© U.S. Geological Survey
Though there were no immediate reports of damage, the quake was felt across a wide area and was a blunt reminder that California is earthquake country. The U.S. Geological Survey put the epicenter about 23 miles off the Channel Islands, about 85 miles west of Los Angeles.
It was centered near the Eastern Santa Cruz Basin Fault Zone, Caltech seismologist Egill Hauksson said. "Earthquakes happen out there now and again. There's a major offshore fault system," he said.
Seismologist Lucy Jones said on Twitter that the fault system "moves Southern California around a bend of the San Andreas fault."
There is a slightly greater likelihood that the the temblor could trigger a larger earthquake, but that chance decreases with time, Hauksson said.
The last big earthquake in the Channel Islands region before Thursday's temblor was in 1981, which was a magnitude 6.0, Hauksson said. A magnitude 4.8 quake struck near the islands in 2013.
The last quake to be felt this widely in the L.A. area was a magnitude 4.4 in Encino in 2014. That quake also shook a wide area and was the largest in the Los Angeles area in four years. It was the strongest to hit directly under the Santa Monica Mountains in the 80 years.
Comment: The earth has been literally 'opening up' in various locations around the globe, due in part to the current slowdown in earth's rotation: