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Seismic and Tsunami Threats to Southern California. Emergency Response Readiness Workshop Joint Forces Training Base, Los Alamitos, California May 10, 2012. Nancy King, Ph.D. U.S. Geological Survey Pasadena Field Office. Northridge earthquake 1994. Northridge earthquake, 1994. - PowerPoint PPT Presentation
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The Use of GPS for Earthquake Hazard Response and Research at USGS
Seismic and Tsunami Threats to Southern California
Nancy King, Ph.D. U.S. Geological SurveyPasadena Field OfficeNorthridge earthquake 1994
Northridge earthquake, 1994Emergency Response Readiness WorkshopJoint Forces Training Base, Los Alamitos, CaliforniaMay 10, 2012Plate Tectonics and Earthquakes
Faults and Plate Tectonics
Plate motion occurs on faults.
What Faults Look Like After Earthquakes
1906 San Francisco earthquake
1979 Imperial Valley earthquake
Scarp of 1971 San Fernando earthquakePhoto fromFinding Fault in California: An Earthquake Tourists Guide,by Susan Elizabeth Hough
Landers earthquake, 1992Faults and Shaking
An earthquake is sudden slip on a fault.
This slip triggers seismic waves.
These waves cause shaking and most of the damage.Seismic Waves
Seismogram
Faults and Earthquakes of the Western U.S.
What the San Andreas Fault Looks Like
Stream offset:420 feet in 3800 yearsFaults of Southern California
Over 300 faults inSouthern CaliforniaOnly the San Andreas can have the Big One (M 7.8+)
But earthquakes on other faults can be disasters, e.g. 1994 Northridge M 6.7But other faults can producedamaging earthquakes
Magnitude and Intensity
Magnitude is the maximumamplitude on a seismogram.
Worldwideneic.usgs.gov/neis/eqlists/eqstats.htmlDoug Given, USGS
The magnitude scale is logarithmic.Each whole number increase is:
10 times more ground motion32 times more energyIntensity is the earthquakes effects,on scale of I to XII. Depends on: Distance from earthquake Geology Type of structure Observer!Varies from place to place.Earthquake History of S. California
Earthquakes in California
1930200750,000Good seismicnetwork begins here.On average in southern California:Over 30 per day, mostly not feltMagnitude 6 every 5 yearsMagnitude 7 every 30 yearsMagnitude 7.7 every 150 yearsWe CANNOT predict these earthquakes!13Earthquake Effects Aftershocks
March 11, 2011 Tohoku M 9.0 earthquake and its aftershocks in the first dayEarthquake Effects - Structure Failure
Ferndale, CA, M 7.1 1992Life-safe
Columbia, M 6.2, 1999NOT life-safe
Northridge, CA,M 6.7 1994Performance depends on Material ConstructionEarthquake Effects - Falling Objects
Stanford University, 1906 earthquakeEarthquake Effects - Utility Line Rupture
USGS Open FileReport 96-263
Northridge earthquake,1994Earthquake Effects - Lifelines
L AHighways, railways, power lines, phone lines, pipelines, and wateraqueducts and pipelines all cross the San Andreas fault
Earthquake Effects - Interior Damage
Dr. Cindy Stern
Earthquake Effects Landslides and Liquefaction
Landslides Northridge, 1994
Steinbrugge Collectionof the UC BerkeleyEarthquake EngineeringResearch CenterLiquefaction Niigata, Japan, 1964
Earthquake Effects - Tsunamis One or more intense waves, usually caused by an earthquake or undersea landslide.
First wave may NOT be the largest. Timing between waves may vary from minutes to several hours apart. The danger lasts hours after the first wave.
Tsunami waves can come ashore in different ways: Wall of water rapidly rising tide series of surf-like breakers
Tsunamis can carry boats, debris and heavy rocks.
Types: Local earthquakes near the coast where first wave can be within 10 minutes and may not be time for a tsunami warning Pacific-wide caused by earthquakes far away from our coast which allows time for an tsunami warning
Vulnerable areas in so. California include: LA and Long Beach Harbor, Venice and West Los Angeles beaches.
TSUNAMI WARNING BROADCAST: Pack up your family and pets and move inland
Earthquake Effects Tsunami in Hawaii, 1946
Hilo, Hawaii, 1946Earthquake Effects - Community
Death and injuryStructure damageNo power/gasFireNo waterRoad/rail closuresPhones out
No emergency servicesStranded commutersSeparated familiesDestroyed homesStores closedBusiness lossesLoss of jobs
The Big One
The last Big One in southernCalifornia was the Fort TejonEarthquake of 1857, which killed 2 people. No one remembers this earthquake.The next Big One will be different, causing casualties and damage in now heavily populated southern California. There will be up to 2 minutes of ground shaking.Preparation and response are local.Its up to us.Earthquake Deaths
Roger Bilham, University of ColoradoJapan 2011Earthquake Preparedness and Response
Retrofit buildingsSecure fixtures/contentsEmergency planEmergency suppliesCheck for damage and injuriesFollow your emergency planExpect aftershocksContact insurance agentRestore documentsBegin repairsContact FEMABeforeDuring Drop, cover,and hold on!After
USGS Products
CISN Display Real time earthquake alert and notification
California-Nevada Earthquake MapEarthquake Notification System
ShakeCast Situational awareness toolfor emergencyresponders andcritical facilityoperatorsUSGS Products
Did You Feel It?ShakeMap
The Take-Home Message
We live in earthquake country!Its up to each of us to prepare.Thank you!Questions?