賈儀平臺灣大學:地質科學研究所劉慶怡Liu, Ching-YiChing-YiLiu2010-05-112018-06-282010-05-112018-06-282008U0001-0107200817140600http://ntur.lib.ntu.edu.tw//handle/246246/182848台灣位於環太平洋地震帶上，由於地震發生頻繁，各種地震監測設施密布，而且裝設了600多口的觀測井，記錄地震相關的地下水位反應，因此適合進行地震水文相關的研究。同震地下水位的變化在空間上的分布可以反映地震發生時大地應力的重新分布，本研究針對2000年6月11日發生芮氏規模6.7地震，探討地震相關之地下水位變化。全球衛星定位系統記錄顯示此次地震造成了地表變形，至於水位記錄分析結果指出，地震發生時，全台共有410口觀測井在記錄水位，其中112口記錄到同震水位上升變化，僅有14口出現同震水位下降變化，變化幅度從下降11公分到上升71公分。空間分布上西南平原出現反應的觀測井以上升變化為主，但其中濁水溪沖積扇接近丘陵的井位，以及嘉南平原之部分井位出現下降反應。位於濁水溪沖積扇上、臨近震央的觀測井反應比例最高，共有98口出現同震變化，其中坪頂一號井除了同震上升22公分外，並於震前一小時出現了5公分異常下降的水位變化。井深204公尺的坪頂一號井位於斗六丘陵的北端，井篩開設於半固結的礫石含水層中，比對1997年至2005年之間發生芮氏規模大於5.5的地震，曾出現13次同震水位反應，大多為水位上升的變化，而且這13次地震的震央機乎都在台灣中部及其外海。在所有同震反應中，2000年芮氏規模6.7地震前的水位下降及同震水位上升變化皆具其獨特性，可能反映了地震引發的現地應力改變及地震發生前地殼的應變狀況，而且符合地震發生時應變出現彈性回跳的理論。Taiwan is located in the Circum-Pacific seismic belt. As earthquakes occurred frequently, various earthquakes monitoring devices have been placed all over this island. More than 600 wells have been installed to monitor earthquake-related groundwater level changes. Co-seismic groundwater level changes may reflect tectonic stress redistribution and crustal strain. This study focuses on the responses of groundwater level recorded by monitoring wells to the 2000 ML6.7 earthquake. When this earthquake occurred, ground deformation was recorded by Global Positioning System data. From the analysis results of water-level record, 410 wells were operational while co-seismic rises were observed in 112 wells and only 14 wells observed co-seismic falls, where the amplitude of co-seismic changes range from 71cm rise to 11cm fall. In spatial distribution, wells located in Southwest plain of Taiwan react as rises, but wells that are near hills and some in Chianan plain react as falls. Monitoring wells located in Choushui river alluvial fan are near to the epicenter and have a high reacting ratio, which 98 wells observed co-seismic water-level changes. One of the well named Pingding No.1 well (PD1) not only reflect 22cm co-seismic water-level change, but also show an abnormal 5cm water-level change one hour before the co-seismic water-level change. The 204m deep well is located at the northern tip of the Douliu Hill, and was installed in an aquifer consisting of semi-consolidated deposits. Further analysis indicated that 13 co-seismic water-level changes were observed in response to earthquakes of magnitude greater than 5.5 during the 1997 to 2005 period; most of the changes are rises. The epicenter of these 13 earthquakes mostly locates around central Taiwan and its outer sea area. Among all the co-seismic responses, the phenomenon due to the 2000 ML6.7 earthquake shows its uniqueness, which might imply the change of tectonic stress induced by earthquake and crustal deformation caused by strain. This phenomenon consists with the poroelastic rebound theory.口試委員會審定書 i謝 ii文摘要 iii文摘要 iv錄 v目 vii目 xi一章 緒論 1-1 研究動機及目的 1-2 研究資料來源 3-3 研究方法 6二章 文獻回顧 7三章 2000年6月11日仁愛地震分析 11-1 仁愛地震 11-2 觀測井之同震水位反應及區域分布 16-3 地下水位同震反應型態 19-4 同震地下水位變化與震源距離之關係 22-5 濁水溪沖積扇三條剖面同震反應量的比較 24-6 複井水位分析 30四章 坪頂一號井地震相關的水位變化 32-1. 仁愛地震相關之異常水位 32-2. 2000年地下水位變化分析 33-3. 坪頂一號井的建構及水文地質背景 36-4. 地下水位對1997年至2005年芮氏規模5.5地震之反應 38-5. 同震水位變化與地震震央距、深度及地震規模之關係 45-6. 坪頂一號井分水位試測資料 45五章 討論 50.1 仁愛地震震源機制對同震水位升降分布的影響 50.2 坪頂一號井水位對地震之反應 52.3 坪頂一號井震前水位異常變化現象 54六章 結論 55考文獻 56錄A 2000年6月11日仁愛地震複井觀測站同震水位反應圖 59錄B 坪頂一號觀測井試測資料水位歷線圖 75application/pdf3676192 bytesapplication/pdfen-US地震地下水同震震前earthquakegroundwaterco-seismicpre-seismicthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/182848/1/ntu-97-R95224109-1.pdf