Deep Electrical Resistivity Tomography (DERT) in the Campi Flegrei area (Naples, Italy)

Within the activities of the Geophysical Prospecting Unit (UR2) of the MS Campi Flegrei project, funded by the Department of Civil Protection, shallow and deep geoelectrical tomography surveys as well as passive seismic surveys, including single-station measurements and 2D arrays, were performed. These investigations aimed to support the development of a subsurface geological model of the study area for seismic microzonation. This paper presents and discusses the preliminary results of a Deep Electrical Resistivity Tomography (DERT) survey, reaching an investigation depth of approximately 2 km. Campi Flegrei, located west of Naples, is one of the most active and extensively studied volcanic areas in the world. It is a large caldera formed by massive explosive eruptions that occurred thousands of years ago. In recent decades, the area has been affected by intensified seismic activity and bradyseism, expressed as ground uplift and subsidence driven by subsurface magmatic processes. Several geological and volcanological aspects of the Campi Flegrei caldera are still debated within the scientific community, and many questions remain open regarding the magmatic systems responsible for caldera-forming eruptions. A single, widely accepted model has yet to emerge; however, ongoing and newly proposed investigations continue to improve our understanding of the dynamics of the Campi Flegrei caldera. In this framework, shallow and deep Electrical Resistivity Tomography were carried out in order to obtain the electrical resistivity distribution associated with volcanic features, such as hydrothermal systems, fluid interactions and temperature variations (Finizzola et al., 2006). The acquired DERT data set was processed and elaborated through a procedure built ad hoc for this type of geoelectric surveys (Rizzo et al., 2004) and an optimization of the field work was used to overcome the logistical difficulties of the area (heavy urbanisation, traffic, restricted traffic area, etc.). All the data acquired was appropriately processed (Rizzo et al., 2022) to obtain a 3D model of the subsoil resistivity, providing useful information on the subsoil of the Campi Flegrei volcanic area. ReferencesFinizola, A. Revil, E. Rizzo, S. Piscitelli, T. Ricci, J. Morin, B. Angeletti, L. Mocochain, and F. Sortino (2006). Hydrogeological insights at Stromboli volcano (Italy) from geoelectrical, temperature, and CO2 soil degassing investigations. Geophysical Research Letters, vol. 33, l17304, 2006Rizzo E., Colella, A., Lapenna, V. and Piscitelli, S. (2004). “High-resolution images of the fault controlled High Agri Valley basin (Southern Italy) with deep and shallow Electrical Resistivity Tomographies”. Physics and Chemistry of the Earth, 29, 321-327Rizzo E., V. Giampaolo, L. Capozzoli, G. De Martino, G., Romano, A. Santilano, A. Manzella (2022). 3D deep geoelectrical exploration in the Larderello geothermal sites (Italy), Physics of the Earth and Planetary Interiors, volume 329-330, 106906 doi: https://doi.org/10.1016/j.pepi.2022.1069