Earthquakes

1
Earthquakes

• Rebecca Greenberger

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Faults

• Most faults in top 10-15 km of crust

http//earth.leeds.ac.uk/faults/types/classes/clas
ses.htm
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Faults in the Mojave

• Part of Eastern California Shear Zone and Mojave
  Block
• 9-23 of movement between Pacific and North
  American plates in this region
• N-NW right-lateral strike-slip faults
• Active for 10.6 million years
• Most discontinuous
• End near zones of extension and zones of
  shortening

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Cinder Cone Volcano
http//wufs.wustl.edu/pathfinder/path202/images/im
ages/0304012.jpg
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Recent Earthquakes

• Landers (1992), magnitude 7.3

• Hector Mine (1999), magnitude 7.1

Earthquakes from March 4, 2007
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Landers Earthquake

• 85 Km rupture
• Average slip 3-4 m
• Faults ruptured Johnson Valley, Landers,
  Homestead, Valley, Emerson, Camp Rock

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Consequences

• Change in predictions for major earthquakes
• San Bernadino 8-10 years earlier
• Coachella Valley 2 years earlier
• San Jancinto Fault 8 years earlier
• Mojave 2 years later

http//earthquake.usgs.gov/eqcenter/recenteqsus/M
aps/special/California_Nevada.php
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Landers Earthquake Groundbreak
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Landers Earthquake
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Hector Mine Earthquake

• 20 km from Landers Earthquake
• Bullion Fault and unnamed fault ruptured
• No earthquake along fault for over 10,000 years

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Hector Mine Groundbreaks
http//earthquake.usgs.gov/regional/sca/hector/pho
tos/PIC00005.JPG
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http//earthquake.usgs.gov/regional/sca/hector/pho
tos/PIC00008.JPG
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What To Do in an Earthquake

• Inside
• Drop, Cover, Hold On
• Avoid glass, windows, outer walls
• Stay in bed
• Dont try to go outside
• Outside
• Stay outside in the open
• Car
• Stop, stay in car

http//seagrant.uaf.edu/features/earthquake/prepar
e2.html
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More Earthquake Survival Tips

• If trapped
• Stay still
• Cover mouth with clothes
• Hit pipe or wall
• Use whistle if you can
• Be ready for aftershocks

http//www.nitro-pak.com/images/530020Getaway.jp
g
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Sources

• Earthquake Damages Neighboring Fault, UCLA and
  USC Scientists Report. Science Daily. 3 Feb
  2003. 3 March 2007 lthttp//www.sciencedaily.com/r
  eleases/2003/02/030203071747.htmgt.
• Faults. University of Leeds. 5 March 2007
  lthttp//earth.leeds.ac.uk/faults/gt.
• Faults and Active Tectonics. USGS. 2 March
  2007 lthttp//pubs.usgs.gov/of/2004/1007/faults.htm
  lgt.
• Faults of Southern California Mojave Region.
  Southern California Data Center. 3 March 2007
  lthttp//www.data.scec.org/faults/mojfault.htmlgt.
• Freed, Andrew M. and Roland Bürgmann. Evidence
  of power-law flow in the Mojave desert mantle.
  Nature 430 (2004) 548-551. 2 March 2007
  lthttp//www.nature.com/nature/journal/v430/n6999/f
  ull/nature02784.htmlgt.

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Sources Continued

• King, G. C. P., R. S. Stein and J. Lin. Static
  Stress Changes and the Triggering of
  Earthquakes. Bull. Seismol. Soc. Amer. 84
  (1994) 935-953. 2 March 2007 lthttp//quake.usgs.
  gov/research/deformation/modeling/papers/landers.h
  tmlgt.
• Landers Earthquake. Southern California
  Earthquake Data Center. 5 March 2007
  lthttp//www.data.scec.org/chrono_index/landersq.ht
  mlgt.
• The October 16, 1999 M7.1 Hector Mine
  Earthquake. USGS. 5 March 2007
  lthttp//earthquake.usgs.gov/regional/sca/hector/gt.
  
• Otis-Diehl, Paul. Aerial Photos of the Surface
  Rupture. 18 Oct. 1999. 4 March 2007
  lthttp//earthquake.usgs.gov/regional/sca/hector/ph
  otos.htmlgt.

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Sources Continued

• Price, Evelyn J and David T. Sandwell.
  Small-Scale Deformations Associated with the
  1992 Landers, California Earthquake mapped by
  synthetic aperture radar interferometry Phase
  Gradients. Journal of Geophysical Research. 10
  Nov. 1998. 3 March 2007 lthttp//topex.ucsd.edu/ev
  elyn/landers_paper/paper_view.htmlgt.
• Savage, J.C., J.L. Svarc and W.H. Prescott.
  Interseismic strain and rotation rates in the
  northeast Mojave domain, eastern California.
  Journal of Geophysical Research 109 (2004). 3
  March 2007 lt http//www.agu.org/pubs/crossref/2004
  /2003JB002705.shtmlgt.
• What to Do During an Earthquake. FEMA. 12
  Apr. 2006. 4 March 2007 lthttp//www.fema.gov/haza
  rd/earthquake/eq_during.shtmgt.