The problem of estimation of the average contrast of a buried object is formulated as a nonlinear inverse scattering problem. An effective scattering model of reduced dimensionality is applied in order to make the inversion scheme numerically fast and well-posed. It is shown that a good estimate of the object's average constitution is obtained if L1-type metric is employed and the two-media background is replaced with the average homogeneous one. The effective scattering model is used in combination with Synthetic aperture radar (SAR) imaging, adding significant value to conventional SAR images. ¿ 1999 American Geophysical Union