Publication Date:
2017-04-04
Description:
We analyze the coseismic stress perturbation during the 17 June 2000 south Iceland
seismic sequence; the main shock (Ms 6.6) was followed by three large events within a few
tens of seconds (8, 26, and 30 s) located within 80 km. The aim of this paper is to
investigate short-term fault interaction and instantaneous triggering. This happens when a
fault perturbed by a stress change fails before the end of the transient stress perturbation.
We compute the shear, normal, and Coulomb stress changes as functions of time in a
stratified elastic half-space by using discrete wave number and reflectivity methods. We
calculate dynamic stresses caused by the main shock at the hypocenters of these three
subsequent events. Our numerical results show that the onset of the last two events is
slightly delayed with respect to the arrival time of the second positive peak of Coulomb
stress variation, while the first event occurred after the first positive stress peak. We have
also analyzed the response of a spring slider system representing a fault governed by a
rate- and state-dependent friction law, perturbed by shear and normal stress variations
caused by the main shock. The fault response to the computed stress perturbations is
always clock advanced. We have found suitable constitutive parameters of the modeled
fault that allow the instantaneous dynamic triggering of these three earthquakes. If the
initial sliding velocity is comparable with the tectonic loading velocity, we obtained failure
times close to the observed origin times for low values of the initial effective normal
stress.
Description:
Published
Description:
B03302
Description:
JCR Journal
Description:
reserved
Keywords:
seismic sequence
;
Iceland
;
2000
;
04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
;
04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability
;
04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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