Neotectonics of Southwest Japan due to the right-oblique subduction of the Philippine Sea plate
Main Article Content
Abstract
The forearc region of Southwest Japan is divided into five equivalent regions called structural units. Each unit is 120 to 150 km long and composed of a forearc basin fringed by an inverted L-shaped structural high extending from each of five promontories on the Pacific coast to the outer ridge zone along the Nankai Trough. The structural units coincide, in both dimension and location, with the source areas of plate-boundary carthquakes caused by low-angle thrusts with a right-lateral component. The topographic and structural features of the unit also correspond to the pattenr of crustal movements associated with the earthquakes. Form these facts, it is concluded that the structural units have been formed fundamentally by accumulation of coseismic crustal movements. The second Paleo-Seto inland sea, which existed east of the present-day Seto sea in Pliocene to Middle Pleistocene time, was composed of three right-handed en echeleon basins elongated in the NE-SW direction oblique to the Median Tectonic Line. The paleogeographic evidence shows that the second Paleo-Seto inland sea was formed as a right-lateral shear zone in association with the right-lateral strike-slip faulting of the MTL in the same manner as the present Seto inland sea. These characteristic neotectonic movement in the forearc region and along the MTL are attributed to the right-oblique subduction of the Philippine Sea plate at the Nankai Trough since the earliest Pliocene about 5 Ma.
Article Details

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
References
AIDA, I., 1981. Numerical experiments of historical tsunamis generated off the coast of the Tokaido District.** Bull. Earthq. Res. Inst., 56, 367-390.
ANDO, M., 1975. Source mechanisms and tectonic significance of historical earthquakes along the Nankai trough, Japan. Tectonophysics, 27, 119-140. DOI: https://doi.org/10.1016/0040-1951(75)90102-X
ANDO, M., 1982. A fault model of the 1946 Nankaido earthquake derived from tsunami data. Phys. Earth Planet. Inter., 28, 320-336. DOI: https://doi.org/10.1016/0031-9201(82)90089-9
ANDO, M., 1985. Fault model. In: Abe, K. et al. eds. Earthquake Prediction II: crustal movement, earthquake prediction and prediction planning. *Gakkai shuppan center, 183-233.
ASHI, J. and A. TAIRA, 1992. Structure of the Nankai accretionary prism as revealed from IZANAGI sidescan imagery and multichannel seismic reflection profiling. Island Arc, 1, 104-115. DOI: https://doi.org/10.1111/j.1440-1738.1992.tb00063.x
AWATA, Y., 1991. Interval between faultings and displacement during each event of major active faults in and around the Japanese Islands.* Bull. Geol. Surv. Japan, 42, 433-434.
AWATA, Y., 1992. Characteristic faulting-variable earthquake model for fault behavior: examples from the large earthquakes along the Nankai and the Sagami troughs.* The Earth Monthly, Supplement, no. 5, 80-84.
AWATA, Y. and Y. SUGIYAMA, 1989. Geological structure due to the right-lateral reverse faulting accompanied with the large earthquakes along the Nankai Trough.* Zisin. Ser. 2, 42, 231-233. DOI: https://doi.org/10.4294/zisin1948.42.2_231
DRUMMOND, K., C. NISHIWAKI, J. CORVALAN, H. F. DOUTCH and C. CRADDOCK, 1981. Plate-tectonic map of the circum-Pacific region, scale 1: 10,000,000. American Assoc. Petroleum Geologists.
FITCH, T. J., 1972. Plate convergence, transcurrent faults, and internal deformation adjacent to Southeast Asia and Western Pacific. J. Geophys. Res., 77, 4432-4460. DOI: https://doi.org/10.1029/JB077i023p04432
GARIEL, J. C., K. IRIKURA and T. IWATA, 1990. Rupture process of the 1946 Nankai earthquake inferred from the strong motion records. * Abstracts, Seismolog. Soc. Japan, 1990, No. 2, 59.
GEOGRAPHICAL SURVEY INSTITUTE, 1980. Vertical movements in Shikoku district.* Rep. Coord. Comm. Earthq. Predict., 24, 228-231.
GEOGRAPHICAL SURVEY INSTITUTE, 1983. Vertical movements in the Shikoku district.* Rep. Coord. Comm. Earthq. Predict., 30, 336-342.
GEOGRAPHICAL SURVEY INSTITUTE, 1992. Crustal movements in the Shikoku district.* Rep. Coord. Comm. Earthq. Predict., 48, 429-435.
HATORI, T., 1974. Sources of large Tsunamis in Southwest Japan.** Zisin, Ser. 2, 27, 10-24. DOI: https://doi.org/10.4294/zisin1948.27.1_10
HATORI, T., 1976. Documents of tsunami and crustal deformation in Tokai district associated with the Ansei earthquake of Dec. 23, 1854.** Bull. Earthq. Res. Inst., 51, 13-28.
HATORI, T., 1988. Tsunami behaviors in the Seto inland sea and Bungo channel caused by the Nankaido earthquakes in 1707, 1854 and 1946.** Zisin, Ser.2, 41, 215-221. DOI: https://doi.org/10.4294/zisin1948.41.2_215
HAYASHIDA, A. and T. YOKOYAMA, 1983. Paleomagnetic chronology of tbe Plio-Pleistocene Kobiwako Group to the southeast of Lake Biwa, central Japan. J. Geol. Soc. Japan, 89, 209-221. DOI: https://doi.org/10.5575/geosoc.89.209
HUZITA, K., 1962. Tectonic development of the Median Zone (Setouti) of Southwest Japan, since the Miocene with special reference to the characteristic structure of central Kinki area. J. Geosci., Osaka City Univ., 6, 103-144.
HUZITA, K., 1968. Rokko movements and its appearance-intersecting structural patterns of Southwest Japan and Quaternary crustal movements.** Quaternary Research, 7, 248-260. DOI: https://doi.org/10.4116/jaqua.7.248
HUZITA, K. and T. KASAMA, 1982. Geology of the Osaka-Seihokubu district with geological sheet map at 1:50,000.** Geol. Surv. Japan, 112p.
IBARAKI, M., 1986. Neogene planktonic foraminiferal biostratigraphy of the Kakegawa area on the Pacific coast of Central Japan. Rep. Fac. Sci., Shizuoka Univ., 20, 39-173.
IKEBE, N., 1957. Cenozoic sedimentary basin in Japan.* Cenozoic Research, 24125, 1-10.
IKEBE, N. and K. HUZITA, 1966. The Rokko Movements, the Pliocene-Pleistocene crustal movements in Japan. Quaternaria, 8, 277-287.
INOUE, E. and E. HONZA, 1982. Marine geological map around Japanese Islands, scale 1:3,000,000. Geological Atlas of Japan, Geol. Surv. Japan, 26-37.
ISHIBASHI, K., 1981. Specification of a soon-to-occur seismic faulting in the Tokai district, central Japan, based upon seismotectonics. In: Simpson, D. W. and Richards, P. G. eds. Earthquake Prediction-An international review, Maurice Ewing Ser. 4, AGU, 297-332. DOI: https://doi.org/10.1029/ME004p0297
ISHIBASHI, K., 1984. Coseismic vertical crustal movements in the Suruga Bay region.** Quaternary Research, 23, 105-110. DOI: https://doi.org/10.4116/jaqua.23.105
ITIHARA, M., K. ICHIKAWA and N. YAMADA, 1986. Geology of the Kishiwada district with geological sheet map at 1:50,000.** Geol. Surv. Japan, 148p.
ITIHARA, M., S. SURUGA and M. SATO, 1991. Geological profiles of Osaka and Nara areas.* Urban Kubota, 30.
IWASAKI, Y., S. SAWADA, T. KAGAWA et al. 1990. Seismic reflection survey in Osaka Bay.* Abstracts, Seismolog. Soc. Japan,1990, No. 2, 320.
IWATA, T. and N. HAMADA, 1986. Seismicity before and after the Tonankai earthquake of 1944.** Zisin, Ser. 2, 39, 621-634. DOI: https://doi.org/10.4294/zisin1948.39.4_621
KAGAMI, H., K. SHIONO and A. TAIRA, 1983. The plate subduction and formation of accretionary complex at the Nankai Trough.* Kagaku, 53, 429-438.
KAIZUKA, S., 1975. A tectonic model for the morphology of arc-trench systems, especially for the echelon ridges and mid-arc faults. Japan. J. Geol. Geogr., 45, 9-28.
KASAMA, T. and K. HUZITA, 1957. Geological properties of Setouti (Inland Sea) province.* Cenozoic Research, 24/25, 11-19.
KAWABE, T., 1989. Block movements of the Pliocene to Pleistocene sedimentary basins in Kinki district, Japan.** Chikyu Kagaku (Earth Science), 43, 402-416.
KIKKAWA, K. and S. YOSHIKAWA, 1990. Chemical compositions of ash layers of Tokai Group, and correlation with ones of Osaka and Kobiwako Groups. * Abstracts, 97th Ann. Meet. Geol. Soc. Japan, 234.
KUWAHARA, T., 1968. The Nobi basin and its fault block movements.** Quaternary Research, 7, 235-247. DOI: https://doi.org/10.4116/jaqua.7.235
KUWAHARA, T., 1985. Characteristics of the tectonic movement in the Setouchi province.** Monograph Assoc. Geol. Collabor. Japan, 29, 171-189.
MAEMOKU, H., 1988a. Holocene crustal movement in Muroto Peninsula, Southwest Japan.** Geogr. Review Japan, 61, Ser. A, 747-769. DOI: https://doi.org/10.4157/grj1984a.61.10_747
MAEMOKU, H., 1988b. Holocene crustal movement around Cape Ashizuri, Southwest Japan.** Geogr. Sciences, 43, 231-240.
MAEMOKU, H. and K. TSUBONO, 1990. Holocene crustal movement in the southern part of Kii Peninsula, Outer Zone of Southwest Japan.** J. Geography, 99, 349-369 DOI: https://doi.org/10.5026/jgeography.99.4_349
MAKINOUCHI, T., 1979. Chita Movements, the tectonic movements preceding the Quaternary Rokko and Sanage Movements. Mem. Fac. Sci., Kyoto Univ., Ser. Geol. and Mineral., 46, 61-106.
MAKINOUCHI, T., 1985. Some problems in the generation stage of the "Second Setouchi Sedimentary Province", with special reference to the sedimentary basin of Lake Tokai.** Monograph Assoc. Geol. Collabor. Japan, 29: 53-64.
MAKINOUCHI, T., T. DANHARA and K. ISODA, 1983. Fission-track ages of the Tokai Group and associate formations in the east coast areas of Ise Bay and their significance in geohistory.** J. Geol. Soc. Japan, 89, 257-270. DOI: https://doi.org/10.5575/geosoc.89.257
MARITIME SAFETY AGENCY, 1978. Submarine structural chart of the northern part of Suruga wan.* Basic map of the sea in coastal waters at 1:50,000, No. 63625-S.
MATSUDA, T., Y. OTA, M. ANDO and N. YONEKURA, 1978. Fault mechanism and recurrence time of major earthquakes in southern Kanto district, Japan, as deduced from coastal terrace data. Geol. Soc. Am. Bull., 89, 1610-1618. DOI: https://doi.org/10.1130/0016-7606(1978)89<1610:FMARTO>2.0.CO;2
MATSU'URA, M. and R. SATO, 1975. Displacement fields due to the fault.** Zisin, Ser. 2, 28, 429-434. DOI: https://doi.org/10.4294/zisin1948.28.4_429
MIYABE, N., 1955. Vertical earth movements in the Nankai district. Bull. Geogr. Surv. Inst., 4, no.3/4, 1-14.
MIZUNO, K., 1992. Age and tectonic development of the Plio-Pleistocene sedimentary basins along the Median Tectonic Line, Southwest Japan.** Mem. Geol. Soc. Japan, 40, 1-14.
MIZUNO, K., H. HATTORI, A. SANGAWA and Y. TAKAHASHI, 1990. Geology of the Akashi district with geological sheet map at 1:50,000.** Geol. Surv. Japan, 90p.
MIZUNO, K., Y. SUGIYAMA and K. SHIMOKAWA, 1987. Tephrostratigraphy of the Sagara Group and the lower part of the Kakegawa Group in the Omaezaki area, Shizuoka Prefecture.** Bull. Geol. Surv. Japan, 38, 785-808.
MOORE, G. F., T. H. SHIPLEY, P. L. STOFFA et al., 1990. Structure of the Nankai Trough accretionary zone from multichannel seismic reflection data. J. Geophy. Res., 95, 8753-8765. DOI: https://doi.org/10.1029/JB095iB06p08753
NAKAYAMA, K. and S. YOSHIKAWA, 1990. Magnetostratigraphy of the late Cenozoic Tokai Group in central Japan.** J. Geol. Soc. Japan, 96, 967-976. DOI: https://doi.org/10.5575/geosoc.96.967
OGAWA, Y., T. SENO, H. AKIYOSHI et al., 1989. Structure and development of the Sagami trough and the Boso triple junction. Tectonophysics, 160, 135-150. DOI: https://doi.org/10.1016/0040-1951(89)90388-0
OHKOUCHI, N., 1990. Active geological structures and tectonics in Sagami Bay area.** J. Geography, 99, 458-470. DOI: https://doi.org/10.5026/jgeography.99.458
OKADA, A., 1980a. Quaternary tectonism in the Pacific side of central Japan-Change of tectonic process and migration of tectonic province.** Quaternary Res. 19, 263-276.
OKADA, A., 1980b. Quaternary faulting along the Median Tectonic Line of Southwest Japan. Mem. Geol. Soc. Japan, 18, 79-108.
OKAMURA, Y., 1990. Geologic structure of the upper continental slope off Shikoku and Quaternary tectonic movement of the outer zone of southwest Japan.** J. Geol. Soc. Japan, 96, 223-237. DOI: https://doi.org/10.5575/geosoc.96.223
OKAMURA, Y. and M. JOSHINA, 1986. Geological map off Muroto zaki, scale 1:200,000 and its explanatory notes.** Geol. Surv. Japan.
OKAMURA, Y., K. KISHIMOTO, F. MURAKAMI and M. JOSHIMA, 1987. Geological map of Tosa Wan, scale 1:200,000 and its explanatory notes.** Geol. Surv. Japan.
OKUDA, T., 1950. On the mode of the vertical and deformation accompanying the great Nankaido earthquake 1946. Bull. Geogr. Surv. Inst., 2, 37-59.
OKUDA, Y., 1977. Geological map off Outer Zone of Southwest Japan, scale 1:1,000,000. Geol. Surv. Japan.
OTOFUJI, Y., T. MAKINOUCHI and J. NISHIDA, 1975. Preliminary report of magnetostratigraphy of Toko-name Group in Chita Peninsula. Rock Mag. and Paleogeophys., 3, 36-40.
SANGAWA, A., 1986. The history of fault movement since late Pliocene in the central part of Southwest Japan. Royal Soc. N. Z. Bull., 24, 75-85.
SANGAWA, A., 1990. Evidences of paleoearthquakes found out in some archaeological sites.** J. Geogr., 99, 471-482. DOI: https://doi.org/10.5026/jgeography.99.471
SAWAMURA, T., 1953. Relation between the activities of the outer earthquake zone in southwestern Japan and the geologic structure and crustal movements of Shikoku and its vicinity.** Res. Rep. Kochi Univ., 2, no.15, 1-46.
SENO, T., 1977. The instantaneous rotation vector of the Philippine Sea plate relative to the Eurasian plate. Tectonophysics, 42, 209-226. DOI: https://doi.org/10.1016/0040-1951(77)90168-8
SENO, T., 1986. Middle Pleistocene in the Japanese Islands: what happened five hundred thousand years ago?* The Earth Monthly, 8, 708-715.
SENO, T. and S. MARUYAMA, 1984. Paleogeographic reconstruction and origin of the Philippine Sea. Tectonophysics, 102, 53-84. DOI: https://doi.org/10.1016/0040-1951(84)90008-8
SENO, T., T. MORIYAMA, S. STEIN, D. WOOD and C. DEMETS, 1989. Redetermination of the motion of the Philippine Sea plate based on NUVEL-1. * Abstracts, Seismolog. Soc. Japan, 1989, No.1, 50.
SHIBA, M., K. NEMOTO, SURUGA BAY COLLABORATIVE RESEARCH GROUP OF CONTINENTAL SHELF OFF THE UDO HILL, 1990. Geological structure of the Udo Hill and its adjacent continental shelf, western Suruga Bay.** J. Fac. Marine Sci. and Technol., Tokai Univ., 30, 47-65.
SHIMAZAKI, K., 1980. Uplift of the Holocene marine terraces, and intra-and inter-plate earthquakes.* The Earth Monthly, 2, 17-24.
SHIONO, K., 1980. Seismological study on the Median Tectonic Line of Southwest Japan. Mem. Geol. Soc. Japan,18, 155-174.
SHIONO, K., 1992. Frontal shape of subducting plate along the Nankai Trough and recent activity of the Median Tectonic Line.** Mem. Geol. Soc. Japan, 40, 197-204.
SUGIYAMA, Y., 1989. Bend of the zonal structure of island arcs and oblique subduction as the cause of the bending.** Bull. Geol. Surv. Japan, 40, 533-564.
SUGIYAMA, Y., 1990. Seismotectonics of the Suruga Bay and Enshu-nada region.* Zisin, Ser. 2, 43, 439-442. DOI: https://doi.org/10.4294/zisin1948.43.3_439
SUGIYAMA, Y., 1991. Right-lateral strike-slip basins in the Second Paleo-Seto Inland Sea-A model of basin development associated with the migration of active domain of a large-scale strike-slip fault.** J. Tectonic Res. Group Japan, 36, 99-108.
SUGIYAMA, Y., 1992. The Cenozoic tectonic history of the forearc region of southwest Japan, based mainly on the data obtained from the Shizuoka district.** Bull. Geol. Surv. Japan, 43, 91-112.
TORII, M., S. YOSHIKAWA and M. ITIHARA, 1974. Paleomagnetism on the water-laid volcanic ash layers in the Osaka Group, Sennan and Senpoku Hills, south-western Japan. Rock Mag. and Paleogeophys., 2, 34-37.
THATCHER, W., 1984. The earthquake deformation cycle at the Nankai Trough, Southwest Japan. J. Geophy. Res., 89, 3087-3101. DOI: https://doi.org/10.1029/JB089iB05p03087
TSUJI, Y., 1980. On the historical documents pertaining to the Meio earthquake and tsunami of 1498.* Marine Science Monthly, 12, 504-526.
TSUKUDA, E., 1990. Active faults and wrench tectonics.* J . Tectonic Res. Group Japan, 35, 77-82.
TSUKUDA, E., 1992. Active tectonics of Southwest Japan are controlled by the westward translation of the forearc sliver.** Mem. Geol. Soc. Japan. 40, 235-250.
USAMI, T., 1987. Materials for Comprehensive List of Destructive Earthquakes in Japan.* Univ. Tokyo Press, 434p.
UTSU, T., 1977. Jishingaku(Seismology).* Kyoritsu Shuppan, 286p.
WAKITA, K., Y. OKAMURA and Y. AWATA, 1992. Tectonic map of Japan, scale 1:3,000,000. Geological Atlas of Japan (2nd edition), Geol. Surv. Japan.
YAMAZAKI, H., 1984. Neotectonics of the South Fossa Magna in Central Japan deduced from active faults.** Quaternary Res. 23, 129-136.
YAMAZAKI, H., 1992. Tectonics of a plate collision along the northern margin of Izu Península, central Japan. Bull. Geol. Surv. Japan, 43, 603-657.
YONEKURA, N., 1979. Late Quaternary sea-level change and crustal movement in the intra-and circum-Pacific region.* The Earth Monthly, 1, 822-829.
YOSHIDA, F., 1990. Stratigraphy of the Tokai Group and paleogeography of the Tokai sedimentary basin in the Tokai region, central Japan.** Bull. Geol. Surv. Japan, 41, 303-340.
YOSHIDA, F., 1992. Geologic development of the Setouchi Geologic Province since Early Miocene-with special reference to the First and Second Setouchi Inland Sea times.** Bull. Geol. Surv.Japan, 43, 43-67.
YOSHIKAWA, T., 1968. Seismic crustal deformation and its relation to Quaternary tectonic movement on the Pacific coast of Southwest Japan.** Quaternary Research, 7, 157-170. DOI: https://doi.org/10.4116/jaqua.7.157
YOSHIKAWA, T., S. KAIZUKA and Y. OTA, 1981. The landforms of Japan. Univ. Tokyo Press, 222p.