2024-03-28T22:30:17Z
https://repository.dl.itc.u-tokyo.ac.jp/oai
oai:repository.dl.itc.u-tokyo.ac.jp:00032633
2022-12-19T05:17:16Z
80:4535:4639:4647
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Shallow seismic reflection profiling across the central part of the Tokachi active fault zone, Hokkaido, Japan
反射法地震探査による十勝活断層帯中部の浅層構造
越後, 智雄
126436
宮内, 崇裕
126437
河村, 知徳
126438
佐藤, 比呂志
126439
蔵下, 英司
126440
加藤, 一
126441
井川, 猛
126442
川中, 卓
126443
折戸, 雅幸
126444
長谷川, 貴志
126445
伊藤, 谷生
126446
453
shallow seismic reflection method
Tokachi Plain
active fault (flexure) zone
deformed fluvial terraces
late Quaternary
application/pdf
The Tokachi active fault zone, a chain of active faults and flextures 80 km long from north to south, exists as the topographic boundary between the Tokachi Plain and the eastern uplands, Hokkaido, Japan. We carried out shallow seismic reflection profiling using a mini-vibrator to clarify the implications between surface deformation and subsurface structures of this fault zone at the most highly active area of the Makubetsu Plateau. The results obtained are as follows. Two distinct flexures are recognized in the seismic reflection profile. The western flexure is about 2 km wide and has at least a 0.25 to 0.30 second vertical displacement, whose sense is concordant with the deformation of the surface of the upper fluvial terraces geomorphologically identified as the Tobatsugawa fault. The eastern one also has the same deformation pattern of fluvial terraces as that geomorphologically identified as the Itaira fault. However, both geomorphic flexures are below one-sixth to one-third of the subsurface flexural zone in width. The seismic reflection method is necessarily required, to evaluate the net displacement of active flexural zone, in addition to morphotectonic observations.
departmental bulletin paper
東京大学地震研究所
2001-07-25
application/pdf
東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo
1
76
129
134
AN00162258
00408972
https://repository.dl.itc.u-tokyo.ac.jp/record/32633/files/ji0761012.pdf
jpn