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Effects of permeability and porosity evolution on simulated earthquakes
Language
English
Obiettivo Specifico
3.1. Fisica dei terremoti
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/38(2012)
ISSN
0191-8141
Electronic ISSN
1873-1201
Publisher
Elsevier Science Limited
Pages (printed)
243-253
Issued date
May 2012
Alternative Location
Abstract
Numerical simulations are a fundamental tool to access the typical conditions attained
during earthquake instabilities and to simulate the large number of dissipative processes
taking places during faulting. In this study we consider a single-degree-of-freedom
spring-slider system, a simplified fault model which can describe the whole seismic cycle
and the dynamics of a fault with spatially homogeneous properties. We assume a rate- and
state-dependent friction in which we incorporate the effects of pore fluid pressure,
thermally-pressurized as a consequence of the frictional heat produced during sliding.
We explore, in a single framework, the role of the time variations of the porosity,
permeability or both, ultimately leading to changes in hydraulic diffusivity, which
has been recognized as one of the key parameters in thermally-pressurized faults.
Our synthetic ruptures show that the changes in the hydraulic diffusivity only due
to porosity variations do not markedly affect the earthquake recurrence (cycle time),
the traction evolution and the thermal history of the fault. On the contrary, when the
evolutions of both the porosity and the permeability are accounted for, the cycle time
is significantly reduced. This result has a clear implication in the context of the
hazard assessment.
during earthquake instabilities and to simulate the large number of dissipative processes
taking places during faulting. In this study we consider a single-degree-of-freedom
spring-slider system, a simplified fault model which can describe the whole seismic cycle
and the dynamics of a fault with spatially homogeneous properties. We assume a rate- and
state-dependent friction in which we incorporate the effects of pore fluid pressure,
thermally-pressurized as a consequence of the frictional heat produced during sliding.
We explore, in a single framework, the role of the time variations of the porosity,
permeability or both, ultimately leading to changes in hydraulic diffusivity, which
has been recognized as one of the key parameters in thermally-pressurized faults.
Our synthetic ruptures show that the changes in the hydraulic diffusivity only due
to porosity variations do not markedly affect the earthquake recurrence (cycle time),
the traction evolution and the thermal history of the fault. On the contrary, when the
evolutions of both the porosity and the permeability are accounted for, the cycle time
is significantly reduced. This result has a clear implication in the context of the
hazard assessment.
Type
article
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Paper 28 2.pdf
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