著者

竹村 恵二 伊藤 康人 鎌田 浩毅

出版者

一般社団法人 日本地質学会

雑誌

日本地質学会学術大会講演要旨 (ISSN:13483935)

巻号頁・発行日

vol.1998, 1998

著者

徳山 英一 本座 栄一 木村 政昭 倉本 真一 芦 寿一郎 岡村 行信 荒戸 裕之 伊藤 康人 除 垣 日野 亮太 野原 壮 阿部 寛信 坂井 眞一 向山 建二郎

出版者

海洋調査技術学会

雑誌

海洋調査技術 (ISSN:09152997)

巻号頁・発行日

vol.13, no.1, pp.27-53, 2001-03-31

参考文献数

56

被引用文献数

6

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We propose the guideline to identify fault in offshore region mainly based on MCS profiles, combining high resolution bathymetric maps and geological data such as bore hole results. Based on the guideline we distinguished total 776 faults developing around Japan since the latest Miocene and 753 faults out of total numbers of faults are interpreted to have been active by Quaternary. Together with distinguishment of fault we examined the attributes of each faults such as surface and vertical distribution, criteria of offset, age of movement, certainty of a fault and so on. <br>The results of the distinguishment and examination of the fault leads to the conclusion that the ongoing tectonic framework around Japan characterized by 1) oblique Subduction along the Nankai Trough, 2) rifting at the Okinawa Trough, 3) E-W compressionl regeme along the Japan Sea margin, 4) E-W compressionl regeme along southwestern margin of the Okhotsk Sea and off southern Hokkaido, 5) E-W compressionl regeme along the Japan Trench, 6) rifting in the central arc of the Izu-Ogasawara Arc has been established since 3 Ma, at the earliest 6 Ma. <br>We utilized high resolution data set which we enable to access. Tow big problems, however, still remain in terms of reliability of fault recognition. Those are 1) age of fault movement and 2) spatial distribution of fault. To solve the first one, new technique is required in order to obtain core samples which provide critical evidence to determine age of fault movement. As is second problem concerned, new intensive seismic survey is indispensable to make a precise fault distribution map, especially in the boundary area between land and sea.

著者

伊藤 康人

出版者

石油技術協会

雑誌

石油技術協会誌 (ISSN:03709868)

巻号頁・発行日

vol.65, no.1, pp.48-57, 2000 (Released:2008-03-27)

参考文献数

44

被引用文献数

6 10

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Late Cenozoic tectonic history around the southern part of the Japan Sea and Kyushu is reconstructed on the basis of offshore reflection seismic survey and borehole stratigraphy together with geologic information on land. Three tectonic episodes are identified in the study area as follows;(1) Paleomagnetic data suggest that western half of the Japan Sea was generated through Early to Middle Miocene rifting and clockwise rotation of southwest Japan. Seismic profiles around the southern margin of the Japan Sea show extensional grabens filled with late Early Miocene sediments. Coeval deformation in the Fukue Basin off northwestern Kyushu, which is located around rotation pivot of the rifted sliver of southwest Japan, is characterized by right-lateral leaky wrenching along a NNE-SSW structural trend.(2) Southern margin of the Japan Sea suffered extensive inversion around the end of Miocene, probably caused by resumption of subduction of the Philippine Sea Plate. ENE-WSW trending folds (San'in Folded Zone) converge into Tsushima Island at the western end of southwest Japan. Shortening of the southern part of the Japan Sea was accommodated by left-lateral movement along the Tsushima-Goto Fault on the western margin of the back-arc basin. In a sharp contrast, Goto-nada and Amakusa-nada Seas, and central Kyushu began to subside with many extensional features in the same period, which may be linked to mantle upwelling.(3) In Quaternary, study area is divided into three tectonic domains: Inner Zone of southwest Japan is characterized by simple shear deformation caused by right-lateral movements on the Median Tectonic Line (MTL). Southern part of the Japan Sea is undulated under E-W compressive stress. Central Kyushu continued to subside alternatively controlled by pull-apart basin formation on the MTL and mantle upwelling.