The quake struck at 10:29 a.m. Local time (11:29 AD) with an epicenter 6.8 miles southwest of Santa Maria Zapotitlan in Oaxaca, near El Koyul.
At least five people have been killed, according to the coordinator of the National Civil Protection Service in Mexico.
Oksaka Governor Alejandro Murat said a 22-year-old woman and a man were among the dead.
Oaxacan Health Services also reported earthquake damage to general hospitals in Pochutla, Puerto Escondido and Pinotepa National, and several municipal hospitals in other areas. According to Murat, two of the hospitals with damage dealt with patients with coronavirus.
“We are checking [damages] as this hospital is also dealing with Covid’s case off the coast of Oaxaca, “he said in an interview with Radio Formula One.
The National Civil Protection Service announced the first death after the collapse of a structure after the earthquake, which occurred just east of the popular tourist destination Huatulco.
Authorities also reported power outages across the state capital and damage to the exterior of a hospital in Oaxaca.
The quake could hit Guatemala, Honduras and El Salvador. In the capital, Mexico City, about 190 miles north of the epicenter, tremors were heard and sirens were heard crying.
Tsunami waves of 0.68 meters (2.2 feet) were observed in Acapulco and 0.71 meters (2.3 feet) in Salina Crewe. An earlier tsunami warning was revised downwards, according to the US tsunami warning system, predicting possible waves of up to a meter (3.3 feet).
Estimates modeled by the USGS suggest that localized casualties and damage are possible, but there are likely to be fewer than 100 casualties and less than $ 100 million in damage. However, the model only includes earthquake shakes, not any potential tsunami impacts on the coastline.
The USGS said recent earthquakes in the area have caused secondary hazards such as tsunamis and landslides.
Earlier earthquake estimates were 7.7, but this has been revised to 7.4 (and further revisions are possible).
Mexico is one of the most seismically active regions in the world and has a long history of devastating earthquakes. The country is located on top of three large tectonic plates and their movement causes regular tremors and accidental volcanic eruptions.
Mexico City is particularly vulnerable to earthquakes, as its very soft and wet ground intensifies the shaking and is prone to liquefaction, whereby the dirt transforms into a thick liquid when it is sufficiently stirred.
This broken story has been updated with additional reporting.
Fidel Gutierrez of CNNE in Mexico City and Clara Lopez of Atlanta contributed with reports. CNN’s Matt Rivers and Natalie Gallon reported from Mexico City, and Tatiana Arias and Brandon Miller from Atlanta. Emma Reynolds writes from London.