Relationship between soil CO2 flux and tectonic structures in SW Sicily

Abstract

The identification and characterization of seismogenic structures in southwestern Sicily is an open debate both for the geological-structural complexity of this sector and the scarce seismicity as well. In addition, clear morphological evidence of tectonic structures is limited. Besides the geophysical methods, the study of the spatial distribution of soil CO 2 flux is a valid methodology to investigate the position and geometry of buried active faults. Indeed, active tectonic structures are channels with high permeability through which deep fluids can migrate toward the atmosphere. Therefore, the alignment of high degassing areas can reveal the presence of preferential ways of rising fluids (i.e. faults). We applied this methodology in SW Sicily in the surrounding of the area hit by the 1968 seismic sequence and in three other areas where evidence of active deformation has been recognized. Furthermore, to investigate the origin of emitted fluids, we measured the carbon isotopic composition of the soil CO 2 in some high emission sites. The results showed high spatial variability of soil CO 2 fluxes with values ranging from 1 to 430 g m −2 d −1. The areal patterns of soil CO 2 fluxes in all the areas reveal a strong influence of the main tectonic structures and active deformations on soil CO 2 emissions. The range of isotopic data and the distribution of soil CO 2 fluxes suggest a supply of deep fluids through the active tectonic structures.

Tree‐ring stable isotopes and radiocarbon reveal pre‐ and post‐eruption effects of volcanic processes on trees on Mt. Etna (Sicily, Italy)

“…During and after the eruption in 2002/2003, the δ 13 C values were somewhat lower than in the years before and could be explained mainly by climate variability. Taking into account that the δ 13 C values of deep‐origin CO 2 in the region are much higher, i.e., less negative (Camarda et al, 2020), we may exclude a possible influence of the ongoing volcanic activity on the carbon isotope ratio within the trees.…”

Hazardous Changes in Soil CO2 Emissions at Vulcano, Italy, in 2021

“…Soil CO 2 emissions occur in several different geological settings (Almagro et al., 2009; Annunziatellis et al., 2003; Camarda et al., 2020; Capasso et al., 2019; Chiodini et al., 2015; Ciais et al., 2021; Di Martino & Capasso, 2019, 2021; Venturi et al., 2019; Zhang et al., 2017), and investigating their changes over time and space has been the subject of many studies in volcanology (Allard et al., 1991; Boudoire et al., 2017; Burton et al., 2013; Camarda et al., 2012, 2019; Capasso et al., 2017; Carapezza & Federico, 2000; Cardellini et al., 2017; Chiodini et al., 1996, 1998; Chiodini & Frondini, 2001; De Gregorio & Camarda, 2016; Di Martino, Camarda, et al., 2016; Farrar et al., 1995; Federico et al., 2011; Giammanco et al., 1997; Valenza, 1993) and earth degassing in seismically active zones (Camarda et al., 2016; Capasso et al., 2021; Raich & Potter, 1995; Raich & Schlesinger, 1992; Raich & Tufekcioglu, 2000; Tamburello et al., 2018).…”

Chemical and isotopic signature of groundwater in the Santa Ninfa karst system and possible inferences on neotectonics

“…10 This interpretation is supported by the values of soil CO 2 flux measured in a transect crossing the surface projection of the main gallery of La Grotta, which are lower (4 g m -2 d -1 ) over the gallery and higher (162 g m -2 d -1 ) on both sides [Camarda et al, 2020].…”