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| Titel |
Tsallis and Levy statistics in the preparation of an earthquake |
| VerfasserIn |
Y. F. Contoyiannis, K. Eftaxias |
| 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 ; 15, no. 3 ; Nr. 15, no. 3 (2008-05-06), S.379-388 |
| Datensatznummer |
250012654
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| Publikation (Nr.) |
 copernicus.org/npg-15-379-2008.pdf |
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| Zusammenfassung |
| Precursory fracture induced electromagnetic (EM) emissions, rooted in opening cracks and ranging from MHz
to kHz, with the MHz appearing earlier, are produced and detected both at laboratory and geophysical scale.
Recently, we have proposed the following two epochs/stages model of EQ generation: (i) The final kHz part is
triggered by the fracture of high strength and large asperities that are distributed along the activated fault
and sustain the system. (ii) The initial MHz part is thought to be due to the fracture of highly heterogeneous
system that surrounds the family of asperities. Interestingly, the MHz EM time-series can be described in analogy
with a thermal second order phase transition. Herein we focus on the MHz pre-seismic activity, and especially on the
naturally arising question: what is the physical mechanism that organizes the heterogeneous system in its critical state?
Combining ideas of Levy and Tsallis statistics and criticality with features hidden in the precursory MHz time-series
we argue that a Levy walk type mechanism can organize the heterogeneous system to criticality. Based on a numerically
produced truncated Levy walk, we propose a way to estimate in the stage of critical fluctuations: (i) the associated
Levy index-a, which describes quantitatively the underlying Levy dynamics, and (ii) the range of values where the
nonextesitive Tsallis index q is restricted. We also show that the kHz EM activity could not be described by a
truncated Levy mechanism. This result further indicates an abrupt sweep of the population of asperities that sustain
the system. |
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