The U.S. Geological Survey says two large earthquakes have struck in the Pacific Ocean off the coast of southern California and Mexico.

The first quake, with a preliminary magnitude of 6.4, was recorded at 2:36 a.m. (1036 GMT) Friday, 163 miles south southwest of the California city of Avalon and 167 miles west southwest of Rosarito, Mexico.

Only seconds later, a second quake with a magnitude of 6.1 struck 88 miles from Avalon. Both were recorded at relatively shallow depths.

No tsunami warning has been issued.