Gridding gravity data using an equivalent layer
Gravity data are routinely gridded in preparation for contouring or imaging, or to enable processing by a fast Fourier transform method. Frequently used gridding techniques such as 1/r(N), minimum curvature, or kriging, interpolate data values with no regard to the nature of the data involved; they will produce the same interpolated values if either magnetic or gravity measurements with the same numerical values are used. Equivalent layer gridding however fits the known potential field data values using the geophysical response of a thin surface layer whose physical properties vary spatially. The response of the surface layer can then be calculated at any other points for the purpose of interpolation. The interpolated data values will then depend on the nature of the data being used. A program to perform such gridding (running under Windows'95 or '98) has been written and is available free via ftp from ftp.cs.wits.ac.za in directory /pub/general/geophys. (C) 2000 Elsevier Science Ltd. All rights reserved.
interpolation geophysics smoothing