Skip to main content

Lateral variations of shallow shear-velocity structure in southwestern Taiwan inferred from short-period Rayleigh waves

Abstract

Short-period fundamental-mode Rayleigh waves with periods of 1.15.5 sec were used to investigate the lateral variations of shallow-depth shear-wave velocity structure up to a depth of 8 km under southwestern Taiwan. Through a priori regionalization, the region was divided into three subregions from the west to the east, and then the regionalized group velocity for each subregion was determined by a standard least-squares technique. By the structure inversion, the study region had obviously lateral velocity variations, which systemically increased from the west region to the east one. On the whole, the shear-wave velocity in the Western Foothills was higher than that in the Western Coastal Plain. Additionally, the three subregions all had a shear-wave velocity of less than 3 km/sec with the lowest one in the Western Coastal Plain near the coast, related to the thick sediments. These results were rather consistent with the geological features. For depths larger than 4 km, the velocity-gradient varying with depth in the Western Foothills was lower than that in the Western Coastal Plain. This is likely to interpret the reason that the seismic waves cannot be easily trapped within the Western Foothills; thus the short-period surface waves are poorly developed in that region.

References

  • Chen, Y.-L., Three dimensional velocity structure and kinematic analysis in Taiwan area, 172 pp., M.S. Thesis, National Central University, Chung-Li, Taiwan, 1995.

    Google Scholar 

  • Chung, J.-K. and Y.-T. Yeh, Shallow crustal structure from short-period Rayleigh-Wave dispersion data in southwestern Taiwan, Bull. Seism. Soc. Am., 87, 370–382, 1997.

    Google Scholar 

  • Constable, S. C., R. L. Parker, and C. G. Constable, Occam’s inversion: A practical algorithm for generating smooth models from electromagnetic sounding data, Geophysics, 52, 289–300, 1987.

    Article  Google Scholar 

  • Dziewonski, A., S. Bloch, and M. Landisman, A technique for the analysis of transient seismic signals, Bull. Seism. Soc. Am., 59, 427–444, 1969.

    Google Scholar 

  • Herrin, E. and T. Goforth, Phase matched filters: Application to the study of Rayleigh waves, Bull. Seism. Soc. Am., 67, 1250–1275, 1977.

    Google Scholar 

  • Herrmann, R. B., Some aspects of band-pass filtering of surface waves, Bull. Seism. Soc. Am., 63, 703–711, 1973.

    Google Scholar 

  • Herrmann, R. B., Computer Programs in Seismology, Vol. IV: Surface Wave Inversion, Department of Earth and Atmospheric Sciences, Saint Louis University, USA, 1991.

    Google Scholar 

  • Ho, C.-S., An introduction to the geology of Taiwan: Explanatory text for the geologic map of Taiwan, 164 pp., Minist. Econ. Aff., Taipei, ROC, 2nd ed., 1988.

    Google Scholar 

  • Huang, B. S., K. C. Chen, and Y. T. Yeh, Source parameters of the December 15, 1993 Tapu earthquake from first P-motions and waveforms, J. Geol. Soc. China, 39, 235–250, 1996.

    Google Scholar 

  • Hwang, R.-D., G.-K. Yu, and W.-Y. Chang, 3-D shallow shear-velocity structure around the source area of the 1999 Chi-Chi (Taiwan) earthquake by tomographic inversion of short-period Rayleigh waves, J. Geophys. Res., 2003 (submitted).

  • Knopoff, L., Phase and group slownesses in inhomogeneous media, J. Geophys. Res., 74, 1701, 1969.

    Article  Google Scholar 

  • Liu, K.-S., T.-C. Shin, and Y.-B. Tsai, A free-field strong motion network in Taiwan: TSMIP, TAO, 10, 373–396, 1999.

    Google Scholar 

  • Menke, W., Geophysical Data Analysis: Discrete inversion theory, 260 pp., Academic Press, San Diego, 1984.

    Google Scholar 

  • Suppe, J., Imbricated structure of western foothills belt, south-central Taiwan, Petro. Geol. Taiwan, 17, 1–16, 1980.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Ruey-Der Hwang.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Hwang, RD., Yu, GK., Chang, WY. et al. Lateral variations of shallow shear-velocity structure in southwestern Taiwan inferred from short-period Rayleigh waves. Earth Planet Sp 55, 349–354 (2003). https://doi.org/10.1186/BF03351768

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1186/BF03351768

Key words