The Role of Faults in Groundwater Circulation before and after Seismic Events: Insights from Tracers, Water Isotopes and Geochemistry
Davide Fronzi,
Francesco Mirabella,
Carlo Cardellini,
Stefano Caliro,
Stefano Palpacelli,
Costanza Cambi,
Daniela Valigi,
Alberto Tazioli
Affiliations
Davide Fronzi
Department of Science and Matter Engineering, Environment and Urban Planning (SIMAU), Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy
Francesco Mirabella
Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli s.n.c., 06123 Perugia, Italy
Carlo Cardellini
Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli s.n.c., 06123 Perugia, Italy
Stefano Caliro
Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli, Osservatorio Vesuviano (INGV-OV), Via Diocleziano 328, 80124 Naples, Italy
Stefano Palpacelli
Department of Science and Matter Engineering, Environment and Urban Planning (SIMAU), Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy
Costanza Cambi
Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli s.n.c., 06123 Perugia, Italy
Daniela Valigi
Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli s.n.c., 06123 Perugia, Italy
Alberto Tazioli
Department of Science and Matter Engineering, Environment and Urban Planning (SIMAU), Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy
The interaction between fluids and tectonic structures such as fault systems is a much-discussed issue. Many scientific works are aimed at understanding what the role of fault systems in the displacement of deep fluids is, by investigating the interaction between the upper mantle, the lower crustal portion and the upraising of gasses carried by liquids. Many other scientific works try to explore the interaction between the recharge processes, i.e., precipitation, and the fault zones, aiming to recognize the function of the abovementioned structures and their capability to direct groundwater flow towards preferential drainage areas. Understanding the role of faults in the recharge processes of punctual and linear springs, meant as gaining streams, is a key point in hydrogeology, as it is known that faults can act either as flow barriers or as preferential flow paths. In this work an investigation of a fault system located in the Nera River catchment (Italy), based on geo-structural investigations, tracer tests, geochemical and isotopic recharge modelling, allows to identify the role of the normal fault system before and after the 2016–2017 central Italy seismic sequence (Mmax = 6.5). The outcome was achieved by an integrated approach consisting of a structural geology field work, combined with GIS-based analysis, and of a hydrogeological investigation based on artificial tracer tests and geochemical and isotopic analyses.