MEXICO CITY (AP) - A powerful earthquake that shook Mexico from its massive capital to its resort-studded southern coast damaged hundreds of homes and sent thousands of panicked people fleeing from swaying office buildings, yet apparently didn't cause a single death.
As of early Wednesday, there were still no reports of deaths from Tuesday's magnitude-7.4 quake centered near the border between the southern states of Oaxaca and Guerrero, even after 10 aftershocks.
Mexico City Mayor Marcelo Ebrard said Wednesday about 300,000 people in the south side of the capital were without water after the quake damaged two aqueducts. He said two people were reported injured, including the driver of an empty bus crashed under a collapsed pedestrian bridge.
Nine other people were injured in Oaxaca state, according to the federal government.
Seismologists and civil protection officials said where the earthquake hit and how it hit appear to have limited the damage, along with improved construction in the capital following a massive 1985 quake.
In Guerrero, home to Acapulco where little damage was reported, officials say about 800 homes were damaged and 60 collapsed. In three villages near the epicenter classes were suspended indefinitely.
"It hasn't stopped shaking here and the truth is that we had to suspend classes because people are really afraid of what can happen to their children," said Guerrero state Education Secretary Silvia Romero told the daily Milenio newspaper.
In the town of San Juan Cacahuatepec, in Oaxaca state, frightened residents spent the night outside their homes and woke up early Wednesday to clean up fallen roof tiles and pieces of brick fences from around their houses.
No buildings were reported to have collapsed in Oaxaca, said civil protection spokeswoman Cynthia Tovar.
Authorities said the absence of tall buildings in the mountainous rural area is one reason for the lack of casualties.
"Another factor to consider is how tested an area has been," said USGS seismologist Susan Hoover.
There have been 15 earthquakes of magnitude 7 or stronger since 1973 within 310 miles of Tuesday's quake. Weaker buildings collapse with each quake, leaving a cadre of stronger ones that can withstand the shaking.
The quake's epicenter was 200 miles south-southeast of Mexico City. Despite the distance, it was felt powerfully in the capital where office towers swayed violently and the streets filled with people fleeing buildings. Some people sat on curbs, head in their hands, to calm themselves.
Mexico City was badly damaged in 1985 when a magnitude-8.0 earthquake killed at least 10,000 people. But experts say Tuesday's quake was smaller and released far less energy.
Mexico City was built on an ancient lakebed and its spongy soil amplifies seismic waves, and the damage they cause. The 1985 quake destroyed 400 buildings and damaged thousands more.
The latest jolt "wouldn't have been nearly as effective at generating those deep bass tones" that caused the damage seen in 1985, USGS seismologist Susan Hough said in an email.
Victor Hugo Espindola Castro of Mexico's national seismological service said another factor was improved building standards following the 1985 quake.
"Many of the buildings that were damaged in 1985 were poorly constructed and from that came the new building regulations, so that now buildings are stronger," he said.
In Mexico City, telephone service was down and some neighborhoods were without power, according to Mayor Marcelo Ebrard, who set up a hotline for people to report damage.
A pedestrian bridge collapsed on an empty transit bus.
About 40 passengers were stranded for a short time on the Mexico City airport air train, but later released. The airport closed briefly but officials said there was no runway damage and they resumed operations.
In the working-class neighborhood of Guerrero, pieces of concrete and plaster fell off some buildings and others had fresh cracks.
"I thought I was having a stroke at first. The earth danced. It was strong," said 42-year-old homemaker Marianela Jimenez. "But it looks like it will end up being some dust and a bad scare."
Tuesday's quake was the strongest shaking felt in the capital since a magnitude-6.5 earthquake struck also in Guerrero state in December. A magnitude-8.0 quake near Manzanillo on Mexico's central Pacific coast killed 51 people in 1995 and a magintude-7.5 quake killed at least 20 people in the southern state of Oaxaca in 1999.