| DC 欄位 |
值 |
語言 |
| DC.contributor | 地球物理研究所 | zh_TW |
| DC.creator | 葉秀柏 | zh_TW |
| DC.creator | Hsiu-po Yeh | en_US |
| dc.date.accessioned | 2010-7-23T07:39:07Z | |
| dc.date.available | 2010-7-23T07:39:07Z | |
| dc.date.issued | 2010 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=976202003 | |
| dc.contributor.department | 地球物理研究所 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 大地電磁法(Magnetotelluric, MT)已經普遍應用在深部的地球物理探勘中，利用大地電磁法可以描繪出地下的電性構造。為了瞭解台灣深部構造形貌，本研究初步整合台灣區域歷年的MT資料，挑選品質佳的資料，共計509個測站，透過Occam一維逆推運算(Constable et al., 1987)建立全台灣一維電性構造模型。進而嘗試使用Oldenburg and Li(1999)所提出的探測深度指標(Depth of investigation index, DOI)來避免「起始模型影響逆推運算結果而誤導解釋」的問題。
電性構造模型顯示，西部平原、麓山帶、中央山脈與海岸山脈各自有其明顯地不同的電性特徵：
(1) 西部平原與西部麓山帶在台灣西南部存在明顯低電阻帶，最深可達10公里，以下則是高電阻帶，其低電阻成因可能是較細小的沉積物填充高鹽度的孔隙水。這再次證實其沉積環境是海相，越往北則漸漸變成陸相的沉積環境，陸相的孔隙水屬於淡水，沉積物也變為粗顆粒，故電阻率高。
(2) 新竹苗栗一帶出現東西向延伸至中央山脈以下的低電阻帶，目前還不能確定此低電阻存在的成因，因其延伸方向隱約與琉球海溝平行，故推測或許此電性構造與板塊隱沒有關。
(3) 中央山脈地區主要的岩層電阻率較高，主要的組成為砂岩礫岩或者變質岩，但台灣北部及南部發現極低阻存在，且向下延伸至10公里以下，很有可能因孔隙率較大使電解液容易流通或發生部份熔融，造成電阻率呈現極低值。但是目前無法確定前述之台灣北部東西向的低電阻帶是否按照此機制。
(4) 海岸山脈地區呈現低電阻值，深度大約5-10公里，以下則為高電阻帶，其低電阻成因是風化的鐵鎂質火成岩與海相沉積物的混合物，並填充鹽度較高的孔隙水。這顯示海岸山脈的地層主要來自板塊隱沒所殘餘的海洋性地殼及其沉積物，因受擠壓而形成海岸山脈。
| zh_TW |
| dc.description.abstract | The purpose of this study is to understand the geoelectrical structure of Taiwan. We used 1D-Occam inversion to get the earth-models of Taiwan. Moreover, we applied the depth of investigation index (DOI) proposed by Oldenburg and Li (1999) to avoid the misleading interpretation. The results show that the Coastal Plains (CP), Western Foothills (WF), the Central Range (CR) and Coastal Range (COR) have distinct electrical characteristics:
(1) There are low resistivity anomalies in CP and WF of southwestern Taiwan. The causes could be the fine sediments and the pore water of high salinity. This implies that the depositional environment is in the marine facies, which changes to continental facies to the north.
(2) We find out that the low resistivity anomalies exist in Hsinchu and Miaoli area. As the location is parallel to the Ryukyu trench, this electrical anomaly maybe related to the subduction of the Philippine Sea Plate.
(3) In the CR, the background resistivity is higher than WF’s at shallow depth, but it changes to low resistivity as the depth great than 10km.
(4) There are also low resistivity anomalies in COR. The reasons could be due to the weathered mafic igneous rocks and the pore water of high salinity. This indicates that the formation of the COR is mainly from remaining oceanic crust and some other sediments.
| en_US |
| DC.subject | 大地電磁法 | zh_TW |
| DC.subject | 電性構造 | zh_TW |
| DC.subject | Magnetotelluric | en_US |
| DC.subject | Geoelectrical structure | en_US |
| DC.title | 應用大地電磁法研究台灣地區之電性構造 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Geoelectrical structure of Taiwan base on magnetotelluric data | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |