山腳斷層位於台北盆地西緣，為一正斷層且一般認為屬於活動斷層。而有鑑於台北盆地為人口聚集、工商發達地區，因此對於活動斷層之調查實為重要，而本研究主要利用淺層反射震測法配合已有之過去資料，並於關渡、蘆洲、五股及泰山地區實地施測，藉由震測剖面觀察地下地層反射訊號之解釋與連續性，以確認山腳斷層位態及特性。 根據本研究所獲得之震測剖面並配合盆地內鑽井資料，認為山腳斷層屬於活動斷層，且呈雁行排列，其走向由泰山至五股地區約為北偏東二十度，經五股一帶往北則有偏轉向東之趨勢，而斷層傾角則約為七十五度以上向東南方傾斜。此外山腳斷層為由不同斷層面所組成之斷層帶，盆地西緣之第三紀地層即為不同斷層面所錯開，呈現一階梯式陷落狀，因而造成基盤深度變化梯度極大；另藉由反射震測剖面之地層深度變化及鑽井資料顯示，第四紀沉積地層厚度變化頗巨，同時經花粉帶對比，推論山腳斷層應屬生長斷層之型態。 Due to highly cultivated development and intensively erosion in Taipei Basin, there is no more outcrops can be found and be located for the active Sanchiao fault locating along the western border of Taipei Basin. Using the shallow reflection seismic method to figure out its orientation of Sanchiao fault. Based on the field seismic survey, the strike of the Sanchiao fault from Taishan area about N20oE extends to Wu-Ku area, then along the border of Taipei Basin dipping to East and increases dipping to about 75oSE in Kuandu area. The seismic sections showed that Sanchiao fault penetrating through the bottom of Songsan formation, might be as an active fault. Additionally, Sanchiao fault consists of different fault plane that separate the rock basement of Taipei Basin into sections and result in a very steep gradient of rock basement near the western Taipei Basin area. According to the seismic profiles, logging data and palynological correlation analysis, one can convience Sanchiao fault might be a growth fault pattern.
