碩士 / 國立中正大學 / 地震研究所 / 102 / The Ilan Plain is situated at the southwestern tip of the Okinawa trough. The triangle-shaped Ilan Plain is bounded by the Shiehshan range in the northwest and the Central range in the south. Although there were many studies conducted, subsurface structure of the Ilan Plain was still not clear. In this paper, we use 19 shallow seismic reflection profiles and 25 core borings to reveal the subsurface structure beneath the Ilan Plain. Results of the study should be able to provide a preliminary three dimensional image for understanding the sediments deposited and the active structures beneath the plain. Integrating seismic images with the interval velocities and results from core borings, we may find that the Ilan Plain is situated on top of a graben. The structure was mainly formed by subsidence of two normal faults; one is located in the south and dipping to the north, and the other is in the north and dipping to the south. In addition to the two main faults, many minor high angle normal faults can be traced in the seismic images as well. On top of the Tertiary basement, we may divide the Quaternary sediment into two zones by a significant interface. The depth of the deepest part of the basement was around 880 m, which is located in the center of the Ilan Plain at north of the Lanyang River. From the deepest part of the basement, we may see the depths of the basement were fast reduced to around 463 m toward the south and the north first, and then the variations were become smaller. It were also reduced to around 320 m toward the west slowly. Subsidence of the graben was gradually reduced along the two normal faults after the early Quaternary; therefore, thicknesses of the Quaternary sediment from south to northward have only minor variation.
| Identifer | oai:union.ndltd.org:TW/102CCU00140001 |
| Date | January 2013 |
| Creators | Tsung-Chi Chen, 陳宗祺 |
| Contributors | Ruey-Chyuan Shih, 石瑞銓 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 149 |
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