Spatial distribution of V P/V S formed an ellipse area,and the earthquakes of anomaly V P/V S were 73% of the total.The coda wave duration of Dawu was a complete anomaly process before the event.

• 波速比空间分布在兴海地震前形成了一个椭圆形的异常分布区 ,异常波速比的地震占总地震的73 %25。