Beyond image analysis in processing archaeomagnetic geophysical data: case studies of chamber tombs with dromos

We analysed the effectiveness of three methods for interpreting magnetic maps in the third dimension, i.e. the depth. The possible synergies among the information obtained by each method have also been examined. The approach is based on a preliminary evaluation of the depth of the causative body according to the solution of Euler's equation; the application of a two-dimensional cross-correlation technique enables the estimation of the spatial orientation, the shape and the susceptibility contrast of the causative bodies. The preliminary interpretation allows the input parameters and the necessary constraints (e.g. susceptibility contrast, maximum depth of the magnetic targets) to be tuned for the subsequent 3D modelling and inversion. We adopt the strategies for the quantitative interpretation, i.e. depths and shape, of the archaeological remains in the Sabine Necropolis of Colle del Forno, Montelibretti, Rome. The approach is shown to be effective for imaging the dromos and cavities of the tombs of this necropolis.