A LEAST-SQUARES MINIMIZATION APPROACH TO DEPTH DETERMINATION FROM NUMERICAL HORIZONTAL GRAVITY GRADIENTS

The sphere and the horizontal cylinder models can be very useful in quantitative interpretation of gravity data measured in a small area over buried structures. The aim of the present study is to develop an interpretive technique based on fitting a simple model convolved with the same horizontal gradient filter as applied to the observed Bouguer gravity data. The depth determination problem from observed horizontal gravity gradient anomaly is transformed into the problem of finding a solution of a nonlinear equation of the form f(z) = 0. Formulae are derived for the sphere and horizontal cylinder. Procedures are also formulated to estimate the radius of the buried structure. -Authors