50 likes | 619 Views
HOW ARE we “BLIND” TO some of our faults?. HANNAH SHAMLOO. Blind thrust faults. Some faults do not break through the surface anywhere along their length. http://earthsci.org/processes/struct/equake1/EQCaseHistories.html. Puente hills thrust fault. Recently discovered, 1999 Los Angeles Basin
E N D
HOW ARE we “BLIND” TO some of our faults? HANNAH SHAMLOO
Blind thrust faults • Some faults do not break through the surface anywhere along their length http://earthsci.org/processes/struct/equake1/EQCaseHistories.html
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
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
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.