Northern California Earthquake Unusual, Seismologists Say

The earthquake that struck Northern California on Thursday night is a curiosity to seismologists because of its location and strength.

The tremors registered at 5.7 on the Richter scale and also caused several dozen aftershocks. Its epicenter was located in a rugged area of the state that has not been studied for seismic activity like the Bay Area and Southern California.

Because of this, the region has less monitoring equipment. Experts were surprised that the quake was felt over such a large area. It struck at 8:47 pm local time about 150 miles northeast of California’s capital, Sacramento.

It is also the first strong earthquake to hit California since 2008. Those tremors were in Chino Hills in July 2008 and had a magnitude of 5.5.

Thursday’s earthquake did happen in a zone known for seismic activity, according to David Schwartz, an earthquake geologist for the Northern California USGS division. The area includes a series of faults that extend from north Lake Tahoe to Oregon. However, 5.7 is the strongest quake ever recorded in the region.

More than 7,000 people felt Thursday’s quake from California, Oregon, and Nevada. Officials in Susanville and Sacramento reported the quake triggering several home and car alarms. It also rattled windows. Thankfully, there was no major damage. Schwartz explained that it wasn’t the quake itself that was surprising. Rather, it was the fact that it “was felt along an unusual distance.” He added:

“Earthquakes in different parts of the state are felt over different distances. We just haven’t had that many examples of earthquakes in this part of the state, really, for comparison.”

While more than four dozen aftershocks seems like a high amount, Schwartz added that they appeared to be “fairly standard.” A USGS probability report released on Friday also shows that there is a 20 percent change an earthquake larger than a magnitude 5 will happen along the same fault line in the next week. There is also a five to 10 percent change a quake larger than 5.7 could hit during that time period.

There were no reports of injuries from the earthquake in Northern California.

[Image via ShutterStock]