张北6.2级地震前宝昌地震台的前兆异常研究

１９９８年１月１０日河北省张北６．２级地震前，距震中１００ｋｍ的内蒙古宝昌地震台石英倾斜仪ＮＳ分量自１９９６年７月出现向南倾斜的趋势异常，ＥＷ分量１９９７年８月向西倾斜的短期异常，并在地震发生前６天之内，倾斜仪固体潮曲线上出现多次阶跃式畸变，可能是张北６．２级地震的临震前兆。与此同时，该台站的地电阻率也在震前２．５个月出现短期异常。

STUDY ON THE ANOMALIES OF BAOCHANG SEISMOLOGICAL OBSERVATORY STATION BEFORTHE ZHANGBEI Ms6.2EARTHQUAKE

Before the Zhangbei Ms6.2 earthquake of January 10,1998 in Hebei province,the NS component of quartz tiltmener of Baochang station loated in Inner Mongolia,100km from the epicenter,showed a south-tilt tendency anomaly from July 1996,and in August 1997 the EW component also showed short-term west-tilt anomaly.Within 6 days before the event,the curve of solid tide recorded by the tiltmeters showed many times jumping distortion,which may be the imminent precursor of the event.At the same time,the earth resistivity of the station also showed short-term anomaly 2.5 month before the quake.