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Fluctuation of group velocity of Love waves across a dent in the continental crust
Earth, Planets and Space volume 52, pages393–402(2000)
The dispersion characteristics of group velocity of Love waves are measured across a dent in the continental crust that has a maximum thickness of about 50 km; the numerical modeling analyses are performed using the finite difference method. Measurement of the group velocity over the entire width of the mountain root displays several distinct dispersions. The group velocities for the crustal dent structure are lower than those for the stratified medium with a maximum crustal thickness of the dent at short periods of 20–30 s. The period range becomes longer as the sloping angle of the dent increases or as the crustal thickness of the dent increases. The period indicating a group velocity minimum for the crustal dent structure is shorter than that for the stratified medium with a maximum crustal thickness of the dent. An example of the interpretation of observational data is shown. In the example, the group velocities for the propagation path over the Tibetan Plateau have properties concordant with the above dispersion characteristics.
Aki, K. and P. G. Richards, Quantitative Seismlogy: Theory and Methods, pp. 728–730, W. H. Freeman and Co., San Francisco, 1980.
Allegre, C. J., V. Courtillot, P. Tapponnier, A. Hirn, M. Mattauer, C. Loulon, J. J. Jaeger, J. Achache, U. Scharer, J. Marcoux, J. P. Bourg, J. Girardeau, R. Armijo, C. Gariepy, C. Gopel, L. Jindong, X. Xuchang, C. Chenfa, L. Guangquin, L. Baoyu, T. Jiwen, W. Naiwen, C. Guoming, H. Tonglin, W. Xibin, D. Wanming, S. Huaibin, C. Yougong, Z. Ji, Q. Hongrong, B. Peisheng, W. Bixiang, Z. Yaoxiu, and R. Xu, Structure and evolution of the Himalaya-Tibet orogenic belt, Nature, 307, 17–22, 1984.
Boore, D. M., Love waves in nonuniform wave guides: Finite difference calculations, J. Geophys. Res., 75, 1512–1527, 1970.
Boore, D. M., Finite difference methods for seismic propagation in heterogeneous materials, in Methods in Computational Physics, Volume 11, edited by B. A. Bolt, pp. 1–37, Academic Press, 1972.
Bostock, M. G., Surface wave scattering from 3-D obstacles, Geophys. J. Int., 104, 351–370, 1991.
Bourjot, L. and B. Romanowicz, Crust and upper mantle tomography in Tibet using surface waves, Geophys. Res. Lett., 19, 881–884, 1992.
Brandon, C. and B. Romanowicz, A “non-lid” zone in the central Chan-thang platform of Tibet: Evidence from pure path phase velocity measurements of long period Rayleigh waves, J. Geophys. Res., 91, 6547–6564, 1986.
Brown, L. D., W. Zhao, K. D. Nelson, M. Hank, D. Alsdorf, A. Ross, M. Clark, X. Liu, and J. Che, Bright spots, structure, magmatism in southern Tibet from INDEPTH seismic reflection profiling, Science, 274, 1688–1690, 1996.
Chen, W. P. and P. Molnar, Constraints on the seismic wave velocity structure beneath the Tibetan Plateau and their tectonic implications, J. Geophys. Res., 86, 5937–5962, 1981.
Chun, K. Y. and T. Yoshii, Crustal structure of the Tibetan Plateau: A surface wave study by a moving window analysis, Bull. Seis. Soc. Am., 67, 1529–1540, 1977.
Clayton, R. and B. Engquist, Absorbing boundary conditions for acoustic and elastic wave propagations, Bull. Seis. Soc. Am., 67, 1529–1540, 1977.
Curtis, A. and J. H. Woodhouse, Crust and upper mantle shear velocity structure beneath the Tibetan plateau and surrounding regions from interevent surface phase velocity inversion, J. Geophys. Res., 102, 11,789–11,813, 1997.
Dahlen, F. A. and J. Tromp, Theoretical Global Seismology, pp. 449, Princeton Univ. Press, 1998.
Dziewonski, A. M. and A. L. Hales, Numerical analysis of dispersed seismic waves, in Method in Computational Physics, Volume 11, edited by B. A. Bolt, pp. 39–85, Academic Press, 1972.
Hirn, A., J. C. Lepine, G. Jobert, M. Sapin, G. Wittlinger, X. Z. Xin, G. E. Yuan, W. X. Jing, T. J. Wen, X. S. Bai, M. R. Pandefy, and J. J. Tater, Crustal structure and variabilityof the Himalayan border of Tibet, Nature, 307, 23–25, 1984.
Honda, S. and H. Sakai, Himalaya sanmyaku no keisei II, Kagaku, 58, 570–579, 1988 (in Japanese).
Its, E. N., Calculation of reflection and transmission coefficients, in Seismic Surface Waves in a Laterally Heterogeneous Earth, edited by V. I. Keilisborok, pp. 112–127, Kluwer Academic Publishers, The Netherlands, 1989.
Kennett, B. L. N., Guided wave propagation in laterally varying media—I. Theoretical development, Geophys. J. R. Astr. Soc., 79, 235–255, 1984.
Kind, R., J. Ni, W. Zhao, J. Wu, X. Yuan, L. Zhao, E. Sandivol, C. Reese, J. Nabelek, and T. Hearn, Evidence from earthquake data for a partially molten crustal layer in southern Tibet, Science, 274, 1692–1694, 1996.
Landisman, M., A. Dziewonski, and Y. Sato, Recent improvement in the analysis of surface wave observations, Geophys. J. R. Astr. Soc., 17, 369–403, 1969.
Levander, A. L., Finite difference calcualtions of dispersive Rayleigh wave propagation, Tectonophys., 113, 1–30, 1985.
Levshin, A. L. and M. N. Ritzwoller, Characteritics of surface waves generated by events on and near the Chinese nuclear test site, Geophys. J. Int., 123, 131–148, 1995.
Levshin, A. L., L. Ratnikova, and J. Berger, Peculiarities of Surface-wave Propagation across continental Eurasia, Bull. Seis. Soc. Am., 82, 2464–2493, 1992.
Makovsky, Y., S. L. Klempere, L. Ratschbacher, L. D. Brown, M. Li, W. Zhao, and F. Meng, INDEPTH wide-angle reflection observation of P-wave-to-S-wave conversion from crustal bright spots in Tibet, Science, 274, 1690–1691, 1996.
Malishewsky, P., Surface Waves and Discontinuities, pp. 170–174, Elsevier, Amsterdam, 1987.
Meissner, R., The Continental Crust, A Geophysical Approach, International Geophysics Series, vol. 34, pp. 265, Academic Press, 1986.
Molnar, P., A review of geophysical constraints on the deep structure of the Tibetan Plateau, the Himalaya and the Karakoram, and their tectonic implications, Phyil. Trans. R. Soc. Lond., A, 326, 33–88, 1988.
Momoi, T, Scattering of Rayleigh waves by a semi-circular rough surface on layered media, Bull. Earthq. Res. Inst., Univ. Tokyo, 62, 163–200, 1987.
Nelson, K. D., W. Zhao, L. D. Brown, J. Kuo, J. Che, X. Liu, S. L. Klempere, Y. Makovsky, R. Meissner, J. Mechie, R. Kind, F. Wenzel, J. Ni, J. Nabelek, C. Leshou, H. Tan, W. Wei, A. G. Jones, J. Booker, M. Unsworth, W. S. Kidd, M. Hauck, D. Alsdorf, A. Ross, M. Cogan, C. Wu, E. Sandvol, and M. Edwards, Partially molten middle crust beneath southern Tibet: Synthesis of project INDEPTH results, Science, 274, 1684–1688, 1996.
Nolet, G., The upper mantle under Western Europe inferred from the dispersion of Rayleigh waves, J. Geophys., 43, 265–285, 1977.
Pedersen, H. A., V. Maupin, and M. Campillo, Wave diffraction in multilayered media with the indirect boundary element method: application to 3-D diffraction of long-period surface waves by 2-D lithospheric structures, Geophys. J. Int., 125, 545–558, 1996.
Pedersen, H. A., J. P. Avouac, and M. Campillo, Anomalous surface waves from Lop Nor nuclear explosions: Observations and numerical modelling, J. Geophys. Res., 103, 15,051–15,068, 1998.
Pollitz, F. F., Surface wave scattering from sharp lateral discontinuities, J. Geophys. Res., 99, 21,891–21,909, 1994.
Romanowicz, B. A., Constraints on the structure of the Tibet Plateau from pure path phase velocities of Love and Rayleigh waves, J. Geophys. Res., 87, 6865–6883, 1982.
Saito, M., DISPER80: A subroutine package for the calculation of seismic normal mode solutions, in Seismic Algorithms, pp. 293–319, Academic Press, 1988.
Sato, Y., Dansei Hadouron (Theory of Elastic Wave Motions), pp. 252–253, Iwanami Shoten, 1978 (in Japanese).
Schwab, F. A. and L. Knopoff, Fast surface waves and free mode computations, in Methods in Computational Physics, Volume 11, edited by B. A. Bolt, pp. 87–180, Academic Press, 1972.
Snieder, R., 3-D linearized scattering of surface waves and a formalism for surface wave holography, Geophys. J. R. Astr. Soc., 84, 581–605, 1986.
Snieder, R., Large-scale waveform inversions of surface waves for Lateral heterogeneity 2. Application to surface waves in Europe and the Mediterranean, J. Geophys. Res., 93, 12,067–12,080, 1988.
Tanimoto, T, Modelling curved surface wave path: membrane surface wave synthetics, Geophys. J. Int., 102, 89–100, 1990.
Tanimoto, T., Crustal structure of the Earth, Global earth physics, in A Handbook of Physical Constants, pp. 214–224, edited by T. J. Ahrens, AGU, 1995.
Wittlinger, G., F. Masson, G. Poupinet, P. Tapponnier, J. Mei, G. Herquel, J. Guilbent, U. Achauer, X. Guanqi, S. Danian, and Lithoscope Kunlun Team, Seismic tomography of northern Tibet and Kunlun: Evidence for crustal blocks and mantle velocity constants, Earth Planet. Sci. Lett., 139, 263–279
Wu, F. T. and A. L. Levshin, Surface-wave group velocity tomography of East Asia, Phys. Earth Planet. Int., 84, 59–77, 1994.
Wu, F. T., A. L. Levshin, and V. M. Kozhevnikov, Rayleigh wave group velocity tomography of Siberia, China and the vicinity, Pure Appl. Geophys., 149, 447–473, 1997.
Yamazaki, K. and H. Ishii, Study of phase and group velocities in a dipping layer overlying an elastic medium using theoretical sismograms, J. Phys. Earth, 21, 445–462, 1973.
Yoshida, M., Spectra of the first higher mode of simulated oceanic Rayleigh waves generated by deep earthquakes of the dip-slip type, Bull. Earthq. Res. Inst., Univ. Tokyo, 57, 609–625, 1982.
Yoshida, M., Study on the propagation of Love waves across irregular structures of the Moho discontinuity, Bull. Earthq. Res. Inst., Univ. Tokyo, 71, 103–236, 1996.
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Yoshida, M. Fluctuation of group velocity of Love waves across a dent in the continental crust. Earth Planet Sp 52, 393–402 (2000) doi:10.1186/BF03352251
- Phase Velocity
- Group Velocity
- Slope Angle
- Rayleigh Wave
- Crustal Structure