DOI QR코드

DOI QR Code

Rayleigh-wave Phase Velocities and Spectral Amplitudes Affected by Insertion of an Anomalous Velocity Layer in the Overburden

천부 속도이상층이 레일리파 위상속도 및 수직변위 스펙트럼 진폭에 미치는 영향

  • Kim, Ki Young (Department of Geophysics, Kangwon National University) ;
  • Jung, Jinhoon (Department of Geophysics, Kangwon National University)
  • 김기영 (강원대학교 지구물리학과) ;
  • 정진훈 (강원대학교 지구물리학과)
  • Received : 2012.10.08
  • Accepted : 2012.11.15
  • Published : 2012.11.30

Abstract

The Thomsen-Haskell method was used to determine sensitivities of the Rayleigh-wave phase velocities and spectral amplitude of vertical ground motion to insertion of a single velocity-anomaly layer into overburden underlain by a basement. The reference model comprised a 9-m thick overburden with shear-wave velocity (${\nu}_s$ of 300 m/s above a half-space with ${\nu}_s$ = 1000 m/s. The inserted layer, with a velocity of 150, 225, 375, or 450 m/s and a thickness of 1, 2, or 3 m, was placed at depths increasing from the surface in increments of 1 m. Phase velocities were computed for frequencies of 4 to 30 Hz. For inserted layer models, we placed an anomalous layer with thickness of 1 ~ 3 m, shear-wave velocity of 150 ~ 450 m/s, and at depths of 0 ~ 8 m in the overburden. The frequency range of 8 ~ 20 Hz were the most sensitive to the difference of $C_R$ between the inserted and reference models (${\Delta}C_R$) for h = 1 m and the frequency range got wide as h increased. For all of the models, the spectral amplitudes of the fundamental mode exceeded those of the $1^{st}$-higher mode except at frequencies just above the low-frequency cutoff of the $1^{st}$-higher mode.

Acknowledgement

Supported by : 기상청

References

  1. Addo, K. O. and Robertson, P. K., 1992, Shear-wave velocity measurement of soils using Rayleigh waves, Can. Geotech. J., 29, 558-568. https://doi.org/10.1139/t92-063
  2. Caldern-Macas, C. and Luke, B., 2007, Improved parameterization to invert Rayleigh-wave data for shallow profiles containing stiff inclusions, Geophysics, 72(1), U1-U10. https://doi.org/10.1190/1.2374854
  3. Gabriels, P., Sneider, R., and Nolet, G., 1987, In situ measurements of shear-wave velocity in sediments with higher-mode Rayleigh waves, Geophys. Prospect., 35, 187-196. https://doi.org/10.1111/j.1365-2478.1987.tb00812.x
  4. Gucunski, N. and Woods, R. D., 1992, Numerical simulation of the SASW test, Soil Dyn. Earthq. Engin., 11, 213-227. https://doi.org/10.1016/0267-7261(92)90036-D
  5. Haskell, N. A., 1953, The dispersion of surface waves in multilayered media, Bulletin of the Seismological Society of America, 43, 17-34.
  6. Kanli, A. I., Tildy, P., Prnay, Z., Pinar, A., and Hermann, L., 2006, $V_{s}^{30}$ mapping and soil classification for seismic site effect evaluation in Dinar region, SW Turkey, Geophys. J. Int., 165, 223-235. https://doi.org/10.1111/j.1365-246X.2006.02882.x
  7. Kitsunezaki. C., Goto, N., Kobayashi., Y., Ikawa, T., Horike, M., Saito, T., Kurota, T., Yamane, K., and Okuzumi, K., 1990, Estimation of P- and S- wave velocities in Deep Soil Deposits for Evaluating Ground Vibrations in Earthquake, SIZEN-SAIGAI-KAGAKU,9-3,1-17 (in Japanese).
  8. Liang, Q., Chen, C., Zeng, C., Luo, Y., and Xu, Y., 2008, Inversion stability analysis of multimode Rayleigh-wave dispersion curves using low-velocity-layer models, Near Surface Geophysics, 6(3), 157-165.
  9. Lu, L., Wang, C., and Zhang, B., 2007, Inversion of multimode Rayleigh waves in the presence of a low velocity layer: numerical and laboratory study, Geophys. J. Int., 168, 1235- 1246. https://doi.org/10.1111/j.1365-246X.2006.03258.x
  10. Ludwig, W. J., Nafe, J. E., and Drake, C. L., 1970, Seismic Refraction, in A.E. Maxwell edited The Sea, Wiley-Interscience, New York, New York, 53-84.
  11. Park, C. B., Miller, R. D., and Xia, J., 1999, Multi-channel analysis of surface waves, Geophysics, 64(3), 800-808. https://doi.org/10.1190/1.1444590
  12. Stoke, K. H., II and Nazarian, S., 1983, Effectiveness of ground improvement from spectral analysis of surface waves, Proc. 8th European Conf. Soil Mechan. Foundation Engin. Helsinki, Finland, 91-95.
  13. Thomson, W. T., 1950, Transmission of elastic waves through a stratified solid. Analytical results, Journal of Applied Physics, 21, 89-93. https://doi.org/10.1063/1.1699629
  14. Tokimatsu, K., Tamura, S., and Kojima, H., 1992, Effects of multimodes on Rayleigh wave dispersion characteristics, J. Geotech. Eng., 118, 1529-1543. https://doi.org/10.1061/(ASCE)0733-9410(1992)118:10(1529)
  15. Xia, J., Miller, R., Park, C. B., Hunter, J. A., Harris, J. B., and Ivanov, J., 2002, Comparison shear-wave velocity profiles from multichannel analysis of surface wave with borehole measurements, Soil Dyn. Earthq. Engin., 22(3), 181-190. https://doi.org/10.1016/S0267-7261(02)00008-8
  16. Xia, J., Miller, R., and Xu, Y., 2008, Data-resolution matrix and model-resolution matrix for Rayleigh-wave inversion using damped least-squares method, Pure and Applied Geophysics, 165, 1277-1248.
  17. Yuan, D. and Nazarian, S., 1993, Automated surface wave method: inversion technique, J. Geotech. Eng., 119, 1112- 1127. https://doi.org/10.1061/(ASCE)0733-9410(1993)119:7(1112)
  18. Zhang, S. X. and Chan, L. S., 2003, Possible effects of misidentified mode number on Rayleigh wave inversion, J. Appl. Geophys., 53, 17-29. https://doi.org/10.1016/S0926-9851(03)00014-4