Abstract
GEOPHYSICAL RESEARCH LETTERS,
VOL. 37,
L06303,
5 PP., 2010
doi:10.1029/2009GL041876
Identification of low-frequency earthquakes in non-volcanic tremor using the subspace detector method
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Department of Geophysics, Stanford University, Stanford, California, USA
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Shelly et al. identified 188 low frequency earthquakes (LFEs) in a one-hour episode of tremor recorded at Japanese Hi-Net borehole stations. Later they proposed that non-volcanic tremor may consist entirely of a sequence of LFEs. We search for additional LFEs using the subspace detector technique. This method uses a matrix of template waveforms and, via singular value decomposition, builds a set of basis vectors that, in some linear combination, can reproduce the templates or similar events that fall within the subspace. We explore the utility of the method to search for additional LFEs within the subspace spanned by our basis vectors. The results compare well with previous LFE detections. We also compare our results with an independent measure of signal polarization and find that the polarization takes on a distinct character during times of known LFEs. This suggests that signal polarization may also have potential for tremor detection, characterization, and monitoring.
Received 24 November 2009; accepted 19 February 2010; published 19 March 2010.
Citation: (2010), Identification of low-frequency earthquakes in non-volcanic tremor using the subspace detector method, Geophys. Res. Lett., 37, L06303, doi:10.1029/2009GL041876.
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