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| Titel |
Stress states and moment rates of a two-asperity fault in the presence of viscoelastic relaxation |
| VerfasserIn |
M. Dragoni, E. Lorenzano |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2198-5634
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics Discussions ; 2, no. 1 ; Nr. 2, no. 1 (2015-02-18), S.297-327 |
| Datensatznummer |
250115149
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| Publikation (Nr.) |
 copernicus.org/npgd-2-297-2015.pdf |
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| Zusammenfassung |
| A fault containing two asperities with different strengths is
considered. The fault is embedded in a viscoelastic shear zone,
subject to a constant strain rate by the motions of adjacent
tectonic plates. The fault is modelled as a discrete dynamical
system where the average values of stress, friction and slip on each
asperity are considered. The state of the fault is described by
three variables: the slip deficits of the asperities and the
viscoelastic deformation. The system has four dynamic modes, for
which the analytical solutions are calculated. The relationship
between the state of the fault before a seismic event and the
sequence of slipping modes in the event is enlightened. Since the
moment rate depends on the number and sequence of slipping modes,
the knowledge of the source function of an earthquake constrains the
orbit of the system in the phase space. If the source functions of
a larger number of consecutive earthquakes were known, the orbit
could be constrained more and more and its evolution could be
predicted with a smaller uncertainty. The model is applied to the
1964 Alaska earthquake, which was the effect of the failure of two
asperities and for which a remarkable postseismic relaxation has
been observed in the subsequent decades. The evolution of the system
after the 1964 event depends on the state from which the event was
originated, that is constrained by the observed moment rate. The
possible durations of the interseismic interval and the possible
moment rates of the next earthquake are calculated as functions of
the initial state. |
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