Post on 08-Jan-2016
description
transcript
Zack Bick
Erin Riggs
Alicia Helton
Cara Dickerson
Presentation by:
What is it?What is it? San Andreas Fault,
geological fault zone in California
800mi long and approx. 10mi deep
Right lateral strike-slip fault Imperial Valley to Point Arena Marks the boundary between
N.American and Pacific plates Movement of the plates
cause earthquakes
Surface FeaturesSurface Features
A linear trough reveals the presence of the fault The fault zone is marked by distinctive landforms These include long straight escarpments, narrow ridges, and small
un-drained ponds Stream channels characteristically jog sharply to the right where they
cross the fault
Brief HistoryBrief History The San Andreas Fault has
been dated at 29 million years old
The greatest recorded movement at one time was 5 meters in the great San Francisco Earthquake of 1906
This measured an 8.25 on the Richter Scale
Major Earthquakes Along the Fault Major Earthquakes Along the Fault 1906, San Francisco Began at 5:12 am, lasted
20-25 seconds and the aftershocks lasted 45-60 seconds
It measured 8.25 on the Richter Scale
1906 San Francisco Quake1906 San Francisco Quake
The number of deaths resulting from the quake and the fire following the quake was 3,000
The total number of injuries was 225,000 The property damage that occurred was estimated
at $400million in 1906 dollars.
1952 Kern County Quake1952 Kern County Quake Occurred on July 21,
at 5 am The quake measured 7.5
on the Richter Scale The quake was felt from
Reno, Nevada to San Diego, California
1952 Quake1952 Quake
The quake came as a surprise to geologists The quake was responsible for:
12 deaths18 injuries $50 million in property damage
1989 Loma Prieta Quake1989 Loma Prieta Quake Occurred October 17th, at
5 pm The magnitude was
estimated 7.1 on the Richter Scale
The quake did not come as a surprise to geologists
1989 Quake 1989 Quake
The quake caused damage in San Francisco and Oakland
The 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
New Designs and Construction of Buildings in Earthquake Prone Areas
Buildings, homes, bridges and overpasses will be built to withstand strong shaking
Some cities have programs to tear down unstable buildings or homes
Automatic 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
liquefaction Landslide prone areas
Selective Use of LandSelective Use of Land
Accurate Prediction of Earthquakes(A Work In Progress)
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 lives However, the next quake they had came unexpected
In Tokyo, Japan they are hard away at work trying to learn how to successfully predict earthquakes
Other geologists around the world are also working to find an answer to predict the quakes
Earthquake ProbabilityEarthquake Probability Research conducted since
the 1989 quake helped USGS and other scientists conclude:
70% probability of at least one magnitude 6.7 or greater quake
21% probability of that 70% is on the San Andreas Fault
The quake might strike the San Francisco Bay region before 2030
Major quakes may occur in any part of this region
Communities in the Bay Area region continue to prepare for earthquakes
Earthquake OddsEarthquake Odds Rates 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, we’ve learned:In Conclusion, we’ve learned: The geography of the San
Andreas Fault A few of the major quakes
on the fault What everyone can do to
help reduce the risk of disaster when a quake hits
Probability of the next big earthquake