An earthquake of magnitude 5.8 struck off northern California in the Pacific Ocean on Friday, the U.S. Geological Survey (USGS) said.
It was quickly followed by a second quake of 5.6 closer to shore, the USGS said.
Both quakes struck west of the California town of Petrolia and were very shallow, amplifying their effects.
— Reporting by Sandra Maler in Washington; Editing by Alistair Bell