The earthquake swarm in California, which spanned from about 4 a.m on Thursday until 11 a.m. on Friday and consisted of more than 600 small earthquakes, have created some nervousness amongst residents in the area. According to multiple reports, the swarm of earthquakes in California struck the Mammoth Lakes area in the northern part of the state.
The physics of the phenomenon is still not well understood, but it's pretty clear that the swarm of earthquakes in California is only a case of geological indigestion, reports the Christian Science Monitor.
According to the Los Angeles Times, at least 109 of the shaking felt during the earthquake swarm in California were of a magnitude 2.0 or greater. Small quakes consisted majority of the activity, said seismologist David Shelly at the USGS' Volcano Science Center.
These small temblors are reportedly too small to be felt by the public, but Shelly added that six of them were greater than magnitude 3.0, which is the minimum magnitude before quakes are felt.
According to the LA Times, the largest temblor from the earthquake swarm in California was measured at magnitude 3.8. It was located six miles from Mammoth Lakes and was reported to have occurred at 9:21 p.m. on Thursday.
The swarm of quakes occurred in the 20-by-10-mile region known to geologists as the Long Valley Caldera, east of the central Sierra Nevada Range.
Despite the massive number of the quakes, according to the LA Times, the phenomenon is common in the region. In July, about 200 small quakes also shook Long Valley Caldera. The largest of the temblors was at a magnitude 2.7.
As for the feared eruption of a volcano after the earthquake swarm in California, fears are proven unfounded, reports CBS San Francisco. The site is reportedly where one of North America's greatest pre-historic eruptions occurred. It is also surrounded by a chain of recently-active volcanoes, but the USGS California Volcano Observatory site states that the string of quakes will "not result from the underground movement of magma" and "pose no immediate hazard."
According to the CS Monitor, Shelly told the Mammoth Times thtat the quakes appears to have come from the release of carbon dioxide gas and water deep in the earth into existing cracks or faults in the ground under the Eastern Sierra.
He said, "This fluid moves episodically into cracks or faults in the crust. We think these quakes were triggered by this movement but driven by existing tectonics."
The USGS California Volcanic Observatory also pointed out that the earthquake swarm in California did not result from magma activity below the surface.
Despite the assurance, Shelly said the recent earthquake swarm in California "is a bit more energetic than what we have seen in a while."
The USGS reports that this throng is the latest of several earthquake swarms in the year under the caldera, which is described as slowly rising.
Meanwhile, seismic analysts still plan on reviewing the latest earthquake swarm in California and will be updating the public on the locations and magnitudes of the quakes.