應用可攜式地磁儀探測土石流淤埋設備

Applying Portable Magnetometers to Detect Buried Instruments After a Debris Flow Event

周憲德(Hsien-Te Chou) ； 黃郅軒(Chih-Hsuan Huang) ； 顏宏元(Horng -Yuan Yen) ； 蔡道賜(Tao-Ssu Tsai)

《中華水土保持學報》 51卷4期 (2020/12) Pp. 140-146

https://doi.org/10.29417/JCSWC.202012_51(4).0002

摘要

2013年7月13日中度颱風蘇力侵台，所挾帶豪雨於苗栗三義火炎山誘發土石流，並沖毀設置於一號坑溪溝左岸的土石流監測儀器箱。土石流在岸外淤埋深度超過2.5 m，掩埋範圍超過100 m^2。因鐵質儀器箱會造成地磁場局部範圍之變化，本研究團隊於2015年2月16日－4月6日間經人工挖掘，並應用可攜式地磁儀進行探測，觀察各次磁力探測所得磁力異常圖之變化。儀器所埋位置之熱點為地磁差值梯度變化劇烈處以及地磁差值靠近零線區位，並據此推估挖掘土方之範圍，本次探測結果證實地磁計可有效應用於小範圍地下埋設鐵箱設備之探測。挖掘坑邊壁的粒徑分布則顯示礫石型土石流在堆積過程具有基質支撐及含泥量高等特性。

關鍵字

可攜式地磁儀 ； 磁力異常 ； 地表下探測 ； 土石流

並列摘要

A debris flow triggered by 575 mm of rainfall over a 24-h period during Typhoon Soulik on July 13, 2013 buried debris-flow monitoring equipment in the gully 1 catchment at Houyenshan, Miaoli, Taiwan. The buried depth and covered area exceeded 2.5 m and 100 m^2, respectively. Portable magnetometers were later deployed to detect a buried iron instrument case, and manual excavation was conducted from February 11 to April 6, 2015. The geomagnetic characteristics of the hot spots for the buried equipment exhibited both a high geomagnetic gradient and a null value on the magnetic anomaly contour map. The particle size distribution in the excavated pit indicated that the gravelly debris flows were both matrix-supported and muddy during the deposition process.

並列關鍵字

portable magnetometer ； magnetic anomaly ； subsurface prospecting ； debris flow