Abstract: Before the 9th July 1979 Liyang earthquake,beginning from mid June the vertical component at the Liyang station about 20km from the epicentral area decreased gradually to a negative anomaly. After decreasing to the lowest level in the last ten days of June,it increased quickly to a positive anomaly. Just before the tectonic event,the observational value was brought back to its initial value. It is consigderd that the seismic fault perhaps responsible for the shock trends WNW or NNE. The shear stress piezomagnetic modol by Stacey has been used to calculate the theoretical values of the surface Z-component anomaly for this skock.A comparision of observations with the theoretical values shows that there have bsen the strong tectonic activities along both the faults. The shock was probably accompanied by conjugated offset on the faults.

摘要： 1979年7月9日江苏溧阳六级地震前,距震中约20公里的溧阳地磁台垂直分量六月中旬开始,出现负的异常,六月下旬降到最低值后,于六月底测值又迅速回升,出现正的异常,震前回到初始值。本文根据Stacey提出的剪切应力压磁模式,选取可能是这次地震的发震构造北北东和北西西断裂,粗略地计算了垂直分量异常地面分布图,与实测对比,说明这两条断裂的构造活动都是强烈的地震时,它们可能发生了共轭错动。