Abstract
The seismicity in the subducting Philippine Sea slab (PHS) beneath southwest Japan shows a variety of modes of occurrence. We try to explain this variety on the basis of dehydration embrittlement in the subducting oceanic crust and/or mantle. The PHS subducting along the Nankai Trough shows commonly a single narrow seismic zone shallower than 60 km, which may reflect dehydration embrittlement in the hydrated subducting oceanic crust only, implying the lack of hydrated slab mantle. The PHS beneath Kanto, however, shows a double seismic zone (Hori, 1997) in the mantle part. Here the serpentinized mantle wedge of the Izu-Bonin fore-arc is subducting, and the double zone can be explained by its dehydration. Beneath Kii Peninsula and Kyushu, seismic events within the slab mantle have also been detected. This indicates that the PHS mantle beneath these areas is also hydrated, which may have resulted from subduction of the serpentine stable in the Izu-Bonin back-arc area. Aqueous fluids released from the serpentinized mantle beneath Kii Peninsula may have initiated partial melting in the mantle wedge, as indicated by the presence of high 3He/4He ratios in the natural gasses and the shallow seismic swarms in this region (Wakita et al., 1987).
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References
Ahrens, T. J. and G. Schubert, Gabbro-eclogite reaction rate and its geophysical significance, Reviews of Geophysics and Space Physics, 2, 383–400, 1975.
Christensen, N. I., Elasticity of ultrabasic rocks, J. Geophys. Res., 71, 5921–5931, 1966.
Davies, J. H. and D. J. Stevenson, Physical model of source region of subduction zone volcanics, J. Geophys. Res., 97, 2037–2070, 1992.
Engdahl, E. R. and C. H. Scholz, A double Benioff zone beneath the central Aleutians: An unbending of the lithosphere, Geophys. Res. Lett., 4, 473–476, 1977.
Fryer, P. and G. Fryer, Origins of nonvolcanic seamounts in a fore-arc environment, in Seamounts Islands and Atolls, edited by H. Keating, P. Fryer, R. Batiza, and G. W. Boehlert, pp. 61–69, Am. Geophys. Union, Washington, D. C., 1987.
Fukao, Y., S. Hori, and M. Ukawa, A seismological constraint on the depth of basalt-eclogite transition in a subducting oceanic crust, Nature, 303, 413–415, 1983.
Hamaguchi, H., H. Goto, and Z. Suzuki, Double-planed structure of intermediate depth seismic zone and thermal stress in the descending plate, J. Phys. Earth, 31, 329–347, 1983.
Hasegawa, A., N. Umino, and A. Takagi, Double-planed structure of the deep seismic zone in the northeastern Japan arc, Tectonophys., 47, 43–58, 1978.
Hess, H. H., History of ocean basins, in Petrological Studies; A Volume in Honor of A. F. Buddington, edited by A. E. Engel, H. L. James, and B. F. Leonard, pp. 599–620, Geol. Soc. Am., Boulder, 1962.
Honda, S., Thermal structure beneath Tohoku, northeast Japan—a case study for understanding the detailed thermal structure of the subdution zone, Tectonophys., 112, 69–102, 1985.
Hori, S., Seismic waves guided by untransformed oceanic crust subducting into the mantle: the case of the Kanto district, central Japan, Tectonophys., 176, 355–376, 1990.
Hori, S., Earthquake mechanism within the Philippine Sea plate subducting beneath the Kanto district, central Japan, Jisin, 50, 203–213, 1997 (in Japanese).
Hori, S., H. Inoue, Y. Fukao, and M. Ukawa, Seismic detection of the untransformed ‘basaltic’ oceanic crust subducting into the mantle, Geophys. J. R. astron. Soc, 83, 169–197, 1985.
Ishida, M., Geometry and relative motion of the Phillippine sea plate and Pacific plate beneath the Kanto-Tokai district, Japan, J. Geophys. Res., 97, 489–513,1992.
Iwamori, H., Transportation of H2O and melting in subduction zone, Earth Planet. Sci. Lett., 160, 65–80, 1998.
Kamimura, A., J. Kasahara, R. Hino, M. Shinohara, H. Shiobara, G. Fujie, and T. Kanazawa, Crustal structure study at the Izu-Bonin subduction zone around 31°N Implications of serpentinized materials along the subduction plate boundary, Scientific activities 2001, Istanbul Technical University, 21–30, 2001.
Kamiya, S. and Y. Kobayashi, Seismological evidence for the existence of serpentinized wedge mantle, Geophys. Res. Lett., 27, 819–822, 2000.
Kirby, S., Intraslab earthquakes and phase changes in subducting lithosphere, Rev. Geophys., Suppl., 287–297, 1995.
Kirby, S., B. S. Hemingway, and R. Lee, Anomalous fracture and thermal behavior of hydrous minerals, Geophys. Monogr., 56, 119–126, 1990.
Kirby, S., E. R. Engdhal, and R. Denlinger, Intermediate-depth intraslab earthquakes and arc volcanism as physical expressions of crustal and uppermost mantle metamorphism in subducting slabs (Overview), edited by G. Bebout, D. Scholl, and S. Kirby, Geophys. Monogr., 96, 195–214, Am. Geophys. Union, Washington, D. C., 1996.
Kodaira, S., E. Kurashimo, N. Takahashi, A. Nakanishi, S. Miura, J.-O. Park, T. Iwasaki, N. Hirata, K. Ito, and Y. Kaneda, Structural factors in controlling a rupture process of a magathrust earthquake at the Nankai trough seismogenic zone: results from asn onshore-offshore seismic study, Geophys. J. Inter., 2001 (submitted).
Murauchi, S., N. Den, S. Asano, H. Hotta, T. Yoshii, T. Asanuma, K. Hagiwara, K. Ichikawa, T. Sato, W. J. Ludwig, J. I. Ewing, N. T. Edgar, and R. E. Houtz, Crustal structure of the Philippine Sea, J. Geophys. Res., 73, 3143–3171, 1968.
Matsumura, S., Focal zone of a future Tokai earthquake inferred from the seismicity pattern around the plate interface, Tectonophys., 273, 271–291, 1997.
Nakamura, M., H. Watanabe, T. Konomi, S. Kimura, and K. Miura, Characteristics activities of subcrustal earthquakes along the outer zone of southwestern Japan, Annuals of the Disaster Prevension Research Instutute, 40, 1–20, 1997 (in Japanese).
Nakanishi, M., K. Tamaki, and K. Kobayashi, A new Mesozoic isochron chart of the northwestern Pacific Ocean: paleomagnetic and tectonic implications, Geophys. Res. Lett., 19, 693–696, 1992.
Nishiyama, S., Mantle hydrology in a subduction zone: A key to episodic geologic events, double Wadati-Benioff zones and magma genesis, Mathematical Seismology VII, Rep. Stat. Math. Inst., 34, 31–67, 1992.
Ohkura, T., Structure of the upper part of the Philippine Sea plate estimated by later phases of upper mantle earthquakes in and around Shikoku, Japan, Tectonophys., 321, 17–36, 2000.
Okino, K., Y. Shimakawa, and S. Nagano, Evolution of the Shikoku Basin, J. Geomag. Geoelectr., 46, 463–479, 1994.
Peacock, S. M., The importance of blueschist—eclogite dehydration reactions in subducting oceanic crust, Geol. Soc. Am. Bull, 105, 684–694, 1993.
Peacock, S. M., Are the lower planes of double seismic zones caused by serpentine dehydration in subducting oceanic mantle?, Geol. Soc. Am. Bull, 29, 299–302, 2001.
Peacock, S. M. and K. Wang, Seismic consequences of warm versus cool subduction metamorphism: Examples from southwest and northeast Japan, Science, 286, 937–939, 1999.
Raleigh, C. B. and M. S. Paterson, Experimental deformation of serpentinite and its tectonic implications, J. Geophys. Res., 70, 3965–3985, 1965.
Sano, Y. and H. Wakita, Geographical distribution of 3He/ 4He rations in Japan: implications for arc tectonics and incipient magmatism, J. Geophys. Res., 90, 8729–8741, 1985.
Sekiguchi, S., Three dimensional P and S velocity structures of uppermost mantle beneath Kanto, Tokai and Chubu districts, Japan, Jisin, 53, 137–151, 2000.
Seno, T., Tectonic evolution of the West Philippine Basin, Modern Geology, 12, 481–495, 1988.
Seno, T. and S. Maruyama, Paleogeographic reconstruction and origin of the Philippine Sea, Tectonophys., 102, 53–84, 1984.
Seno, T. and Y. Yamanaka, Double seismic zones, deep compressional trench—outer rise events and superplumes, in Subduction Top to Bottom, edited by G. E. Bebout, D. W. Scholl, S. H. Kirby, and J. P. Platt, Geophys. Monogr., 96, 347–355, Am. Geophys. Union, Washington, D. C., 1996.
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., 98, 17941–17948, 1993.
Seno, T., T. Sakurai, and S. Stein, Can the Okhotsk plate be discriminated from the North American plate?, J. Geophys. Res., 101, 11305–11315, 1996.
Shimizu, H., K. Uyehira, and K. Goto, The detailed structure of the deep seismic zone and focal mechanism solutions from the western end of Chugoku-Shikoku district to the Kyushu district, Abstr. Seism. Soc. Jpn., B39, 2000 (in Japanese).
Sleep, N. H., The double seismic zone in downgoing slabs and the viscosity of the mesosphere, J. Geophys. Res., 84, 4565–4571, 1979.
Suyehiro, K., N. Takahashi, Y. Ariie, Y. Yokoi, R. Hino, M. Shinohara, T. Kanazawa, N. Hirata, H. Tokuyama, and A. Taira, Continental crust, crustal underplating, and low-Q upper mantle beneath an oceanic Island arc, Science, 272, 390–392, 1996.
Takahashi, N., K. Suyehiro, and M. Shinohara, Implications from the seismic crustal structure of the northern Izu-Bonin arc, Isl. Arc, 7, 383–394, 1998.
Tatsumi, Y., Migration of fluid phases and genesis of basalt magmas in subduction zones, J. Geophys. Res., 94, 4697–4707, 1989.
Ulmer, P. and V. Trommsdorff, Serpentine stability to mantle depths and subduction-related magmatism, Science, 268, 858–859, 1995.
Wakita, H., Y. Sano, and M. Mizoue, High 3 He emanation and seismic swarms observed in a nonvolcanic, forearc region, J. Geophys. Res., 92, 12539–12546, 1987.
Wang, K., R. D. Hyndman, and M. Yamano, Thermal regime of the Southwest Japan subduction zone: effects of age history of the subducting plate, Tectonophys., 248, 53–69, 1995.
Yamano, M., Recent heat flow studies in and around Japan, Terrestrial heat flow and geothermal energy in Asia, in Terrestrial Heat Flow and Geothermal Energy in Asia, edited by M. L. Gupta and M. Yamano, pp. 173–201, Oxford & IBH Publishing Co., New Delhi, 1995.
Yamazaki, F. and T. Ooida, Configuration of subducted Philippine Sea plate beneath the Chubu District, central Japan, Jisin, 38, 193–201, 1985 (in Japanese).
Zhao, D. and H. Negishi, The 1995 Kobe earthquake: Seismic image of the source zone and its implications for the rupture nucleation, J. Geophys. Res., 103, 9967–9986, 1998.
Zhao, D., K. Asamori, and H. Iwamori, Seismic structure and magmatism of the young Kyushu subduction zone, Geophys. Res. Lett., 27, 2057–2060, 2000a.
Zhao, D., F. Ochi, A. Hasegawa, and A. Yamamoto, Evidence for the location and cause of large crustal earthquakes in Japan, J. Geophys. Res., 105, 13579–13594, 2000b.
Zhao, D., M. Di, F. Ochi, and T. Seno, Dehydration and earthquakes of the Philippine Sea slab (2) Evidence from seismic tomography, Abstr. Seism. Soc. Jpn., P141, 2000c.
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Seno, T., Zhao, D., Kobayashi, Y. et al. Dehydration of serpentinized slab mantle: Seismic evidence from southwest Japan. Earth Planet Sp 53, 861–871 (2001). https://doi.org/10.1186/BF03351683
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DOI: https://doi.org/10.1186/BF03351683