Faults of Los Angeles
Ernest Scapini
Luis Gomez
Alicia Sellsted
Elena Pierce
Paulo Dos Santos
Francisco Raygoza
Los Angeles: The City of
Ernest Scapini
Faults in Los Angeles
● There is a total of 16 faults in Los
● Los Angeles is composed of Reverse,
Right lateral, and left lateral faults
● They are 7 faults in Los angeles
capable of creating a Magnitude 7
Significant Faults in Los Angeles
Puente Hills Fault
Compton Thrust Fault
Newport-Inglewood Fault
Raymond Fault
Northridge Thrust Fault
Santa Susana Fault
Sierra Madre Fault Zone
Hollywood Fault
Northridge Thrust
TIME: January 17, 1994 / 4:30:55 am
Damage: 40,000 buildings were
damaged in Los Angeles, Ventura,
Orange, and San Bernardino Counties
Northridge Thrust
Shake Map
LOCATION: 34° 12.80' N, 118° 32.22'
W 20 miles west-northwest of Los
Angeles 1 mile south-southwest of
Depth: 18.4 km
Deaths: 57
Palos Verde Fault
• Largest fault in Los Angeles
• Type of Fault: Right Lateral
• Length: Roughly 80 km
Palos Verde Fault
• Probable Magnitude: MW 6.0-7.0
( could be greater) It may rupture
partially due to the geometry of
the fault.
• Slip Rate: between 0.1 and 3.0
• Los Angeles Port is close to the
Puente Hills Faults
• Type: Blind Thrust
• Largest probable magnitude
• Was discovered in 1999
• USC is right above the Puente
Hills fault
• Length: 40 km
• Probable Magnitude: MW 7.2 7.5
Puente Hills Faults
Compton Thrust
• Type: Blind Thrust
• Slip Rate: 1.4 ± 0.4 mm/year
• Probable Magnitude: MW 7.0 –
• LAX will be greatly impacted by
this fault
• Displacement can be from 1.3 to
4.2 m
• Length: 60 km
• Has had 6 large earthquakes in
the past 14,000 years
Work Cited
Dolan, J.F., Sieh, K., and Rockwell, T.K., 2000a, Late Quaternary activity and seismic potential
of the Santa Monica fault system, Los Angeles, California: Geol. Soc. America Bull.
*Dolan F. James, Eldon M. Gath, Lisa B. Grant, Mark Legg, Scott Lindvall, Karl Mueller,
Michael Oskin, Daniel F. Ponti, Charles M. Rubin, Thomas K. Rockwell, John H, Shaw, Jerome
A. Treiman, Chris Walls, and Robert S. Yeat
Dewell, Henry D. and Willis, Bailey (1925). Earthquake Damage to Buildings. Bulletin of the Seismological Society of America,
Vol. 15, No. 4, pp. 282-301, Plates 31b and 42a.
Leon, L. A., J. F. Dolan, J. H. Shaw, and T. L. Pratt (2009), Evidence for large Holocene earthquakes on the Compton thrust
fault, Los Angeles, California, J. Geophys. Res., 114, B12305, doi:10.1029/2008JB006129.
Marquis John “New Study Reveals the Behavior of the Puente Hills Thrust Fault”
USC News April 4, 2003. Web 19 Jun. 2014
Shaw H. John, Suppe John 1996 “Earthquake hazards of active blind-thrust faults under the central Los Angeles basin, California” Journal of Geophysical Research vol 101 p8623-8641
Los Angeles Basin
Luis Gomez
Why areas
within the
L.A. basin are
dangerous in
than areas in
(San Gabriel,
Santa Monica,
Santa Ana
don't kill
buildings do”
Luis Gomez
- Susan Hough and Lucile
“Sedimentary” Los Angeles Basin
● The Center of Los Angeles basin at 33.917466° N, -118.193538° W
(Intersection of 105 and 710 FWY)
- Deepest spot of basin, ≈ 10 km (6 mi)
● Giant Bowl feature has walls consisting of San Gabriel, Santa Monica,
Santa Ana mountains, and the Palos Verdes Peninsula
● “Bowl of sediment” amplifies the motion of an earthquake in unpredictable
ways, somewhat similar to shaking a bowl of Jello
Los Angeles Basin
● Basin primarily
consists of sand,
clay, and silt
● ≈81 km (50mi) long
● ≈40 km (25mi) wide
Basin Walls
The Palos Verdes Peninsula
and mountain ranges line the
Los Angeles basin
Shaking from an earthquake in the basin
could be 5 or more times intense than in
the nearby mountains
Puente Hills Earthquake Simulation
2 sec.
20 sec.
5 sec.
8 sec.
23 sec.
11 sec.
30 sec.
14 sec.
47 sec.
"Earthquake Shaking - Putting Down Roots in Earthquake Country." Earthquake Shaking - Putting Down Roots in Earthquake
Country. Southern California Earthquake Center/ USGS/ FEMA/ Cal EMA, 2011. Web. 13 June 2014.
"The Los Angeles Basin - A Huge Bowl of Sand." The Los Angeles Basin - A Huge Bowl of Sand. The Los Angeles Almanac, n.d.
Web. 13 June 2014. <>.
"Movie: Instantaneous Peak Velocity." Http:// SDSC, n.d. Web. 13 June 2014.
Nelson, Stephen A. "EQ Hazards & Risks." EQ Hazards & Risks. N.p., 28 Aug. 2013. Web. 17 June 2014.
The Santa Monica,
Hollywood, and Raymond
Alicia Sellsted
Santa Monica Fault
● Oblique left-reverse fault
● 24 km in length
● Slip rate ranges from .27-.39mm
per year
Hollywood Fault
● Left-lateral strike slip fault
● 14-15 km in length
● Slip rate ranges from
.33-.75mm per year
Raymond Fault
● Reverse-left-oblique slip fault
● 25-26 km in length
● Slip rate ranges from .1-.22mm
per year
Hollywood and Santa Monica Faults
“Hollywood fault has not
been officially mapped,
even though the state has
known of its existence for
decades.” -LA Times
Many buildings have been
built on top of these faults
because without official
state maps the city isn’t
required to follow state law.
All three faults are
part of the Southern
Transverse Ranges
fault system. These
faults could act coseismically in an
earthquake of
magnitude 7 or above
because of their
proximity to each
“3.2 Earthquake Hits Hollywood Fault – UPDATE: New 3.4 quake.” Save Hollywood. 4 September 2012. Web.
“Hollywood Fault.” Southern California Earthquake Data Center. 31 January 2013. Caltech. Web:
“Raymond Fault.” Southern California Earthquake Data Center. 31 January 2013. Caltech. Web:
“Santa Monica Fault.” Southern California Earthquake Data Center. 31 January 2013. Caltech. Web:
Dolan, James, “Faults of Los Angeles.” Southern California Earthquake Center:
Lin II, Rong-Gong, Xia, Rosanna, Smith, Doug. 2013, “Campaign to map earthquake faults has slowed to a crawl.”
Los Angeles Times:
Blind Thrust Faults
Elena Pierce
Blind Thrust Faults Basics
- A thrust fault that does not rupture all the way to the
surface, no evidence on the ground “blind”
- May create ridges or anticlines
(Fold Belts)
- Buried under uppermost layer of rock
Northridge Blind Thrust Fault
Date: January 17, 1994 Time: 4:30 am
Magnitude: 6.7
Depth: 18.4 km
Killed 57 people $20 Billion in Damage
(SCEDC and CNN News)
Impact if Northridge
After the earthquake technology began to
NASA led agencies towards creating 250 new
GPS stations
Puente Hills Blind Thrust Fault
- Extends from Northern Orange County to San Gabriel, runs
under Downtown to Los Angeles
- 11 X greater movement in Sedimentary Basin
- Duration said to be 4X longer because
energy flows through sediment faster
- Dense population makes earthquake
damage potential much higher
(NBC, LA Times)
Compton Blind Thrust Fault
- average slip rate of 1.4 +/-0.4 mm/ year
- active fault in sedimentary basin
- found through displacements in the earth
- can harm the Los Angeles
II, Rong-Gong Lin. "La Habra Quake a Reminder about Dangerous Puente Hills Fault." Los Angeles Times. Los Angeles Times, 29
Mar. 2014. Web. 13 June 2014.
Moore, Ireene. "Experts Warn of Dangers on Puente Hills Fault." NBC Southern California. NBC, 1 Apr. 2014. Web. 13 June
"Significant Earthquakes and Faults." Southern California Earthquake Data Center at Caltech. SCEDC, n.d. Web. 10 June 2014.
The San Gabriel
Paulo Dos Santos
How the San Gabriel Mountains were uplifted
● Transverse Ranges
● SAF Big Bend
● Movement of the Plates
o Pacific Plate
o North American Plate
SCEC UseIT Intern Paulo Henrique Dos Santos
How the San Gabriel Mountains were uplifted
● Fault Zones
o San Andreas
o San Gabriel
o Sierra Madre
o Cucamonga
SCEC UseIT Intern Paulo Henrique Dos Santos
How the San Gabriel Mountains were uplifted
● Transform Faults
o Strike-slip
● Reverse Faults
o Thrust Faults
(less than 45°)
SCEC UseIT Intern Paulo Henrique Dos Santos
Work Cited
"California Coast Ranges." Wikipedia. Wikimedia Foundation, 06 Mar. 2014. Web. 16 June 2014. <>
Fei, Yongxin. "Formation of the San Gabriel Mountains." Formation of the San Gabriel Mountains. N.p., n.d. Web. 16 June 2014.
"Geology of the San Gabriel Mountains." Geology of the San Gabriel Mountains. N.p., n.d. Web. 16 June 2014. <>
"Humboldt County, California." Wikipedia. Wikimedia Foundation, 16 June 2014. Web. 16 June 2014. <,_California>
"Transverse Range." Wikipedia. Wikimedia Foundation, 22 Apr. 2014. Web. 16 June 2014. <>
McClay, K. R. Thrust Tectonics. London: Chapman & Hall, 1992. Web. <>
Structural Geology Lab – Week 1, and Attitudes Of Lines And Planes In 3.Structural Geology Lab – Week 1 Attitudes of Lines and Planes in 3-D(n.d.): n. pag. Web.
SCEC 2014 - Team 3 - Question 6 - UseIT Intern Paulo Henrique Dos Santos
The San Fernando and
Northridge Earthquakes
Francisco Raygoza
1971 San Fernando Earthquake
● Magnitude 6.6 occurred on 2/9/1971
at 6AM
● The hypocenter was located at a
depth of 12-15 km
● Losses
o 58 deaths
o Over 500 million dollars in
● First major earthquake to be well
studied, greatly influenced structural
engineering advancement
1971 San Fernando Earthquake
The Earthquake occurred in the San
Fernando Fault Zone
o On the Santa Susana Fault (maybe)
The fault has an average slant angle of 45
degrees dipping beneath the San Gabriel
Land movement included strike-slip and
over-thrust motion
o surface displacements up to 1 meter
o The northern block in which the San
Gabriel Mtns lie rose an average of 1
o around 1.8 meters shortening across
Sylmar Fault trace
1994 Northridge Earthquake
● Magnitude 6.7 on 1/17/1994 at 4:31AM.
● Most damaging earthquake since the 1906
● Rupture began at a depth of 19 km and
ended about 8 km below the surface
● It was preceded by 2 clusters of foreshocks
● Loss
o 60 deaths
o 7,000 injured
o 40,000 buildings damaged
o Over 20 Billion dollars
1994 Northridge Earthquake
Northridge thrust fault
o blind thrust part that many consider part
of the the Oak Ridge Thrust fault
o south-dipping fault below the San
Fernando Valley
Rupture resulted from a fault movement of
about two meters
Strong shaking above 1.0g felt in the
surrounding area
Only physical evidence of is ground
deformation with some uplift of the Santa
Susana Mountains
What is the Relationship Between the Two
Earthquakes occurred on faults belonging to a complex system caused by compressional forces
due to the Big Bend of the San Andreas Fault
If we consider the Northridge thrust fault part of the Oak Ridge Thrust fault then geographically
we can see the earthquake hazard in the occurrence of an earthquake
● Staff, (1971), The San Fernando Earthquake-- One of the Most Important,
Engineering and Science, 34, p. 4-15
● Hauksson, Egill, (1994), The Northridge Earthquake and the “Earthquake
Deficit”, Engineering and Science, 57 (4), p. 12-22
● (2004), The Northridge, California Earthquake, Risk Management
● Hough, S., 2004, Finding Fault in California, Mountain Press Publishing
Company, p. 42-50

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