Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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3D SH-wave Velocity Structure of East Asia using Love-Wave Tomography and Implication on Radial Anisotropy

러브파 토모그래피를 이용한 동아시아의 3차원 SH파 속도구조와 이방성 연구

  • Min, Kyungmin (Division of Geology and Geophysics, Kangwon National University) ;
  • Chang, Sung-Joon (Division of Geology and Geophysics, Kangwon National University)
  • 민경민 (강원대학교 지질.지구물리학부) ;
  • 장성준 (강원대학교 지질.지구물리학부)
  • Received : 2016.11.29
  • Accepted : 2017.01.31
  • Published : 2017.02.28
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Abstract

We present a 3D SH-wave velocity model of the crust and uppermost mantle and seismic radial anisotropy beneath East Asia. The SH-wave velocity structure model was built using Love-wave group-velocity dispersion data from earthquake data recorded at broadband seismic networks of Korea, Japan, and China. Love-wave group-velocity dispersion curves were obtained by using the multiple filtering technique in the period range of 3 to 150 s for 3,369 event-station pairs. The inverted model using these data sets provides a crust and upper mantle SH-wave velocity structure down to 100 km depth. At 10 ~ 40 km depths SH-wave velocity beneath the East Sea is higher than beneath the Japanese island region. We estimated the Moho beneath the East Sea to be between 10 ~ 20 km depth, while Moho beneath the Korean Peninsula at around 35 km based on the depth where high-velocity anomalies are detected. We estimated the lithosphere-asthenosphere boundary beneath the East Sea to be at around 50 km based on the depth where strong low-velocity anomalies are observed. Widespread low-velocity anomalies are found between 50 ~ 100 km depth in the study region. Positive radial anisotropy ($V_{SV}$ > $V _{SH}$) is observed down to 35 km depth, while negative radial anisotropy ($V_{SV}$ > $V _{SH}$) is observed for deeper depth.

이 연구는 동아시아 지역의 지각과 상부맨틀의 3차원 SH파 속도구조 및 지진파 속도 방사 이방성을 알아보기 위하여 수행되었다. SH파 속도모델은 한국과 일본, 중국에 설치되어 있는 광대역 지진관측소에 기록된 지진자료로부터 러브파 군속도 분산 자료를 획득한 후 이를 역산하여 구하였다. 군속도 분산곡선은 총 3,369개의 파선경로에 대하여 다중필터기법을 사용하여, 접선 성분에 기록된 주기 3 ~ 150 초 범위의 러브파 군속도를 획득하였다. 획득한 군속도자료를 역산하여 깊이 100 km까지의 SH파 속도구조를 계산하였다. 10 ~ 40 km 깊이에서 동해지역은 일본지역보다 SH파 속도가 빠르게 나타난다. 고속도 이상이 나타나는 깊이로 판단할 때, 모호면의 깊이는 동해의 경우 10 ~ 20 km 사이, 한반도의 경우에는 35 km 부근에서 모호면이 존재한다고 생각된다. 50 km 깊이에서 동해지역은 강한 저속도 이상이 관측이 되고, 저속도 이상이 나타나는 깊이로 판단할 때, 50 km 부근에 암석권과 연약권의 경계가 존재한다고 생각된다. 연구지역 아래 50 ~ 100 km 깊이에서는 저속도 이상이 광범위하게 관측된다. 지진파 속도 이방성은 35 km 깊이 까지는 평균적으로 SH파의 속도가 빠른 양의 이방성을 보이며, 그보다 더 깊은 깊이에서는 평균적으로 SV파의 속도가 빠른 음의 이방성이 관측된다.

Keywords

References

  1. Abdelwahed, M. F., and Zhao, D., 2007, Deep structure of the Japan subduction zone, Physics of the Earth and Planetary Interiors, 162, 32-52. https://doi.org/10.1016/j.pepi.2007.03.001
  2. Aki, K., and Richard, P. G., 1980, Quantitative Seismology Theory and Methods, Freeman, 641-718.
  3. Bath, M., 1974, Spectral Analysis in Geophysics, Elsevier.
  4. Baumgardner, R. B., and Frederickson, P. O., 1985, Icosahedral discretization of the two-sphere, SIAM Journal of Numerical Analysis, 22, 1107-1115, doi:10.1137/0722066.
  5. Chang, S.-J., and Baag, C.-E., 2005, Crustal structure in southern Korea from joint analysis of teleseismic receiver functions and surface wave dispersion, Bulletin of the Seismological Society of America, 95, 1516-1534. https://doi.org/10.1785/0120040080
  6. Chang, S.-J., van der Lee, S., Flanagan, M. P., Bedle, H.,Marone, F., Matzel, E. M., Pasyanos, M. E., Rodgers, A. J., Romanowicz, B., and Schmid, C., 2010, Joint inversion for three-dimensional S velocity mantle structure along the Tethyan margin, Journal of Geophysical Research, 115,B08309, doi:10.1029/2009JB007204.
  7. Chen, M., Niu, F., Liu, Q., Tromp, J., and Zheng, X., 2015, Multiparameter adjoint tomography of the crust and upper mantle beneath East Asia: 1. Model construction and comparisons, Journal of Geophysical Research, 120, doi:10.1002/2014JB011638.
  8. Chough, S. K., Kwon, S.-T., Ree, J.-H., and Choi, D. K., 2000, Tectonic and sedimentary evolution of the Korean Peninsula:a review and new view, Earth-Science Reviews, 52, 175-235. https://doi.org/10.1016/S0012-8252(00)00029-5
  9. Dziewonski, A. M., Bloch, J., and Landisman, M., 1969, A new technique for the analysis of transient seismic signals, Bulletin of the Seismological Society of America, 59, 427-444.
  10. Elsasser, W. M., 1971, Sea-floor spreading as thermal convection, Journal of Geophysical Research, 76(1), 101-112.
  11. Estey, L. H., and Douglas, B. J., 1986, Upper mantle anisotropy: A preliminary model, Journal of Geophysical Research, 91, 393-11 406.
  12. Guo, Z., Gao, X., Shi, H., and Wang, W., 2013, Crustal and uppermost mantle S-wave velocity structure beneath the Japanese islands from seismic ambient noise tomography, Geophysical Journal International, 193, 394-406. https://doi.org/10.1093/gji/ggs121
  13. Herrmann, R. B., 2013, Computer programs in seismology: Anevolving tool for instruction and research, Seism. Res. Lett.,84, 1081-1088, doi:10.1785/0220110096.
  14. Jolivet, L., Tamaki, K., and Fournier, M., 1994, Japan Sea, opening history and mechanism: A synthesis, Journal of Geophysical Research, 99, 22237-22259. https://doi.org/10.1029/93JB03463
  15. Karato, S., Jung, H., Katayama, I., and Skemer, P., 2008, Geodynamic significance of seismic anisotropy of the uppermantle: new insights from laboratory studies, Annual Review of Earth and Planetary Sciences, 36, 59-95. https://doi.org/10.1146/annurev.earth.36.031207.124120
  16. Kennett, B. L. N., and Engdahl, E. R., 1991, Travel times for global earthquake location and phase identification, Geophysical Journal International, 105, 429-465. https://doi.org/10.1111/j.1365-246X.1991.tb06724.x
  17. Kim, H. J., Park, C. H., Hong, J. K., Jou, H. T., Chung, T. W., Zhigulef, V., and Anosov, G. I., 1994, A seismic experiment in the Ulleung basin (Tsushima basin), Southwestern Japan sea (East sea of Korea), Geophysical Research Letters, 21,1975-1978. https://doi.org/10.1029/94GL01596
  18. Kim, I. S., 1992, Origin and Tectonic Evolution of the East Sea(Sea of Japan) and the Yangsan Fault System: A New Synthetic Interpretation, Journal of the Geological Society of Korea, 28, 84-109. (In Korean with English abstract)
  19. Kim, K. Y., Hong, M. H., Lee, J. M., Moon, W. L., Baag, C. E., and Jung, H. O., 2005, Crustal Structure of the Korean Peninsula by Inverting the travel Times of First-arrivals from Large Explosions, Journal of the Korean Geophysical Society,8-1, 45-48. (In Korean with English abstract)
  20. Kim, S., Tkalcic, H., Rhie, J., and Chen, Y., 2016, Intraplate volcanism controlled by back-arc and continental structures in NE Asia inferred from trans-dimensional Bayesian ambient noise tomography, Geophysical Research Letters, 43, 8390-8398. https://doi.org/10.1002/2016GL069483
  21. Kim, S. K., 1995, A Study on the Crustal Structure of the Korean Peninsular, Journal of the Geological Society of Korea, 31, 393-403. (In Korean with English abstract)
  22. Kustowski, B., Ekstrom, G., and Dziewonski, A. M., 2008, Anisotropic shear-wave velocity structure of the Earth's mantle: A global model, Journal of Geophysical Research, 113, B06306, doi:10.1029/2007JB005169.
  23. Lee, H., and Sheen, D.-H., 2015, A study on determination of orientation of borehole seismometer, Journal of the Geological Society of Korea, 51, 93-103. https://doi.org/10.14770/jgsk.2015.51.1.93
  24. Nishizawa, A., and Asada, A., 1999, Deep crustal structure off Akita, eastern margin of the Japan Sea, deduced from ocean bottom seismographic measurements, Tectonophysics, 306, 199-216. https://doi.org/10.1016/S0040-1951(99)00056-6
  25. Otofuji, Y., Matsuda, T., and Nohda, S., 1985, Paleomagnetic evidence for the Miocene counter-clockwise rotation of Northeast Japan-rifting process of the Japan arc, Earth and Planetary Science Letters, 75, 265-277. https://doi.org/10.1016/0012-821X(85)90108-6
  26. Paige, C. C., and Saunders, M. A., 1982a, LSQR: An algorithm for sparse linear equations and sparse least squares, Transactions on Mathematical Software, 8, 43-71, doi:10.1145/355984.355989.
  27. Paige, C. C., and Saunders, M. A., 1982b, LSQR: Sparse linear equations and least squares problems, Transactions on Mathematical Software, 8, 195-209, doi:10.1145/355993.356000.
  28. Shinohara, M., Hirata, N., Nanbu, H., Suyehiro, K., Kanazawa, T., and Kinoshita, H., 1992, Detailed crustal structure of northern Yamato Basin, Proceedings of the Ocean Drilling Program, Scientific Results, 127/128, 1075-1106.
  29. Tatsumi, Y., Otofuji, Y., Matsuda, T., and Nohda, S., 1989, Opening of the Sea of Japan back-arc basin by asthenospheric injection, Tectonophysics, 166, 317-329. https://doi.org/10.1016/0040-1951(89)90283-7
  30. Wang, Z., Huang, R., Huang, J., and He, Z., 2008, P-wave velocity and gradient images beneath the Okinawa Trough, Tectonophysics, 455, 1-13. https://doi.org/10.1016/j.tecto.2008.03.004
  31. Witek, M., van der Lee, S., and Kang, T.-S., 2014, Rayleigh wave group velocity distributions for East Asia using ambient seismic noise, Geophysical Research Letters, 41, 8045-8052. https://doi.org/10.1002/2014GL062016
  32. Yoshizawa, K., Miyake, K., and Yomogida, K., 2010, 3D upper mantle structure beneath Japan and its surrounding region from inter-station dispersion measurements of surface waves, Physics of the Earth and Planetary Interiors, 183, 4-19. https://doi.org/10.1016/j.pepi.2010.02.012
  33. You, S. H., and Chang, S.-J., 2016, 3D SV-wave velocity structure of East Asia using Rayleigh-wave tomography, Submitted to Geophysics and Geophysical Exploration. (In Korean withEnglish abstract)
  34. Zheng, Y., Shen, W., Zhou, L., Yang, Y., Xie, Z., and Ritzwoller, M. H., 2011, Crust and uppermost mantle beneath the North China Craton, northeastern China, and the Sea of Japan from ambient noise tomography, Journal of Geophysical Research, 116, B12312. https://doi.org/10.1029/2011JB008637