No casualties have been reported.   Later, it was reported that the epicenter was offshore Pichilemu, a coastal town in the O'Higgins Region.   There was no tsunami warning. ONEMI (Chile's National Emergencies Office) has reported no casualties or structural damage; and reported the earthquake was felt between the Metropolitan Region and Bío Bío.  The University of Chile Geological Survey reported the epicenter of the earthquake was located 28 kilometers at the south of Pichilemu, and it is most likely an aftershock to the March 11 earthquake.  Wikinews reporter Diego Grez reports the aftershock was clearly felt in Pichilemu.  Arévalo was patrolling the Las Terrazas beach, when the earthquake occurred.  There was no tsunami warning, and Mayor Córdova was away on holiday when the earthquake struck.   'We are here because we fear about our safety': Residents scramble after second earthquake  On March 11, Chile was hit by a second earthquake, that reached a magnitude of 6.9, and that occurred 40 kilometers southwest of Pichilemu.  Agustín Ross Balcony after the earthquake and tsunami.  It was felt in cities such as Melipilla (Santiago Metropolitan Region), Pichilemu (O'Higgins Region) and Rancagua (O'Higgins Region).   It occurred 64 kilometers west of Navidad, O'Higgins Region at a depth of 31 kilometers, University of Chile reported.  According to the University of Chile, it had a magnitude of 5.6, and occurred 32 kilometers south of Pichilemu, O'Higgins Region at a depth of 41.9 kilometers.  No damage was reported.   