邢台地电台的地电阻率异常研究

ON THE EARTH RESISTIVITY ANOMALY AT XINGTAI GEOELECTRICAL STATION

研究1973年7月至1992年6月邢台地电台的ρ_2月均值,具有总趋势一道为上升,三道为下降,似年周期明显的正弦形正相年变规律。有趣的是上升或下降加速的时段,伴随年变幅度增大或减小时,往往与距台站400 km左右发生的7级以上地震,或220 km内发生的5级以上地震有关。本文用差值法定量地消除年变以后,对出现的异常进行研究讨论,认为该台反映220 km内5级以上地震的效果是好的.

Study of monthly average Ps Value (Jul. 1973-Jun. 1992) at Xingtai Geoelectric Station indicates that a general tendency of the value tends to rises at one channel, but descends at three channels, just like a pattern of sine positive annual variation of annual period. It is of interest to note that in accompany with increase or decrease in annual variation amplitute, the time interval during which the Ps value rises or descends is related with earthquake of M<7 at 400 km or M<5 at 220 km away from the station. Study of the anomaly which is found after annual variation being quantitatively eliminated by difference method suggests that the earth resistivity observed at the station very effectively reflects earthquakes of M<5 occuring within 220 km.