陕西泾阳4.8级地震前后重力变化与断裂活动
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摘要
本文对泾阳MS4.8级地震前后陕西关中地区流动重力观测资料和有关断裂垂直形变资料进行了分析研究。结果表明:①波速比高值区很可能存在地下深部地幔物质的入侵,由此引发地震和重力场的显著下降;②用震源机制解和GPS所作的运动矢量图可以较好地解释泾阳地震前后重力场时空演化特征及有关断裂活动——其变化是北西向剪切应力带作用的结果。
The mobile gravity data and fault vertical deformation data before and after the Jingyang M_S4.8 earthquake in Guanzhong region of Shaanxi province are systematically analyzed.According to the results we have the following understanding.First,the high zone of VP/VS ratio may reflect deep mantle material invasion which may conduce the earthquake and result in obvious gravity field decrease.Second,the characteristics of gravity field spatio-temporal variation and fault activity before and after the earthquake due to the effect of NW shear stress field can be explained by the focal mechanism solution and vector diagram of ground movement obtained by GPS measurement.
The mobile gravity data and fault vertical deformation data before and after the Jingyang M_S4.8 earthquake in Guanzhong region of Shaanxi province are systematically analyzed.According to the results we have the following understanding.First,the high zone of VP/VS ratio may reflect deep mantle material invasion which may conduce the earthquake and result in obvious gravity field decrease.Second,the characteristics of gravity field spatio-temporal variation and fault activity before and after the earthquake due to the effect of NW shear stress field can be explained by the focal mechanism solution and vector diagram of ground movement obtained by GPS measurement.
引文
[1]王卫东.泾阳4.8级地震的构造背景[J].西北地震学报,2002,24(2):145—149.
[2]高好林,孙兵林,戴王强.泾阳4.8级地震前后重力变化探析[J].地震地磁观测与研究,2005,26(2):82—88.
[3]高好林,邵辉成.关中地区重力场动态演化特征与地震活动分析[J].大地测量与地球动力学.2005,25(1):91-97.
[4]王卫东,邹志伟,彭建兵.西安北部地区强震孕育深部背景研究[J].灾害学,2005,20(2):41—43.
[5]曾融生,朱露培,何正勤.华北盆地强震的震源模型兼论强震和盆地的成因[J].地球物理学报,1991,34(3):288—301.
[6]中国地震局预测预防司.大陆地震预报的方法和理论——中国“八五”地震预报研究进展[M].北京:地震出版社,1998.273—278,483—488.
[7]王卫东,王平.泾阳4.8级地震的震源参数和震源机制[J].西北地震学报,1998,20(6):656—658.
[8]戴王强,王庆良,冯希杰等.用GPS资料分析渭河盆地及邻近地区地壳运动特征[J].地震,2003,23(4):32-36.
[9]高好林,祝意青.重力段差变化与断裂垂直位移的对比分析[J].大地测量与地球动力学,2006,26(1):待定.
[2]高好林,孙兵林,戴王强.泾阳4.8级地震前后重力变化探析[J].地震地磁观测与研究,2005,26(2):82—88.
[3]高好林,邵辉成.关中地区重力场动态演化特征与地震活动分析[J].大地测量与地球动力学.2005,25(1):91-97.
[4]王卫东,邹志伟,彭建兵.西安北部地区强震孕育深部背景研究[J].灾害学,2005,20(2):41—43.
[5]曾融生,朱露培,何正勤.华北盆地强震的震源模型兼论强震和盆地的成因[J].地球物理学报,1991,34(3):288—301.
[6]中国地震局预测预防司.大陆地震预报的方法和理论——中国“八五”地震预报研究进展[M].北京:地震出版社,1998.273—278,483—488.
[7]王卫东,王平.泾阳4.8级地震的震源参数和震源机制[J].西北地震学报,1998,20(6):656—658.
[8]戴王强,王庆良,冯希杰等.用GPS资料分析渭河盆地及邻近地区地壳运动特征[J].地震,2003,23(4):32-36.
[9]高好林,祝意青.重力段差变化与断裂垂直位移的对比分析[J].大地测量与地球动力学,2006,26(1):待定.
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