Mexico City rocked by 5.8 earthquake
A magnitude 5.8 earthquake shook Mexico on Thursday, causing buildings to sway in the capital some 300 kilometers (187 miles) away from the epicenter, an AFP correspondent and US seismologists said.
The quake struck at 1324 GMT near the town of Ometepec in the state of Guerrero, at a depth of 10 kilometers (six miles), the US Geological Survey (USGS) said.
The tremor rattled Mexico City, where earthquake alarms rang out in some quarters and office workers briefly spilled onto the streets.
Helicopters patrolled the capital -- whose metropolitan area has a population of about 21 million people -- while civil protection authorities reported no immediate damages.
"Mexico City usually feels quakes a bit more because it's built on a former lake bed," USGS geophysicist John Bellini told AFP.
The sediment under the city is largely unconsolidated layers of silt and volcanic clay, and "it behaves like a bowl of jelly," amplifying seismic shockwaves, said Bellini.
Such an effect was at work in Mexico's historic 8.1-magnitude quake of 1985, which occurred off the Pacific coast some 350 kilometers from Mexico City but devastated the capital, killing at least 10,000 people.
Dozens of moderate to strong temblors are recorded each year in Mexico, where movement of the North American plate against the Pacific and other plates makes it one of the most active seismic regions in the world.
A strong 6.5-magnitude quake struck southern and central Mexico on April 7.