A large shallow 6.6-magnitude earthquake struck off the coast of mexico Thursday. The quake struck just after 1 p.m. about 235 kilometres southwest of Tomatlan according to the U.S. Geological survey. The quake was initially measured at 6.9-magnitude. A tsunami is not expected the USGS said. Tomatlan is location about 100 kilometres south of the resort town of Puerto Vallarta. Mexico's national coordinator of civil protection tweeted that no damage has been reported. Mexico is among the world's most active regions for earthquakes.