1887
Volume 36, Issue 1
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

Inversion of multi-mode surface-wave phase velocity for shallow engineering site investigation has received much attention in recent years. A sensitivity analysis and inversion of both synthetic and field data demonstrates the greater effectiveness of this method over employing the fundamental mode alone. Perturbation of thickness and shear-wave velocity parameters in multi-modal Rayleigh wave phase velocities revealed that the sensitivities of higher modes: (a) concentrate in different frequency bands, and (b) are greater than the fundamental mode for deeper parameters. These observations suggest that multi-mode phase velocity inversion can provide better parameter discrimination and imaging of deep structure, especially with a velocity reversal, than can inversion of fundamental mode data alone.

An inversion of the theoretical phase velocities in a model with a low velocity layer at 20 m depth can only image the soft layer when the first higher mode is incorporated. This is especially important when the lowest measurable frequency is only 6 Hz.

Field tests were conducted at sites surveyed by borehole and PS logging. At the first site, an array microtremor survey, often used for deep geological surveying in Japan, was used to survey the soil down to 35 m depth. At the second site, linear multichannel spreads with a sledgehammer source were recorded, for an investigation down to 12 m depth. The power spectrum method was applied for dispersion analysis, and velocities up to the second higher mode were observed in each test. The multi-mode inversion results agree well with PS logs, but models estimated from the fundamental mode alone show a large underestimation of the depth to shallow soft layers below artificial fill.

© 2005 ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG05026
2005-03-01
2026-01-20

  • From This Site

    /content/journals/10.1071/EG05026
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Beaty, K.S., Schmitt, D.R., and Sacchi, M., 2002, Simulated annealing inversion of multimode Rayleigh wave dispersion curves for geological structure: Geophysical Journal International, 151, 622–631.
  2. Capon, J., 1969, High-resolution frequency-wavenumber spectrum analysis: Proceedings of the IEEE, 57, 1408–1418.
  3. Feng, S., Sugiyama, T., and Yamanaka, H., 2001, Application of sensitivity analysis to array design for microtremor array survey: Proceedings of the 104th SEGJ Conference, 35–39.
  4. Feng, S., Sugiyama, T., and Yamanaka, H., 2003, Multi-station Inversion in array microtremor survey: Butsuri Tansa, 56, 1–11.
  5. Haskell, N.A., 1953, The dispersion of surface waves on multilayered media: Bulletin of the Seismological Society of America, 43, 17–24.
  6. Horike, M., 1985, Inversion of phase velocity of long-period microtremors to the Swave-velocity structure down to the basement in urbanized areas: Journal of the Physics of the Earth, 33, 59–96.
  7. O’Neill, A., Dentith, M., and List, R., 2003, Full-waveform P-SV reflectivity inversion of surface waves for shallow engineering applications: Exploration Geophysics, 34, 158–173.
  8. Okada, H., Matsushima, T., Moriya, T., and Sasatani, T., 1990, An exploration technique using long-period microtremors for determination of deep geological structures under urbanized areas: Butsuri Tansa, 43, 402–417.
  9. Park, C.B., Ivanov, J., Miller, R.D., Xia, J., and Ryden, N., 2001, Multichannel analysis of surface wave (MASW) for pavement: Feasibility test: Proceedings of the 5th SEGJ International Symposium, 25–30.
  10. Park, C.B., Miller, R.D., and Xia, J., 1999, Multichannel analysis of surface wave: Geophysics, 64, 800–808.
  11. Xia, J., Miller, R.D., and Park, C.B., 1999, Estimation of near-surface shear-wave velocity by inversion of Rayleigh wave: Geophysics, 64, 691–700.
  12. Xia, J., Miller, R.D., Park, C.B., and Tian, G., 2003, Inversion of high frequency surface waves with fundamental and higher modes: Journal of Applied Geophysics, 52, 45–57.
  13. Yamanaka, H., and Ishida, H. 1996, Application of genetic algorithm to an inversion of surface-wave dispersion data: Bulletin of the Seismological Society of America, 86, 436–444.
  14. Yamanaka, H., Saito, H., Kurita, K., and Seo, K., 1999, Array measurements of longperiod microtremors in southwestern Kanto Plain, Japan – Estimation of S-wave profiles in Kawasaki and Yokohama cities: Journal of the Seismological Society of Japan, 51, 355–365.
/content/journals/10.1071/EG05026
Loading
  • Article Type: Research Article
Keyword(s): higher mode; multi-mode; phase velocity inversion; sensitivity; surface wave; Vs structure

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error