Approximation to Cutoffs of Higher Modes of Rayleigh Waves for a Layered Earth Model Export

@article{citeulike:4097818, abstract = {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.}, author = {Xu, Yixian and Xia, Jianghai and Miller, Richard}, citeulike-article-id = {4097818}, citeulike-linkout-0 = {http://dx.doi.org/10.1007/s00024-008-0443-4}, citeulike-linkout-1 = {http://www.springerlink.com/content/2484x0t72418342k}, doi = {10.1007/s00024-008-0443-4}, journal = {Pure and Applied Geophysics}, posted-at = {2009-02-25 12:01:53}, title = {Approximation to Cutoffs of Higher Modes of Rayleigh Waves for a Layered Earth Model}, url = {http://dx.doi.org/10.1007/s00024-008-0443-4} }

TY - JOUR ID - citeulike:4097818 L3 - citeulike-article-id:4097818 N2 - 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. JF - Pure and Applied Geophysics TI - Approximation to Cutoffs of Higher Modes of Rayleigh Waves for a Layered Earth Model AU - Xu, Yixian AU - Xia, Jianghai AU - Miller, Richard UR - http://dx.doi.org/10.1007/s00024-008-0443-4 ER -