Approximation to cutoffs of higher modes of Rayleigh waves for a layered earth model
A cutoff defines the long-period termination of a Rayleigh-wave higher mode and, therefore is a key characteristic of higher mode energy relationship to several material properties of the subsurface. Cutoffs have been used to estimate the shear-wave velocity of an underlying half space of a layered earth model. In this study, we describe a method that replaces the multilayer earth model with a single surface layer overlying the half-space model, accomplished by harmonic averaging of velocities and arithmetic averaging of densities. Using numerical comparisons with theoretical models validates the single-layer approximation. Accuracy of this single-layer approximation is best defined by values of the calculated error in the frequency and phase velocity estimate at a cutoff. Our proposed method is intuitively explained using ray theory. Numerical results indicate that a cutoffs frequency is controlled by the averaged elastic properties within the passing depth of Rayleigh waves and the shear-wave velocity of the underlying half space. ?? Birkh??user Verlag, Basel 2009.
Citation Information
Publication Year | 2009 |
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Title | Approximation to cutoffs of higher modes of Rayleigh waves for a layered earth model |
DOI | 10.1007/s00024-008-0443-4 |
Authors | Y. Xu, J. Xia, R. D. Miller |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Pure and Applied Geophysics |
Index ID | 70036006 |
Record Source | USGS Publications Warehouse |