Integrated geophysical and participative approaches for geothermal resources evaluation in urban areas in Southern Italy

This work is supported by the projects TOGETHER – Sustainable geothermal energy for two Southern Italy regions: geophysical resource evaluation and public awareness (https://www.together-prin.it/) and ITINERIS – Italian Integrated Environmental Research Infrastructures System (https://itineris.cnr.it/), funded by the European Union – Next Generation EU (PNRR, M4C2, Investments 1.1 and 3.1, respectively).

As part of the ITINERIS project, the geophysical laboratory of CNR-IMAA was upgraded with advanced geophysical instrumentation characterized by lower operational costs, increased flexibility, higher sensitivity, and faster acquisition rates. The availability of dense and flexibly deployable geophysical sensors significantly improves survey resolution, particularly in complex urban and semi-urban environments, thereby supporting sustainable and resilient urban development.

Under the TOGETHER project, the upgraded instrumentation was tested at pilot sites, including the Sele River Valley (SRV) in the Campania region (Southern Italy). This area hosts numerous thermal springs and wells with temperatures reaching up to 48 °C, currently used for spa and therapeutic purposes. These characteristics make the SRV a natural laboratory for testing integrated geophysical approaches aimed at identifying geothermal targets in proximity to existing communities and infrastructure.

Geothermal energy, particularly low- to medium-enthalpy systems, represents a key renewable resource for the energy transition, enabling the sustainable exploitation of local resources, the reduction of greenhouse gas emissions, and the strengthening of regional energy resilience. Integrated geophysical investigations play a crucial role in reducing exploration uncertainty and promoting environmentally responsible geothermal development.

In the SRV area, geophysical surveys were conducted over a target zone of approximately 6 × 8 km², centered on the hottest thermal manifestations. A comprehensive geophysical dataset was successfully acquired in a challenging urban and semi-urban context characterized by logistical constraints and high levels of anthropogenic noise. Multi-scale and multi-resolution three-dimensional subsurface electrical resistivity models were derived using shallow and deep Electrical Resistivity Tomography (ERT/DERT) and Magnetotelluric (MT) surveys. In parallel, ambient seismic noise recordings were acquired and processed using single-station HVSR analyses and array-based Ambient Noise Tomography (ANT).

In parallel with fieldwork, public engagement activities were implemented to foster trust and collaboration with local stakeholders. These activities included the involvement of high school students and teachers, communication through municipal social media channels, the distribution of participation certificates, and the organization of a final dissemination event aimed at citizens, local institutions, schools, and stakeholders. The event was dedicated to sharing the results and research activities developed in the area as part of the TOGETHER project, with a particular focus on energy sustainability and the enhancement of local geothermal resources, also through direct dialogue between researchers and the public. These initiatives proved essential for ensuring transparency, site accessibility, and awareness of local geothermal potential.

The results demonstrate the feasibility and effectiveness of an integrated geophysical and participatory approach, highlighting the importance of public engagement and standardized workflows for sensor deployment and data processing.