Complexity and interactions within low-frequency earthquakes activity in western Shikoku
Abstract
Short-duration transient events known as low-frequency earthquakes (LFEs) are a component of slow earthquakes family observed in the transition zone, at the root of seismogenic regions of the subduction zones or active faults. LFEs are linked with the seismic energy radiation associated to tectonic tremor and are appearing as impulsive transients mixed within the complex tremor signal. Detailed analysis and characterization of LFE space-time activity in relation to other slow earthquake phenomena can provide important information about the state of the fault interface.
We derive a catalog of LFEs in western Shikoku (Japan) by applying a full waveform coherency-based detection and location method to the 4-year continuous data covering the period of 2013-2016 and recorded at Hi-net seismic stations of NIED. The advanced time-frequency statistical signal processing scheme, combined with the network-based coherency analysis implemented in the method, provides an efficient tool for extracting the LFEs from noisy tremor signals and estimating corresponding source location without a prior assumption about the event source (i.e., template event). The derived catalog of over 150,000 events allows to look into the details of LFE space-time activity during the tectonic tremor sequences and inter-sequence periods. Using the derived LFE catalog, we perform a systematical statistical examination of the event occurrence patterns by applying the correlation and clustering analysis for inferring the large-scale (long temporal durations of ~1-2 days) space-time characteristics and interaction patterns of activity and their potential relation to the structural complexity of the subducting plate. We also analyse the correlation between the migration of clustered LFE activity during the energetic tremor sequences and the short-term slow slip events occurring in the area during the analysed period.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S12B..07P
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGY;
- 7215 Earthquake source observations;
- SEISMOLOGY;
- 7230 Seismicity and tectonics;
- SEISMOLOGY;
- 8170 Subduction zone processes;
- TECTONOPHYSICS