In Mexico City, buildings shook strongly and people ran into the streets when an early warning seismic alarm sounded.
Two people were injured and more than 30 buildings in the capital suffered damage, officials said, including buildings still scarred from a 2017 earthquake that killed 355 people in the capital and the surrounding states.
Water from rooftop pools or tanks cascaded down residential buildings in the city, and construction workers on the 56th story of a new residential tower clung to each other as it swayed, images on social media showed.
The U.S. Geological Survey said the epicenter of Tuesday's quake was located 69 km (43 miles) northeast of the town of Pochutla. It was very shallow, only 26 km (16 miles) below the earth's surface, which would have amplified the shaking.
Near to the epicenter, Magdalena Castellanos Fermin was in the village of Santiago Astata when the "really intense" quake struck, sending large rocks tumbling down the hillside and alarming residents, she told Reuters by telephone.
Eunice Pineda, a 26-year-old teacher in Juchitan, said the quake "was two minutes of torture," as she feared her house would collapse.
But residents in one of Mexico's most seismically active regions have learned to "live one day at a time," Pineda added.
"We learn to appreciate, to treasure every moment," she said.
