Temporal and spatial correlations between soil CO2 flux and crustal stress

• Published in: Journal of geophysical research. Solid earth Vol. 121; no. 10; pp. 7071 - 7085
• Main Authors: Camarda, Marco, De Gregorio, Sofia, Di Martino, Roberto M. R., Favara, Rocco
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-10-2016
• Subjects: Area; Automation; Carbon dioxide; Carbon dioxide flux; Correlation; Correlation analysis; Crustal stress; Deformation; Discharge; Fluctuations; Fluxes; Geophysics; Parameters; Plate tectonics; Rock; Rocks; Seismic activity; Seismicity; Seismology; seismotectonic process; Soil; Soil CO2 flux; Soil investigations; Soil stresses; Soils; Tracking
• ISSN: 2169-9313; 2169-9356
• DOI: 10.1002/2016JB013297

In seismically active areas, tectonic stress deforms and breaks the rocks of the crust. Ongoing deformation produces detectable modifications in the shallower portions of the crust, resulting in a wide variety of changes in several parameters. In this paper, we report the results of a large‐scale spatial (across an area of 15,000 km2) and temporal (up to 3 years) investigation of the relationship between active crustal stress and soil CO2 flux. We deployed a network of 10 automatic stations in most of the seismically active districts of southern Italy to monitor the soil CO2 fluxes, and we used seismicity data to track crustal stress. The results of the investigation show that the CO2 flux signals varied independently in the districts with low and sporadic seismicity. Conversely, in the only district with nearly continuous seismic activity, almost all of the CO2 flux signals were well correlated with each other, and we recorded a clear synchronous sharp increase of the seismicity and signals recorded by several stations. The high spatial and temporal correlation between seismicity and gas discharge evidenced in this study prove that the crustal stress associated with the seismogenic process is able to effectively modulate the gas release in a seismically active area.
Key Points
First investigation between crustal stress and soil CO2 flux relationship on broad spatial and temporal scale.
Clear evidence of connection between soil CO2 flux variations and the action of crustal stress
Experimental proof of the variations of fluid release associated to seismogenic process