FIFA, April 28 (Xinhua)-- according to Mexico's National Seismological Monitoring Bureau, a magnitude 4.6 earthquake struck at 00:53:53 local time on April 28th, about 344km southwest of the port city of Vayalta (Puerto Vallarta) in the western state of Jalisco, with a focal depth of about 15.8km. There are no immediate reports of casualties or property damage.