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Small-aperture seismic array data processing using a representation of seismograms at zero-crossing points
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SYSNO ASEP 0496419 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Small-aperture seismic array data processing using a representation of seismograms at zero-crossing points Author(s) Brokešová, J. (CZ)
Málek, Jiří (USMH-B) RID, ORCID, SAISource Title Physics of the Earth and Planetary Interiors. - : Elsevier - ISSN 0031-9201
Roč. 280, JUL (2018), s. 53-68Number of pages 16 s. Publication form Print - P Language eng - English Country NL - Netherlands Keywords Array data analysis ; True backazimuth ; Apparent seismic phase velocity ; Surface wave dispersion ; Seismic phase gradiometry ; Seismic rotations Subject RIV DC - Siesmology, Volcanology, Earth Structure OECD category Geology R&D Projects GA15-02363S GA ČR - Czech Science Foundation (CSF) Institutional support USMH-B - RVO:67985891 UT WOS 000435054100005 EID SCOPUS 85046778671 DOI 10.1016/j.pepi.2018.04.010 Annotation A new method for representing seismograms by using zero-crossing points is described. This method is based on decomposing a seismogram into a set of quasi-harmonic components and, subsequently, on determining the precise zero-crossing times of these components. An analogous approach can be applied to determine extreme points that represent the zero-crossings of the first time derivative of the quasi-harmonics. Such zero-crossing and/or extreme point seismogram representation can be used successfully to reconstruct single-station seismograms, but the main application is to small-aperture array data analysis to which standard methods cannot be applied. The precise times of the zero-crossing and/or extreme points make it possible to determine precise time differences across the array used to retrieve the parameters of a plane wave propagating across the array, namely, its backazimuth and apparent phase velocity along the Earth's surface. The applicability of this method is demonstrated using two synthetic examples. In the real-data example from the Pribram-Haje array in central Bohemia (Czech Republic) for the Mw 6.4 Crete earthquake of October 12, 2013, this method is used to determine the phase velocity dispersion of both Rayleigh and Love waves. The resulting phase velocities are compared with those obtained by employing the seismic plane-wave rotation-to-translation relations. In this approach, the phase velocity is calculated by obtaining the amplitude ratios between the rotation and translation components. Seismic rotations are derived from the array data, for which the small aperture is not only an advantage but also an applicability condition. Workplace Institute of Rock Structure and Mechanics Contact Iva Švihálková, svihalkova@irsm.cas.cz, Tel.: 266 009 216 Year of Publishing 2019
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