The practical gradio meter systems for rapidly measuring GGT have been developed (Bell et al., 1997; Jekeli, 1993). Mikus and Hinojosa (2001) propose the method of approximating of the GGT from measured gravity data. The full gravity gradient tensor, symbol T, can be written in the form : T = [\(\frac{\partial^{2}U}{\partial_{x}^{2}}\) \(\frac{\partial^{2}U}{\partial_{x}\partial_{y}}\) \(\frac{\partial^{2}U}{\partial_{x}\partial_{x}}\)\(\frac{\partial^{2}U}{\partial_{y}\partial_{x}}\) \(\frac{\partial^{2}U}{\partial_{y}^{2}}\) \(\frac{\partial^{2}U}{\partial_{y}\partial_{z}}\)] = [11-11121202]
\begin{equation} \label{eq.1} \label{eq.1}p=g_{xx}g_{yy}+g_{xx}g_{zz}+g_{yy}g_{zz}−g_{zx}g_{xz}−g_{xy}g_{yx}−g_{zy}g_{yz};\\ \end{equation}kankanba haikeyi a a a a a