Publication Date:
2017-04-04
Description:
We investigate the role of frictional heating and thermal pressurization on earthquake
ruptures by modeling the spontaneous propagation of a three-dimensional (3-D) crack on a
planar fault governed by assigned constitutive laws and allowing the evolution of
effective normal stress. We use both slip-weakening and rate- and state-dependent
constitutive laws; in this latter case we employ the Linker and Dieterich evolution law for
the state variable, and we couple the temporal variations of friction coefficient with those
of effective normal stress. In the companion paper we investigate the effects of thermal
pressurization on the dynamic traction evolution. We solve the 1-D heat conduction
equation coupled with Darcy’s law for fluid flow in porous media. We obtain a relation
that couples pore fluid pressure to the temperature evolution on the fault plane. We
analytically solve the thermal pressurization problem by considering an appropriate heat
source for a fault of finite thickness. Our modeling results show that thermal pressurization
reduces the temperature increase caused by frictional heating. However, the effect of the
slipping zone thickness on temperature changes is stronger than that of thermal
pressurization, at least for a constant porosity model. Pore pressure and effective normal
stress evolution affect the dynamic propagation of the earthquake rupture producing a
shorter breakdown time and larger breakdown stress drop and rupture velocity. The
evolution of the state variable in the framework of rate- and state-dependent friction laws
is very different when thermal pressurization is active. In this case the evolution of the
friction coefficient differs substantially from that inferred from a slip-weakening law. This
implies that the traction evolution and the dynamic parameters are strongly affected by
thermal pressurization.
Description:
Published
Description:
B05303
Description:
JCR Journal
Description:
reserved
Keywords:
thermal pressurization
;
04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology
;
04. Solid Earth::04.02. Exploration geophysics::04.02.03. Heat flow
;
04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
