A moderate earthquake shook Mexico City on Tuesday, but officials reported no damage in the sprawling capital, where street activity continued as normal moments after the tremor hit. The U.S. Geological Survey said the epicenter of the 5.5-magnitude earthquake was in the central state of Michoacan, about 200 kilometers southwest of Mexico City. Mochoacan Governor Fausto Vallejo said there were no reports of damage in the state, and Mexico City Mayor Marcelo Ebrard issued a similar message about the capital.