Earthquake Scenario Presented to Congress and Cal. Geological Survey:
Today a scientific report describing what is referred to as the ShakeOut Scenario,
jointly published by the U.S. Geological Survey (USGS) and the California Geological
Survey (CGS), was released during a Congressional hearing in Washington, D.C.
The House Committee on Natural Resources, Subcommittee on Energy and Mineral
Resources, led by Chairman Jim Costa (D-CA), held an oversight hearing on USGS
efforts to prepare for future earthquakes.
From USGS Press Release:
Scientists today unveiled a hypothetical Scenario describing how a magnitude
7.8 Southern California earthquake similar to the recent earthquake in China
would impact the region, causing loss of lives and massive damage to infrastructure,
including critical transportation, power, and water systems. In the Scenario,
the earthquake would kill 1800 people, injure 50,000, cause $200 billion in damage,
and have long-lasting social and economic consequences. This is the most comprehensive
analysis ever of what a major Southern California earthquake would mean, and
is the scientific framework for what will be the largest earthquake preparedness
drill in California history, scheduled for November 13, 2008..
Although imaginary, the Shakeout Scenario is based on scientists best
predictions of what would actually occur during and after a major earthquake
on the San Andreas Fault. The Scenario outlines a hypothetical earthquake in
which:
The strongest shaking and greatest damage is near the stretch of the San Andreas
Fault that extends through the fastest growing areas of Southern California,
including the Coachella Valley, Inland Empire and Antelope Valley.
At least 10 million people will be exposed to heavy shaking. Californias
efforts at mitigation have concentrated on life safety and have been largely
successful. Thus, in spite of the large numbers of people in highly shaken
areas, deaths are estimated at only 1,800.
Building types known to be vulnerable to damage and collapse, do indeed sustain
major damage. All un-reinforced masonry buildings within 15 miles of the
San Andreas Fault are completely destroyed. Those that are not retrofitted
kill many occupants. Many other older building types without retrofitting
contribute to over $33 billion in damage to buildings.
The fault offsets all lifelines crossing into Southern California at Cajon
Pass (Interstate 15), San Gorgonio Pass (Interstate 10) and along Route 14,
including pipelines, power lines, roads, railways, telecommunications and aqueducts.
Strong shaking continues in downtown Los Angeles for 55 seconds nearly 8 times
longer than in the Northridge Earthquake.
The prolonged, strong shaking heavily damages and sometimes collapses hundreds
of old brick buildings, thousands of older commercial and industrial concrete
buildings, many wood-frame buildings, and even a few, high-rise steel buildings.
Over 600,000 buildings suffer at least some damage that causes tens of thousands
of injuries and hundreds of deaths, and leaves many thousands of people without
homes or jobs.
Fire doubles the fatalities and economic losses. Around Southern California,
there will be 1,600 fires started large enough to warrant a 911 call, and some
fires merge into conflagrations that burn hundreds of city blocks. Assuming
no Santa Ana winds, the models still indicate a further $65 billion in direct
losses and $22 billion in indirect losses from the fires.
Nearly two thirds of the hospital beds are non-functional in Los Angeles,
Orange, Riverside, and San Bernardino counties. At the same time, 50,000 people
will seek treatment at emergency rooms.
Thanks to a $6 billion investment in seismic safety, the State highway system
fares well. However, although collapse is avoided, some bridges are non-functional
so that much of the highway is not passable on the day of the event. The long
duration of shaking takes a greater toll on bridges and overpasses under the
jurisdiction of cities and counties where the retrofitting processes are not
complete or have not begun.
The largest long-term economic disruption comes from damage to the water distribution
system. Damage to this system will be so extensive that some areas will have
to replace the whole system, and some buildings will be without water for as
long as 6 months. The direct and indirect business interruption costs attributed
to the lack of water will be $50 billion.
Most of the damage is predictable and much is preventable. Individuals can
protect themselves and help their community by:
- Storing more water than they already have
- Keeping a fire extinguisher and knowing how to use it.
- Securing their space.
- This means securing building contents from flying around and reinforcing
a building they own to the most current standards..
The ShakeOut Scenario is the product of an interdisciplinary collaboration
of over 300 scientists, engineers, and other experts from several agencies,
including the USGS, the California Geological Survey, Southern California Earthquake
Center, California Office of Emergency Services and Seismic Safety Commission.
To create the Scenario, geologists determined the amount of potential
motion on the part of the San Andreas Fault with the greatest risk of imminent
rupture, a 200-mile long section from the Salton Sea in the Coachella Valley
to just south of Gorman. From this, seismologists and computer scientists modeled
the ground shaking. Engineers and building professionals used the models of
ground shaking to estimate damage to the built environment. And from these
damages, social scientists evaluated emergency response, casualties, and the
impact on our economy and society..
A copy of the full technical report, The ShakeOut Scenario, is available online
at http://pubs.usgs.gov/of/2008/1150.
A non-technical summary narrative of the Scenario is online at http://pubs.usgs.gov/circ/1324/.
High resolution images, and a computer animation showing the earthquake rupture
and its waves of energy spreading across Southern California are online at
http://urbanearth.usgs.gov/shakeout.
The Congressional Hearing website is: http://resourcescommittee.house.gov/index.php?option=com_jcalpro&Itemid=54&extmode=view&extid=177
Much of the prepared testimony at the hearing dealt with cuts in the Administrations
budget request for earthquake programs and appeals to Congress to restore
funding.