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A review of time-frequency analysis techniques for estimation of group velocities

Argun H. Kocaoglu and Leland T. Long
A review of time-frequency analysis techniques for estimation of group velocities
Seismological Research Letters (June 1993) 64 (2): 157-167

Abstract

Time-frequency analysis techniques, including the classical use of zero crossings to measure period, have been widely used in seismology for the estimation of surface wave group velocities. Group velocity estimation by the short-time Fourier transform and the multiple filter techniques are equivalent. Although these techniques are used most often, their resolution is limited. The resolution is controlled by the window length in the short time Fourier transform and the filter band width in the multiple filter technique. The moving-window autoregressive spectral estimation provides the highest resolution with the shortest possible window length by predicting the properties of the signal outside the analysis window; however, high resolution is obtained at the expense of uncertainty in the amplitude. Recently, the Wigner distribution has been introduced as a tool for mapping dispersed surface waves into the time-frequency domain. Resolution of the Wigner distribution is comparable to that of the moving-window autoregressive spectral estimation. When the spectral density at a given time contains two or more dominant frequencies, their interference causes the Wigner distribution to introduce spurious spectral peaks complicating the interpretation. The Choi-Williams distribution, in which these interference effects are minimized, can be used for such dispersed signals. However, the implementation is computationally complex and the distribution offers only a medium resolution.


ISSN: 0895-0695
EISSN: 1938-2057
Serial Title: Seismological Research Letters
Serial Volume: 64
Serial Issue: 2
Title: A review of time-frequency analysis techniques for estimation of group velocities
Affiliation: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA, United States
Pages: 157-167
Published: 199306
Text Language: English
Publisher: Seismological Society of America, El Cerrito, CA, United States
References: 24
Accession Number: 2018-009077
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 2018
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