geologic hazards and space geodesy

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geologic hazards and space geodesy

• part 2 GPS specifics

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How does GPS work?
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How does GPS work?
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How does GPS work?
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How does GPS work?
sources of uncertainty

• Satellite positioning (tracking network)
• Ionosphere effects (differencing and
  two-frequency combinations)
• Troposphere effects (model wetness)
• Near-station effects (site selection)
• Accuracy approaching 1 mm/yr

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What data are produced?
observation types
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What data are produced?
point position over time
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What data are produced?
relative position over time
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What data are produced?
Mt. Hamilton
Loma Prieta
Grizzly Peak
Mt. Diablo
Clayton
Pre-earthquake
Post earthquake
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What data are produced?
Larson et al., 2003
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How are these data used?
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How are these data used?

• From global space geodesy (e.g., GPS) station
  velocity measurements as well as other data, the
  GSRM group compiled this map showing relative
  plate motions (GSRM by Kreemer et al., 2003 for
  the ILP).

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How are these data used?
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How are these data used?

• GPS surveys before and after the earthquake are
  differenced to obtain 3D vectors of permanent
  deformation (courtesy of CESS, SEIRES)
• Deformation data are modeled to obtain slip on
  the fault plane, especially in areas
  complementary to seismology

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How are these data used?
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How are these data used?
Freed Burgmann, 2004
Burgmann et al., 2002
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How are these data used?
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How are these data used?
Miller et al., 2002
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How are these data used?

• From the global earthquake catalog, seismic
  source characterization, strong motions and PSHA,
  GSHAP compiled this map (GSHAP by Giardini et
  al., 2003 for the ILP).

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How can we use GPS for science and management
efforts relevant to you?