We have analyzed Long-Period (LP) seismic events of Volcan de Colima (Mexico) recorded by four three-component broad-band seismometers during January 2006. Frequency-domain analysis shows spectra mainly peaked in the range 0.3-2 Hz and characterized by a monotonic decreasing envelope, as those produced in a cylindrically-symmetric self-oscillating cavity interacting with a confined jet. Independent Component Analysis, a time-series decomposition method, extracts two or three nonlinear oscillation modes depending on the station, with the fundamental one peaked at 0.4-0.5 Hz. These decomposed waves have a well defined spectral content and are self-sustained oscillations with low dimensionality, as shown by dynamic system reconstruction methods. Moreover, they show radial polarization in near field and transverse polarization in far field in North-West South-East direction. Finally, we hypothesize a branched plumbing system with two principal conduits having alignments orthogonal to one another.
Self-sustained oscillations at Volcán de Colima (México) inferred by Independent Component Analysis
DE LAURO, ENZA;DE MARTINO, Salvatore;
2012-01-01
Abstract
We have analyzed Long-Period (LP) seismic events of Volcan de Colima (Mexico) recorded by four three-component broad-band seismometers during January 2006. Frequency-domain analysis shows spectra mainly peaked in the range 0.3-2 Hz and characterized by a monotonic decreasing envelope, as those produced in a cylindrically-symmetric self-oscillating cavity interacting with a confined jet. Independent Component Analysis, a time-series decomposition method, extracts two or three nonlinear oscillation modes depending on the station, with the fundamental one peaked at 0.4-0.5 Hz. These decomposed waves have a well defined spectral content and are self-sustained oscillations with low dimensionality, as shown by dynamic system reconstruction methods. Moreover, they show radial polarization in near field and transverse polarization in far field in North-West South-East direction. Finally, we hypothesize a branched plumbing system with two principal conduits having alignments orthogonal to one another.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
