华北地区的水平运动场与昆仑山8.1级地震的可能关系

POSSIBLE RELATION OF HORIZONTAL MOVEMENT FIELD IN NORTH CHINA TO KUNLUN MOUNTAIN Ms8.1 EARTHQUAKE

为从整体上把握区域应变场的时-空变化态势并更加真实地描述区域运动场,在区域无旋转的基础上,使用以提取中、低频应变信息为主的连续应变模型,利用“中国地壳运动观测网络”在华北地区400余个GPS测站的复测资料(1999年、2001年和2004年),分析了华北地区1999～2001年水平运动场的空间变化及2001～2004年相对于1999～2001年运动的差异性变化,结果表明:1)华北地区非均匀应变比较明显,不同时段的结果在空间上的表现形式也不一样;2)前后两个时段的运动具有明显的不一致特性;3)2001年昆仑山8.1级地震等事件对华北地区地壳变形可能起主要控制作用,使华北地区在东西向出现明显的拉伸;4)从整体上讲,2001年昆仑山8.1级地震等事件的发生对华北地区积累的能量具有一定程度的减缓与释放作用,华北即将进入强震活动期的条件似乎还不完全具备。

In order to have a good grasp of the space-time variation trend of regional strain field on the whole and describe regional movement field more vividly, on the basis of the region with no rotation, by use of the repeatedly measured GPS data（ in 1999,2001 and 2004） come from more than 400 GPS monitoring stations in North China in the Project of ＂China Crust Movement Measuring Network＂ , the space variation of horizontal movement field during 1999 -2001 in North China and the distinction of variations of horizontal movement field during 2001 -2004 in contrast with that during 1999 -2001 are analyzed with continuous strain model focused on extracting mediumlow frequency strain information. The results show that firstly, the uneven strains in North China are obvious, resuits in different periods are distinct from each other on space ; secondly , the movements of former and latter periods are inconsistent obviously; thirdly, Kunlun Mountain Ms8.1 earthquake in 2001 may act as the main role in controlling the variation of crustal deformation in North China , and cause an obvious extension along the EW direction; fourthly, as a whole, Kunlun Mountain Ms8. 1 earthquake in 2001 decreased and released the accumulated energy in North China to a certain degree. North China may not enter into strongly seismic activity period soon because there has not been the enough condition yet.