大庆长垣西缘断裂浅部构造特征

大庆石油物探资料结果表明,大庆长垣西缘断裂的上盘,即东侧的北西向断裂可能存在第四纪活动断裂。为了确定大庆长垣西缘断裂的空间展布以及该区的地壳浅部地质构造特征,本项研究布设了2条跨大庆长垣西缘断裂的浅层地震探测剖面。结果表明,大庆长垣西缘断裂表现为走向北东、倾向南东的逆断层,为一条中生代晚期活动断裂。断裂的上盘,即东侧发育有一系列次级断裂,断裂的断层性质以及断层倾向多样化,两条测线东部均发育错断第四纪地层的断层,使得该区浅部地层形成地堑与地垒构造。本项研究不仅可进一步提高对大庆长垣地区浅部构造特征的认识,而且为大庆市地震危险性评价提供依据。

Shallow Tectonic Characteristics of the Changyuan Western Margin Fault of Daqing

The results obtained from Daqing petroleum geophysical data suggested that there may be buried quaternary active faults in the increase plate of the Changyuan western margin fault. In order to determine shallow tectonic characteristics and the geometry of buried fault, two shallow reflection profiles crossing the buried fault was completed in the region of Changyuan in Daqing. The results show that the Changyuan western margin fracture of Daqing is a NE trending reverse faults, and is active in late Mesozoic. There are series of secondary faults on the increase plate; and the fault properties are various and the fault trending tend to diversification. Changyuan western margin fault is of normal mode cutting the Quaternary strata in the eastern of L2 line, which makes the shallow strata as a graben with horst. The results of our study may not only further improve the understanding of the characteristics of shallow structures in the Daqing area, but also provide a basis for the earthquake hazard assessment of Daqing.