张北6．2级地震前断层活动特征研究

运用变化率分析了张北6．2级地震前山两地区跨断层流动短水准资料变化特征，发现：在张北6．2级地震孕育过程中，特别是地震孕育中短期阶段，断层活动存在明显的异常变化且一致性好，主要表现为：①断层异常活动集中在震前3．5-0．5年且存在阶段性，断层异常恢复后发生地震；②断层异常活动性质发生剧烈快速的变化，离地震发生越近断层异常活动幅度越大、变化率越快；③山西地区跨断层流动水准异常特别是前中短期异常变化主要集中在山西带的北部地区，范嗣主要集中在震中周围500km左右范围内。

Study on Fault Activity before Zhangbei Ms6.2 Earthquake Using Shanxi Mobile Cross-fault Short-level Data

In this paper,the mobile cross-fault short level data before Zhangbei 6.2 earthquake in Shanxi Province is analyzed;the results indicate that there are obvious fault activity anomalies during the preparation period of Zhangbei 6.2 earthquake,especially in the medium and short term period of the earthquake preparation.These anomalies are consistent with each other and have following characteristics.(1)The fault activity anomalies are concentrated in 0.5-3.5 years just before the earthquakes.(2)The amplitude of the anomalies become bigger as the origin time comes near.(3)Shanxi abnormal cross-fault current levels,especially in the short-term anomalies before earthquakes mainly concentrated in Shanxi Province with the northern region,mainly in the range of about 500km range around the epicenter.