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| Titel |
The activation of a single fault as a reduced self-affine image of the whole regional seismicity and a magnified self-affine image of the laboratory seismicity in terms of kHz electromagnetic precursors |
| VerfasserIn |
C. Papadimitriou, M. Kalimeri, J. Kopanas, G. Antonopoulos, A. Peratzakis, K. Eftaxias |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021018
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| Zusammenfassung |
| Huang and Turcotte [1] have pointed out that the statistics of regional seismicity could be
merely a macroscopic reflection of the physical processes in earthquake (EQ) source. Herein,
we check this hypothesis in terms of precursory kHz electromagnetic (EM) emissions
possibly associated with the fracture of high strength and large asperities that are distributed
along the activated single fault sustaining the system [2]. The study has been attempted by
means of:
(i) A regional fault dynamics in terms of the slipping of two rough and rigid Brownian
profiles one over the other [3];
(ii) Gutenberg-Richter law;
(iii) A comparison between “roughness” of topography of fracture surfaces on one hand
and “roughness” of pre-seismic kHz EM emissions on the other hand;
(iv) A model for EQ dynamics consisting of two rough profiles interacting via fragments
filling the gap has been recently introduced by Solotongo-Costa and Posadas [4]. The
irregularities of the fault planes can interact with the fragments between them to develop a
mechanism for triggering EQs. The fragments size distribution function comes from a
nonextensive Tsallis formulation, starting from first principles. An energy distribution
function, which gives a Gutenberg-Richter type law as a particular case, is analytically
deduced:
( ) [ ( ) ( )]
log(N (> m)) = logN + 2--q- × log 1- 1--q- 102m--
1- q 2- q α2∕3
(1)
where N is the total number of EQs, N(> m) the number of EQs with magnitude larger
than m, and m ≈ log(ɛ). α is the constant of proportionality between the EQ energy, ɛ, and
the size of fragment, r. The above mentioned equation provides an excellent fit to seismicities
generated in large geographic areas usually identified as “seismic regions”, each of them
covering many geological faults.
The main result of the present distribution is that the statistics of regional seismicity can
really be a macroscopic reflection of the physical processes in EQ source and a magnified
self-affine image of the laboratory seismicity.
[1] Huang, J., and Turcotte, D.: Fractal distributions of stress and strength and variations
of b-value, Earth Planet Sci. Lett., 91, 223-230, 1998.
[2] Contoyiannis, Y, Kapiris, P. and Eftaxias, K, A Monitoring of a Pre-Seismic Phase
from its Electromagnetic Precursors, Physical Review E, 71, 061123-1 – 061123-14,
2005.
[3] Hallgass, R., Loretto, V, Mazzela, O, Paladin, G, and Pietronero, L., Self-affine model
of earthquakes, Phys. Rev. Lett., 76, 2559-2562, 1977.
[4] Solotongo-Costa, O., and Posadas, A., Fragment-Asperity Model for Earthquakes,
Physical Review Letters 92, 048501-1 / 4, 2004. |
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