Soil CO2 emissions are widely used to trace fluid circulation in the crust, as faults and fracture networks act as preferential pathways for fluid ascent from depth. Their spatial distribution may reveal tectonic lineaments controlling fluid migration, while temporal variations may reflect stress changes associated with seismogenic processes. In active volcanic systems, however, identifying tectonic influences is challenging because volcanic and hydrothermal activity can mask tectonically controlled signals. Vulcano Island is particularly suitable for investigating these interactions, as it is characterized by both persistent volcanic–hydrothermal activity and a tectonic setting shaped by major regional fault systems. In this study, we analyze continuous soil CO2 flux records and periodic surveys conducted over a fixed measurement grid during the last 20 years. Continuous records show that a clear tectonic signal is recognizable only at the Faraglione site, where the most pronounced increase in soil CO2 flux occurred after the 16 August 2010 M 4.8 earthquake. Spatial analysis reveals two anomalous phases following this event, in September 2010 and January 2011, both showing a NNW-SSE alignment consistent with the regional structural framework. Analysis of data collected during the 2021 unrest confirms that the tectonic framework exerts strong control on fluid release both during quiescence and during phases of enhanced volcanic activity.
Gregorio et al. (Thu,) studied this question.