A massive earthquake initially measured at 7.4 magnitude struck off the coast of Guatemala at about 8 a.m. on July 17, according to the U.S. Geological Survey (USGS).
The National Weather Service has issued a tsunami threat warning near the coast of Chiapas, Mexico.
The USGS initially measured the quake at 7.4 magnitude but downgraded it slightly to 7.3 after review.
The agency expects the event could be felt across the state of Chiapas and into Oaxaca, Tabasco, Veracruz, and in parts of Guatemala and El Salvador, according to initial maps.
Local officials have not yet reported damage or injuries from the earthquake.
Residents were urged to move away from the coast and seek higher ground during the resulting tsunami threat alert, which triggered public alarms in nearby cities.
The quake was centered about 10 miles deep in the Gulf of Tehuantepec, about 45 miles from Puerto Madero in the state of Chiapas, Mexico, the USGS reported.
A 5.3-magnitude aftershock struck about 30 minutes after the first quake.
The area experienced several additional aftershocks ranging from 5 to 6 magnitude in the first few hours of the event, including one 5-magnitude quake on land near Tapachula de Cordova y Ordonez, Mexico, the USGS reported.
Mexican President Claudia Sheinbaum reported no damage in Chiapas and Tabasco after speaking with the governors.
“Protocols are being activated in neighboring states,” Sheinbaum said in a post on X.
Mexico’s navy secretary recommended the public stay away from beaches for the next six hours because of the tsunami risk. Sheinbaum advised the public to follow public safety warnings.
“Authorities from all three levels of government are conducting inspections in the territory to assess possible structural impacts and coordinate preventative measures,” Sheinbaum said.
Eduardo Ramirez, the governor of Chiapas, reported no injuries or casualties in the state as the aftershocks continued. The governor suspended state government activities and asked private businesses to do the same while the region continued to experience aftershocks.
“Stay in your homes and remain calm,” Ramirez said in a video posted on X. “I will be providing constant follow-up to this event.”
The earthquake was not expected to cause tsunami issues for California, the National Weather Service in Los Angeles said.
Videos shared on social media show local shops shaking during the morning earthquake, which sent items crashing to the floor. Some tall buildings swayed in other videos taken in Chiapas.
SASSLA—the Mexican earthquake early warning system—did not alert the public because there were no sensors installed in Chiapas, the epicenter of the quake, the agency said.
The earthquake was only detected when it was felt at sensors in neighboring Oaxaca, where the magnitude reached a high enough level to trigger the alert system, SASSLA reported.
An analysis by the USGS found the quake was caused by two undersea slabs colliding on the Pacific Ocean floor in a deep ocean trench. The Cocos plate slid northeastward beneath Mexico and Central America at the Middle America Trench, according to the agency.
Two small quakes, called foreshocks, occurred in the lead-up to the larger quake—a 4.1-magnitude temblor on July 14 and a 4.7-magnitude event around 90 minutes prior to the main quake, the USGS said.
The location has a history of larger earthquakes, according to USGS.
“Magnitude 7 and larger earthquakes in Mexico and Guatemala have led to varying societal impacts, with the impacts largely dependent on the proximity of these earthquakes to major population centers,” the agency reported.
Since 1950, 50 quakes at a 7.0 magnitude or more have occurred in Central America, according to USGS. Shaking in a 1993 7.2-magnitude quake caused one death and resulted in considerable damage in Guatemala.
