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| Titel |
Wavefield decomposition and phase space dynamics of the seismic noise at Volcàn de Colima, Mexico: evidence of a two-state source process |
| VerfasserIn |
M. Palo, P. Cusano |
| 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 ; 20, no. 1 ; Nr. 20, no. 1 (2013-01-18), S.71-84 |
| Datensatznummer |
250017730
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| Publikation (Nr.) |
 copernicus.org/npg-20-71-2013.pdf |
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| Zusammenfassung |
| We analyse the seismic noise recorded at the Colima Volcano (Mexico) in the
period December 2005–May 2006 by four broadband three-component seismic
stations. Specifically, we characterize the spectral content of the signal
and follow its time evolution along all the data set. Moreover, we infer the
properties of the attractor in the phase space by false nearest neighbours
analysis and Grassberger–Procaccia algorithm, and adopt a time-domain
decomposition method (independent component analysis) to find the basic
constituents (independent components) of the system. Constraints on the
seismic wavefield are inferred by the polarization analysis. We find two
states of the background seismicity visible in different time-intervals
that are Phase A and Phase B. Phase A has a spectrum with two peaks at
0.15 Hz and 0.3 Hz, with the latter dominating, an attractor of correlation
dimension close to 3, three quasi-monochromatic independent components, and a
relevant fraction of crater-pointing polarization solutions in the
near-field. In Phase B, the spectrum is preserved but with the highest
peak at 0.15 Hz, the attractor has a correlation dimension close to 2, two
independent components are extracted, and the polarization solutions are
dominated by Rayleigh waves incoming from the southwest direction. We
depict two sources acting on the background seismicity that are the
microseismic noise loading on the Pacific coastline and a low-energy
volcanic tremor. A change in the amplitude of the microseismic noise can
induce the switching from a state of the system to the other. |
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