Abstract
Clear images of the seismic velocity discontinuities in the crust and the uppermost mantle beneath southwest Japan have been obtained with Receiver Function (RF) analyses of teleseismic waveforms observed at extraordinary dense short-period and broadband stations. For imaging, we construct several 2-D profiles of depth-transformed RFs to delineate the fine crustal structure and the 3-D configuration of the Philippine Sea plate (PHS). The Moho is clearly seen and locally depressed just beneath the Chugoku Mountains. The Conrad, the velocity discontinuity within the crust, in the northern Kinki region is recognized and depressed just beneath the Chugoku Mountains as well as the Moho. RF analyses also clearly elucidate the largely contorted configuration of the PHS including aseismic portions. The PHS subducts aseismically under the western Chugoku region with a high dip angle of 35 degrees at least to a depth of 65 km. In the western Kii Peninsula, it descends steeply to a depth of 90 km with some curvature, while it subducts with a low dip of 20 degrees to a depth of 60 km from the eastern Kii Peninsula to the Lake Biwa.
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Baba, T., Y. Tanioka, P. R. Cummins, and K. Uhira, The slip distribution of the 1946 Nankai earthquake estimated from tsunami inversion using a new plate model, Phys. Earth Planet Int., 132, 59–73, 2002.
Chevrot, S. and N. Giardin, On the detection and identification on converted and reflected phases from receiver functions, Geophys. J. Int., 141, 801–808, 2000.
Hagiwara, Y., Analyses of gravity values in Japan, Bull. Earthq. Res. Inst., Univ. Tokyo, 45, 1091–1228, 1967.
Hori, S., H. Inoue, Y. Fukao, and M. Ukawa, Seismic detection of the untransformed ‘basaltic’ oceanic crust subducting into the mantle, Geophys. J. R. astr. Soc., 83, 169–197, 1985.
Ito, K., Seismic layer, reflective lower crust, surface heat flow and large inland earthquakes, Tectonophys., 306, 423–433, 1999.
Kurashimo, E., M. Tokunaga, N. Hirata, T. Iwasaki, S. Kodaira, Y. Kaneda, K. Ito, R. Nishida, and S. Kimura, Geometry of the subducting Philippine Sea plate and the crustal and upper mantle structure beneath eastern Shikoku Island revealed by seismic refraction/wide-angle reflection profiling, J. Seismol. Soc. Jpn., Ser. 2, 54, 489–505, 2002 (in Japanese and English abstract).
Langston, C. A., The effect of planar dipping structure on source and receiver responses for constant ray parameter, Bull. Seism. Soc. Am., 67, 1029–1050, 1977.
Langston, C. A., Structure under Mount Rainier, Washington, inferred from teleseismic body waves, J. Geophys. Res., 84, 4749–4762, 1979.
Li, X., S. V. Sobolev, R. Kind, X. Yuan, and Ch. Estabrook, A detailed receiver function image of the uppermantle discontinuities in the Japan subduction zone, Earth Planet. Sci. Lett., 183, 527–541, 2000.
Nakamura, M., H. Watanabe, T. Konomi, S. Kimura, and K. Miura, Characteristic activities of subcrustal earthquakes along the outer zone of southwestern Japan, Annuals of Disas. Prev. Res. Inst., Kyoto Univ., 40(B-1), 1997 (in Japanese).
Nakanishi, I., Precursors to ScS phase and dipping interface in the upper mantle beneath southwest Japan, Tectonophys., 69, 1–35, 1980.
Shibutani, T., The crust and slab structure beneath the eastern Shikoku by receiver function analyses, Monthly Chikyu, 23, 708–713, 2001 (in Japanese).
Shiomi, K., The heterogeneous structure of seismic velocity beneath the Chugoku and Shikoku districts based on receiver function analysis, Ph.D. Thesis of the Tohoku University, pp. 152, 2002 (in Japanese).
Yamane, T., I. Nakanishi, and S. Kamiya, P-wave velocity structure of the Philippine Sea plate subducting from the Nankai trough and its relation with seismicity and volcanism in Southwestern and Central Japan, Bull. Earthq. Res. Inst. Univ. Tokyo, 75, 335–374, 2000 (in Japanese).
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Yamauchi, M., Hirahara, K. & Shibutani, T. High resolution receiver function imaging of the seismic velocity discontinuities in the crust and the uppermost mantle beneath southwest Japan. Earth Planet Sp 55, 59–64 (2003). https://doi.org/10.1186/BF03352463
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DOI: https://doi.org/10.1186/BF03352463