2 Earthquake Swarms Hit Northern and Southern California in a Week

An earthquake swarm hit California on Feb. 7. USGS

A swarm of earthquakes hit a remote area of San Bernardino County, California, according to the U.S. Geological Survey (USGS).

The quake, namely, was centered around Twentynine Palms near a Marine Corps base.

The strongest earthquake was a 4.0 magnitude quake that struck at 8:41 a.m. on Feb. 7, centered about 7 miles from Ludlow, said the USGS.

By 9 a.m., about nine earthquakes hit the area, CBS Los Angeles reported. They ranged from 2.1 to 4.0 in magnitude on the Richter scale.

The quake, namely, was centered around Twentynine Palms near a Marine Corps base. USGS

It’s unclear if there was any damage done in the area.

KTLA reported the swarm of quakes occurred “just north” of the Twentynine Palms Marines base.

The strongest Feb. 7 quake was felt as far away as Laughlin, Nevada, which is about 90 miles away from the epicenter. The quake was also felt in Los Angeles, located 125 miles away, CBS LA reported.

It comes a few days after another earthquake swarm occurred in Humboldt County, located in Northern California, in about a week.

The largest of those quakes registered as a 4.5 on the Richter scale, happening on Sunday, Feb. 3, reported the Times-Standard.

“Sheriff’s OES recommends that all Humboldt County residents work toward a goal of two weeks of disaster supplies for your family, including a gallon of water per person per day, non-perishable food, and extra water and food for pets,” said Dori Lanni, Emergency Services Manager for the Humboldt County Office of Emergency Services, reported the Times-Standard.

She added: “We recommend that residents in remote areas maintain supplies for more than two weeks. Following a countywide disaster, rural communities may be inaccessible while roads and bridges are inspected and repaired. Following a major earthquake, we can expect a long series of aftershocks that can cause additional damages and require multiple inspections.”

Lori Dengler, the emeritus professor of geology at Humboldt State University, said the region is due for a larger earthquake that can cause damage.

“What we know is we have had a long, an unusually long quiet spell on the North Coast, so if you look at the earthquake activity we haven’t had a whole lot since 2010,” Dengler said. “There was one earthquake offshore that wasn’t felt strongly and Jan. 9, 2010, was our last strong earthquake. If you look at all the earthquakes since the turn of the century, on average we have an earthquake that will cause damage every seven years.”

There were no tsunami warnings after the Northern California swarm.

Earthquake swarms are defined as events where a local area has many earthquakes hitting in a relatively short period of time, but the length varies. It could last hours, days, or even weeks.

“When people ask me what do those earthquakes mean, most likely the 4.5 is the largest we will get in that sequence,” Dengler said. She added, “Would I be surprised with a (magnitude) 5 or 6? No, I would not be surprised and we should take this as a reminder we live in earthquake country. Yes, we will have a damaging earthquake and we are one day closer to that event today than we were yesterday.”