The San Andreas Fault
Team 2
UseIT Intern Class of 2014
Thanh-Nhan Le, Mark Krant, Krista McPherson,
Rachel Hausmann , Rory Norman, and Krystel Rios
Strike-Slip Only?
Thanh Le
San Andreas Fault (SAF)
What is the San Andreas Fault?
• SAF is a system of segmented faults that goes across
California
• The most famous fault in the world
• About 800 miles (1300 km) long
• About 28 million years old
• Between the Pacific and North American Plate
• Discovered after the 1906 San Francisco earthquake
• Known as a right lateral transform fault
San Andreas Fault (SAF)
What are faults?
• Faults can be classified in three main directions:
Strike-slip, thrust, and normal.
• Strike-Slip Fault: Also known as transform fault in
which the motions move horizontal and parallel to
the fault.
San Andreas Fault (SAF)
Thrust Fault: When the hanging wall moves over the
footwall in an angle that is less than 45ᵒ.
• Normal Fault: Occurs when the hanging wall
drops below the footwall, so they move away
from each other.
San Andreas Fault (SAF)
• Factors show that SAF
does not only consist
of strike-slip faults.
• The Big Bend starts
from Garlock fault
shows the
complexities of
different faulting in
Southern California.
References Cited
•
•
•
•
Popov, Anton.,Sobolev, S., Zoback, M. “Modeling evolution of the San Andreas Fault system
in northern and central California.” AGU and the Geochemical Society. Web:
https://pangea.stanford.edu/researchgroups/stress/sites/default/files/Popov,%20Sobolv%2
0and%20Zback%202012.pdf, August 2012.
Fuis, Gary., Scheirer,D.,Langenheim, V., Kohler, M. “A New Perspective on the Geometry of
the San Andreas Fault in Southern California and Its Relationship to Lithospheric Structure.”
Bulletin of the Seismological Society of America. Web:
http://seismosoc.org/society/press_releases/BSSA_102-1_Fuise_t_al.pdf, February 2012.
Irwin, William. “ Geology and Plate-Tectonic Development.”Web:
http://www.pmc.ucsc.edu/~crowe/S109/readings/Irwin%2090%20SanAndreas.pdf
Zoback, M.,Lou M., Mount V., Suppe J., Eaton J.,Healy J., Oppenheimer .,Reasenberg P.,John
L.,Raleigh B., Wong I., Scotti O., Wentworth C. “New Evidence on the State of Stress of the
San Andreas Fault System.”
Web:http://seismo.berkeley.edu/~rallen/teaching/S04_SanAndreas/Resources/Zobacketal19
87.pdf, February 2004.
The Big Bend
Mark Krant
What is the Big Bend?
• Stretch of the San Andreas
Fault beginning near the
Garlock fault and continuing
to the San Bernardino
Mountains
• Despite the majority of the
San Andreas Fault pointing
in the North West direction,
the Big Bend flattens out
and points more towards
the West than any other
part of the fault
Why is it important?
• Along the majority of the San
Andreas Fault, the North
American and Pacific plate
scrape past each other in near
perfect right-lateral movement
• The Big Bend disrupts the
right-lateral movement of the
Pacific and North American
plates
• The plates crash into each
other, creating compression
and tension
http://geology.campus.ad.csulb.edu/people/bperry/geology303/geol303chapter5.html
Faults
• Tension causes the
rocks within the earth’s
crust to fracture,
creating numerous
thrust and strike-slip
faults in the area
• Sierra Madre Fault –
reverse
• San Gabriel Fault – right
lateral strike-slip
http://www.earthquakecountry.info/roots/image11829-1791.html
http://www.webpages.uidaho.edu/~simkat/geol345_files/bigbend_step.jpg
Transverse ranges
• Compression forces
caused by the Big Bend
form the Transverse
Ranges
San Bernardino Mountains
San Gabriel Mountains
http://www.tripadvisor.com/LocationPhotos-g33009San_Bernardino_California.html
http://www.csupomona.edu/~marshall/research/san.gab.htm
http://en.wikipedia.org/wiki/San_Bernardino_Mountains#mediaviewer/File:Wpdms_shdrlfi0
20l_san_bernardino_mountains.jpg
References
•
•
•
•
•
Singer, E., “The San Andreas Fault System.” The San Diego State University:
http://www.sci.sdsu.edu/salton/San%20AndreasFaultSyst.html
Zachariasen , J., 2012, “Earthquake Chronology on the Big Bend Segment of
the San Andreas Fault: Filling a Gap Towards a Better-Constrained Rupture
Scenarios.” U.S. Geological Survey:
http://earthquake.usgs.gov/research/external/reports/G08AP00014.pdf, April
2012
Eberhart- Phillips, Lisowski, Zoback, 1990, “Crustal Strain Near the big Bend of
the San Andreas Fault: Analysis of the Los Padres-Tehachapi Trilateration
Networks, California.” University of Nebraska-Lincoln:
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1469&context=us
gsstaffpub
“The ‘Big Bend’ of California's San Andreas fault.” Southern California
Earthquake Center: http://www.scec.org/education/public/allfacts.html
“Southern California Faults.” Putting down roots in earthquake country :
http://www.earthquakecountry.info/roots/socal-faults.html
Segments of the
San Andreas Fault
Krista McPherson
University of Southern California
Southern California Earthquake Center
UseIT 2014 Intern
Why is this important to study?
The San Andreas is not one fault, but a complicated
system of faults
Breaking down the San Andreas allows us to
look at the interfaces between segments
Help us understand future earthquakes
Segmentation of the San Andreas
Can be divided into three sections:
• Northern
• Central
• Southern
Southern Segment
MAJOR EARTHQUAKES:
• 1680 Earthquake
• Magnitude: 7.7 Mw
• 1812 Wrightwood Earthquake
• Magnitude: 7.5 Mw
• 1857 Fort Tejon Earthquake
• Magnitude: 7.9 Mw
http://geology.com/earthquake/california.shtml#fort-tejon
Shake Map of Fort Tejon Earthquake
Northern Segment
MAJOR EARTHQUAKES:
• 1906 San Francisco
• Magnitude: 7.8 Mw
• Began directly off the
coast of San Francisco
Why did none of these major
earthquakes rupture the entire
length of the fault?
http://earthquake.usgs.gov/regional/nca/1906/shakemap/
Shake Map of San Francisco Earthquake
Central Segment
(Creeping section)
• Occurs between Cholame Valley
and San Juan Bautista
• Slip rate of 28mm/yr
• Prevents the San Andreas from
rupturing all the way through
• The presence of serpentinite
and talc allows for constant
slipping
http://www.geology.neab.net/minerals/serpenti.htm
Serpentinite
http://www.johnbetts-fineminerals.com/jhbny
Lizardite
http://www.beg.utexas.edu/mainweb/publications/graphics/talc400
Talc
Sources
•
•
•
•
•
•
•
•
•
Bennett, R.A., Friedrich, A.M., and Furlong, K.P. 2004. Codependent histories of the San Andreas
and San Jacinto fault zones from inversion of fault displacement rates. Geology 2004; 32; 961964. doi: 10.1130/G20806.1
Jacoby, G.C. Jr., Sheppard, P.R., and Sieh, K.E. (1988). Irregular Recurrance of Large Earthquakes
Along the San Andreas Fault: Evidence from Trees. Science, Vol. 241, No. 4862, pp. 196-199.
Lomax, A. 2006. Location of the Focal Region and Hypocenter of the California Earthquake of
April 18, 1906. March, 2006.
Meisling, K.E., Sieh, K.E. 1980. Disturbance of Trees by the 1857 Fort Tejon Earthquake, California.
Journal of Geophysical Research. Vol. 85. No. B6. Pages 3225-3238. June 10, 1980.
Moore, D.E., Rymer, M.J. 2007. Talc-bearing serpentinite and the creeping section of the San
Andreas Fault. Nature 448, 795-797. 16 August 2007. doi: 10.1038/nature06064.
Schleicher, A.M., van der Pluijm, B.A., and Warr, L.N. 2010. Nanocoatings of clay and creep of the
San Andreas Fault at Parkfield, California. Geology 2010; 38;667-670. Doi: 10.1130/G31091.1
Sieh, K., Stuiver, M. and Brillinger, D. (1989). A More Precise Chronology of Earthquakes produced
by the San Andreas Fault in Southern California. Journal of Geophysical Research, Vol. 94, No. B1,
pp. 603-623.
Thatcher, W. 1975. Strain Accumulation and Release Mechanism of the 1906 San Francisco
Earthquake. Journal of Geophysical Research. December 10, 1975. Vol. 80. No. 35.
Townley, Sidney D. (1939). Earthquakes in California, 1769 to 1928. Bulletin of the Seismological
Society of America, Vol. 29, No. 1, pp. 21-252.
Mini Grand Challenge #1
Team 2
Rachel B Hausmann
Oregon State University
College of Earth, Ocean, and Atmospheric Sciences
University of Southern California
Southern California Earthquake Center
Summer 2014
SCEC UseIT Intern
What is a recurrence interval?
Recurrence Interval = Average slip per major rupture / Slip Rate
Earthquake
Aka: the frequency of a certain seismic event
Avg. slip rate
(mm/year)
Seismic
Condition
Last major
earthquakes
Displacement
(m)
Northern
35 mm/year
Locked
1906 San Francisco
7.8M
3 - 4.5 m
Central
28 mm/year
Aseismic creep
2004 Parkfield
6.0M
0.58 m (max)
Southern
35 mm/year
Locked
1857 Fort Tejon
7.9M
9m
 Complex fault geometries of
the Southern and Northern
allow for large earthquakes
(Li and Liu, 2006).
And this is how we know…
Plate motion
measurements
using geodic
data!!
Motion Magnitude Intensity
Citations
Abaimov, S.G., Turcotte, D.L., and Rundle, J.B., 2007, Recurrence-time and requency slip
statistics of slip events on the creeping section of the San Andreas fault in central California,
Geophysics Journal International. Vol. 170, p. 1289Fialko, Y, 2006, Interseismic strain accumulation and the earthquake potential on the
southern San Andreas Fault system, Nature. vol. 441, p. 968- 971
Shelly, D., 2010, Periodic, Chaotic, and Doubled Earthquake Recurrence Intervals on the Deep
San Andreas Fault, Science. vol. 328, p. 1385-1388
Shelly, D.R., and Johnson, K.M., 2011, Tremor reveals stress shadowing, deep postseismic
creep, and depth dependent slip recurrence on the lower crustal San Andreas fault near
Parkfield, Geophysical Research Letters. vol. 38, p. 13312-13318
Sieh, Kerry E., 1978, Slip Along the San Andreas Fault Associated with the Great 1957
Earthquake, Bulletin of the Seismological Society of America. vol. 68, No. 5, p. 1421-1448
Stock, J.M., and Lee, J., 1994, Do microplates in subduction zones leave a geological record?
Tectonics. vol. 13, p. 1472-1487
Wallace, R.E., 1970, Earthquake Recurrence Intervals on the San Andreas Fault, Geological
Society of America Bulletin. vol. 81, p. 2875-2890
Zachariasen, J., 2008, Detailed Mapping of the Northern San Andreas Fault Using LiDAR Imagery,
United States Geological Survey. Final Technical Report, p. 1-47
Zielke, O., et al, 2010, Slip in the 1857 and earlier large earthquakes along the Carrizo Plain, San
Andreas Fault, Science Magazine. vol 327, p. 1119-1121
San Gorgonio pass
The San Andreas traffic jam
• The San Andreas rarely
contains discontinuity.
• In between this split are
many faults, a feature
uncharacteristic of the
San Andreas fault line.
Southeast Coachella Valley
Southern San Bernardino Mts.
Banning Fault
• Many parts of Banning
Fault are dead
• Tendency to transfer
slip to Garnet Hill fault.
SOURCES
• Allen, Clarence Roderic (1954) The San Andreas Fault Zone
in San Gorgonio Pass, California. Dissertation (Ph.D.),
California Institute of Technology.
• J.C. Matti, U.S. Geological Survey, December, 1979.
http://geomaps.wr.usgs.gov/archive/scamp/html/dec79p4_
34M.html
• Sieh, K., Slip along the San Andreas fault associated with
the great 1857earthquake, Seismol. Soc. Am. Bull., 68,
1421– 1428, 1978.
• Tucker, Carol, 1992 “Landers Earthquake Added Stress to
San Andreas” USC News
http://www.usc.edu/uscnews/stories/68.html December
1992.
SOURCES (cont.)
• Sieh, K., and J. C. Matti, The San Andreas fault system
between Palm Springs and Palmdale, southern
California: Field trip guidebook, in Earthquake Geology
San Andreas Fault System Palm Springs to Palmdale,
pp. 1– 12, Assoc. of Eng. Geol., South. Calif. Sec., 1992
• Clark, M., Map showing recently active breaks along
the San Andreas fault and associated faults between
the Salton Sea and Whitewater River-Mission Creek,
California, Misc. Geol. Invest. Map, I-1483, U.S. Geol.
Surv., Boulder, Colo., 1984.
By Krystel Rios
East Los Angeles College – Civil Engineering, Geology
THE SALTON TROUGH
WHERE IS THE SALTON TROUGH LOCATED?
WHAT IS THE SALTON TROUGH?
Basin: Large low-elevation area, common for
sediments to collect here.
 Example of a “Graben”.
 Associated with pull apart centers and bound
by parallel faulting.
 This sinking is called subsidence.

HOW HAVE EXTENSIONAL FORCES CAUSED THE
FORMATION OF THE TROUGH?

Extensional Forces: Increase the distance between
two points, or pulls them apart. In our case rock is
being pulled apart alleviating pressure on the crust.
TWO MAIN CULPRITS


Brawley Spreading
Center
Spreading Center at
Cerro Prieto Thermal
Fields

Strong evidence of this
spreading and rifting is
presented by strong geothermal activity in these
centers. So much at the
Cerro Prieto that Thermal
plants for energy
collection are stationed
here.
These two spreading centers are
connected and accommodated by
The San Andreas, Imperial, and
Cerro Prieto Faults.
MORE COMPLICATIONS?
Works Cited
•
Barker E. Charles (2000) Salton Trough Province
•
Gleick, P. H. (2003). Global Freshwater Resources: Soft-Path Solutions for the 21st Century. Science, 302(Nov. 28),
1524-1528.
•
Hough, Elizabeth Susan (2004). Finding Fault in California
•
Jenning, S., and Thompson, G. R. (1986). Diagensis of Plio-Pleistocene sediments of the Colorado River Delta,
southern California. Journal of Sedimentary Petrology 56(1), 89-98.
•
Lizarralde, D., et al. (2007). Variation in styles of rifting in the Gulf of California. Nature, 448(July 26), 466-469.
(doi:10.1038/nature06035)
•
Sykes, G. (1937). The Colorado River Delta. American Geographical Society Special Publication, no. 19. American
Geographical Society: New York.
•
Winker, C. D., and Kidwell, S. M. (1986). Paleocurrent evidence for lateral displacement of the Pliocene Colorado
River Delta by the San Andreas fault system, southeastern California. Geology, 14(9), 788-791.
•
Geology of the Imperial Valley, California, a Monograph by Eugene Singer
http://fire.biol.wwu.edu/trent/alles/SingerImperialValley.pdf
•
Geology of the Salton Trough Edited by edited by David L. Alles. (2011) Western Washington University