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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 |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 22, no. 3 ; Nr. 22, no. 3 (2015-06-30), S.349-359 |
| Datensatznummer |
250120985
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| Publikation (Nr.) |
 copernicus.org/npg-22-349-2015.pdf |
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| Zusammenfassung |
| A fault containing two asperities with different strengths is considered. The
fault is embedded in a 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 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 post-seismic 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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