|
INCLINE VILLAGE, Nev.
– California and Nevada share more than
just a border. They share faults. A map
unveiled by the Department of
Conservation’s California Geological
Survey today shows earthquake shaking
potential in the Reno-Tahoe area.
“The seismic hazard
in the Tahoe area is related to faults
on both sides of the California-Nevada
border, which is why we’re involved,”
said California State Geologist John
Parrish, head of CGS. “Fault lines don’t
care about state lines. We’re happy to
work with our partners in this growing
region of Nevada.”
The map covers
Washoe, Storey, Carson City, Douglas,
Lyon, Churchill and Mineral counties in
Nevada, as well as parts of Nye and
Esmeralda counties. Also included are
all or parts of the following California
counties: Lassen, Plumas, Sierra,
Nevada, Placer, El Dorado, Amador,
Alpine, Calaveras, Tuolumne, Mono,
Mariposa, Madera, Fresno, Stanislaus,
Merced and Inyo.
Areas of Nevada just
south of the Reno-Sparks area and in the
Fish Lake Valley are among the most
likely to receive strong shaking during
a large earthquake, according to the
map.
The map also
indicates a high level of shaking
potential along the Genoa fault from
just south of Reno-Sparks through Carson
City through the Minden-Gardnerville
area to just north of Markleeville in
California. High shaking potential is
also shown in the Mono and Mammoth lakes
areas due to active faults and soil
amplification, and in the area around
Dyer, Nev., at the northern end of the
Death Valley fault system.
The map shows shaking
that has a 10 percent chance of
occurring in a 50-year period, according
to Chris Wills, the CGS Supervising
Geologist who oversaw the mapping
project. The California Building Code
specifies critical structures such as
schools and hospitals be able to
withstand the highest anticipated levels
of shaking. Local planners can use the
map to determine whether extra care
should be taken in new construction and
whether it might be appropriate to
retrofit some existing structures.
Last summer, a swarm
of 1,600 tiny earthquakes – most
unnoticed by the public -- occurred in
the region. The temblors may have
indicated magma moving deep beneath the
Earth’s surface, according to
researchers at the
Nevada Seismological Laboratory, Nevada
Bureau of Mines and Geology, the
California Institute of Technology, and
the Harvard-Smithsonian Center for
Astrophysics.
There have been
several strong earthquakes in the
greater Reno-Tahoe area in the past.
Before seismic instruments were
available, in 1860 and 1887, the region
experienced two earthquakes in the
magnitude 6.5 range. In 1950, a
magnitude 5.6 earthquake was centered
near Honey Lake northwest of Reno in
Lassen County and in 1966, a magnitude 6
was centered north of Truckee. The 1966
quake damaged the dome of the Nevada
state capitol in Carson City, cracked
dams on the Truckee River and was felt
as far away as San Francisco.
“People don’t
necessarily relate the thought of
earthquakes to the Reno-Tahoe area as
readily as they do to Los Angeles or San
Francisco,” CGS Chief Seismologist
Michael Reichle said. “But it’s prudent
for Californians and Nevadans alike in
that area to be aware of the
inevitability of future earthquakes and
always be prepared.”
CGS, part of the
California Department of Conservation,
used soil information provided by Nevada
officials and a seismic hazards model
developed by the United States
Geological Survey to produce the map.
CGS previously produced a potential
shaking map for California in
cooperation with California Seismic
Safety Commission and has extended the
work into the greater Reno-Tahoe area
with help from the Nevada Bureau of
Mines and Geology as well as the Nevada
Seismological Laboratory at the
University of Nevada-Reno.
Copies of the map are
available for $10 each from the
California Geological Survey library at
(916) 445-5716.
For more information
about seismic activity in the Tahoe-Reno
area and earthquake preparedness,
click
here.
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.
###
|