和泉山脈南麓域における中央構造線の断層変位地形と断層運動

DOI Web Site 被引用文献14件

書誌事項

タイトル別名
  • FAULT MORPHOLOGY AND QUATERNARY FAULTING ALONG THE MEDIAN TECTONIC LINE IN THE SOUTHERN PART OF THE IZUMI RANGE
  • イズミ サンミャク ナンロクイキ ニ オケル チュウオウ コウゾウセン ノ ダ

この論文をさがす

抄録

In the western part of the Kii Peninsula, the Median Tectonic Line separates the Izumi Range from the Kino-kawa lowland with a conspicuous topographical contrast, forming a great geological boundary between the Upper Cretaceous Izumi group of the Inner Zone and the Paleozoic crystalline schist of the Outer Zone, the latter of which is mostly overlain by the Plio-Pleistocene lacustrine sediments, the late Quaternary terrace gravels, and the Holocene alluvial deposits.<br> The writers investigated mainly fault features and related faulting along the southern foot of the Izumi Range. The results are briefly summarized as follows.<br> 1) Many distinct evidences of the right-lateral movement are continuously discernible along the active fault system of the Median Tectonic Line in this area.<br> 2) The Negoro fault, the principal fault in the western part of the area surveyed, vertically and horizontally interrupts the several steps of terrace surfaces (dissected fans) and the dissected valleys. Calculated from the known ages of the terrace surface, cliff, and dissected valley etc. across the active faults, which are roughly estimated by the correlation and the dated values such as carbon-14, fission track, and K-Ar methods in the neighboring areas, the mean rates of faulting are 0.9_??_3.1m/103 years laterally, and 0.11._??_0.40m/103 years in the vertically northward direction.<br> 3) As the horizontal displacement (D) is in proportion to length (L) of the river upstream from the fault with a certain coefficient of correlation (a), the relation is expressed as D=aL. Calculation gives the coefficient, a=0.38 for the Negoro fault and a=0.22 for the Gomyo-dani fault, the principal one in the eastern half of this area. They implicate that the both are among the most active transcurrent faults in the inland Japan, and that the displacements have been taken place with an almost uniform rate at least during the late Quaternary.<br> 4) The mean slip rates of vertical and horizontal displacements in this area are slightly lower in comparison with those in Shikoku. This may be accounted for by the fact that this area is located at the eastern end of the active fault system of the Median Tectonic Line, and that the displacements are scattered among many other active faults in the Inner Zone of the hinki district.<br> 5) There are some differences in place and mode of displacement among the faults along the Median Tectonic Line int his area. Reverse faulting, which occurred in the first half of the Quaternary along the great geological boundary, formed the general outline of the fault angle depression. On the contrary, right-lateral faulting began from the middle Quaternary as the new fracture within the uppermost Cretaceous Izumi group, and has continued to the present with a mountain-building movement.

収録刊行物

  • 地理学評論

    地理学評論 51 (5), 385-405, 1978

    公益社団法人 日本地理学会

被引用文献 (14)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ