2010年玉树Ms7.1地震前的重力变化

利用中国地壳运动观测网络1998—2008年绝对重力和相对重力观测资料，获得了玉树地震区域重力场及其动态变化，从动态的观点研究了2010年4月14日玉树Ms7.1地震前区域重力场演化特征及其与地震活动的关系。结果表明：1)重力变化与甘孜 玉树断裂构造活动存在密切的空间联系，重力测量较好地反映了伴随活动断层的物质迁移和构造变形引起的地表重力变化效应；2)区域重力场动态图像较完整地反映了2010年4月14日玉树7.1级地震孕育、发生过程中出现的流动重力观测得到的异常前兆信息；3)玉树震中附近重力点值时序变化累积量超过80× 10^-8 ms-2,较好地反映了玉树地震前重力测点随时间的剧烈波动性上升变化。

GRAVTITY CHANGES BEFORE YUSHU Ms7.1 EARTHQUAKE,2010

On the basis of the absolute and relative gravity observations of the national major scientific project—China Crustal Movement Observation Network from 1998 to 2008，gravity field and its dynamic variations of Yushu earthquake are obtained, and the evolution characteristics of regional gravity field and its relation with the seismic activity before and after Yushu Ms7.1 earthquake occurred on April 14,2010 are studied in the sight of dynamics. The results show as follows. 1)The gravity change are closely related to Ganzi Yushu active fault i.e., the gravity observation can reflect material migration accompanying active fault and crustal tectonic activity well. 2)The dynamic variation images of gravity field reflect the anomalous informations of the gravity field observed with mobile survey with the development and occurrence of Yushu Ms7.1 earthquake clearly. 3)Temporal changes of gravity points nearby Yushu epicenter amount to more than 80×10 ^-8 ms ^-2 ,it reflected wavelike rises with gravity change before Yushu earthquake in time.