1999 年，Mw7.6 的集集地震在臺灣的車籠埔斷層北部產生了約10 米的滑動。本研究分析來自臺灣車龍埔斷層深鑽計畫（Taiwan Chelungpu fault Drilling Project；TCDP）中可能記錄同震事件的黑色斷層泥中的主要滑動帶（Principal Slip Zone；PSZ）來估計 破裂能量及推斷該區域可能的斷層機制。透過場發射掃描式電子顯微鏡，穿透式電子顯微鏡和軟體ImageJ 的分析，我們根據顯著的裂隙和顆粒粒徑的差異將黑色斷層泥分為六層。由於微構造的分析顯示第一層中沒有明顯的破裂及剪切特徵，與目前鑑定之主要滑動帶特徵相似，因此我們將其認定為集集地震的主要滑動帶，並與其他層進行比較。有趣的是，第三層和第五層在微構造的特徵上與第一層相似。由於有奈米顆粒的富集，第一層、第三層和第五層具有相似的碎形維數和模式。此外，第五層具有尚未變形的紋理，暗示該層的產生是經由最近的同震事件，類似於第一層。由於斷層滑動形成的Clay Clast Aggregates (CCAs)在第五層中不能被觀察到，而卻產生在第一層中，表明第五層的物質可能由第一層注入。我們認為第三層可能是舊的同震事件的主要滑 移帶。由於其本身變形裂縫的特徵，這可能是由於其厚度大於Chi-Chi 的事件。此外，車籠埔斷層的地震破裂似乎不會產生巨大的破裂能，而是轉由釋放摩擦熱。;The 1999 Mw7.6 Chi-Chi Earthquake produced ~10m slip along the northern Chelungpu fault in Taiwan. This study aims to recognize the Primary Slip Zone (PSZ) in the black gouge from Taiwan Chelungpu-fault Drilling Project (TCDP) sample material which might experience past coseismic events, estimate the fracture energy and infer plausible faulting mechanism in this region. By means of Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and ImageJ analysis, we divide the black gouge into six layers according to the distinguished fracture and grain size. Layer-1 recognized as the Chi-Chi PSZ showing a massive structure, was utilized to compare with all layers. Interestingly, Layer-3 and Layer-5 are microstructurally similar to Layer-1. Because of the abundance of nanoparticles, Layer-1, Layer-3, and Layer-5 have similar fractal dimensions and patterns. Layer-5 has a not-yet-deformed texture implying this layer produced by the recent event, similar to Layer-1. CCAs, as formed from fault sliding, cannot be observed in layer-5 while it occurs in layer-1, suggesting that this layer-5 may have injected by the layer-1. Layer-3 is suggested as the PSZ of the ancient coseismic event from its deformation fissure which may have resulted from a larger event than Chi-Chi from its large thickness. Chelungpu fault seems to have a small fracture energy value that the huge remaining part of breakdown work released as the frictional heat.
