从重复重力测量资料中提取河西—祁连地区的地震特征的研究

STUDY ON THE EANTHQUANE CHARACTERISTICS FROM REPEATED GRAVITY SURVEY IN HEXI-QILIAN

利用富里叶分析法分离出了河西—祁连地区重力变化的长波项和短波项，并结合该区的几次地震进行了分析研究，得到以下初步认识：１．长波项图象特征表明，地震前地壳深处物质的迁移性运动是地震活动的背景性因素；短波图象则是地震发生前的异常表现。２．无论是长波项，还是短波项，在地震前其图象都有高梯度带，但其物理意义不同：长波图象的高梯度带是由于地壳深部的结构不同，使物质迁移受到一定程度的阻档所致；短波图象的高梯度带则是未来地震的危险地带。３．河西—祁连地区的垂直力源的局部性和短暂性的根源在于形成力源的地壳深部物质迁移的局部性和短暂性。

In this paper, the long wave and short wave were separated from gravity deformation in Hexi-Qilian area by using Fourier analysis method,then a study has beed completed by combining with several earthquakes.The results show that:1.The long wave shows that the material migration in the deep crust before earthquake is the background of earthquake activity, but the short wave is the warning signs of earthquake.2.Not only the long wave item, but also short wave item have high gradient zones before earthquake,but the physical mean is different.The former due to the difference deepcrustal structure and the latter are some risk areas of future earthquskes.3.The source of the vertical force of Hexi-Qilian area in some areas and in a short duration due to the material migration of deep crust who is in some areas and in a short duration.