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SACRAMENTO -- Magma
moving deep in the Earth may have been
behind a recent earthquake swarm near
Lake Tahoe and may also have caused
Slide Mountain the Sierra Nevada to grow
slightly taller, according to a report
in the online version of the journal
Science.
But that does not
mean there’s an imminent danger of a
volcanic eruption, according to the
California Geological Survey (CGS).
“This is a very
interesting scientific discovery, but
there’s no cause for the public to be
alarmed,” said Michael Reichle, acting
California State Geologist and head of
CGS. “The most recent instances of magma
reaching the surface in the Lake Tahoe
area occurred about a million years
ago.”
Added Darryl Young,
director of the California Department of
Conservation, which includes CGS: “The
chances of us seeing a volcanic eruption
the Tahoe region in our lifetime are
practically nil.”
Research conducted by
the Nevada Seismological Laboratory,
Nevada Bureau of Mines and Geology, the
California Institute of Technology, and
the Harvard-Smithsonian Center for
Astrophysics showed that a swarm of
1,600 tiny earthquakes coincided with
the slight horizontal and vertical shift
of a Global Positioning System station
on Slide Mountain in Nevada, about 10½
miles northeast of the swarm’s center.
The full text of the
report is available on the Web at the
following address:
www.sciencemag.org/sciencexpress/recent.shtml.
That information was
shared with CGS, which tracks seismic
activity in California, since most of
the earthquakes occurred in California.
“With this new
information, we’ll be keeping a close
eye on future seismic activity in the
Tahoe area,” Reichle said.
According to Reichle,
the swarm and other recent temblors are
a reminder that residents of the Lake
Tahoe-Reno region, like other
Californians, should prepare for future
earthquakes.
“When someone says
`earthquake,’ most people probably think
of San Francisco or Los Angeles,”
Reichle said. “But there’s an
appreciable earthquake hazard in the
Reno-Tahoe region, too, as well as other
locations, such as Eureka and the Mojave
Desert.”
Nearly 90 earthquakes
of magnitude 3 or larger have struck the
Reno-Tahoe area since 1943. A 1966
magnitude 6.0 temblor in the Donner Pass
area damaged the dome of the Nevada
state capitol in Carson, cracked dams on
the Truckee River and was felt as far
away as San Francisco. The largest known
earthquake to strike the area was a
magnitude 6.5 in 1887.
In addition to
studying and mapping earthquakes and
other geologic phenomena, the Department
of Conservation regulates oil, gas and
geothermal wells; ensures reclamation of
land used for mining; administers
agricultural and open-space land
conservation programs; and promotes
beverage container recycling.
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