In this work we report a GPR study across a tectonic discontinuity in Central Italy. The surveyed area is located in the
Castelluccio depression, a tectonic basin in the Central Apennines, close to thewestern border of theMt. Vettore. Its
West flank is characterised by a set ofW-dipping normal faults, considered active and capable of generating strong
earthquakes (Mw=6.5, Galli et al., 2008). A secondary fault strand, already studied with paleo-seismological analysis
(Galadini and Galli, 2003), has been observed in the Quaternary deposits of the Prate Pala alluvial fan. We first
defined the survey site using the data available in literature and referring to topographic and geological maps, evaluating
also additional methodologies, such as orthophoto interpretation, geomorphologic analysis and integrating
all the information in a GIS environment. In addition, we made extensive use of GPR modelling, reproducing the
geometric characteristics of the inferred fault area and interpreting the synthetic profiles to recognise local geophysical
indications of faulting on the radargrams. Finally, we performed a GPR survey employing antennas with different
frequencies, to record both 2D Common Offset profiles and Common Mid Point (CMP) gathers for a more
accurate velocity estimation of the investigated deposits. In this paper we focus on the evaluation of the most appropriated
processing techniques and on data interpretation. Moreover we compare real and synthetic data,
which allow us to better highlight some characteristic geophysical signatures of a shallow fault zone.
