Earthquake-related signals recorded in Central Italy, Southern Italy and in Sicily by geochemical and hydrogeologic methods

Crustal deformative processes are usually monitored by GPS or by satellite-based techniques. Significant signals have been recorded in many places of the world after strong earthquakes. Only in a few cases similar signals were detected before seismic events due to the relatively low sensitivity of equipments (Roeloffs, 2006; Cicerone et al., 2009). Due to the about non compressible character of water and to deep origin of CO2, deep originated fluid monitoring could be more sensitive in revealing weak signals related to crustal deformations and contribute to earthquake precursors researches (Martinelli and Albarello, 1997; Martinelli and Dadomo, 2017). Dissolved and bubbling CO2 and related gases (e.g. Pierotti et al., 2017) have been automatically monitored in thermal spring waters located in selected areas of Tuscany and Umbria regions (Central Italy). Water level has been automatically recorded in deep wells located in Eastern Sicily and in Southern Italy (Campania region). Recorded data do not show significant dependence to meteorological or artificial parameters. Part of the observed signals have been detected before mainshocks and could be related to aseismic slip (e.g. Johnston and Linde (2002) or to seismic slip eventually induced by fluctuations in minor seismicity. Earthquake forecasting researches could benefit by the joint utilization of different monitoring techniques applied to geofluids.