Zack Bick Erin Riggs Alicia Helton Cara Dickerson Presentation by:
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Transcript of Zack Bick Erin Riggs Alicia Helton Cara Dickerson Presentation by:
Zack BickErin RiggsAlicia HeltonCara DickersonPresentation by:
What is it?San Andreas Fault, geological fault zone in California800mi long and approx. 10mi deepRight lateral strike-slip faultImperial Valley to Point ArenaMarks the boundary between N.American and Pacific platesMovement of the plates cause earthquakes
Surface FeaturesA linear trough reveals the presence of the faultThe fault zone is marked by distinctive landformsThese include long straight escarpments, narrow ridges, and small un-drained pondsStream channels characteristically jog sharply to the right where they cross the fault
Brief HistoryThe San Andreas Fault has been dated at 29 million years oldThe greatest recorded movement at one time was 5 meters in the great San Francisco Earthquake of 1906This measured an 8.25 on the Richter Scale
Major Earthquakes Along the Fault 1906, San Francisco Began at 5:12 am, lasted 20-25 seconds and the aftershocks lasted 45-60 secondsIt measured 8.25 on the Richter Scale
1906 San Francisco QuakeThe number of deaths resulting from the quake and the fire following the quake was 3,000The total number of injuries was 225,000The property damage that occurred was estimated at $400million in 1906 dollars.
1952 Kern County QuakeOccurred on July 21, at 5 amThe quake measured 7.5 on the Richter ScaleThe quake was felt from Reno, Nevada to San Diego, California
1952 QuakeThe quake came as a surprise to geologists The quake was responsible for:12 deaths18 injuries $50 million in property damage
1989 Loma Prieta QuakeOccurred October 17th, at 5 pmThe magnitude was estimated 7.1 on the Richter Scale The quake did not come as a surprise to geologists
1989 Quake The quake caused damage in San Francisco and OaklandThe 1989 earthquake caused: $7 billion in damage 12,000 displaced people 3,757 injuries and 67 deaths
New Designs and Construction of Buildings in Earthquake Prone Areas
Buildings, homes, bridges and overpasses will be built to withstand strong shakingSome cities have programs to tear down unstable buildings or homesAutomatic shut off of gas lines when the P-wave hits to limit fire hazards
Places not to build homes or buildings:Ground failure areas of liquefactionLandslide prone areas
Selective Use of Land
Accurate Prediction of Earthquakes(A Work In Progress)
China has been the only country who has predicted an earthquake nine hours before, in which they saved livesHowever, the next quake they had came unexpectedIn Tokyo, Japan they are hard away at work trying to learn how to successfully predict earthquakesOther geologists around the world are also working to find an answer to predict the quakes
Earthquake ProbabilityResearch conducted since the 1989 quake helped USGS and other scientists conclude:
70% probability of at least one magnitude 6.7 or greater quake21% probability of that 70% is on the San Andreas Fault The quake might strike the San Francisco Bay region before 2030Major quakes may occur in any part of this region Communities in the Bay Area region continue to prepare for earthquakes
Earthquake OddsRates of large earthquakes in the San Francisco have dropped after the Great 1906 Earthquake.
San Andreas Fault slipped so much over such a great length in that quake that the strain was reduced on most faults throughout the region. Strain has been slowly building up again. However, level of seismic activity has not yet reached that of the late 1800's.
In Conclusion, weve learned:The geography of the San Andreas FaultA few of the major quakes on the faultWhat everyone can do to help reduce the risk of disaster when a quake hitsProbability of the next big earthquake
Liquefaction- when water saturated soil or sediment turns from a solid to a liquid as a result of earthquake shaking.