Natural-time analysis of critical phenomena: The case of seismicity
Varotsos, P. A.; Sarlis, N. V.; Skordas, E. S.; Uyeda, S.; Kamogawa, M.; Varotsos, P. A.; Solid State Section and Solid Earth Physics Institute, Physics Department, University of Athens Panepistimiopolis, Zografos 157 84, Athens, Greece, EU; Sarlis, N. V.; Solid State Section and Solid Earth Physics Institute, Physics Department, University of Athens Panepistimiopolis, Zografos 157 84, Athens, Greece, EU; Skordas, E. S.; Solid State Section and Solid Earth Physics Institute, Physics Department, University of Athens Panepistimiopolis, Zografos 157 84, Athens, Greece, EU; Uyeda, S.; Japan Academy - Ueno Koen, Taitou-ku, Tokyo, 110-0007, Japan; Kamogawa, M.; Department of Physics, Tokyo Gakugei University - Koganei-shi, 184-8501, Japan
Журнал:
EPL (Europhysics Letters)
Дата:
2010-10-01
Аннотация:
We first investigate in natural time the numerical simulations of a simple deterministic self-organized critical system introduced to describe avalanches in stick-slip phenomena. It is one-dimensional and belongs to the same universality class as the train model for earthquakes introduced by Burridge and Knopoff. We show that the variance κ<sub>1</sub>=⟨χ<sup>2</sup>⟩−⟨χ⟩<sup>2</sup> of natural time χ, becomes approximately equal to 0.070 when the system approaches the critical state. Next, we analyze in natural time the small earthquakes subsequent to the low-frequency magnetic-field precursor observed near the epicenter of the Ms7.1 Loma Prieta earthquake in 1989. We find that almost five days before the mainshock, the condition κ<sub>1</sub>≈0.070 was reached.
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