京津唐地区深部挤压带特征及其与地震的关系

京津唐地区的深部挤压带轴线沿宁河、香河、昌平一线呈南东—北西走向，在通过该带的北东向Ｍ和Ｃ面上均有一向北西弯曲的弧形。地壳下部和上地幔顶部层位呈透镜状增厚，浅部的北东向断裂也向北西弯曲。应力测量表明现今该带的应力场为向北西挤压。深部挤压作用是由渤海底部的扩张所产生的。该挤压带控制着地震的发生，特别其北东侧是一个强地震区

FEATURES OF THE DEEP COMPRESSION ZONE IN THE BEIJING TIANJIN TANGSHAN REGION AND ITS RELATION TO EARTHQUAKES

The axis of the deep compression zone in the Beijing Tianjin Tangshan region is oriented in a SE NW direction along the line of Ningbo Changping. The NE trending M plane and C plane across the zone display an arcuate shape conex toward the NW. The lower crust and top of the upper mantle thicken in the lenticular form. The NE trending faults at shallow depths also bend toward the NW. Stress measurements indicate that the present stress field of the zone is still subjected to NW compression. The deep compression is produced by sea floor spreading of the Bohai Sea. This compression zone has controlled the occurrence of earthquakes. In particular its NE side is a zone of strong earthquakes.