汾渭断陷带现今垂直形变与近期地震活动性
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摘要
本文针对2008年汶川地震后鄂尔多斯块体周缘出现的小震活跃现象,利用分布于汾渭断陷带不同部位的跨断裂水准资料,分析了其近期的垂直形变演化过程。结果表明:①各水准剖面的垂直差异运动幅度基本稳定在±20mm之间,且在小震活动期间未出现明显的形变异常;②鄂尔多斯块体周缘近期小震活跃可能是缘于汶川地震后,青藏块体挤压应力减弱,华北块体对其推挤作用相对增强而造成鄂尔多斯块体的水平挤压应力场的"暂态失稳"所致。
In order to investigate seismicity in the peripheral areas of the Ordos block after the 2008 Wenchuan earthquake,we analyzed evolutive course of the current vertical deformation in the Fenwei fault-depression zone using fault-crossing leveling data situated on different locations.The following are obtained: ① the vertical movement extent of ascending and sinking difference is about 20 mm,and there is no obvious exceptional deformation;② Small earthquake activities may be transient instability of horizontal stress field of Ordos block,due to adjustment of compressional stress from Qinghai-Tibet plate and relative strengthening of compressional stress from North China sub-plate.
In order to investigate seismicity in the peripheral areas of the Ordos block after the 2008 Wenchuan earthquake,we analyzed evolutive course of the current vertical deformation in the Fenwei fault-depression zone using fault-crossing leveling data situated on different locations.The following are obtained: ① the vertical movement extent of ascending and sinking difference is about 20 mm,and there is no obvious exceptional deformation;② Small earthquake activities may be transient instability of horizontal stress field of Ordos block,due to adjustment of compressional stress from Qinghai-Tibet plate and relative strengthening of compressional stress from North China sub-plate.
引文
①中国地震局第一监测中心,中国地震数字观测网络流动形变监测系统—跨断层综合观测场地水准测量技术总结,2007年。
[1]汪良谋.华北强震时空变化某些特点与近期强震活动趋势[J].地震地质,1987,9(2):39-47.
[2]张国民,马宗晋,蒋铭.华北强震规律的研究[J].中国地震,1988,4(3):66-70.
[3]国家地震局鄂尔多斯周缘活动断裂系课题组.鄂尔多斯周缘活动断裂系[M].北京:地震出版杜,1988.
[4]邓起东,程绍平,闵伟,等.鄂尔多斯块体新生代构造活动和动力学的讨论[J].地质力学学报,1999,5(3):395-398.
[5]苏钢.以运动地块为单元的区域地震活动研究[J].西北地震学报,1984,6(2):1-9.
[6]苏钢.鄂尔多斯地块的反时针扭动及其地震和地质意义[J].山西地震,1988,(3):21-28.
[7]邵辉成,苏刚.鄂尔多斯地块周缘近期地震活动趋势分析[J].西北地震学报,1999,21(4):395-398.
[8]张四新,张希,陈兵,等.西—海—固地区垂直形变分析及地震趋势研究[J].地震,2000,20(3):48-52.
[9]张四新,王双绪,刘立炜.汶川MS8.0地震前后青藏块体东北缘的垂直形变[J].大地测量与地球动力学,2011,31(6):25-31.
[10]杨少敏,聂兆生,贾志革,等.GPS解算的日本MW9.0地震的远场同震地表位移[J].武汉大学学报(信息科学版),2011,36(11):1336-1339.
[1]汪良谋.华北强震时空变化某些特点与近期强震活动趋势[J].地震地质,1987,9(2):39-47.
[2]张国民,马宗晋,蒋铭.华北强震规律的研究[J].中国地震,1988,4(3):66-70.
[3]国家地震局鄂尔多斯周缘活动断裂系课题组.鄂尔多斯周缘活动断裂系[M].北京:地震出版杜,1988.
[4]邓起东,程绍平,闵伟,等.鄂尔多斯块体新生代构造活动和动力学的讨论[J].地质力学学报,1999,5(3):395-398.
[5]苏钢.以运动地块为单元的区域地震活动研究[J].西北地震学报,1984,6(2):1-9.
[6]苏钢.鄂尔多斯地块的反时针扭动及其地震和地质意义[J].山西地震,1988,(3):21-28.
[7]邵辉成,苏刚.鄂尔多斯地块周缘近期地震活动趋势分析[J].西北地震学报,1999,21(4):395-398.
[8]张四新,张希,陈兵,等.西—海—固地区垂直形变分析及地震趋势研究[J].地震,2000,20(3):48-52.
[9]张四新,王双绪,刘立炜.汶川MS8.0地震前后青藏块体东北缘的垂直形变[J].大地测量与地球动力学,2011,31(6):25-31.
[10]杨少敏,聂兆生,贾志革,等.GPS解算的日本MW9.0地震的远场同震地表位移[J].武汉大学学报(信息科学版),2011,36(11):1336-1339.
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