Correlation between tectonic CO2 Earth degassing and seismicity is revealed by a 10-year record in the Apennines, Italy

摘要

Deep COsub2/sub emissions characterize many nonvolcanic, seismically active regions worldwide, and the involvement of deep COsub2/sub in the earthquake cycle is now generally recognized. However, no long-time records of such emissions have been published, and the temporal relations between earthquake occurrence and tectonic COsub2/sub release remain enigmatic. Here, we report a 10-year record (2009–2018) of tectonic COsub2/sub flux in the Apennines (Italy) during intense seismicity. The gas emission correlates with the evolution of the seismic sequences: Peaks in the deep COsub2/sub flux are observed in periods of high seismicity and decays as the energy and number of earthquakes decrease. We propose that the evolution of seismicity is modulated by the ascent of COsub2/sub accumulated in crustal reservoirs and originating from the melting of subducted carbonates. This large-scale, continuous process of COsub2/sub production favors the formation of overpressurized COsub2/sub-rich reservoirs potentially able to trigger earthquakes at crustal depth.