Earthquake hits off coast of California, Mexico; 6.3 quake followed by 4.7 aftershock

A powerful 6.3 earthquake struck off of the coasts of California and Mexico early Friday morning.

According to DecodedScience.com, it was the biggest earthquake California has seen in 2012. US Geological Survey data last updated in November appears to confirm that — and suggests Friday's tremor may have been the second largest the US experienced this year.

The USGS reported that the initial quake, centered 163 miles south southwest of Avalon, California hit at 2:36 a.m. local time. A strong 4.7-magnitude aftershock hit about 15 minutes later, according to the USGS.

The Associated Press had earlier reported that two quakes occured within seconds of each other at magnitudes of 6.4 and 6.1.

No tsunami was anticipated as a result of the quakes. A local ABC station in California said that the quake had not caused any damage on land; only that "Eyewitness News viewers across the Southland said they felt some shaking, including in Newport Beach, Santa Ana, Temecula and Long Beach."