ERT and SP measurements for the characterization of fault-controlled soil CO2 degassing

Due to the significant impact that high atmospheric CO2 concentrations can have on human and ecosystem health, a growing interest is focused on the characterization of non-volcanic CO2 degassing. The natural release of CO2 is often controlled by faults and fracture systems that favor the formation of permeable channels allowing gas migration toward the surface. In this framework, geophysical methods represent very useful investigation tools as they not only are able to identify focused gas release, but also to provide an estimate of the extent of influence areas of CO2 degassing and their preferential ascent pathways. To detect fault-controlled soil CO2 degassing, electrical resistivity and self-potential measurements were performed in a survey area located to the south of Matese Ridge (southern Apennines, Italy), where very high gas emissions are observed. Due to the nature of the investigated soils, preferential pathways associated with CO2 flux are found as resistive channels and negative self-potential anomalies.