Uniformly asymptotic eigensolutions of the Earth's toroidal modes
- 16 August 2021
- journal article
- research article
- Published by Oxford University Press (OUP) in Geophysical Journal International
- Vol. 228 (1), 250-258
- https://doi.org/10.1093/gji/ggab329
Abstract
A novel approach to computing the Earth's normal modes is presented. With the Langer approximation incorporated into the framework of the theory of the generalized reflection/transmission coefficients, our method, when applied to calculate the toroidal modes, produces results that agree extremely well with the exact results from Mineos and successfully overcomes the limitations of the WKBJ analysis. Given any 1-D earth model, regardless of the number of discontinuities, our method can perform the calculations reliably with satisfactory accuracy at high frequencies. The success achieved with the toroidal modes encourages us to tackle in a future study the asymptotic computation of the spheroidal modes, especially those high-frequency trapped modes for which the accuracy of Mineos is demonstrably inadequate.Funding Information
- National Natural Science Foundation of China (41704041, 41790465)
- Leading Talents Program of Guangdong Province (2016LJ06N652)
This publication has 21 references indexed in Scilit:
- Regional Variation of Inner Core Anisotropy from Seismic Normal Mode ObservationsScience, 2010
- Improvements on Computation of Phase Velocities of Rayleigh Waves Based on the Generalized R/T Coefficient MethodBulletin of the Seismological Society of America, 2008
- Normal Modes Computation by Generalized Reflection-Transmission Coefficients Method in Planar Layered Half SpaceChinese Journal of Geophysics, 2006
- Earth's Free Oscillations Excited by the 26 December 2004 Sumatra-Andaman EarthquakeScience, 2005
- Speed and size of the Sumatra earthquakeNature, 2005
- Modal solutions in stratified multi-layered fluid-solid half-spaceScience in China Series D Earth Sciences, 2002
- On high-frequency spheroidal modes and the structure of the upper mantleGeophysical Journal International, 1978
- Asymptotic results for elastodynamic propagator matrices in plane-stratified and spherically-stratified earth modelsGeophysical Journal International, 1978
- PROPAGATOR MATRICES IN ELASTIC WAVE AND VIBRATION PROBLEMSGeophysics, 1966
- On the Connection Formulas and the Solutions of the Wave EquationPhysical Review B, 1937