昆仑山口西8.1级地震与山西断陷带水平运动变化的探讨

Discussions of the Relation Between Kunlun Mountain Earthquake and the Variation of Horizontal Movement in Shanxi Fault Zone

本文以沿山西断陷带所布设的GPS监测网的11期复测资料(1996—2006)为基础,在统一的参考基准和相同的模式下进行了计算处理。结果发现:①以昆仑山口西8.1级地震为时间界限,其地震前后的运动具有一定的差异性,其具体表现为震前较震后东或北东东向快;②震前运动的非线性特征比较明显,尤其是地震发生的前两年,震后运动的线性特性比较明显;③统计显示震前运动非线性度除个别点外均大于震后。这些现象与该地震的孕发过程与机理上所表现的运动形式相吻合,虽然计算结果中不排除诸如参考基准的框动影响,但完全归于这方面的扰动似乎也不客观,所以这可能预示着强震有时的影响范围会很大,同时也为认知某些强震发生前的远场场兆提供了一种可能的机会。

On the basis of the 11 times repeated observational data during the period 1996-- 2006 from GPS monitoring network which is arranged along the Shanxi fault zone, the author calculates and processes the data according to the same reference frame and mode, The results show： ① The fault movement before and after the Kunlun earthquake exists certain differences, the movement before the earthquake is faster than that afterthe earthquake in the E or NEE direction. ② The nonlinear characteristic of the movement before the earthquake is comparatively obvious, especially in the two years prior to the earthquake, but after the earthquake, the linear characteristic is comparatively distinct.③ Statistics show that the non-linear degrees of the movement on the whole before the earthquake are greater than that after the earthquake except at some individual sites. These phenomena are coincide with the seismogenetic process . Although the influence of the reference frame and so on in the calculation cant be excluded completely, it seems the results obtained are objective. It probably indicates that the influence of strong earthquakes is quite large in scale than that expected, at the same time, it also provides us a chance to realize the long-distance effect before certain strong earthquakes.