Accession Number:

ADA200958

Title:

Research in Geodesy and Geophysics Based Upon Radio Interferometric Observations of Extragalactic Radio Sources

Descriptive Note:

Final rept. 3 Apr 1986-15 Jun 1988

Corporate Author:

HARVARD COLL OBSERVATORY CAMBRIDGE MA

Personal Author(s):

Report Date:

1988-10-01

Pagination or Media Count:

82.0

Abstract:

We have used data from the Mark III very-long-baseline interferometry VLBI system to study the relative motions of radiotelescopes on the Pacific, North American, and Eurasian plates, and in the deformation zone between the North American and Pacific plates in the California region. These results are in accord with recent geologic plate motion models, and a distributed deformation zone between the North American and Pacific plates. We have carried out a number of studies on the accuracy of the results being obtained with VLBI. The most notable of these studies are of the repeatability of the estimates of three- dimensional coordinates of the sites for long baselines approx. 4,000 km, and the effects of calibrations of the wet tropospheric delays using water-vapor radiometers. We have also been studying the usefulness of observations made at very low elevation angles approx. 4 deg. for improving the accuracy of VLBI baseline determinations. We have also studied the forced nutations of the Earth which yielded results consistent with the flattening of the core-mantle boundary being about 5 greater than that predicted by the assumption of hydrostatic equilibrium within the Earth. The effects of ocean tides and the anelasticity of the mantle on the forced nutations are not clearly evident in our results, and are still being investigated. Keywords Plate tectonics Kalman filtering.

Subject Categories:

  • Geodesy
  • Geology, Geochemistry and Mineralogy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE