Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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Multiple Lapse Time Window Analysis using Focal Mechanism

진원함수를 고려한 다중지연시간창 해석

  • Chung, Tae-Woong (Department Energy & Mineral Resources Engineering, Sejong Univ.) ;
  • Yoshimoto, Kazuo (Graduate School of Nanobioscience, Yokohama City University)
  • Received : 2012.04.24
  • Accepted : 2012.05.21
  • Published : 2012.05.31
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Abstract

Multiple Lapse Time Window (MLTW) analysis for obtaining intrinsic attenuation value require numerous data without directional bias to compensate focal mechanism. The first window of MLTW, therefore, shows large deviation in fitting smoothed theoretical curve. The information on the focal mechanism may reduce burdens of number and distribution. This study combined algorithm of computing focal mechanism to DSMC method by Yoshimoto (2000). However, the MLTW method based on the numerous data was not applicable to this study, because of the limited data to the almost same fault plane solution. This study showed that the available data was too insufficient to construct smoothed theoretical curve, although the deviation of the first window was improved. Instead of conventional solution by more data, the study seems to be needed for new constraints to obtain smoothed curve.

고유감쇠 분리를 위한 다중지연시간창(MLTW) 해석은 진원의 방사 형태에 크게 의존하여 제 1차 시간창의 분산이 매우 크다. 이를 보완하기 위하여 진원의 방위각에 따라 고르게 분포하는 많은 자료를 사용하여야 한다. 만일 진원함수를 알고 있는 자료를 이용하면 이용하면 이러한 오차를 줄이게 되어 적은 자료 및 방위각 분포에 상관없는 자료연구가 가능할 수 있다. Yoshimoto(2000)의 DSMC에 진원구조를 계산하는 알고리즘을 결합하여 MLTW 해석을 시도하였다. 진원함수를 고려한 MLTW법에서 같은 단층면해를 이용해야 하는 제약으로 최소자승을 이용할 수 있는 자료 수가 극히 제한된다. 따라서 진원구조 계산 알고리즘을 기존 다량의 자료를 이용하는 역산 방법에 적용하는 것이 불가능하다는 것을 확인하였다. 즉, 제1차 시간창의 분산이 줄어든 대신 완곡한 이론곡선을 구하기에는 자료가 턱없이 부족함을 확인하였다. 자료를 더 확보해야 한다는 일반적인 해결책 이외에, 새로운 제약조건을 부과하기 위한 연구가 필요할 것으로 사료된다.

Keywords

References

  1. 백진주, 경재복, 최호선, 2011, 최근 5년간 한반도 중서부 지역에서 발생한 지진의 진원특성 분석, 한국지구과학회지, 32, 161-169.
  2. 이기화, 정태웅, 1999, 1996년 양산단층 일대의 미소지진을 이용한 복합단층면해, 지구물리, 2, 235-240.
  3. 정태웅, 사또 하루오, 이기화, 2001, 한반도 남동부 지역 9 관측점 자료의 확장Coda규격화법에 의한 한반도남동부지역의 $Q_P^{-1}$ 및 $Q_S^{-1}$ 연구, 한국지구과학회지, 22, 500-511.
  4. 정태웅, 윤숙영, 2009, 다중지연시간창법(MLTW)의 한반도 지진자료 적용성 분석, 지구물리와 물리탐사, 12, 199-207.
  5. 정태웅, 이원상, 유승훈, 유현재, 조광현, 이상현, 윤숙영, 정순원, 이준희, 김선주, 2004, 한반도 지각의 감쇠구조 (Q-Structure) 연구, 한국원자력안전기술원 보고서, KINS/HR-641, pp. 198.
  6. 정태웅, Lees, J. M., 2008, R 패키지를 이용한 토모그라피 지도 제작, 물리탐사, 11, 373-378.
  7. 정태웅, Lees, J. M., 윤숙영, 2008, R을 이용한 지진자료처리, 물리탐사, 11, 378-384.
  8. Aki, K., 1969, Analysis of the seismic coda of local earthquakes as scattered waves, Journal of Geophysical Research, 74, 615-631. https://doi.org/10.1029/JB074i002p00615
  9. Aki, K., 1980, Attenuation of shear waves in the lithosphere for frequencies from 0.05 to 25 Hz, Physics of the Earth Planetary Interior, 21, 50-60. https://doi.org/10.1016/0031-9201(80)90019-9
  10. Aki, K., and Chouet, B., 1975, Origin of coda waves; source, attenuation and scattering effects, Journal of Geophysical Research, 80, 3322-3342. https://doi.org/10.1029/JB080i023p03322
  11. Aki, K., and Richards, P. G., 1980, Quatitative Seismology, W.H. Freeman and Company, San Francisco
  12. Cerveny, V., and Ravindra, R., 1971, Theory of Seismic Head Waves, Univ. of Toronto Press, Toronto, Ontario.
  13. Chung, T. W., and Sato, H., 2001, Attenuation of highfrequency P- and S-waves in the crust of the southeastern Korea, Bulletin of the Seismological Society of America, 91, 1867-1874. https://doi.org/10.1785/0120000268
  14. Chung, T. W., Lees, J. M., Yoshimoto, K., Fujita, E., and Ukawa, M., 2009, Intrinsic and scattering attenuation of the Mt. Fuji region, Japan, Geophysical Journal International, 177, 1366-1382. https://doi.org/10.1111/j.1365-246X.2009.04121.x
  15. Chung, T. W., Noh, M. H., Kim, J. K., Park, Y. K., Yoo, H. J., and Lees, J. M., 2007, A Study of the Regional Variation of Low-Frequency $Q_{Lg}^{-1}$ around the Korean Peninsula, Bulletin of the Seismological Society of America, 97, 512-520.
  16. Chung, T. W., Yoshimoto, K., and Yun, S., 2010, The Separation of intrinsic and scattering seismic attenuation in South Korea, Bulletin of the Seismological Society of America, 100, 3183-3193. https://doi.org/10.1785/0120100054
  17. Fehler, M., Hoshiba, M., Sato, H., and Obara, K., 1992, Separation of scattering and intrinsic attenuation for the Kanto-Tokai region, Japan, using measurements of S-wave energy versus hypocentral distance, Geophysical Journal International, 108, 787-800. https://doi.org/10.1111/j.1365-246X.1992.tb03470.x
  18. Hoshiba, M., 1991, Simulation of multiple-scattered coda wave excitation based on the energy conservation law, Physics of the Earth and Planetary Interior, 67, 123-136. https://doi.org/10.1016/0031-9201(91)90066-Q
  19. Hoshiba, M., 1993, Separation of scattering attenuation and intrinsic absorption in Japan using the multiple lapse time window analysis of full seismogram envelope, Journal of Geophysical Research, 98, 15,809-15,824. https://doi.org/10.1029/93JB00347
  20. Hoshiba, M., Sato, H., and Fehler, M., 1991, Numerical basis of the separation of scattering and intrinsic absorption from full seismogram envelope: a Monte-Carlo simulation of multiple isotropic scattering, Paper of the Meteorolgical Geophysics, 42, 65-91. https://doi.org/10.2467/mripapers.42.65
  21. Kampfmann, W., and Berckhemer, H., 1985, High temperature experiments on the elastic and anelastic behavior of magmatic rocks, Physics of the Earth and Planetary Interior, 40, 223-247. https://doi.org/10.1016/0031-9201(85)90132-3
  22. Kim, K. D., Chung, T. W., and Kyung, J. B., 2004, Attenuation of high-frequency P and S waves in the crust of Choongchung provinces, central south Korea, Bulletin of the Seismological Society of America, 94, 1070-1078. https://doi.org/10.1785/0120030137
  23. Lees, J. M., 2008a, GEOmap: topographic and geographic mapping, http://www.r-project.org
  24. Lees, J. M., 2008b, RSEIS: time series seismic analysis tools, http://www.r-project.org
  25. Park, J.-C., Kim, W., Chung, T.W. Baag, C.-E., and Ree, J.-H., 2007, Focal mechanism of recent earthquakes in the Southern Korean Peninsula, Geophysical Journal International, 169, 1103-1114. https://doi.org/10.1111/j.1365-246X.2007.03321.x
  26. R Development Core Team, 2006, R: A language and environment for statistical computing, edited by R.F.F.S. Computing, Vienna, Austria.
  27. Sato, H., 1993, Energy transportation in one- and two-dimensional scattering media; analytic solutions of the multiple isotropic scattering model, Geophysical Journal International, 112, 141-146. https://doi.org/10.1111/j.1365-246X.1993.tb01443.x
  28. Sato, H., and Fehler, M. C., 1998, Seismic wave propagation and scattering in the heterogeneous earth, Springer-Verlag New York, Inc. 308 pp.
  29. Stocker, R. L., and Gordon, R. B., 1975, Velocity and internal friction in partial melts, Journal of Geophysical Research, 80, 4828-4836. https://doi.org/10.1029/JB080i035p04828
  30. Yoshimoto, K., 2000, Monte Carlo simulation of seismogram envelopes in scattering media, Journal of the Geophysical Research, 105, 6153-6161. https://doi.org/10.1029/1999JB900437
  31. Zeng, Y., Su, F., and Aki, K., 1991, Scattering wave energy propagation in a random isotropic scattering medium; 1, Theory, Journal of Geophysical Research, 96, 607-619. https://doi.org/10.1029/90JB02012