HTDP: A tool to correct survey data for tectonic motion Chris Pearson, National Geodetic Survey
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Transcript of HTDP: A tool to correct survey data for tectonic motion Chris Pearson, National Geodetic Survey
HTDP: A tool to correct survey data for tectonic motion
Chris Pearson, National Geodetic SurveyRichard Snay, National Geodetic SurveyRob McCaffrey, Troy Geophysics
Updated model of the secular field
• An analytical model representing horizontal crustal motion developed using DEFNODE– Incorporates all major active
faults in a single model.– Provides a more accurate
model of crustal deformation in western US
• data comprise – 4890 GPS velocities– 170 fault slip rates from
paleoseismic & paleomag studies – 258 fault slip vectors taken from
earthquakes and geologic studies
Residuals
Data Type Num. Data Nrms WrmsGPS 9780.00 1.15 0.98 mm/yr
Slip rates 170.00 1.41 1.23 mm/yrSlip vectors 258.00 0.94 12.9º
Total 10208.00 1.16 ---
• Fit with all data sets is excellent• Of 6462 original velocities, 1570 were removed for the following reasons: • either near volcanoes or unmodeled faults (244), • high uncertainties (754), • anomalous velocities (343), • not within the model region (228)•
Un-modeled deformation• 6 circular regions were
excluded from the inversion. These included 4 active volcanic areas
• Mammoth Lakes Caldera, Three Sisters Volcanoes, Yellowstone Caldera and Mt St Helens Volcano
• Two in southern CA are associated with un-modeled post seismic deformation
• We intend to expand the model to cover these areas – By fitting a model to the
smoothed residuals
Test of HTDP 3.0• Testing of HTDP is underway• So far we have used two data sets.
– The velocities used to develop HTDP – Velocities for the CORS network
Rob’s data NGS CORS data