GNGTS 2021 - Atti del 39° Convegno Nazionale

403 GNGTS 2021 S essione 3.1 3D inversion of MT data from the Travale geothermal field Derivative-based 3D MT inversion is currently a field of very intensive research because it exploits all the information stored in the full MT impedance tensor and the vertical magnetic transfer function (i.e., tipper). 3D inversion ofMT data fromthe Travale geothermal field represents a novelty (Pace et al., under revision ). 51 of the MT sites shown in Fig.1 were chosen for 3D inversion, which was computed using the ModEM software (Kelbert et al., 2014). Several 3DMT inversion tests were performed by changing the components of the tensor to be inverted, the rotation of the mesh, the error floor of the data and the starting model, in order to assess the resistivity distribution of this complex and largely-investigated geothermal system. The outcome of the 2D PSO of the Travale MT profile was used to build the a priori starting model for some of the 3D inversion tests. The final 3D resistivity models of the different tests generally imaged similar structures. Fig. 2 shows a vertical section drawn from the 3D model of the test with the best data fitting and Fig. 2 – Vertical cross-section of the 3D resistivity model. The SW-NE profile is orthogonal to the geoelectrical strike direction and crosses sites from k5 to a8.