本研究採用58條橫跨正交於車籠埔斷層主斷裂帶及集集地震斷層與16條橫跨及位於梅山斷層破裂帶之電阻率影像剖面探測，針對車籠埔斷層及其破裂帶兩側之地質構造、梅山斷層在開元後地區至豐收村範圍內之地下構造，從地層電阻率的觀點去分析斷層帶的特性、位態與形貌，及其兩側地層的電阻率與對應的岩性及其所屬的地層。 1. 在石岡－豐原地區，斷層傾角約60°-80°向東。在大甲溪北側的一條破裂線其寬度在地表約30公尺，在深度30-80公尺間為10-15公尺。在大甲溪南側之斷層破裂帶寬度在西側約為90公尺。豐原地區斷層破裂帶寬度在地表約90公尺，在深度30-120公尺間為60公尺。集集地震斷層破裂帶在石岡地區位於卓蘭層中，而在豐原地區則位於錦水頁岩層中。 2. 在潭子地區，車籠埔斷層主斷裂帶與集集地震斷層相距300-800公尺；后里斷層之斷層傾角在深度0-120公尺為15°-25°向東，深度120-3000公尺約30°-50°向東；集集地震斷層之斷層傾角在深度0-120公尺為30°-40°向東，深度120-3000公尺約25°-35°向東；后里斷層在接近地表處將三義斷層截切，三義斷層之在深度50-120公尺約30°-40°向東；集集地震斷層破裂於卓蘭層中；車籠埔斷層主斷裂帶在淺部上盤為錦水頁岩，下盤為頭嵙山層；三義斷層上盤為桂竹林層，下盤為頭嵙山層。在台中市地區集集地震斷裂處則位於車籠埔斷層主斷層帶上，淺部之斷層傾角約55°-65°向東。 3. 在霧峰地區集集地震斷裂處位於車籠埔斷層主斷層帶上，斷層傾角50°-70°向東南。斷層上盤為錦水頁岩，下盤為沖積層與頭嵙山層。 4. 在草屯地區集集地震產生數條破裂，集集地震斷層在此處並不是沿著車籠埔斷層主斷裂帶破裂，破裂面向東偏移，斷層傾角50°-60°向東，但這些破裂並不是集集地震所產生之新的斷裂，而是之前就已活動多次。集集地震所產生的背衝斷層斷裂於卓蘭層中，斷層傾角40°-70°向西；南端存在數條破裂面，其傾角高角度接近垂直。 5. 在南投－名間－竹山段，集集地震斷層是沿車籠埔斷層主斷裂帶或是附近破裂，斷層傾角大多為50°-70°向東，部份地區斷層面成階狀。車籠埔斷層在此段已活動多次。 6. 在竹山－桶頭段，集集地震斷裂沿大尖斷層發生，大尖山斷層是車籠埔斷層之南向延伸，破裂於卓蘭層與桂竹林層中，斷層傾角60°-70°向東，地表淺部破裂帶寬50-100公尺。 7. 車籠埔斷層沿線分布之地層電阻率分別為沖積層60-2400 Ω-m、階地堆積層100-2400 Ω-m、頭嵙山層100-4000 Ω-m、卓蘭層5-100 Ω-m、錦水頁岩5-60 Ω-m及桂竹林層5-150 Ω-m。 8. 梅山斷層主斷裂線在崎腳與開元後至大埔美農場地區為南側之頭嵙山層之香山相逆衝至北側之紅土台地堆積層上，在麻園寮地區斷層南側為階地堆積層，北側則為沖積層，斷層傾角65°-75°向東南；副斷裂帶傾角高角度接近垂直。 9. 梅山斷層沿線分布之地層電阻率分別為沖積層20-500 Ω-m、階地堆積層200-400 Ω-m、紅土台地礫石層200-4000 Ω-m、頭嵙山層40-300 Ω-m。 10. 由梅山斷層之主斷裂線與副斷層帶之分布顯示，梅山斷層有多次活動，地層破裂寬度在崎腳與開元後至麻園寮地區可能至少達1200公尺寬。We conducted electric resistivity surveys consisting of fifty-eight resistivity image profilings across the Chelungpu fault zone and sixteen resistivity image profilings in the Mei-Shan fault area to investigate the character, attitude, resistivity of layers and the subsurface structures of the two faults. 1. The Chi-Chi earthquake fault dips 60°-80°eastwardly in the Shihkang-Fengyuan area. The fracture zone is about 30 meters wide on the ground surface and is 10-15 meters in depth of 30-80 meters in the northern side of the Tachia river. The one of the Chi-Chi earthquake fracture zone is about 90 meters wide in the southern side of the Tachia river. The fracture zone is about 90 meters wide on the ground surface and is 60 meters in depth of 30-120 meters in the Fengyuan area. The Chi-Chi earthquake rupture developed in the Cholan Formation in the Shihkang area and in the Chinshui Shale in the Fengyuan area. 2. In the Tanzi area, the main shear zone of the Chi-Chi earthquake rupture is 300-800 m apart to the east of the Chelungpu fault on the ground surface. The Chelungpu fault dips 15°-25°eastwardly in depth of 0-120 m and about 30°-50° in depth of 120-3000 m. The Chi-Chi earthquake rupture dips 30°-40°eastwardly in depth of 0-120 m and about 25°-35° in depth of 120-3000 m. Sanyi fault is cut by the Chelungpu fault near the ground surface and dips 30°-40° eastwardly in depth of 50-120 m. The Chi-Chi earthquake rupture developed in the Cholan Formation in this area. The main shear zone developed in the boundary between the Chinshui Shale and the Toukoshan Formation. The Sanyi fault developed in the boundary between the Kueichulin Formation and the Toukoshan Formation. The Chi-Chi earthquake rupture in Taichung developed in the main shear zone and dips about 55°-65° eastwardly. 3. The Chi-Chi earthquake rupture in the Taichung area developed in the main shear zone which developed in the Chinshui Shale on the hanging wall and in the alluvium and the Toukoshan Formation on the foothill and dips about 50°-70°east-southwardly. 4. The Chi-Chi earthquake rupture is a reverse fault including several fracture zones in the Tsaotun area and dips 50°-60° eastwardly. Not all the fractures of the Chelungpu fault system moved during the Chi-Chi earthquake, but they were active previously. The back thrust developed in the Cholan Formation and dips 40°-70°westwardly. Several fracture zones exists in the south end of the back thrust and there dip angle are vertical approximately. 5. In the Nantou-Mingjian-Zhushan area, the Chi-Chi earthquake rupture developed in or near the main shear zone of the Chelungpu fault and dips 50°-70°eastwardly. The fault zone is the shape of stairs in several areas. The Chelungpu fault has been very active in this area. 6. In the Zhushan-Tongtou area, the Tachienshan fault which developed in the boundary between the Cholan Formation and the Kueichulin Formation is the southward extension of the Chelungpu fault and dips 60°-70°eastwardly. The fracture zone is 50-100 m wide on the ground surface. 7. The resistivity of the layer along the Chelungpu fault are alluvium 60-2400 Ω-m, terrace deposits 100-2400 Ω-m, Toukoshan Formation 100-4000 Ω-m, Cholan Formation 5-100 Ω-m, Chinshui Shale 5-60 Ω-m and Kueichulin Formation 5-150 Ω-m. 8. The main shear zone of the Meishan fault developed in the boundary which the southern the Hsiangshan Facies of the the Toukoshan Formation thrust to the northern lateritic terrace deposits in the Kaiyuanhou-Dapumei farm area and developed in the boundary between the southern terrace deposits and the northern alluvium in the Mayuanliao area. The main shear zone dips 65°-75°east-southwardly and the dip angle of sub-ruptures are vertical approximately . 9. The resistivity of the layer along the Meishan fault are alluvium 20-500 Ω-m, terrace deposits 200-400 Ω-m, lateritic terrace deposits 200-4000 Ω-m, Toukoshan Formation 40-300 Ω-m. 10. The distribution of main shear zone and the sub-rupture of the Meishan fault shows the fault zone may be 1200 m wide at least in the Kaiyuanhou-Mayuanliao area.
