Accession Number:

ADA164608

Title:

An Isostatic Earth Model.

Descriptive Note:

Technical rept.,

Corporate Author:

OHIO STATE UNIV COLUMBUS DEPT OF GEODETIC SCIENCE AND SURVEYING

Personal Author(s):

Report Date:

1985-09-01

Pagination or Media Count:

59.0

Abstract:

The concept of the conventional AiryHeiskanen isostatic model is investigated from scratch, based on the harmonic analysis of the topographic-isostatic potential. First and higher order approximations for those coefficients are discussed and rule of thumb formulas given. The estimated frequency transfer function between the power spectrum of the observed gravitational field and the power spectrum implied by the isostatic model strongly suggests a smoothing of the compensation surface according to Vening Meinesz with a smoothing operator of Gaussian bell-shaped type, and a depth of compensation of about 24 km. A proof of equivalence of using a standard AiryHeiskanen model with a larger comepnsation depth and a corresponding Poisson smoothed Vening Meinesz model at a smaller depth has been given for the case of linear approximation, yielding an entirely new interpretation of recent isostatic models. An iterative least-squares process has been designed which provided parameter estimates of that isostatic model in best possible agreement with the observed gravitational potential of the earth. Based on these parameters a set of harmonic coefficients of the topographic-isostatic potential, complete up to degree and order 180 was computed. Several maps of topography-isostasy implied geoidal heights are presented for comparison. Keywords Isostasy Harmonic analysis and synthesis Fast Fourier transform Smoothing operators OperatorsMathematics.

Subject Categories:

  • Geodesy
  • Statistics and Probability

Distribution Statement:

APPROVED FOR PUBLIC RELEASE