An earthquake that rattled central and south Texas Thursday morning was the strongest ever recorded in the area at 4.6 magnitude, officials said. The earthquake struck about 47 miles southeast of San Antonio in Atascosa County, the U.S. Geological Survey said. A 4.3-magnitude earthquake moved through the area on April 9, 1993, the San Antonio Express-News reported. Employees were briefly evacuated from a seven-story federal building in San Antonio, then allowed to re-enter an hour and a half later. There was no visible damage to the building, which contains offices of the U.S. Marshals Service, the Bureau of Prisons and the Social Security Administration. There were no injuries or damage reported anywhere as a result of the temblor, the Express-News said.