Multivariate modelling of geophysical tomography data to identify a tectonized area

Abstract

An integrated analysis approach, based on geological investigations and 2D high-resolution shallow geophysical data, was proposed along a slope in the Bellolampo landfill area (Palermo, Italy) where the presence of a fault zone was hypothesized. Geophysical surveys included electrical resistivity tomography (ERT), induced polarization tomography (IPT) and seismic refraction tomography (SRT) techniques. The inversion of single geophysical parameter often does not allow to justify the complexity of the subsoil structures. The most appropriate solution should be to add additional physical or geological information so to get a constrained geological model. However, it is not at all easy to work with multivariate datasets due to the lack of well-defined relationships between different parameters. A solution can be a joint inversion procedure with mathematical constraints that favoured final models providing similar spatial distribution of the discontinuities (Gallardo and Meju 2007; 2011). In addition, the use of post-inversion techniques of independent univariate models can help to understand the relationships between different observable parameters (Bedrosian et al. 2007; Dell'Aversana 2001; Di Giuseppe et al. 2014). In particular, these techniques have shown excellent results when applied to seismic and electrical tomography data (Bohm et al. 2017; Capizzi et al. 2017; Gallardo and Meju 2003; 2004).