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| Titel |
Faults self-organized by repeated earthquakes in a quasi-static antiplane crack model |
| VerfasserIn |
D. Sornette, C. Vanneste |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 3, no. 1 ; Nr. 3, no. 1, S.1-12 |
| Datensatznummer |
250000698
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| Publikation (Nr.) |
 copernicus.org/npg-3-1-1996.pdf |
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| Zusammenfassung |
| We study a 2D quasi-static discrete
crack anti-plane
model of a tectonic plate with long range elastic
forces and
quenched disorder. The plate is driven at its border
and the
load is transferred to all elements through elastic
forces.
This model can be considered as belonging to the
class of
self-organized models which may exhibit
spontaneous
criticality, with four additional ingredients
compared to
sandpile models, namely quenched disorder, boundary
driving,
long range forces and fast time crack rules. In this
"crack"
model, as in the "dislocation" version previously
studied, we
find that the occurrence of repeated earthquakes
organizes the
activity on well-defined fault-like structures. In
contrast
with the "dislocation" model, after a transient,
the time
evolution becomes periodic with run-aways ending each
cycle.
This stems from the "crack" stress transfer rule
preventing
criticality to organize in favour of cyclic behaviour. For
sufficiently large disorder and weak stress drop, these
large
events are preceded by a complex spacetime
history of
foreshock activity, characterized by a
Gutenberg-Richter power
law distribution with universal exponent B =
1±0.05. This is
similar to a power law distribution of small
nucleating
droplets before the nucleation of the macroscopic
phase in a
first-order phase transition. For large disorder and
large
stress drop, and for certain specific initial
disorder
configurations, the stress field becomes frustrated
in fast
time: out-of-plane deformations (thrust and normal
faulting)
and/or a genuine dynamics must be introduced to
resolve this
frustration. |
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