利用三分量磁力資料對大屯火山底下之電導率初探

The Preliminary Result of the Electrical Conductivity under Tatun Volcanoes by using Fluxgate Magnetic Data

楊元中(Daniel Yang)

指導教授 ： 顏宏元

國立中央大學/地球科學學院/地球科學系/碩士(2015年)

摘要

台灣北部大屯火山群至今仍存在明顯的火山活動，且鄰近於人口稠密的大台北地區，因此對於火山活動的監測以及火山構造的探勘仍然是現今重要的研究。台灣過去利用地磁資料對於構造之研究，皆為利用全磁場磁力儀所獲得之資料對於磁感率構造作探討。本研究利用三分量磁力資料，藉由磁場轉換式得到地磁場垂直向(Z)和水平向(X、Y)之間的關係，並利用此關係得到帕金森向量在研究時間內的分布。
本研究於2014年5月陸續架設之三分量磁力儀，加上原有位於陽明山觀測站之三分量磁力儀，分別計算各測站於不同深度帕金森向量之分布情形，並將其結果結合得到高電導率之塊體所存在之位置。研究結果顯示在六公里的深度，高電導率構造出現於小油坑附近地區底下;七公里深的深度在竹子湖站東邊有一明顯之帕金森向量集中區;八公里深之結果則在大油坑底下出現集中區;九公里以及十公里之結果則是在大油坑及小油坑之間底下區域存在著帕金森向量的集中區。將本研究與前人於大屯火山群區域所做之研究做比對，其結果類似，推測其構造和地底熱液作用有關。

關鍵字

磁力 ； 大屯火山 ； 電導率

並列摘要

There is still volcano activities exist under Tatun volcanoes, which is in the vicinity of Taipei, a densely populated area. Due to the potential hazard that could happen at the area, monitoring of the volcano activity and the exploration of the underground structure is an important subject to the area. In Taiwan, the studies that used geomagnetic data to explore the magnetic susceptibility structure are all done by using total filed geomagnetic data. In this study, we used 3-components magnetic data and through the magnetic transfer function, we obtained the relationship between the vertical component (Z) and horizontal components (X, Y). And we used the relationship to calculate the distribution of Parkinson vectors at three stations in different depth.
In this study, we used the data recorded by the magnetometer that we installed in May 2014 and the magnetometer at Tatun volcano observatory to calculate the distribution of Parkinson vectors at three different stations. After combining the separated results together, we were able to detect the location of high conductivity area. In the result of 6 km deep, the Parkinson vectors focused area is located beneath Hsiaoyoukeng area; at the depth of 7 km, the Parkinson vectors are focus beneath the east part of ZHU station; The result of 8 km deep shows that the location of high conductivity area is located beneath Tayiokeng area; In the result of 9 and 10 km deep, there are both one obvious focused area exists in the center of the study area. Compare ours and the one whcih have been done by the others, the results are similar and we speculate that the high conductivity area is related to the hydrothermal activity under Tatun volcanoes.

並列關鍵字

Tatun Volcanoes ； Fluxgate Magnetic Data ； Electrical Conductivity

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