1986年8月23日门源6.4级地震前,地震波速度比异常从1984年起即开始出现,异常过程中由于受1985年7月14日冷龙岭3.6级地震的影响而略有回升,以后继续呈负异常,最大幅度达7%。震前在震中以西地区的波速比值未出现回升以后的明显高值,而震中以东的九条岭地区虽然长趋势波速比值负异常不明显,但震前的趋势上升及高值的出现却十分清楚。 Before the M6.0 magnitude earthquake on Aug. 23, 1986, the seismic wave velocity ratio anomaly began to appear in 1984 and recovered slightly in the anomaly due to the impact of the Cold Longling M 3.6 M on July 14, 1985 Continue to be negative anomalies, the most significant rate of 7%. Before the earthquake, the wave velocity ratio in the area west of the epicenter did not show obvious high value after the rebound, while in the Jiulianling area to the east of the epicenter, although the negative anomaly of the long-range trend velocity ratio was insignificant, the rising trend and the occurrence of high value before the earthquake were clear .