Parkfield

1
Parkfield
http//quake.wr.usgs.gov/research/deformation/mode
ling/whatsnew/parkfield/map4.jpg
2
The Setting

• Straight section of SAF
• Between two locked sections
• Creeping from San Juan Bautista to Parkfield
• Transition to locked fault between Parkfield and
  Gold Hill

http//quake.wr.usgs.gov/research/parkfield/geolog
y.html
3
Past seismicity

• Characteristic earthquakes have occurred about
  every 22 years (through 1966) and appear to
  rupture the same area of the fault

http//quake.wr.usgs.gov/research/parkfield/hist.h
tml
4
Prediction?

• Events every 22 years (uncertainty of 10 years)
• 90 probability of M5.5-6 between 1985 and 1993
  (USGS press release in April 1985)
• Event occurred on September 28, 2004 38 years
  following the previous event

5
September 2004 earthquake

• Ruptured from SE to NW (opposite previous events)
• No M5 foreshock

6
http//quake.wr.usgs.gov/research/parkfield/overvi
ew.html