A 6.4 magnitude earthquake has hit the West Coast of southern Mexico on Thursday, roughly about 60 miles northwest of the resort city of Acapulco. According to the U.S. Geological Survey, this is the second big quake in the region in a month.

On April 18, a 7.2-magnitude earthquake with an epicenter in the same area rattled central and southern Mexico.

According to reports, the earthquake was very shallow, with a depth of 6.2 miles and there was just gentle shaking in Acapulco. In fact, Mexico City is vulnerable to far-off earthquakes, as much of the area is located on top of muddy sediments of worn out lake beds. They shake like jelly when the waves of an earthquake hit.

The quake shook downtown Mexico City, situated approximately 170 miles northeast of the epicenter, in Guerrero state. However, initial analysis did not report any serious injury or major damage in the capital.

A portion of a highway bridge fell in the Tecpan de Galeana region, located about 9 miles from the epicenter. The bridge was already damaged due to floods last fall and was being repaired.

Taking to the Los Angeles Times, a secretary in Mexico City, Carmen Lira said, "It was very scary. Some of my colleagues suffered panic attacks because the buildings moved," adding, "It felt very strong." Meanwhile, describing Thursday's quake as "ferocious," the Mayor Marcelo Ebrard said, "It caused a wave of panic, as some roofs collapsed."

Residents of the affected area were given a 68-second warning by the earthquake detection system that was developed in the aftermath of the 1985 earthquake that devastated Mexico City, killing about 10,000 people. It gave Mexico City residents time to get out of buildings.