The U.S. Geological Survey's (USGS) California Volcano Observatory said that over 500 earthquakes with a magnitude 1.0 and above, plus eight earthquakes between magnitude 3.0 and 3.8, were recorded beginning Sept. 25 at 4 a.m. PDT to Sept.26 at 11 a.m.
The "earthquake swarm" -- as referred to by the observatory -- has been located seven miles east of Mammoth Lakes town, which is around one mile north of the airport.
"We have been closely tracking an earthquake swarm in California's Long Valley Caldera," the USGS observatory said.
The current earthquake swarm is one of the many swarms that have transpired in caldera this 2014, the agency added.
As compared to the similar earthquake swarm that transpired in the 1980s and 90s, the current swarm is still considered a "modest activity," according to the agency.
"We do not see any evidence for anomalous ground deformation associated with the swarm at this time," the USGS added.
Residents said they have felt periodic shakes within the day but were accustomed to it considering that the Mammoth area is one that is seismically active.
The USGS said that a portion of the Long Valley Caldera, which is recognized as "resurgent dome," has been elevating or uplifting around an inch every year beginning late 2011 and has remained unchanged. The uplift has transpired irregularly for the past few decades.
As compared to the observed rates in the 80s and 90s, the uplift rate in 2011 was considered small by the agency.
The USGS also described the earthquakes as "small, brittle-failure (rock breaking) events," which are sometimes called "tectonic." Earthquakes also do not lead to underground magma movement, the agency said.
"We can distinguish between brittle-failure earthquakes and those resulting from magma movement by the characteristics of the seismic waveforms," said the USGS.
The observatory said that the current earthquake swarm poses no instant hazard but that it will continue to keep a close track of the events and give updates whenever appropriate.
"At this point, we don't know if it would continue to die down, or if there'd be another stage to this swarm," USGS research seismologist David Shelly said in a Los Angeles Times report.
Shelley has been examining the volcanic system close to Mammoth Lakes and acknowledged that the current activity is "an interesting scientific opportunity to better understand the processes that are driving this activity."
Reports said that the last biggest earthquake swarm happened in 1997 with a magnitude as high as 4.9 shook the Mammoth region.
