拉萨盆地隐伏断裂浅层反射地震探测及断层活动性分析

Shallow Seismic Reflect Exploration and Fault Activity Analysis of the Buried Faults within Lhasa Basin

为探测拉萨山间盆地隐伏活动断裂,采用人工震源的浅层地震勘探方法,提出了该地区地质条件下隐伏断裂勘探时震源选择、观测系统设计以及参数确定、数据处理与资料解释、断层识别的基本方法,查明了娘热断裂、那林拉卡断裂、拉萨断裂、夺底断裂的走向、倾向、上断点埋深及其在地表的垂直投影位置等主要参数,探测表明拉萨市城近地区发育有娘热、那林拉卡、拉萨、夺底等4条北西-北西西向断裂;娘热断裂和夺底断裂近垂直或高角度北倾,为逆走滑或走滑断层;那林拉卡断裂和拉萨断裂近垂直或高角度南倾为主,也是逆走滑断层;娘热、那林拉卡、拉萨、夺底等4条断裂均为晚更新世活动断层,平均垂直滑动速率为0.27~0.40 mm/a。为拉萨盆地及周边地区活动断层研究提供了基础资料,填补了该地区浅层地震勘探资料的空白。

Based on the artificial source of shallow seismic acquisition method the active faults buried within Lhasa inter-mountain basin is detected.The key technical problems are discussed for seismic profiling of buried faults in this geological condition.The choice of seismic instruments,scheme design,parameter selection,data processing,data interpretation and the method of fault recognition are put forward.The main parameters such as strike,dip direction,upper break-point and so on were ascertain in Niangre fracture,Nalinlaka fracture,Lhasa fracture and Duodi fracture,providing the first information for active fault research in Lhasa area.