Optimisation of Density Parameter in Gravity Prediction from Bathymetry
This paper describes experiments conducted to examine the combination of gravity values predicted from bathymetric data with observed gravity data to increase the resolution of offshore gravity data. The density parameter in the prediction is optimised empirically.
The gravity effect resulting from bathymetric features can provide short wavelength features of the gravity field, but at longer wavelengths geophysical features below the seafloor begin to influence the gravity signal. A model of the isostatic response might help to determine these longer wavelength features, but these models are inconclusive so in this case the calculations are restricted to the bathymetry.
By using a combination of observed gravity and gravity predicted from bathymetry, the long wavelength features present in the direct observations can be preserved while using the bathymetric data to fill-in the short wavelength features.
The computation scheme is described, and some numerical results are presented. The effect of increasing the distance between the observed gravity data is examined.
For the calculation of the gravity signal arising from the bathymetry, a single density value is chosen for the entire area. Due to density variations this density may not be optimal. Different density values are tested to examine the effect this choice has on the resulting predicted gravity.
KeywordsBathymetry gravity prediction
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