SAN DIEGO – A swarm of mostly small earthquakes were reported Wednesday afternoon in Imperial County, the largest of which was recorded at a magnitude of 4.9, according to the U.S. Geological Survey.
The agency has recorded nearly 200 quakes of a magnitude of 1 or greater within about a three-mile radius of the 4.9 magnitude quake near Westmorland, a small city in Imperial County north of El Centro, according to Rob Graves, a research geophysicist with USGS. Graves said it’s “not uncommon and certainly not unheard of” for a swarm of earthquakes to be recorded in the area of the Salton Sea, located north of Westmorland.
The area has a complex web of faults between the San Andreas Fault Zone to the north and the Imperial Fault Zone to the south, he said.
“The No. 1 takeaway is that this is a reminder that we’re all living in earthquake country,” Graves said. “We’re in Southern California or California. In general, earthquakes are going to happen. Every once in a while, it’s going to be a large, damaging earthquake.”
He adds, “I can’t say with 100% certainty what’s going to happen with this swarm activity, but what I take away from that is that it’s a reminder to be prepared.”
According to agency modeling, Graves said the most likely scenario is that similar activity will continue for another day or two. Less likely, he said, would be for a larger quake — between magnitudes 5.5 and 6.5 — to hit the area.
“Most likely is that they’ll continue, possibly up to magnitude above 5,” he said. “But over the next week or so, that’s going to taper off and kind of go back down to the typical level.”
A similar swarm of quakes was reported in the area in 2012, according to Graves. In August, USGS reported a dozen small quakes in roughly the same area, which drew concern from SDSU professor and geologist Pat Abbott.
The agency reported ripples of the quake were felt north of the Salton Sea and to the south near the U.S.-Mexico border as well as in parts of San Diego County.
No injuries or damage have been reported thus far.