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Waveform modelling of local earthquakes in southwest Japan


The crustal structure beneath southwest Japan is investigated through waveform modellings of four local crustal earthquakes by using the generalized ray theory. High-quality seismograms recorded by the Hi-net seismic network are used. The focal mechanism solutions of the events used are estimated by using the first P-wave polarity data. Twenty-nine paths are used to characterize the crustal waveguide in SW Japan. Optimal 1-D velocity models for different paths are derived individually by waveform modelling. Synthetic tests are conducted to study the effects of different model parameters and to confirm the focal mechanism solutions. Modelling the waveforms individually is proven applicable for the heterogeneous regions. The resulted synthetics match the observed seismograms well. Considerable variations of the Conrad and Moho depths are found in the study area. The Conrad depth ranges from 14.8 to 19.7 km, and the Moho depth ranges from 28.4 to 33.4 km. Considerable variations in the crustal structure are found for the eastern portion of the study area where Biwa Lake lies. The effects of Biwa Lake on different paths are examined in detail.


  1. Ali, M., H. Oda, A. Hayashida, K. Takemura, and M. Torii, Holocene paleomagnetic secular variation at Lake Biwa, central Japan, Geophys. J. Int., 136, 218–228, 1999.

  2. Blair, D. P. and A. T. Spathis, Seismic source influence in pulse attenuation studies, J. Geophys. Res., 89, 9253–9258, 1984.

  3. Dreger, D., Modeling earthquakes with local and regional broadband data, Ph.D. Thesis, California Institute of Technology, Pasadena, California, 1993.

  4. Dreger, D. and D. V. Helmberger, Broad-band modeling of local earthquakes, Bull. Seism. Soc. Am., 80, 1162–1179, 1990.

  5. Dreger, D. and D. V. Helmberger, Determination of source parameters at regional distances with three-component sparse network data, J. Geophys. Res., 98, 8107–8125, 1993.

  6. Helmberger, D. V., Generalized ray theory for shear dislocations, Bull. Seism. Soc. Am., 64, 45–64, 1974.

  7. Helmberger, D. V., Theory and application of synthetic seismograms in earthquakes: Observation, theory and interpretation, Proc. Int. Sch. Phys, ‘Enrico Fermi’ course LXXXV, edited by H. Kanamori and E. Boshi, pp. 174–221, North-Holland, Amsterdam, 1983.

  8. Helmberger, D. V., X. J. Song, and L. Zhu, Crustal complexity from regional waveform tomography: Aftershocks of the 1992 Landers earthquake, California, J. Geophys. Res., 106, 609–620, 2001.

  9. Jones, L. E. and D. V. Helmberger, Earthquake source parameters and fault kinematics in the eastern California shear zone, Bull. Seism. Soc. Am., 88, 1337–1352, 1998.

  10. Kudo, T. and K. Yamaoka, Pull-down basin in the central part of Japan due to subductions-induced mantle flow, Tectonophysics, 367, 203–217, 2003.

  11. Langston, C. A., Local earthquake wave propagation through Mississippi embayment sediments, Part I: Body-wave phases and local site responses, Bull. Seism. Soc. Am., 93, 2664–2684, 2003.

  12. Langston, C. A. and D. V. Helmberger, A procedure for modelling shallow dislocation sources, Geophys. J. R. Astron. Soc., 42, 117–130, 1975.

  13. Mori, J. and D. V. Helmberger, Large amplitude Moho reflections (SmS) from Landers aftershocks, southern California, Bull. Seism. Soc. Am., 86, 1845–1852, 1996.

  14. Obara, K., Nonvolcanic deep tremor associated with subduction in southwest Japan, Science, 296, 1679–1681, 2002.

  15. Ohtake, M., Temporal change of Q p in focal area of 1984 western Nagano, Japan, earthquake as derived from pulse width analysis, J. Geophys. Res., 90, 4846–4852, 1987.

  16. Saikia, C. K. and L. J. Burdick, Fine structure of Pnl Waves from Explosions, J. Geophys. Res., 96, 14,383–14,401, 1991.

  17. Saikia, C. K., B. B. Woods, and H. K. Thio, Calibration of the regional crustal waveguide and the retrieval of source parameters using wave-form modelling, Pure Appl. Geophys., 158, 1301–1338, 2001.

  18. Salah, M. K. and D. Zhao, 3-D seismic structure of Kii Peninsula in southwest Japan: evidence for slab dehydration in the forearc, Tectonophysics, 364, 191–213, 2003.

  19. Salah, M. K. and D. Zhao, Mapping the crustal thickness in southwest Japan using Moho reflected waves, Phys. Earth Planet. Int., 141, 79–94, 2004.

  20. Savage, B., C. Ji, and D. V. Helmberger, Velocity variations in the upper-most mantle beneath the southern Sierra Nevada and Walker Lane, J. Geophys. Res., 108 (B7), 2325, doi: 10.1029/2001JB001393, 2003.

  21. Scherbaum, F., Of Poles and Zeroes, Fundamentals of Digital Seismology, Kluwer academic publishers, 1996.

  22. Song, X. J. and D. V. Helmberger, Pseudo green’s functions and waveform tomography, Bull. Seism. Soc. Am., 88, 304–312, 1998.

  23. Tani, H., A study on the 3-D crustal structure of southwest Japan, Thesis, Ehime Univ., 53, 2002.

  24. Thio, H. K., X. Song, C. K. Saikia, D. V. Helmberger, and B. B. Woods, Seismic source and structure estimation in the western Mediterranean using a sparse broadband network, J. Geophys. Res., 104, 845–861, 1999.

  25. Wallace, T. C, D. V. Helmberger, and G. R. Mellman, A technique for the inversion of regional data in source parameter studies, J. Geophys. Res., 86, 1679–1685, 1981.

  26. Yamauchi, M., K. Hirahara, and T. Shibutani, High resolution receiver function imaging of the seismic velocity discontinuities in the crust and the uppermost mantle beneath southwest Japan, Earth Planets Space, 55, 59–64, 2003.

  27. Zhao, L. S. and D. V. Helmberger, Source estimation from broadband regional seismograms, Bull. Seism. Soc. Am., 84, 92–104, 1994.

  28. Zhao, D., S. Horiuchi, and A. Hasegawa, Seismic velocity structure of the crust beneath the Japan islands, Tectonophysics, 212, 289–301, 1992.

  29. Zhao, D., A. Hasegawa, and H. Kanamori, Deep structure of Japan subduction zone as derived from local, regional and teleseismic events, J. Geophys. Res., 99, 22313–22329, 1994.

  30. Zhao, D., F. Ochi, A. Hasegawa, and A. Yamamoto, Evidence for the location and cause of large crustal earthquakes in Japan, J. Geophys. Res., 105, 13579–13594, 2000.

  31. Zhao, D., O. P. Mishra, and R. Sanda, Influence of fluids and magma on earthquakes: seismological evidence, Phys. Earth Planet. Inter., 132, 249–267, 2002.

  32. Zhu, L. and D. V. Helmberger, Advancement in source estimation techniques using broadband regional seismograms, Bull. Seism. Soc. Am., 86, 1634–1641, 1996.

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Correspondence to Mohamed F. Abdelwahed.

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Abdelwahed, M.F., Zhao, D. Waveform modelling of local earthquakes in southwest Japan. Earth Planet Sp 57, 1039–1054 (2005).

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Key words

  • Waveform modelling
  • generalized ray theory
  • synthetic seismogram
  • velocity structure
  • southwest Japan