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Three-dimensional seismic velocity structure as determined by double-difference tomography in and around the focal area of the 2005 West off Fukuoka Prefecture earthquake
Earth, Planets and Space volume 58, pages 1621–1626 (2006)
Abstract
On March 20, 2005 the West off Fukuoka Prefecture earthquake (magnitude of 7.0 on the JMA scale) occurred in southeastern Japan. The earthquake fault was a left-lateral strike-slip having a nearly vertical fault plane and a strike in the WNW-ESE direction. The largest aftershock with a magnitude of 5.8 (JMA) followed 1 month later. To gain more detailed aftershock data, several teams from different Japanese universities jointly installed a number of temporary seismic stations and positioned Ocean Bottom Seismometers (OBSs) immediately above the focal area. Double-difference tomography was used to estimate the three-dimensional (3D) (Zhang and Thurber, 2003) velocity structures in and around the focal area based on the travel time data collected during seismic observations. The high-velocity regions estimated by the inversion are located on the edge of the aftershock area and on the shallow part of asperity, as inferred from the slip distribution. Conversely, the Vp/Vs ratio is not always as high as that found at the location of the asperity. This finding suggests that the construction of the medium is not uniformly elastic but complex, with different relations between elastic constants and strength.
References
Asano, K. and T. Iwata, Source process and near-source ground motions of the 2005 West Off Fukuoka Prefecture earthquake, Earth Planets Space, 58(1), 93–98, 2006.
Geological Survey of Japan, AIST, http://unit.aist.go.jp/igg/rg/geophysmap-rg/grav/fukuoka grav fig.html, 2005.
Morijiri, R., T. Hiroshima, M. Komazawa, M. Makino, Y. Murata, K. Nawa, J. Nishijima and T. Mogi, Bouguer Gravity Anomalies in the Fukuoka area, Kyushu, Japan, Bull. Geol. Surv. Jpn., 53(7/8), 73–594, 2002 (in Japanese with English abstract)
Okada, T., A. Hasegawa, H. Zhang, and C. Thurber, Detailed seismic velocity structure around the focal area of the 2000 Western Tottori earthquake (M7.3) by Double-Difference tomography, 2004 Japan EPS Joint Meeting, J078–P001, 2004.
Okada, T., N. Umino, T. Matsuzawa, J. Nakajima, N. Uchida, T. Nakayama, S. Hirahara, T. Sato, S. Hori, T. Kono, Y. Yabe, K. Ariyoshi, S. Gamage, J. Shimizu, J. Suganomata, S. Kita, S. Yui, M. Arao, S. Honda, T. Mizukami, H. Tsushima, T. Yaginuma, Y. Asano, H. Zhang, and C. Thurber, Aftershock distribution and 3D seismic velocity structure in and around the focal area of the 2004 mid Niigata prefecture earthquake obtained by applying double-difference tomography to dense temporary seismic network data, Earth Planets Space, 57, 435–440, 2005a.
Okada, T., A. Hasegawa, J. Suganomata, N. Umino, H. Zhang, and C. Thurber, Imaging the fault plane of the 2003 M6.4 northern Miyagi, NE Japan, earthquake by double-difference tomography, Chikyu Monthly, 27(2), 132–138, 2005b (in Japanese).
Shibutani, T., H. Katao, and Group for the dense aftershock observations of the 2000 Western Tottori Earthquake, H, High resolution 3-D velocity structure in the source region of the 2000 Western Tottori Earthquake in southwestern Honshu, Japan using very dense aftershock observations, Earth Planets Space, 57(9), 825–838, 2005.
Shimizu, H., H. Takahashi, T. Okada, T. Kanazawa, Y. Iio, H. Miyamachi, T. Matsushima, M. Ichiyanagi, N. Uchida, T. Iwasaki, H. Katao, K. Goto, S. Matsumoto, N. Hirata, S. Nakao, K. Uehira, M. Shinohara, H. Yakiwara, N. Kame, T. Urabe, N. Matsuwo, T. Yamada, A. Watanabe, K. Nakahigashi, B. Enescu, K. Uchida, S. Hashimoto, S. Hirano, T. Yagi, Y. Kohno, T. Ueno, M. Saito, and M. Hori, Aftershock seismicity and fault structure of the 2005 West Off Fukuoka Prefecture Earthquake (MJMA 7.0) derived from urgent joint observations, Earth Planets Space, 58, this issue, 1599–1604, 2006.
Uehira, K., T. Yamada, T. Shinohara, K. Nakahigashi, H. Miyamachi, Y. Iio, T. Okada, H. Takahashi, N. Matsuwo, K. Uchida, T. Kanazawa, and H. Shimizu, Precise aftershock distribution of the 2005 West Off Fukuoka Prefecture Earthquake (Mj=7.0) using a dense onshore and offshore seismic network, Earth Planets Space, 58, this issue, 1605–1610, 2006.
Waldhauser, hypoDD: a computer program to compute double-difference hypocenter locations, U. S. Geological Survey, Open File Report, 25, 01-113, 2001.
Waldhauser and Ellsworth, A double-difference earthquake location algorithm: method and application to the northern Hayward Fault, California, Bull. Seism. Soc. Am., 80, 1548–1368, 2000.
Zhang, H. and C. Thurber, Double-Difference Tomography: the method and its application to the Hayward Fault, California, Bull. Seism. Soc. Am., 93, 1875–1889, 2003.
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Hori, M., Matsumoto, S., Uehira, K. et al. Three-dimensional seismic velocity structure as determined by double-difference tomography in and around the focal area of the 2005 West off Fukuoka Prefecture earthquake. Earth Planet Sp 58, 1621–1626 (2006). https://doi.org/10.1186/BF03352672
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DOI: https://doi.org/10.1186/BF03352672