A GRAVIMETRIC 3D GLOBAL INVERSION FOR CAVITY DETECTION

A gravimetric survey, covering a site 200 m square, was carried out in order to locate karstic cavities. After eliminating the regional tren d using a polynomial fit, the residual is modelled by least-squares pr ediction. Correlated signals for several wavelengths are detected. The inversion of these anomalies is performed by a global 3D adjustment u sing spherical bodies as models. The adjustment is repeated in order t o obtain a stable configuration. The results show the probable presenc e of a system of cavities and galleries. Data collected from boreholes and the subsequent appearance of sink-holes are consistent with the r esults.