The complete gravity gradient tensor derived from the vertical component of gravity: a Fourier transform technique

A technique has been to developed to determine the complete gravity gradien t tensor from pre-existing vertical gravity data using the fast Fourier Tra nsform (FFT). Since direct measurement of the entire gravity gradient tenso r is generally unavailable, our technique provides an alternative determina tion of the gravity gradient tensor components. Traditionally, derivatives of vertical gravity (g(z,x), g(z,y), and g(z,z)) have been the only gravity gradient tensor components that have been computed directly. Gravity gradi ent tensor components are computed for four different. three-dimensional (3 -D), idealized horst-and-graben models, with varying depths to the horst. C omparing the FFT results with calculated gradient components from the 3-D m odels shows that the RMS error for each component, between the two results, is at most similar to 3.3 Eotvos Units. In addition, measured gravity grad ient components from an airborne survey over the Wichita Uplift and Anadark o Basin region of southwest Oklahoma compare favorably with the FFT-derived results using available vertical gravity data. No error analysis was attem pted between the two results due to a low signal-to-noise ratio in the meas ured data. Our technique offers a novel way to transform and visualize the available data, and it also offers an inexpensive and previously unavailabl e subsurface mapping capability. (C) 2001 Published by Elsevier Science B.V .