Adjusting VLBI data to obtain geophysical information for mobile VLBI sites
- 52 Downloads
We have used Very Long Baseline Interferometry (VLBI) data to compute the site coordinates and constant velocity components for 29 fixed antenna sites and 25 mobile sites. The three singularities which occur in the adjustment with respect to the rotation of the system have been resolved by a constraint holding the net rotation of seven fixed antennas, distributed on the stable portions of four of the geologic plates, to the net rotation for these sites as defined by the NNR-NUVEL1 no net rotation model. In order to achieve a minimally constrained adjustment of this type we have found it necessary to use a new adjustment procedure in which we solve for the coordinates of each site at the weighted mean epoch of all the observations involving that site.
Using the results of the above solution we have computed the departure for each site from the NNR-NUVEL1 rigid plate model. These departures show that the transition zone in western North America from the region of rigidity to the plate boundary is at least 400 km wide, in general agreement with Ward (1988,1990).
KeywordsRoot Mean Square Difference Very Long Baseline Interferometry Pacific Plate North American Plate Very Long Baseline Interferometry Data
Unable to display preview. Download preview PDF.
- American Association of Petroleum Geologists, 1981: “Plate-Tectonic Map of the Circum-Pacific Region, Northwest Quadrant.” Post Office box 979, Tulsa, Oklahoma 74101.Google Scholar
- Carter, W.E., D.S. Robertson, and F.W. Fallon (1989) “Polar Motion and UT1 Time Series Derived from VLBI,”IERS Technical Note 2, Observatoire de Paris, Paris, France, pp 35–36.Google Scholar
- Chao, C.C. (1972) “A Model for Tropospheric Calibration from Daily Surface and Radiosonde Balloon Measurements,” California Inst. Tech., Jet Propulsion Lab. Technical Memo. No. 391-350.Google Scholar
- Dillinger, W.H. and D.S. Robertson (1986) “A Program for the Combined Adjustment of VLBI Observing Sessions,”Manuscripta Geodaetica 11, pp 278–281.Google Scholar
- Jordan, T.H., and J.B. Minster (1988) “Beyond Plate Tectonics: Looking at Plate Deformation with Space Geodesy,” inThe Impact of VLBI on Astrophysics and Geophysics, M.J. Reid and J.M. Moran, eds., Kluwer, Dordrecht, Holland, pp 341–350.Google Scholar
- Ma, C., Caprette, D. S., Ryan, J. W. (1992a) “Earth Orientation Parameters, Site Positions with Estimated Site Velocities, and Source Positions from the NASA Crustal Dynamics Project using AM0-2 and Uniform Velocity for HRAS 085: Solution GLB831,”IERS Technical Note 11, pp 3–7, Observatoire de Paris, Paris, France.Google Scholar
- Ma, C., Ryan, J. W., Caprette, D. S. (1992b) Crustal Dynamics Project Data Analysis—1991; VLBI Geodetic Results 1979–1990, NASA Technical Memorandum 104522, GSFC Greenbelt Md.Google Scholar
- McCarthy, D. D.,(ed.) (1989) “IERS Standards 1989,”IERS Technical Note 3, Observatorie de Paris, Paris, France.Google Scholar
- McCarthy, D. D.,(ed.) (1992) “IERS Standards 1992,”IERS Technical Note 13, Observatorie de Paris, Paris, France.Google Scholar
- Ray, Jim R. (April 1991) “Radio Interferometry,”Reviews of Geophysics, Supplement, pp 148–156.Google Scholar
- Saastamoinen, J. (1972) “Atmospheric Correction for the Troposphere and Stratosphere in Radio Ranging of Satellites,” inThe Use of Artifical Satellites for Geodesy, Geodesy. Monogr. Ser. 15, (S.W. Henriksenet al., eds.), AGU, Washington, D.C., pp 247–251.Google Scholar