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Faults of the Los Angeles Field Trip

Faults of the Los Angeles Field Trip. Faults of the Los Angels Field trip. How were the San Gabriel Mountains uplifted? –Kim Gloersen How the Raymond, Hollywood, and Santa Monica faults are related? –Diego Furtado How are we “blind” to some of our faults? – Hannah Shamloo

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Faults of the Los Angeles Field Trip

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  1. Faults of the Los Angeles Field Trip

  2. Faults of the Los Angels Field trip • How were the San Gabriel Mountains uplifted? –Kim Gloersen • How the Raymond, Hollywood, and Santa Monica faults are related? –Diego Furtado • How are we “blind” to some of our faults? – Hannah Shamloo • How the 1971 San Fernando and the 1994 Northridge earthquakes compare? –Miguel Frias-Rodriguez • How are fault features expressed in an urban environment? – Miguel Villasana • How is Los Angeles a city of faults? - Matt Rieman

  3. How were the San Gabriel Mountains Uplifted? Kim Gloersen One mountain said to the other across the rift "Hey, it's not my fault!"

  4. Plate Movements • 30 Ma. , subductive tectonic movements occurred between the Farallon, North American, and Pacific plates. • 20 Ma. the relative movements of the North American and the Pacific Plate changed from a head on head contact with the Farallon Plate to a lateral slipping against each other.

  5. The Big Bend The “big bend” of the San Andreas fault causes compression that pushes up the Transverse Ranges. Perspective of Big Bend compressional areas, with the addition of thrust faulting from the Sierra Madre.

  6. Thrust Faulting Compressional zones and thrust faulting. North-south cross section of the San Gabriel Mountains

  7. References • Atwater, Tanya. "Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America." Geological Society of America Bulletin 81.12 (1970): 3513-536. Print. • "Geology of the San Gabriel Mountains, Transverse Ranges Province." Western Region Geology and Geophysics Science Center. Western Earth Surface Processes Team, 26 May 2006. Web. 15 June 2013. • Masters, Nathan. "Rise of the Sierra Madre: A Brief History of the San Gabriel Mountains | LA as Subject | SoCal Focus | KCET." KCET. KCET, 30 May 2012. Web. 15 June 2013. • Phillips, Donna E. "Geology of the San Gabriel Mountains, Transverse Ranges Province." Western Region Geology and Geophysics Science Center. USGS, 1 Jan. 1990. Web. 15 June 2013.

  8. Relationship between the santamonica, hollywood, and raymond faults. BY DIEGO FURTADO

  9. COMPRESSION ZONE • The “BIG BEND”: Cause of • Compression between the Pacific • Plate and North American Plate • Mountains and faults are formed: • San Gabriel Mountains and • Santa Monica Mountains • Transverse Range Southern • Boundary Fault System: Extends • from east to west unlike other • California mountains

  10. TRANSVERSE RANGES FAULT SYSTEM • Base of San Gabriel and Santa Monica Mountains • West- trending system of faults that extends for 200 km • Oblique-slip, reverse-slip, and strike-slip

  11. RAYMOND, SANTA MONICA, AND HOLLYWOOD FAULTS SANTA MONICA HOLLYWOOD RAYMOND ▼ ▼ ▼ TYPE OF FAULT : Left-reverse Left-reverse Left-lateral (minor reverse) LAST KNOWN SURFACE RUPTURE: ~900 A.D ~800 A.D. ~1000 A.D PROBABLE MAGNITUDES: 6.0 - 7.0 5.8 – 6.5 6.0 – 7.0 SLIP RATE (mm/yr): 0.27 – 0.39 0.33 – 0.75 0.10 - 0.22 LENGTH: 40 km 15 km 26 km • Santa Monica fault connects with Hollywood • fault at west Beverly Hills Lineament • Hollywood fault likely connects to Raymond • fault at Los Angeles River floodplain

  12. REFERENCES • http://geomaps.wr.usgs.gov/archive/scamp/html/scg_flt.html • http://qcode.us/codes/malibu-general-plan/view.php?topic=ii-5_0-5_2-5_2_2&frames=on • http://www.data.scec.org • Kristin D. Weaver, Paleoseismology and Geomorphology of the Raymond Fault, • Los Angeles County, California, Bulletin of the Seismological Society of America • pp. 1409–1429, December 2000, P. 1410-1413. • James F. Dolan, 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. Yeats (compiler), P. 1-7. • James F. Dolan, David D. Bowman, and Charles G. Sammis, Data Repository for “Long • range and long term fault intersections in southern California”, Supporting data, references, • and notes for paleo-earthquakes in the Los Angeles region.

  13. HOW ARE we “BLIND” TO some of our faults? HANNAH SHAMLOO

  14. Blind thrust faults • Some faults do not break through the surface anywhere along their length http://earthsci.org/processes/struct/equake1/EQCaseHistories.html

  15. Puente hills thrust fault • Recently discovered, 1999 • Los Angeles Basin • Runs about 40 km • Three segments • Slip rate 5mm/year • 4 Major E.Q.’s last 11,000 years http://www.scec.org/research/030404dolan.html

  16. DANGER Compared to Northridge… Northridge’s E.Q. directed strongest shaking towards N to sparsely populated mountains PHT fault focuses its shaking toward downtown LA LA Basin amplifies shaking 15x stronger energy release Viz Credits: AmitChourasia

  17. REFERENCES • Marquis, John. "New Study Reveals The Behavior Of The Puente Hills Thrust Fault." New Study Reveals The Behavior Of The Puente Hills Thrust Fault. Southern California Earthquake Center, 4 Apr. 2003. Web. 18 June 2013. • Maugh II, Thomas H. (May 26, 2005). "Big Fault Under L.A. Could Be Devastating". Los Angeles Times 26 May 2005. Web. 18 Jan. 2013 • Shaw, John H., Andreas Plesch, James F. Dolan, Thomas L. Pratt, and Patricia Fore. "Puente Hills Blind-Thrust System, Los Angeles, California." Thesis. N.d. Bulletin of the Seismological Society of America, 16 Nov. 2001. Web. 18 Jan. 2013.

  18. How the 1971 San Fernando and the 1994 Northridge earthquakes compare Miguel Frias-Rodriguez

  19. COMPARING TWO the EARTHQUAKES SAN FERNANDO 1971 NORTHRIDGE 1994

  20. SAN FERNANDO EARTHQUAKE (1971)

  21. NORTHRIDGE EARTHQUAKE (1994)

  22. references Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.r earthquake [updated] Posted By: Scott Harrison Posted On: 12:25 a.m. | February 9, 2011, PHOTOGRAPH BY: BRUCE COX / LOS ANGELES TIMES. U.S. Department of the Interior | U.S. Geological Survey URL: http://pubs.usgs.gov/of/1996/ofr-96-0263/execsum.htm Bolt, Bruce A. (1971). The San Fernando Valley, California, Earthquake of February 9, 1971: Data on Seismic Hazards. Bulletin of the Seismological Society of America, Vol. 61, No. 2, pp. 501-510, Figure 2. R. S. Stein, G. C. P. King and J. Lin, Stress triggering of the 1994 M 6.7 Northridge , California, Earthquake by its Predecessors.

  23. How Fault Features are expressed in an urban Environment Miguel Villasana

  24. http://www.artinaid.com/wp-content/uploads/2013/04/Types-of-Faults.jpghttp://www.artinaid.com/wp-content/uploads/2013/04/Types-of-Faults.jpg

  25. http://la.streetsblog.org/wp-content/uploads/2011/10/source-westside-fault-lines.jpghttp://la.streetsblog.org/wp-content/uploads/2011/10/source-westside-fault-lines.jpg

  26. REFERENCES Newton, Damien, “Rest In Peace: Santa Monica Blvd. Subway”. Wednesday, Oct 19,2011. Web Braid, Barbara, “What are the three types of Earthquakes Faults?”, Jan23, 2010. Web

  27. Los Angeles: A City of Faults Los Angeles, A City of Faults Matt Rieman

  28. Faults in Los Angeles

  29. Effect on Infrastructure • Freeways cross faults in many locations creating potential risk. • Collapse of freeway bridges during the Northridge earthquake caused widespread recognition of the hazard.

  30. - Faults run throughout the LA basin Blind thrust faults such as the PuenteHills fault are particularly dangerous -Skyscrapers are not designed for all possible motions and still have the potential to collapse during specific (and uncommon) motions

  31. Another Result of Faulting • Oil can become trapped along faults • Yet seepage can also occur along faults • Tar pits- Caused by oil seeping up along a fault and degrading to asphalt

  32. Questions?

  33. References: • 405 Traffic. 2012. MNG Interactive. Photograph. Web. 20 Jun 2013. Uuuuuuu iiiiiiiiiiiiiiiiiii<http://extras.mnginteractive.com/live/media/site200/2012/0615/2012061 5__405_traffic_01.JPG>. • Elle, Alli. Texture 79. Photograph. Deviant Art. Web. 20 Jun 2013. <http://couch-and- uuuuuuucanvas.deviantart.com/art/Texture-79-159359821>. • La Brea Tar Pits March 2010. Photograph. Web. 20 Jun 2013. uuuuuuu<http://www.thegypsiestownsend.com/2011/03/la-brea-tar-pits-march-iiiiiiiiiiiiiiii2010.html>. • Los Angeles Skyline. Photograph. Web. 20 Jun 2013. Uuuuuuu<http://www.thewallpapers.org/photo/17314/los_angeles_skyline-003.jpg>. • Northridge Earthquake. Photograph. Natural Disaster Atlas of the United States. Web. 20 uuuuuuuuJun2013.<http://naturaldisasteratlas.weebly.com/uploads/5/1/2/3/5123992/ 938 6727_orig.jpg>. • Sheibley, Mari. LA at Night. 2012. Photograph. Web. 20 Jun 2013. <http://www.marisheibley.com/post/19185422109/3-11-12-la-at-night>. • Weber, Betsy. La Brea Tar Pits. 2010. Photograph. Flickr. Web. 20 Jun 2013. <http://www.flickr.com/photos/betsyweber/5301040950/>.

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