Effective dispersion curve and pseudo multimode dispersion curves for Rayleigh wave

Abstract

The hi-energy bands in the dispersion image are usually interpreted as the true dispersion phase velocities. However, the multiple dispersion modes of Rayleigh wave in layered media stack in space, producing the effective dispersion curve and the pseudo multimode dispersion curves in dispersion image. The effective dispersion curve has the maximum energy with lower phase velocities than pseudo dispersion phase velocities, and thus is often misunderstood as the fundamental mode. Within the tolerable misfit, the effective dispersion curve can approach the true fundamental mode. Different from the true multimode dispersion curves, the pseudo multimode dispersion curves are related to the effective dispersion curve. A numerical model is adapted to simulate the true dispersion curves, effective dispersion curve, and pseudo multimode dispersion curves. Their differences and mutual relations are demonstrated.

Keywords

Rayleigh wave / pseudo multimode dispersion curves / effective dispersion curve / numerical simulation / layered media

References

[1] Aki K., Richards P. G.. Quantitative Seismology, 2002 2nd ed. Sausalito, California: University Science Books

[2] Bodet L., Abraham O., Clorennec D.. Near-Offset Effects on Rayleigh-Wave Dispersion Measurements: Physical Modeling. J. Appl. Geophys., 2009, 68(1): 95-103.

[3] Park, C. B., Miller, R. D., Xia, J., 2001. Offset and Resolution of Dispersion Curve in Multichannel Analysis of Surface Waves (MSW). Proceedings of the SAGEEP 2001, Denver, Colorado. SSM-4

[4] Rix G. J., Leipski E. A.. Accuracy and Resolution of Surface Wave Inversion. Geotechnical Special Publication, 1991, 29: 17-32.

[5] Ryden N., Park C. B., Ulriksen P., . Multimodal Approach to Seismic Pavement Testing. Journal of Geotechnical and Geoenvironmental Engineering, 2004, 130(6): 636-645.

[6] Song X., Gu H., Liu J., . Estimation of Shallow Subsurface Shear-Wave Velocity by Inverting Fundamental and Higher-Mode Rayleigh Waves. Soil Dynamics and Earthquake Engineering, 2007, 27(7): 599-607.

[7] Stokoe K. H. II, Wright G. W., Bay J. A., . Woods R. D., . Characterization of Geotechnical Sites by SASW Method. Geophysical Characterization of Sites. ISSMFE Technical Committee #10, 1994, New Delhi: Oxford Publishers

[8] Tokimatsu K., Tamura S., Kojima H.. Effects of Multiple Modes on Rayleigh Wave Dispersion Characteristics. J. Geotech. Eng., 1992, 118(10): 1529-1543.

[9] Xia J. H., Miller R. D., Park C. B.. Estimation of Near-Surface Shear-Wave Velocity by Inversion of Rayleigh Wave. Geophysics, 1999, 64(3): 691-700.

[10] Xia J. H., Miller R. D., Park C. B., . Comparing Shear-Wave Velocity Profiles from MASW with Borehole Measurements in Unconsolidated Sediments, Fraser River Delta, B.C., Canada. Journal of Environmental & Engineering Geophysics, 2000, 5(3): 1-13.

[11] Xia J. H., Miller R. D., Park C. B., . Inversion of High Frequency Surface Waves with Fundamental and Higher Modes. J. Appl. Geophys., 2003, 52(1): 45-57.

[12] Zhang S. X., Chan L. S.. Possible Effects of Misidentified Mode Number on Rayleigh Wave Inversion. J. Appl. Geophys., 2003, 53(1): 17-29.

[13] Zhang S. X., Chan L. S., Chen C. Y., . Apparent Phase Velocities and Fundamental Mode Phase Velocities of Rayleigh Waves. Soil Dynamics and Earthquake Engineering, 2003, 23(7): 563-569.

[14] Zhang S. X., Chan L. S., Xia J. H.. The Selection of Field Acquisition Parameters for Dispersion Images from Multichannel Surface Wave Data. Pure and Applied Geophysics, 2004, 161(1): 1-17.

[15] Zywicki, D. J., Rix, G. J., 1999. Frequency-Wavenumber Analysis of Passive Surface Waves. Proceedings of the Symposium on the Application of Geophysics to Environmental and Engineering Problems (SAGEEP). 75–84