Approximation to cutoffs of higher modes of Rayleigh waves for a layered earth model

Pure and Applied Geophysics
By: , and 

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Abstract

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.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Approximation to cutoffs of higher modes of Rayleigh waves for a layered earth model
Series title Pure and Applied Geophysics
DOI 10.1007/s00024-008-0443-4
Volume 166
Issue 3
Year Published 2009
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Pure and Applied Geophysics
First page 339
Last page 351