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Verification of correctness of using real part of complex root as Rayleigh-wave phase velocity with synthetic data

Pan, Y.; Xia, J.; Zeng, C.


High-frequency (≥ 2 Hz) Rayleigh-wave phase velocities have been utilized to determine shear-wave velocities in near-surface geophysics since the early 1980s. One of the key steps is to calculate theoretical dispersion curves of an earth model. When the earth model contains a low-velocity half-space, however, some roots of the dispersion equation turn out to be complex numbers, which makes phase velocities disappear at some frequencies. When encountering this situation, the common practice is to append an additional high velocity layer as the half-space to the model to make the roots real or use the real parts of complex roots as Rayleigh-wave phase velocities. The correctness of the first method has been verified. The correctness of the second method, however, remains to be unproved. We use synthetic data generated by numerical modeling of the wave equation to verify the correctness of the second method. In this paper, we firstly discuss the reasons that only complex numbers of the dispersion equation exist at some frequencies when an earth model contains a low velocity half-space. Then we discuss how the nearest offset affects a synthetic model and recommend an optimal nearest offset in generating synthetic data that are close to real-world situations. ... mehr

DOI: 10.1016/j.jappgeo.2012.09.012
Zitationen: 29
Web of Science
Zitationen: 26
Zitationen: 31
Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2013
Sprache Englisch
Identifikator ISSN: 0926-9851, 1879-1859
KITopen-ID: 1000059100
Erschienen in Journal of applied geophysics
Verlag Elsevier
Band 88
Seiten 94-100
Nachgewiesen in Scopus
Web of Science
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