1 EGC 2013 Shallow geothermal exploration using SkyTEM data: the VIGOR experiment Adele Manzella 1 , Andrea Viezzoli 2 , Antonio Menghini 2 , Alessandro Santilano 1 , Assunta Donato 1 , Domenico Montanari 1 , Sabino Maggi 3 , Enzo Rizzo 4 11 Institute of Geosciences and Earth Resources – CNR-IGG, Via Moruzzi 1 – 56124 Pisa, Italy 2 Aarhus Geophysics, C.F.Møllers Allé 4, 8000 Århus C, Denmark 3 CNR-IRSA, Via F. De Blasio 5, 70132 Bari, Italy 4 CNR-IMAA, C.da S. Loja - Zona Industriale, 85050 Tito Scalo (PZ), Italy manzella@igg.cnr.it Keywords: geothermal exploration, geophysical data, electromagnetic data, resistivity, thermal properties ABSTRACT As part of planned geophysical activities within the “VIGOR Project”, aimed at assessing regional and local scale geothermal potential of four southern Italian Regions, Airborne EM survey has been carried out in Sicily, in late 2011, on two test sites (Termini and Western Sicily). After acquisition, data have been processed and modeled, providing 3D cell distribution of resistivity that has been used for detailed geological and geothermal interpretation. In particular, we describe here the results of the geological modelling of one of the two areas, constrained using resistivity data, and its geothermal interpretation focused on the detection of shallow circulation of geothermal fluids and to the reconstruction of thermal conductivity distribution at depth. 1. INTRODUCTION Within the “VIGOR” project, aimed at assessing the geothermal potential of four regions in southern Italy (Manzella, 2013), airborne geophysical electromagnetic (AEM) data have been acquired, modeled and interpreted. The AEM survey was performed using SkyTEM system with data delivered by SkyTEM Surveys Aps, processed and inverted by Aarhus Geophysics Aps. SkyTEM is a time-domain helicopter electromagnetic system with a maximum magnetic moment of approximately 150000 A/m 2 . Measurements are carried out continuously while flying. The SkyTEM system provides, after data acquisition, analysis, processing and modeling, a distribution volume of electrical resistivity, spanning an investigation depth from ground surface of few hundred meters, depending on resistivity condition. Resistivity is an important physical parameter for geothermal investigation, since it proved to be very effective in mapping anomalies due to hydrothermal fluid circulation, which usually has high salt content and produces clayey alteration minerals. Besides, resistivity data may help in characterizing hydrogeological or tectonic features. The attempt is also to define relations between resistivity distribution, lithological units and thermal conductivity. The AEM survey was carried out in Sicily, Italy, in the Fall 2011. The flight lines covered two areas: in the “Termini” area about 5000 km total flight lines spaced 150 m were acquired over an area of (15 x 15) km 2 ; in the “Western Sicily” area two different line spacing were used to cover the (30 x 50) km 2 : the 1 km spacing was used for the preliminary mapping, whereas for infill areas, around the main hydrothermal springs, the flight lines had 200 m spacing. Figure 1: The two areas covered by airborne surveys: “Termini” area in pink, “western Sicily” area in blue (top). Flight lines details in the two areas (bottom). Note the infill in the “western Sicily” area, bottom left.