Investigating the Tzuojen Fault and Nearby Structures by Seismic Reflection Method

Chien-YingWang

Abstract

The Tzuojen fault lies Shinhua hills area. The fault, length is about 11 kilometers. As a result of absence maturely geological survey. The fault is ranked as a ‘suspect’ fault in the Chinese Geologic Survey’s (CGS) active fault list. This research uses the seismic reflection method to study the Tzuojen fault including the location and the configuration of the fault. The possible mechanism of the fault’s evolution is also under investigation.

The Tzuojen fault location west out of deformation front southernmost. Cause for the deep profile by seismic reflection data, we can divided into the northern and southern parts. At the northern part, the structural style controlled by Peikang High which displayed a ‘pop up’ forms. At the southern part, the structural style displayed a ‘Triangle’ forms. And we also can be found of the similar condition in GPS data. The GPS displacement field was south of the Tzuojen fault (to Bai Sha of Penghu) that was obvious difference with the north side. The GPS displacement field of the north side was in the northwest direction that turned to the west and southwest direction gradually in the southern side. It mean the Tzuojen fault may be an important geological boundary.

The Tzuojen fault didn’t through the Chukou fault, its been cut by the Chukou fault. In the northwest of the Tzuojen fault, the variation of the structural strata are relatively gentle, forming the Da-nei structural flat area. The strata is only crooked and out of shape slightly in this area, and the main river ‘Tseng-wen river’ of this area were located in flowing through crookedly the strata. that shows the surface controlledly by the underground structure. Both sides of the Tzuojen fault has obvious difference, it is very complicated to structure in the north side of the fault that exist a series of folds. In the southern side of the fault, it is relatively flat.

Integrate above-mentioned method, the Tzuojen fault seem has not had fatalness, but its meaning in geology should not be underestimated.

 

Reference

黃旭燦，2004. 台灣中南部褶皺逆衝斷層帶地質構造特徵分析，國立中央大學地球物理研究所博士論文，131頁。

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