Overview
- A sequence of earthquakes hit Wednesday morning, beginning with a magnitude 5.7 about 3:53 a.m. offshore near Crescent City, followed by a magnitude 5.1 about 5:45 a.m. west of Petrolia and a magnitude 4.5 aftershock at 6:11 a.m.
- The U.S. Geological Survey listed the 5.7 at roughly 10 kilometers deep and the 5.1 at about 0.2 kilometers, and said those very shallow depths can increase surface shaking near the epicenter.
- USGS collected felt reports as far as about 80 miles from the Petrolia-area quake, with people reporting shaking across Humboldt County and other North Coast communities.
- State emergency officials and the U.S. Tsunami Warning Center said there were no reports of injuries or major damage and no tsunami warning, and USGS warned that preliminary magnitudes and depths could be revised as more data are processed.
- The quakes occurred near the Mendocino Triple Junction, a seismically active plate boundary, and officials urged residents to review basic earthquake preparedness steps such as securing heavy items and having an emergency kit.