The quake struck at 10:44 a.m. west of Ferndale, a small city in coastal Humboldt County near the Oregon border, according to the U.S. Geological Survey.
A strong earthquake was felt widely across Northern California on Thursday and authorities have issued a tsunami warning.
The quake struck at 10:44 a.m. west of Ferndale, a small city in coastal Humboldt County near the Oregon border, according to the U.S. Geological Survey.
It was felt as far south as San Francisco, where residents felt a rolling motion for several seconds. It was followed by smaller aftershocks.