The Attenuation and Scattering Signature of Fluid Reservoirs and Tectonic Interactions in the Central‐Southern Apennines (Italy)

• Published in: Geophysical research letters Vol. 50; no. 22
• Main Authors: Talone, D., Siena, L., Lavecchia, G., Nardis, R.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.11.2023; Wiley
• Subjects: Anomalies; Aseismic zones; Attenuation; Carbon dioxide; central Apennines; Degassing; Detection; Fluids; Geological hazards; Geophysical exploration; Geophysical methods; Imaging techniques; P-waves; Quaternary; Quaternary tectonics; Saturation; Scattering; Seismic activity; Seismic attenuation; Seismic energy; Seismic hazard; seismic scattering; Seismic wave propagation; Seismic waves; Seismicity; Sensitivity; southern Apennines; Tectonics; Tomography; Wave propagation; Italy
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL106074

Despite the high detection level of the Italian seismic network and the risk associated with its fault networks, Central‐Southern Italy has no unique geophysical model of the crust able to illuminate its complex tectonics. Here, we obtain seismic attenuation and scattering tomography models of this area; both reveal high attenuation and scattering anomalies characterizing the entire Apenninic Chain and related to its East‐ and West‐dipping extensional Quaternary tectonic alignments. Fault‐associated fractured zones become preferential ways for circulating and degassing high‐attenuation CO2‐bearing fluids. A previously undetected fluid source area is a high‐attenuation volume below the Matese complex, while a similar smaller anomaly supports a fluid source near L'Aquila. The most prominent low attenuation and scattering volumes reveal a locked aseismic zone corresponding to the Fucino‐Morrone‐Porrara fault systems, representing a zone of significant seismic hazard. Plain Language Summary Geophysical methods are the most used tools for imaging the subsurface. Still, their resolution and reliability depend on the amount of good‐quality data and the sensitivity of the technique used for the target structures. Improvements in the seismic detection infrastructures of the last decade allow imaging zones characterized by sparse seismicity, like Central‐Southern Italy. Once combined with these data, new imaging techniques targeting attributes with higher sensitivity to stress and fluid saturation provide unprecedented resolution on tectonic interactions and fluid sources in this area. Here, we measured and mapped in 3D the energy lost by seismic waves during their propagation. Our results show a high‐attenuation volume elongated in the direction of the Apenninic Chain and particularly intense in Southern Italy, mapping fluid‐filled fracturing and a fluid source likely coinciding with the Matese area. The principal normal and reverse faults in the area control high‐attenuation zones. The most prominent low attenuation and scattering volume marked locked areas with low seismic energy release, suggesting them as the zones of stress accumulation. Key Points Scattering and attenuation tomography image the tectonics of the Apennine Mountain Belt Chain High‐attenuation anomalies mark crustal sources of CO2 following major structural alignments A high‐attenuation/high‐scattering volume reveals an extended fluid source beneath the Matese Mountains