Transcript Alaska 1964 Earthquake

Alaska 1964 Earthquake
Tectonic Deformation
Veronica Schnitzer
EPSC 330
Background Info
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Occurred March 27, 1964
Prince William Sound, Alaska
Magnitude 9.2
128 deaths
$311 million in property loss
Extreme uplift
Landslides
usgs.gov
Coseismic deformation
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George Plafker, 1965
Saw uplift and subsidence visible on land
Measured change in barnacle line
Drew contour map
Plafker, 1965
Plafker, 1965
Postseismic deformation
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Savage & Plafker, 1991
Measured postseismic uplift and subsidence pattern
Looked at change in annual mean sea levels
5 year postseismic slip
100 year flow in aesthenosphere
Savage & Plafker, 1991
Postseismic deformation
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Zweck et al, 2002
GPS, triangulation, leveling data
Created models to measure distribution of slip
Found more than one time-decaying component
Creep on fault
Viscous/viscoelastic relaxation
Conclusion
• The Alaska 1964 earthquake was the second most
powerful ever recorded
• It resulted in extreme uplift and subsidence on land
• Coseismic measurements showed strong evidence
for a subduction zone
• Postseismic measurements showed two time
components of postseismic deformation: short term
postseismic slip, and long term viscous/viscoelastic
flow.
References
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Plafker, G., 1965. Tectonic Deformation Associated with the 1964 Alaska Earthquake.
American Association for the Advancement of Science 148, no. 3678, pp. 1675-1687.
Savage, J.C. & Plafker, G., 1991. Tide Gage Measurements of Uplift Alone the South
Coast of Alaska. Journal of Geophysical Research 96, no. B3, pp. 4325-4335.
Stover, C.W. & Coffman, J.L., 1993. Seismicity of the United States 1568-1989(Revised).
U.S. Geological Survey Professional Paper 1527. Retrieved from
http://earthquake.usgs.gov/earthquakes/states/events/1964_03_28.php
Zweck, C., Freymueller, J.T. & Cohen, S.C., 2002. The 1964 great Alaska earthquake:
present day and cumulative postseismic deformation in the western Kenia Peninsula.
Physics of the Earth and Planetary Interiors 132, pp. 5-20.