Diffuse soil CO2 degassing from Linosa island.

Herein, we present and discuss the result of 148 measurements of soilCO2 flux performed for the first time in Linosa island (Sicily Channel,Italy), a Plio-Pleistocene volcanic complex no longer active but still of interestowing to its location within a seismically active portion of the SicilyChannel rift system. The main purpose of this survey was to assess theoccurrence of CO2 soil degassing, and compare flux estimations from thisisland with data of soil degassing from worldwide active volcanic as wellas non-volcanic areas. To this aim soil CO2 fluxes were measured over asurface of about 4.2 km2 covering ~80% of the island. The soil CO2 degassingwas observed to be mainly concentrated in the eastern part of theisland likely due to volcano-tectonic lineaments, the presence of which isin good agreement with the known predominant regional faults system.Then, the collected data were interpreted using sequential Gaussian simulationthat allowed estimating the total CO2 emissions of the island.Results show low levels of CO2 emissions from the soil of the island (~55ton d-1) compared with CO2 emissions of currently active volcanic areas,such as Miyakejima (Japan) and Vulcano (Italy). Results from this studysuggest that soil degassing in Linosa is mainly fed by superficial organicactivity with a moderate contribution of a deep CO2 likely driven by NWSEtrending active tectonic structures in the eastern part of the island.