A strong earthquake struck a sparsely populated area in the mountains of western Mexico on Wednesday, and caused tall buildings to sway more than 200 miles away in Mexico city. People evacuated some buildings in the capital, but the city government said there were no victims or signs of major damage.
A quake of that magnitude is capable of producing severe damage in an urban area, but this one occurred about 41 miles (65.6 kilometers) below the surface and a tremor's power to cause damage is often dissipated when it is so deep.
The USGS said the tremor was centered in Michoacan state 238 miles (384 kilometers) west-southwest of Mexico City and 88 miles (143 kilometers) northwest of the Pacific resort of Zihuantanejo.
Manuel Ortiz Rosete, the Michoacan state civil protection director, said no damage had been reported in major cities and coastal communities of the state.
Maria Luna Garcia, a resident of the town of Arteaga, said she and her children became very scared when the quake hit less than 30 miles away.
"I went out to the streets with my three children, one of them in my arms, just to be safe," she said. "Fortunately, nothing happened."
Wednesday's tremor was the latest in a series of strong shakes to hit Mexico City since a powerful 7.4-magnitude quake hit southern Mexico three weeks ago. But this was not an aftershock of that one, USGS geophysicist Dale Grant said.
"It's a different earthquake. We are calling it an individual earthquake," Grant said. "There's a potential for aftershocks."
Last month's big earthquake was felt strongly in the nation's capital, and it damaged hundreds of homes and killed at least two people near the border between Guerrero and Oaxaca states. Mexico's seismological service said that quake has been followed by close to 400 aftershocks, including one of magnitude 6.0.