本文对张北近场地震资料进行了重新定位,并通过网格化处理得到震源空间分布图像、发震时间图像和定位残差图像.震源空间分布图像和发震时间图像细致地显示了极震区周围的发震构造时空特征为明显的北西方向,另外还存在断续的北东向特征.该震区在中新生代以来有过多期岩浆活动,极震区米家沟附近有一个火山口并且地壳内存在低速带和深断裂,复杂的地壳构造为孕震提供了必要的深部环境.
In this paper , near field earthquake records of Zhangbei earthquake region are relocated. Image of hypocenter distribution, image of origin time and image of locating error are obtained by gridding method. Image of hypocenter distribution and image of origin time show that the temporal-spatial feature of the seismogenic structure in Zhangbei earthquake region is obviously in NW-striking direction and it also has NE-striking discontinuously. There were multiphase magmations during Meso-Cenozoic in Zhangbei earthquake region and mezoseismal area-- Mijiagou has a crater. And low-velocity zone and deep fault exist in crust. Complicated crust tectonics provide deep environment in the formation of seismogenic structure.