Frequency-dependent tectonic tremor beneath southern Vancouver Island

摘要: Most analyses of tectonic tremor and associated low-frequency earthquakes (LFEs) are restricted to the~ 1-8 Hz frequency band, although the reason for the band-limited nature of LFEs is controversial. Some authors contend that both signals are stochastic in nature and continuous through lower frequencies (< 1 Hz) but drowned within increased microseismic noise levels, whereas others suggest that band limitation in LFEs manifests a characteristic asperity dimension, consistent with the spatial fixity of LFE locations across multiple ETS episodes. In this study, we investigate the frequency dependence of tectonic tremor in the Cascadia subduction zone using a small-aperture seismic array on southern Vancouver Island. The Pacific Geoscience Centre & Institute for Ocean Sciences Array (PISA) comprises 12 three-component stations over a 667 mx 664 m aperture, that recorded an extended ETS event between …