Inferring Geoid Change from Vertical Crustal Motion

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Inferring Geoid Change from Vertical Crustal
Motion
Richard Snay NOAAs National Geodetic
Survey October 21, 2009
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Determining Vertical Crustal Velocities

• NGS is computing vertical crustal velocities for
  sites in the U.S. CORS network by reprocessing
  all pertinent GPS data collected since 1994.
• These velocities will be expressed relative to
  ITRF2008, and they should be available by the
  fall of 2010.
• Understanding the underlying physics (glacial
  isostatic adjustment, fluid withdrawal,
  subduction, etc.) will be critical for relating
  these crustal velocities to geoid change.

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CORS Network
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CORS for Monitoring Vertical Crustal Motion
Vertical velocities associated with Glacial
Isostatic Adjustment
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Tide Gauges Located Near a CORS Whose Vertical
Crustal Velocity Has Been Accurately Determined
CORS-calibrated tide gauge data indicate that the
rate of sea level rise around North America was
1.8 /- 0.2 mm/yr during the 1900-1999 time
interval
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Vertical Motion Associated with Subduction
Hyndman and Wang, 1994