Abstract
The 2005 west off Fukuoka prefecture earthquake (MJMA = 7.0) occurred on March 20, 2005 in northwest Kyusyu, Japan. The fault geometry and rupture propagation of the main shock are investigated by applying the centroid moment tensor (CMT) inversion method to densely-distributed broadband seismic network data. An accurate distribution of small aftershocks is also examined by a double-difference method. The source fault of the main shock whose moment magnitude was 6.6 had a strike of 123°, and the rupture propagated in the southeast direction. We obtain forty-four CMT solutions of the main shock and aftershocks with a moment magnitude greater than 3.5. For the main shock, the fault strike estimated using P-wave first-motion polarities differs from that of the moment tensor solution by 13° in the counterclockwise direction. Some aftershocks with a moment tensor solution similar to the focal mechanism of the main shock derived from the P-wave first motions are distributed north of the epicenter of the main shock. The largest aftershock with a strike of 8° in the clockwise direction, which differs from that of the CMT solution of the main shock, was located south of the main shock. These changes in the fault strike play an important role in the initiation and termination of the rupture process of the main shock.
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References
Asano, K. and T. Iwata, Source process and near-source ground motions of the 2005West Off Fukuoka Prefecture earthquake, Earth Planets Space, 58, this issue, 93–98, 2006.
Dreger, D. S. and D. V. Helmberger, Broadband modeling of local earthquakes, Bull. Seismol. Soc. Am., 80, 1162–1179, 1990.
Fukuyama, E., M. Ishida, D. S. Dreger, and H. Kawai, Automated seismic moment tensor determination by using on-line broadband seismic waveforms, J. Seismol. Soc. Japan (Zisin), 51, 149–156, 1998 (in Japanese with English abstract).
Fukuyama, E., W. L. Ellsworth, F. Waldhauser, and A. Kubo, Detailed fault structure of the 2000 western Tottori, Japan, earthquake sequence, Bull. Seismol. Soc. Am., 93, 1468–1478, 2003.
Harvard Seismology CMT catalog, http://www.seismology.harvard.edu/, Harvard University, 2005.
Hori., S., Comparison of earthquake mechanism solutions obtained from first motion analysis with those from waveform analysis, J. Seismol. Soc. Japan (Zisin), 55, 275–284, 2002 (in Japanese with English abstract).
Ito, Y., Mechanisms of aftershock generation, Rep. Nat’l. Res. Inst. Earth Sci. Disas. Prev., 68, 27–89, 2005, (in Japanese with English abstract).
Ito, Y., H. Matsubayashi, H. Kimura, T. Matsumoto, Y. Asano, and S. Sekiguchi, Spatial distribution for moment tensor solutions of the 2003 Tokachi-oki earthquake (MJMA = 8.0) and aftershocks, Earth Planets Space, 56, 301–306, 2004.
Ito, Y., T. Matsumoto, H. Kimura, H. Matsubayashi, K. Obara, and S. Sekiguchi, Spatial distribution of centroid moment tensor solutions for the 2004 off Kii peninsula earthquakes, Earth Planets Space, 57, 351–356, 2005.
Japan Meteorological Agency, The Seismological and Volcanological Bulletin of Japan, Japan Meteorological Agency, Tokyo, 2005.
King, G. and J. Nábělek, Role of fault bends in the initiation and termination of earthquake rupture, Science, 228, 984–985, 1985.
Kubo, A. and E. Fukuyama, Stress fields and fault reactivation angles of the 2000 western Tottori aftershocks and the 2001 northern Hyogo swarm in southwest Japan, Tectonophysics, 378, 223–239, 2004.
Kubo, A., E. Fukuyama, H. Kawai, and K. Nonomura, NIED seismic moment tensor catalogue for regional earthquakes around Japan: quality test and application, Tectonophysics, 356, 23–48, 2002.
Matsumoto, T., Y. Ito, H. Matsubayashi, and S. Sekiguchi, Spatial distribution of F-net moment tensors for the 2005West Off Fukuoka Prefecture Earthquake determined by the extended method of the NIED F-net routine, Earth Planets Space, 58, this issue, 63–67, 2006.
Miyake, H. and K. Koketsu, Source Process, Strong Motion and Damages, http://www.eri.u-tokyo.ac.jp/topics/fukuoka200503/index-e.html/topics/fukuoka200503/index-e.html, University of Tokyo, 2005.
Nakata, T. and T. Imaizumi, Digital Active Fault Map of Japan, University of Tokyo press, Tokyo, 2002.
Nishimura, T., S. Fujiwara, M. Murakami, H. Suito, M. Tobita, and H. Yarai, Fault model of the 2005 Fukuoka-ken Seiho-oki earthquake estimated from coseismic deformation observed by GPS and InSAR, Earth Planets Space, 58, this issue, 51–56, 2006.
Obara, K. and Y. Ito, Very low frequency earthquakes excited by the 2004 off the Kii peninsula earthquakes: A dynamic deformation process in the large accretionary prism, Earth Planets Space, 57, 321–326, 2005.
Obara, K., K. Kasahara, S. Hori, and Y. Okada, A densely distributed highsensitivity seismograph network in Japan: Hi-net by National Research Institute for Earth Science and Disaster Prevention, Rev. Sci. Instrum., 76, 021301, 2005.
Okada, Y., K. Kasahara, S. Hori, K. Obara, S. Sekiguchi, H. Fujiwara, and A. Yamamoto, Recent progress of seismic observation networks in Japan—Hi-net, F-net, K-NET, KiK-net, Earth Planets Space, 56, xv–xxviii, 2004.
Sekiguchi, H., S. Aoi, R. Honda, N. Morikawa, T. Kunugi, and H. Fujiwara, Rupture process of the 2005 West Off Fukuoka Prefecture earthquake obtained from strong motion data of K-NET and KiK-net, Earth Planets Space, 58, this issue, 37–43, 2006.
Seno, T., S. Stein, and A. E. Gripp, A model for the motion of the Philippine Sea plate consistent with NUVEL-1 and geological data, J. Geophys. Res., 89, 17941–17948, 1993.
Tsuboi, S. and Y. Fukao, Determination of doublet source parameters by CMT analysis, Seismol. Soc. Jpn. Program Abstr., A21, 1996.
Tsuboi, S., S. Hori, and Y. Fukao, A method of determining the centroid of CMT solution, The 1998 Japan Earth and Planetary Science Joint Meeting, Sc-p004, 1998.
USGS fast moment tensor solutions, http://neic.usgs.gov/neis/FM/, USGS, 2005.
Waldhauser, F. and W. L. Ellsworth, A double-difference earthquake location algorithm: Method and application to the Northern Hayward fault, California, Bull. Seismol. Soc. Am., 90, 1353–1368, 2000.
Wessel, P. and W. H. F. Smith, Free software helps map and display data, Eos Trans. AGU, 72, 445–446, 1991.
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Ito, Y., Obara, K., Takeda, T. et al. Initial-rupture fault, main-shock fault, and aftershock faults: Fault geometry and bends inferred from centroid moment tensor inversion of the 2005 west off Fukuoka prefecture earthquake. Earth Planet Sp 58, 69–74 (2006). https://doi.org/10.1186/BF03351916
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DOI: https://doi.org/10.1186/BF03351916