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Calculation of Rayleigh-wave phase velocities due to models with a high-velocity surface layer

Pan, Yudi; Xia, Jiangha; Gao, Lingli; Shen, Chao; Zeng, Chong

Abstract:
Rayleigh-wave phase velocities have been utilized to determine shear (S)-wave velocities in near-surface geophysics since early 1980s. One of the key steps is to calculate theoretical dispersion curves of an earth model. When the S-wave velocity of the surface layer is higher than some of the layers below, however, the Rayleigh-wave phase velocity in a high-frequency range calculated by existing algorithms approaches the lowest S-wave velocity among the layers above the half-space, rather than a value related to the S-wave velocity of the surface layer. According to our numerical modeling results based on wave equation, trends of the Rayleigh-wave dispersive energy approach about a 91% of the S-wave velocity of the surface layer at a high-frequency range when its wavelength is much shorter than the thickness of the surface layer, which cannot be fitted by a dispersion curve calculated by existing algorithms. We propose a method to calculate Rayleigh-wave phase velocities of models with a high-velocity surface layer by considering its penetration depth. We build a substituted model that only contains the layer with the lowest S-wave ... mehr


Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
Publikationstyp Zeitschriftenaufsatz
Jahr 2013
Sprache Englisch
Identifikator ISSN: 0926-9851, 1879-1859
KITopen ID: 1000059099
Erschienen in Journal of applied geophysics
Band 96
Seiten 1-6
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