From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy

Abstract We retrieve 3‐D attenuation images of the crustal volume embedding the fault system associated with the destructive Ms 6.9, 1980 Irpinia earthquake by tomographic inversion of t* measurements. A high QP anomaly is found to be correlated with the 1980 fault geometry, while the QS model shows...

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Main Authors: O. Amoroso, G. Russo, G. De Landro, A. Zollo, S. Garambois, S. Mazzoli, M. Parente, J. Virieux
Format: Article
Language:English
Published: Wiley 2017-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL072346
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author O. Amoroso
G. Russo
G. De Landro
A. Zollo
S. Garambois
S. Mazzoli
M. Parente
J. Virieux
author_facet O. Amoroso
G. Russo
G. De Landro
A. Zollo
S. Garambois
S. Mazzoli
M. Parente
J. Virieux
author_sort O. Amoroso
collection DOAJ
description Abstract We retrieve 3‐D attenuation images of the crustal volume embedding the fault system associated with the destructive Ms 6.9, 1980 Irpinia earthquake by tomographic inversion of t* measurements. A high QP anomaly is found to be correlated with the 1980 fault geometry, while the QS model shows regional‐scale variations related to the NE edge of the uplifted pre‐Tertiary limestone. An upscaling strategy is used to infer rock properties such as porosity, consolidation, type of fluid mixing, and relative saturation percentage at 8–10 km fault depth. We constrain the porosity and consolidation in the ranges 4–5% and 5–9, respectively, with the possible fluid mixes being both brine‐CO2 and CH4‐CO2. The consolidation parameter range indicates high pore pressures at the same depths. These results support the evidence for a fracture system, highly saturated in gases and a seismicity triggering mechanism at the fault zone, which is strongly controlled by fluid‐induced pore pressure changes.
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institution Kabale University
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publishDate 2017-07-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-7ae26344cf0d45378d477a6c6a73c5542025-08-20T03:49:46ZengWileyGeophysical Research Letters0094-82761944-80072017-07-0144136752676010.1002/2016GL072346From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern ItalyO. Amoroso0G. Russo1G. De Landro2A. Zollo3S. Garambois4S. Mazzoli5M. Parente6J. Virieux7Department of Physics ‘Ettore Pancini’ University of Naples ‘Federico II’ Naples ItalyDepartment of Physics ‘Ettore Pancini’ University of Naples ‘Federico II’ Naples ItalyDepartment of Physics ‘Ettore Pancini’ University of Naples ‘Federico II’ Naples ItalyDepartment of Physics ‘Ettore Pancini’ University of Naples ‘Federico II’ Naples ItalyISTerre Université Grenoble Alpes, CNRS Grenoble FranceDepartment of Earth Sciences, Environment and Georesources (DiSTAR) University of Naples ‘Federico II’ Naples ItalyDepartment of Earth Sciences, Environment and Georesources (DiSTAR) University of Naples ‘Federico II’ Naples ItalyISTerre Université Grenoble Alpes, CNRS Grenoble FranceAbstract We retrieve 3‐D attenuation images of the crustal volume embedding the fault system associated with the destructive Ms 6.9, 1980 Irpinia earthquake by tomographic inversion of t* measurements. A high QP anomaly is found to be correlated with the 1980 fault geometry, while the QS model shows regional‐scale variations related to the NE edge of the uplifted pre‐Tertiary limestone. An upscaling strategy is used to infer rock properties such as porosity, consolidation, type of fluid mixing, and relative saturation percentage at 8–10 km fault depth. We constrain the porosity and consolidation in the ranges 4–5% and 5–9, respectively, with the possible fluid mixes being both brine‐CO2 and CH4‐CO2. The consolidation parameter range indicates high pore pressures at the same depths. These results support the evidence for a fracture system, highly saturated in gases and a seismicity triggering mechanism at the fault zone, which is strongly controlled by fluid‐induced pore pressure changes.https://doi.org/10.1002/2016GL072346attenuation tomographyrock physics modelingfluid saturation
spellingShingle O. Amoroso
G. Russo
G. De Landro
A. Zollo
S. Garambois
S. Mazzoli
M. Parente
J. Virieux
From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy
Geophysical Research Letters
attenuation tomography
rock physics modeling
fluid saturation
title From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy
title_full From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy
title_fullStr From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy
title_full_unstemmed From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy
title_short From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy
title_sort from velocity and attenuation tomography to rock physical modeling inferences on fluid driven earthquake processes at the irpinia fault system in southern italy
topic attenuation tomography
rock physics modeling
fluid saturation
url https://doi.org/10.1002/2016GL072346
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