2015阿拉善左旗Ms5.8地震区布格重力异常及归一化总梯度的构造意义  

Tectonic Implication of Images of Bouguer Gravity Anomaly and Its Normalized Total Gradient in 2015 Alashanzuoqi Ms5.8 Area

作　　者：吴桂桔[1] 申重阳[1] 谈红波 杨光亮[1] 

机构地区：[1]中国地震局地震研究所(地震大地测量重点实验室),武汉市洪山侧路40号430071

出　　处：《大地测量与地球动力学》2015年第6期936-940,共5页Journal of Geodesy and Geodynamics

基　　金：中国地震局地震行业专项(201308011);中国地震局地震研究所所长重点基金(IS201326126)

摘　　要：分析阿拉善左旗Ms5.8地震区区域布格重力异常与断裂带的展布关系,并重点利用苏海图-平罗-鄂托克旗实测剖面,计算得到较为精细的剖面布格重力异常和布格重力异常归一化总梯度(简称GH)图像。剖面结果分析表明:1)区域主要活动断裂均对应GH等值线的条带或切分局部区,这些部位一般显示强变形特征,如巴彦乌拉山山前断裂(F1)或阿拉善块体东南边界与约10km宽、延伸约30km深的西倾高GH变化带一致;2)阿拉善左旗Ms5.8地震的发震构造不是磴口-本井断裂(F3),但受F3控制;3)银川-平罗断裂(F6)为平罗8.0地震的发震构造,震源深度约15km。The paper firstly analyzes the relationship between the area of Bouguer gravity anomaly and faults. It mainly utilizes measured gravity section （Suhaitu-Pingluo-Etuokeqi）, and gets a more exquisite section of the Bouguer gravity anomaly, and a figure of normalized full gradient of the section of the Bouguer gravity a- nomaly （GH）. The results of the section show that： 1） The main active faults are corresponding with GH con- tour strip or cut local region, which generally show strong deformation characteristics. For example, the Bayan- wulashanshanqian fault （F1） or the southeast boundary of Alxa block is in accord with the western change belt of GH ; the belt is about 10 km wide and extends to about 30 kin. 2） The seismogenic structure of the Alashanzuoqi Ms5.8 earthquake is not Dengkou-Beniing fault （F3）, but is controlled by F3. 3） The Yinchuan-Pingluo fault （F6） is the seisrnogenic structure of Pingluo MsS. 0 earthquake, and its focal depth is about 15 km.

关 键 词：布格重力异常 归一化总梯度 阿拉善地块 鄂尔多斯西缘 银川-贺兰山隆起-吉兰泰活动断陷带 

分 类 号：P312[天文地球—固体地球物理学]