a method is disclosed for determining improved estimates of properties of a model , on the basis of estimated prior constraints , by running a mathematical inversion several times using the output posterior estimate of the previous inversion , or any of the previous inversions to provide an input for the next inversion . this iterative inversion may be repeated until the prior and posterior estimates converge to within a given threshold . the method may be applied to seismic data , using a seismic inversion , in order to improve the prediction of the viability of potential petroleum reservoirs by determining improved estimates of volumetric properties of a subsurface region .