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
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摘要
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 after the earthquake in the E or NEE direction.② The non-linear 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 can't 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.
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 after the earthquake in the E or NEE direction.② The non-linear 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 can't 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.
引文
[1]陈杰,陈玉坤,丁国瑜,等.2001年昆仑山口西MS8.1级地震地表破裂带.第四纪研究,2003,23(6):629-639
[2]乔学军,王琪,杜瑞林,等.昆仑山口西MS8.1级地震的地壳形变特征.大地测量与地球动力学,2002,22(4):6-11
[3]王秀文.山西中强地震前形变前兆的异常特征.山西地震,1995,2:3-8
[4]杨国华,巩曰沐,杨春花.大同地震与华北北部地壳异态垂直运动.中国地震,1994,10(1):13-18
[5]杨国华,赵承坤,韩月萍,等.应用GPS技术监测山西断裂带的水平运动.地震学报,2000,22(5):465-471
[6]杨国华,王敏,韩月萍,等.山西断裂带活动趋势与动态特征.中国地震,2002,18(2):148-156
[7]安美建,李方全.山西地堑系现今构造应力场.地震学报,1998,20(5):461-465
[8]徐锡伟,邓起东,董瑞树,等.山西地堑系强震的活动规律和危险区段的研究.地震地质,1992,14(4):305-316
[9]杨国华,江在森,刘峡,等.华北地区水平运动动态特征与昆仑山地震的可能关系.大地测量与地球动力学,2007,28(2):6-10
[10]韩月萍,杨国华,马庆尊.首都圈及山西断陷带北部地壳垂直形变与地震危险性分析.华北地震科学,2003,21(3):8-13
[11]Stein R S.The role of stress transfer in earthquake occurrence.Nature,1999,402:605-609
[12]Freed AM.Earthquake triggering by static,dynamic,and postseismic stress transfer.An.Rev.Earth Planet.Sci.,2005,33:335-367
[2]乔学军,王琪,杜瑞林,等.昆仑山口西MS8.1级地震的地壳形变特征.大地测量与地球动力学,2002,22(4):6-11
[3]王秀文.山西中强地震前形变前兆的异常特征.山西地震,1995,2:3-8
[4]杨国华,巩曰沐,杨春花.大同地震与华北北部地壳异态垂直运动.中国地震,1994,10(1):13-18
[5]杨国华,赵承坤,韩月萍,等.应用GPS技术监测山西断裂带的水平运动.地震学报,2000,22(5):465-471
[6]杨国华,王敏,韩月萍,等.山西断裂带活动趋势与动态特征.中国地震,2002,18(2):148-156
[7]安美建,李方全.山西地堑系现今构造应力场.地震学报,1998,20(5):461-465
[8]徐锡伟,邓起东,董瑞树,等.山西地堑系强震的活动规律和危险区段的研究.地震地质,1992,14(4):305-316
[9]杨国华,江在森,刘峡,等.华北地区水平运动动态特征与昆仑山地震的可能关系.大地测量与地球动力学,2007,28(2):6-10
[10]韩月萍,杨国华,马庆尊.首都圈及山西断陷带北部地壳垂直形变与地震危险性分析.华北地震科学,2003,21(3):8-13
[11]Stein R S.The role of stress transfer in earthquake occurrence.Nature,1999,402:605-609
[12]Freed AM.Earthquake triggering by static,dynamic,and postseismic stress transfer.An.Rev.Earth Planet.Sci.,2005,33:335-367
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