The Parkfield Experiment

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The Parkfield Experiment

• Failure or Success?

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Parkfield M 6.0 earthquake

• Tuesday, September 28, 2004
• 1015 am local time
• Preceded by a M5.9 quake
• On the San Andreas Fault

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San Andreas at Parkfield

• Juncture of the creeping and locked sections of
  the San Andreas Fault

Earthquakes in 1980
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Historical Seismicity

• The wave forms of 1922, 1934 and 1966 quakes were
  very similar
• The next significant earthquake was supposed to
  happen 1988-1993

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Characteristic Earthquake

• Each fault segment may rupture episodically with
  characteristic rupture area and recurrence
  interval

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1857 rupture
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Seismic Gap hypothesis

• The next segment to rupture will be the one that
  hasnt in a while.

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Creepmeters at Parkfield site

• Coseismic offset

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Strain gauges at Parkfield site

• Coseismic distortion

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(No Transcript)
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SAFOD San Andreas Fault Observatory at Depth
http//www.icdp-online.de/sites/sanandreas/news/ne
ws.html
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2004 the experiment is a success

• The earthquake recurrence is every 22- 35 years.
• From SAFOD
• Parkfield, the self-proclaimed earthquake capital
  of the world, was the location of a Magnitude 6
  earthquake at 1015am today. The epicenter was 15
  miles south of the drill site on the San Andreas
  fault at a depth of 7.9 km. The drill site was
  subjected to fairly intense shaking but nobody
  was hurt and no significant damage was sustained.
  Scientists are thrilled to have witnessed "the
  Big One" and we anticipate a wealth of data
  associated with this event.