Gradient (Tzz) Versus Gravity (Tz) Response
The following images provide an indication of gravity versus gradient signal/noise and resolution. Two stand-alone examples are used to compare high-resolution marine gravity and Full Tensor Gradient (FTG) data. The surveys overlap (bottom right) with gravity shown as image A and FTG as image B. The image on the left compares the measured gravity (Tz) with a calculated gravity (Tze) from the gradiometer. The latter shows better discrimination of subsurface geology with its higher S/N ratio. The image on the right shows a calculated (1st vertical derivative) gradient Tzz response from gravity compared to the measured Gradient Tzz. The higher S/N ratio in the measured Tzz once again provides improved structural resolution. Thus, measured gradients are preferred and contain both higher resolution and valuable directional/shape and lineament information.
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FTG-computed Tze Vs. measured Tz Image A is measured Tz from a gravimeter and the overlapping Image B is a computed Tze from FTG response |
FTG-measured Tzz Vs. computed Tzz Image A is a computed gradient to be compared to the overlapping Image B, which is FTG-measured Tzz |