鄂尔多斯和塔里木地块运动与中国大陆强震关系探讨

Relationship between the Movements of Ordos and Tarim Blocks and Strong Earthquakes in China Continent

本文在综合分析地质、古地磁、GPS和地震活动资料的基础上,讨论了鄂尔多斯和塔里木地块的运动与中国大陆强震的关系。鄂尔多斯和塔里木地块同为中国大陆古老、完整、坚固的地块,内部结构简单。而两个地块周缘断陷带或挤压造山带较破碎,其内部结构较复杂。综合研究表明,鄂尔多斯地块的整体向东平移并叠加逆时针旋转的运动控制着周缘走滑断裂和地震活动;塔里木地块向北平移叠加的顺时针旋转及向周缘造山带的俯冲导致周缘断裂和强震的发生。尽管天山构造带为主要的地震带,但塔里木地块与天山造山带边界的MS≥6.0地震主要受塔里木地块运动的影响。像鄂尔多斯和塔里木这样传统意义上的稳定地块,实质上是边界强震的主要贡献者。鄂尔多斯和塔里木完整坚固地块的整体运动,对其周缘强震的发生起着关键作用。

On the basis of comprehensive analysis of geology,paleomagnetics,GPS data and seismicity,the relationship between the movement of Ordos and Tarim blocks and strong earthquakes in China continent was discussed.Both Ordos and Tarim blocks are old intact solid blocks with simple inner structure.Fault depression zones or orogens around the two blocks are fractural and the inner structures are complex.The results show that the whole movement to the east and anticlockwise rotation of the Ordos block control the strike-slip fault and earthquake occurrences and that the movement to the north,clockwise rotation and underthrusting under orogens of Tarim block result in faults and earthquake occurrences around the block.The MS6.0 earthquakes are mainly affected by the movement of the Tarim block,although Tianshan tectonic zone is a well-known seismic zone.The traditional stable blocks like Ordos and Tarim are truly intact solid active block,which is the main contributer to strong earthquakes on the border.The whole motion of the intact solid block plays a crucial role in strong earthquake occurrence around its border.