still closed to guests.
The state oil company, Petróleos Mexicanos, reported that the earthquake caused the temporary shutdown of its refinery in the port city of Salina Cruz, and that a fire there was quickly put out.
The quake put people on the lookout for a possible tsunami.
The U.S. National Oceanic and Atmospheric Administration said there was a “potential threat” of a tsunami along the coasts of Mexico, Guatemala, Honduras and El Salvador, but withdrew the advisory a few hours later.
The agency’s ocean buoys recorded small seismic waves after the quake — too small to have much noticeable affect.
Powerful offshore earthquakes can trigger devastating tsunamis like the ones that hit Fukushima, Japan in 2011, and Aceh, the Indonesian province, in 2004. But it is difficult to predict which quakes will cause such destructive waves.
Oaxaca State has been devastated by earthquakes before.
Many Mexicans have grown accustomed to earthquakes, taking them as an immutable fact of life. The country is situated near the colliding boundaries of several sections of the earth’s crust.
In 2017, at least 90 people were killed after an earthquake with a magnitude of 8.2 struck offshore in the middle of the night, mostly affecting the states of Oaxaca and Chiapas. That earthquake did generate a tsunami.
Aftershocks continued for days as volunteers in Juchitán, a provincial city of 100,000, clawed through mounds of debris left by collapsed buildings, searching for survivors. Weeks later, a separate quake near Mexico City killed at least 248 people, including children who were buried beneath a collapsed school.
In 1985, a devastating earthquake killed as many as 10,000 people in Mexico City. After the disaster, construction codes were reviewed and stiffened. Today, Mexico’s construction laws are considered as strict as those in the United States or Japan.
The 8.2 earthquake in 2017, the most powerful quake in Mexico in a century, occurred near the Middle America Trench, a zone in the eastern Pacific where one slab of the earth’s crust, called the Cocos Plate, is sliding under another, the North American, in a process called subduction.
Subduction releases vast amounts of energy and, if the slip occurs under the ocean, can move a lot of water suddenly. Subduction zones, which ring the Pacific Ocean, cause the world’s largest earthquakes and most devastating tsunamis.
Elda Cantú and Natalie Kitroeff contributed reporting from Mexico City.