Abstract: The ionic content of groundwater increases gradually from the east to the west along the Haiyuan active fault. In the same hydrogeological conditions it is obviously higher on the segments which have high seismicities and larger displacement. There are regularities in the distribution of the components of gas in the overlying soil within the fault zone. The farther distance from the fault,the fewer the element content is. An anomalous zone of higher value is formed in the vicinity of the fault. The highest points,however,are not located entirely on the fault. In extension area,there is a bigger anomaly in amplitude of the contents of Rn,Hg and H. In compressional area,the largest anomalies of Hg and H appear at the segment which has the biggest displaument. The content of H changed obviously before and after the occurrence of Lingwu Earthquake.

Key words: Active fault, Stepping area, Geochemical fielld, Anomalous zone

摘要： 沿海原断裂带,地下水离子含量由东向西逐渐递增。同一水文地质条件下,地震中活动性强,错动大的地段上离子含量明显较高。断裂带上覆盖层中气体组分的分布具有规律性,由断层向两侧,一些元素含量由高变低,在断层附近形成高值异常带,但峰值点不完全与地表断层位置重合,拉张区的氡、汞、氢均有较大幅度异常,压扭区中地震错动最大地段,汞、氢异常最大,灵武5.3级地震前后,氢值有显著变化。

关键词: 活断层, 阶, 区, 地球化学场异常带