MEXICO CITY — A strong new earthquake shook Mexico on Saturday, killing at least two people, toppling already damaged homes and a highway bridge, and causing new alarm in a country reeling from two even more powerful quakes that together have killed more than 400 people.
The U.S. Geological Survey said the new, magnitude 6.1 temblor was centered about 11 miles (18 kilometers) south-southeast of Matias Romero in the state of Oaxaca, which was the region most battered by a magnitude 8.1 quake on Sept. 7.
It was among thousands of aftershocks recorded in the wake of that earlier quake, which was the most powerful to hit Mexico in 32 years and killed at least 96 people.
The government of Oaxaca state reported that some homes collapsed. A woman died when a wall of her home fell on her in the town of Asuncion Ixtaltepec, and a man died after a wall fell on him in San Blas Atempa.
Four people were injured in Juchitan and three in Tlacotepec, but none of their lives were in danger. Another person suffered a broken clavicle in the town of Xadani. Three hotels and two churches were damaged and a highway bridge collapsed. The Federal Police agency said the bridge already been closed due to damage after the Sept. 7 quake.
Bettina Cruz, a resident of Juchitan, Oaxaca, said by phone with her voice still shaking that the new quake felt “horrible.”
“Homes that were still standing just fell down,” Cruz said. “It’s hard. We are all in the streets.”
Cruz belongs to a social collective and said that when the shaking began, she was riding in a truck carrying supplies to victims of the earlier quake.
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U.S. Geological Survey geophysicist Paul Caruso said the new temblor was an aftershock of the 8.1 quake, and after a jolt of that size even buildings left standing can be more vulnerable.
“So a smaller earthquake can cause the damaged buildings to fail,” Caruso said.
“At the moment the greatest damage has been to the Ixtaltepec bridge, which should be rebuilt, and structures with previous damage that collapsed,” President Enrique Pena Nieto tweeted. He said government workers were fanning out in Juchitan to provide help to anyone who needs it.
Jaime Hernandez, director of the Federal Electrical Commission, said the quake knocked out power to 327,000 homes and businesses in Oaxaca but service had been restored to 72 percent of customers within a few hours.
Buildings swayed in Mexico City, where nerves are still raw from Tuesday’s magnitude 7.1 temblor that has killed at least 305 across the region. Many residents and visitors fled homes, hotels and businesses, some in tears.
And the Popocatepetl volcano near Mexico City spewed a cloud of vapor with some ash about a mile (2 kilometers) into the air Saturday, but experts said it was not related to the quakes. The 17,797-foot (5,426-meter) volcano has been periodically erupting since 1994.
Mayor Miguel Angel Mancera said there were no reports of significant new damage in the capital, and rescue efforts related to Tuesday’s quake were continuing. He reported that two people died of apparent heart attacks during the new temblor.
At the site of an office building that collapsed Tuesday and where an around-the-clock search for survivors was still ongoing, rescuers briefly evacuated from atop the pile of rubble after the morning quake before returning to work removing cement, tiles and other debris.
As rescue operations stretched into Day 5, residents throughout the capital have held out hope that dozens still missing might be found alive. More than half the dead — 167 — perished in the capital, while another 73 died in the state of Morelos, 45 in Puebla, 13 in Mexico State, six in Guerrero and one in Oaxaca.
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In a city still on edge, many residents have spoken of lingering anxiety: imagining the ground is moving when it isn’t, hearing a police siren wail and thinking it’s a quake alarm, breaking into sobs at unexpected moments.
“There is collective panic. I feel afraid even when a car passes by,” said Dulce Bueno, who came Saturday morning with her husband and daughter to the hard-hit Condesa neighborhood. They brought suitcases to collect the belongings of their daughter, who lived in a damaged building beside one that collapsed and who is now moving in with them.
“They have told us it is well constructed, that it’s a bunker,” Bueno said of her own home. “But if the tremors continue, will it hold up?”