【摘要】 近些年来一些地震表明,强震不仅发生在地表出露的活动断裂上,还发育在一些隐伏的未出露地表的构造上。大陆内部块体间的变形带不只是一条活动断裂,而是具有很大宽度的构造变形带,这已被大量的地震活动性资料所证实。因此,要正确评估地震危险性,就要研究构造带上地层变形的模型,而不仅是单条断裂的变形。湟水河隐伏断裂为一条隐伏在西宁市的断裂,位于西宁盆地中部,长12km,走向EW,浅层地震探测结果表明该断裂由两条正断层组成地堑式构造,横跨西宁地区的地层剖面研究结果指出湟水河隐伏断裂发育在宽缓背斜的核部,而宽缓的背斜和向斜由新近系红色泥岩组成。根据褶皱与断裂的关系认为,湟水河隐伏断裂为在北东向的区域主压应力作用下,褶皱变形过程中,在背斜的核部伴生形成的次级张性地堑式正断层。该褶皱及相关断裂发育在西宁盆地滑脱面之上,属于浅表性的断层,活动性不显著。更多还原

【Abstract】 A few facts observed in recent years show that strong earthquakes occur not only in the exposed surface of active faults but also in some concealed structures.The deformation zone is not only an active fault in the mainland block but also a structural deformation zone with great width,as has been confirmed by a lot of seismic activity data.In order to correctly assess the risk of earthquakes,it is necessary to study the deformation of the stratigraphic model of the structure instead of studying only a single fault.The Huangshui River concealed fault is buried under the city of Xining,and the shallow seismic survey results show that the rupture fault is composed of two normal faults,and the area is across Xining City.Based on a study and analysis of the stratigraphic section,the authors hold that the broad anticline and syncline are composed of Neogene red mudstone,which was formed through deformation.The Huangshui River fault was developed in the core of the anticline,as shown by the relationship between the folds and faults.The Huangshui River concealed fault was formed under the main pressure in northeast direction,composed of two normal faults in the core of the anticline.The fault is on the slideway of Xining basin and belongs to a superficial fault,whose activity is not significant.更多还原