臺東金崙地熱區微震測勘初步研究

A preliminary microearthquake survey in the Taimali-Chinlun geothermal area, Taitung

羅仕榮(Shyh-Zung Lo) ； 林國安(Kuo-An Lin)

《鑛冶：中國鑛冶工程學會會刊》 28卷3期 (1984/09) Pp. 133-138

https://doi.org/10.30069/MM.198409_28(3).0013

摘要

臺東太麻里金崙地區經55天之初步微震勘測結果，共定出規模介於0.52至2.10之微震119次。微震震央在大溪、臺坂村之間有呈東北－西南方向帶狀分佈趨勢，可能與由合成斷層面解推測之左移斷層有關（走向N44°W，傾角80°W）。地質調查所推測之斷層位置，溫泉附近有僅少許微震發生，地表地熱徵兆強烈之比魯、金黃兩溫泉區幾無微震，可能位在本次微震震網有效涵蓋範圍以外，或係觀測時間不够長未能有效偵測。由大屯山、清水土場、花蓮瑞穗等地熱區微震震源深度分佈有一明顯下限值存在，而非地熱區的楊梅、豐原地區微震震源深度分佈則無明顯的下限，經與地球化學分析，鑽探結果比對，發現地熱區之微震震源深度分佈之下限值與地熱源相對深度有密切關係。本區震源深度分佈集中於地下20公里以上，推測本區地熱源來自相當深部地層。根據本次微震測勘及中央研究院環島測震網在本區所測獲之微震資料，配合其他地熱探勘資料，供作地熱探勘解釋應用。

並列摘要

A preliminary microearthquake survey have been conducted in the Taimali-Chinlun geothermal area for 55 days from Dec. 15, 1982 to Feb. 10, 1983. The epicentral distribution of microearthquakes between Tahsi and Taifan showed in a southeast-northwest elongated zone. It may be correlated to the left-strike slip fault which was deduced from the composite fault-plane solution. The rest of epicenters did not show any relationship with the hot springs' joints, cleavages, surface fractured zones and faults which were infered by geological survey, and the structural lines which were explained by SLAR due to their random distributions. Based on the study of distributions of focal depths, geochemical analysis and drilling which have been done in some other geothermal areas, there is a lower limit of focal depths which is closely correlated with the relative depths of geothermal sources. The focal depths in the Taimali-Chinlun geothermal area are within 17 kilometeers, It may imply that the geothermal sources in this area are very deep. In order to understand the relationship between microearthquake and geothermal exploration in details, further microearthquake data are needed.