Residents rushed into the streets after feeling the temblor in Mexico City. Tourists and residents also felt the earthquake in the resort city of Acapulco. Local authorities in Guerrero state reported aftershocks.
The quake shook residents in Mexican resort towns, as well as the capital city of, but there were no reports of injuries or seriousu damage, other than the loss of phone service to some areas. President Calderon said in another Twitter post that there were no immediate reports of serious damage.
The epicenter was about 15 miles (25 km) east of Ometepec, Guerrero, the USGS said, and its depth was about 11 miles (17 km). The agency earlier reported the magnitude of the quake at 7.9, but later revised that figure.
Residents in the southwestern states of Oaxaca and Guerrero and the eastern state of Veracruz reported that phone service had been knocked out in their areas.
In Mexico City, Mayor Marcelo Ebrard sent tweets saying that there was no visible damage in the capital and that the sprawling city's strategic services and water system were functioning. Regardless, he tweeted, numerous buildings were being evacuated.