A moderately strong earthquake measuring 5.1 struck the North Pacific Ocean early Wednesday, according to the U.S. Geological Survey. The quake occurred at 5:45 a.m. Pacific time, about 40 miles west of Petrolia, California. USGS data indicates the shaking was mainly concentrated in areas with intensity level 3 or higher, which the agency classifies as weak, though the quake may have been felt beyond the mapped region.
Scientists said the reported magnitude could change as more seismic data is reviewed. The shaking-severity map may also be updated if additional information becomes available. Earthquakes of this size can trigger aftershocks, and several subsequent quakes were detected in the same area after the initial event. These follow-on tremors are usually caused by small adjustments along the fault segment that slipped during the main quake.
Aftershocks may occur days, weeks, or even years after a larger earthquake. In some cases, they can be as strong as or stronger than the original temblor. While the immediate impact of this quake appears limited, aftershocks can still affect already damaged areas and remain an important part of seismic monitoring.
The map and charts associated with the quake use data from the U.S. Geological Survey for the epicenter, aftershocks, and shaking intensity, and LandScan from Oak Ridge National Laboratory for population density. Shaking categories are based on the Modified Mercalli Intensity scale. When aftershock data is available, the maps and charts include earthquakes within 100 miles of the initial quake over the following seven days. All times referenced are Pacific time.
The quake was recorded on Wednesday, June 3, and the aftershock information was updated on Thursday, June 4. Seismologists continue to monitor the region as they assess the event and any related seismic activity.
