山陰地方西部沖の神田岬沖断層周辺の海底段丘と発達過程

広島大学文学部論集 Volume 81 Page 19-38 published_at 2021-12-25
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Title ( jpn )
山陰地方西部沖の神田岬沖断層周辺の海底段丘と発達過程
Title ( eng )
Development of Submarine Geomorphology Based on Analysis of Submarine Terraces around the Kandamisaki-oki Fault off the Coast of San-in Region
Creator
Source Title
広島大学文学部論集
The Hiroshima University studies, School of Letters
Volume 81
Start Page 19
End Page 38
Journal Identifire
[PISSN] 2436-410X
[NCID] AA12917288
Abstract
This study aims to describe the submarine geomorphology near the Kandamisaki-oki fault off the coast of the Sanin region and examine its development. The NW-SE trending Kandamisaki-oki fault is a series of fault scarps on the seafloor and is a northwestern extension of the onshore Kikukawa fault, an active sinistral strike-slip fault. Although the distribution and activity of the Kandamisaki-oki fault have been studied, the submarine geomorphology near the fault has been ignored.
This study produced a topographical anaglyph image using a 0.3-s-mesh digital elevation model that used point-cloud data obtained through a multi-beam acoustic survey by the Japan Coast Guard. The image was exaggerated vertically and overlapped with a relief map and an isobath. When viewed with red-cyan glasses, it enables easy identification of topographical features, such as submarine terraces and small fault scarps.
By interpreting the anaglyph, the submarine terraces were divided into six surfaces, named the S1, S2, S3, S4, S5, and S6 surfaces, in descending order. The angles indicating the paleo-shoreline behind the flat surface of each submarine terrace were at a depth of approximately 30m for S1, approximately 50m for S2, approximately 80m for S3, approximately 110m for S4, approximately 120m for S5, and approximately 130m for S6. In the study area, these depths were similar and correlated to the terrace surfaces around the Tsushima Strait and the Nanseishoto islands. Therefore, the submarine terraces in the study area developed in association with the global sea-level changes resulting from the changes in the volume of the glaciers since the last glacial period.
Keywords
海底段丘
海底活断層
数値標高モデル
アナグリフ
菊川断層
submarine terrace
active submarine fault
digital elevation model
topographic anaglyph
Kikukawa fault
Descriptions
科学研究費補助金(課題番号:19H01374)の一部を使用した。
Language
jpn
Resource Type departmental bulletin paper
Publisher
広島大学文学部
Date of Issued 2021-12-25
Publish Type Version of Record
Access Rights open access
Source Identifier
[ISSN] 2436-410X
[NCID] AA12917288