著者

千田 昇

出版者

THE TOHOKU GEOGRAPHICAL ASSOCIATION

雑誌

東北地理 (ISSN:03872777)

巻号頁・発行日

vol.31, no.3, pp.172-179, 1979 (Released:2010-04-30)

参考文献数

15

被引用文献数

2 1

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The Hinagu fault running nearly from NNE to SSW can be traced more than 40km long from Tanoura through Hinagu and Yatsushiro to the north of Mifune. The fault cut diagonally to the Usuki-Yatsushiro Tectonic Line which is westernmost continuation of Median Tectonic Line. At the southern part of the fault, the fault divides Kyushu mountains to the east and Yatsushiro plain to the west. The fault runs through the river terraces and the depositional surface of Aso pyroclastic flow, at the northern part of the fault.Recent activity of Hinagu fault is mainly characterized by right lateral movement and the horizontal displacement along the fault trace amounts 106 meters in maximum. The average rate of the horizontal displacement is estimated at 0.8 meters per 1, 000 years, judging from the 12 meters offset valley dissecting the Middle fan formed at about 15, 000 years ago. At the southern part of the trace, the Middle and Lower fans are vertically displaced by the fault. At the northern part of the fault, the fault trace arranges en echelon and displaces the depositional surface of Aso pyroclastic flow and the Lower river terraces, vertically. The average rate of vertical displacement is estimated at 0.5-0.7 meters per 1, 000 years.In Central Kyushu, the crustal movement with the directions of NNE-SSW and NE-SW is typically recognized at the Hinagu fault and Shigi trough which located at the northwest Amakusa Islands (CHIDA, 1976). The activity of recent right lateral faulting along the Hinagu fault agree with the formation of Shigi trough, in age. This agreement is considered as the activity of Ryukyu arc corresponded to the change of stress states during Late Quaternary period.