Fluctuations of gas concentrations in three mineral springs of the East Eifel Volcanic field (EEVF)

We present a geochemical dataset acquired during continual sampling over 7 months (bi-weekly) and 4 weeks (every 8 hours) in the Neuwied Basin, a part of the East Eifel Volcanic Field (EEVF). We used a combination of geochemical, geophysical, and statistical methods to identify potential causal processes underlying the correlations of degassing patterns of four gases (He, Rn, CO2, O2), earth tides, and tectonic processes in three mineral springs (Nette, Kaerlich and Kobern). We explored whether temporal relations in gas concentrations in the three mineral springs could be indicators of hidden faults through which the gases migrate to the surface from deeper underground. Our results do not confirm CO2 as a primary carrier gas for trace gases in all springs. Temporal analyses of the CO2-He couple indicate that Nette and K\"arlich are directly linked via a continuous tectonic fault in an ENE-WSW trending direction. There is also evidence that Kaerlich and Kobern (NNE-SSW fault system) and Nette and Kobern (NW-SE fault system) are tectonically linked. These fault linkages are unknown previously but could be related to the rising numbers of earthquake events occurring in this area since 2010. We did not find any evidence that weather processes (e.g., barometric pressure), earth tides, or low local earthquake magnitudes actively modulate degassing. The volcanic activity in the EEVF is dormant but not extinct and to understand and monitor its magmatic and degassing systems, we recommend bi-weekly samplings at minimum.