Abstract

There is an ongoing debate on the processes producing background seismicity and deformation transients across seismic gaps, i.e., regions that lack historical large-magnitude earthquakes. Essential missing elements are geophysical images that resolve sources of geophysical unrest. Here, we apply seismic scattering and absorption tomography to data recorded during the 2010–2014 seismic sequence within the Mt. Pollino seismic gap region (Southern Italy). The tomographic models show high sensitivity to fluid content, deformed fractured structures, and impermeable layers stopping fluid migrations. They bridge the gaps between geological and geophysical models and provide a highly-resolved image of the source of seismic and deformation unrest within this seismic gap. High absorption topping the western Pollino seismic volume appears pressurized between the low-Vp/Vs and low-scattering San Donato metamorphic core and a deep basement. Absorbing fluids can only migrate laterally to the east, blocked in the west and southwest by deep low-scattering barriers associated with east-dipping faults and to the north and southeast by saturated overpressurized low-scattering basins. This eastern migration is only partially effective, producing seismicity across the lowest boundary of the high-absorption volume. Our results showcase the potential of seismic scattering and absorption when imaging structures causing geophysical unrest processes across fault networks.

Details

Title
Imaging overpressurised fracture networks and geological barriers hindering fluid migrations across a slow-deformation seismic gap
Author
Napolitano, Ferdinando 1 ; Gabrielli, Simona 2 ; De Siena, Luca 3 ; Amoroso, Ortensia 1 ; Capuano, Paolo 1 

 Università degli Studi di Salerno, Dipartimento di Fisica “E. R. Caianiello”, Fisciano, Italy (GRID:grid.11780.3f) (ISNI:0000 0004 1937 0335) 
 Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy (GRID:grid.410348.a) (ISNI:0000 0001 2300 5064) 
 Johannes Gutenberg University, Institute of Geosciences, Mainz, Germany (GRID:grid.5802.f) (ISNI:0000 0001 1941 7111); Alma Mater Studiorum Università di Bologna, Dipartimento di Fisica e Astronomia “Augusto Righi”, Bologna, Italy (GRID:grid.6292.f) (ISNI:0000 0004 1757 1758) 
Pages
19680
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2888703369
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.