利用双台脉动记录的相关系数估计福建地区瑞利面波的群速度

Extracting the Group Velocity of Rayleigh Waves from the Cross Correlation of the Ambient Seismic Noise between Two Seismic Stations

本文利用福建省数字地震监测台网中8个宽频带台站的速度型脉动记录,计算两两台站之间垂直分量的脉动在相同时间窗(窗长为5分钟)的相关系数,按照移动窗技术得到各个不重叠窗口的相关系数,并对其进行相干叠加,依此计算出两个台站之间瑞利面波的群速度及其在福建地区的空间分布。结果表明,叠加结果的信噪比随叠加次数的增加而增加,不同时间段叠加结果波形相似;峰值到时稳定,台风不会对结果产生明显影响;利用这个方法得到的福建地区周期约为3～5秒的瑞利面波群速度在2.9～3.1km/s之间,这和传统方法得到的瑞利面波的传播速度很接近。

This paper firstly used the 8 broad-band stations＇ microseisms records given by the Seismic Monitoring Network of Fujian Province to calculate the vertical correlation coefficient between two stations at intervals of 5 minutes.According to the technique of time intervals,the authors get the different coefficients and added the interferential coefficients.Depend on this,the authors extracted the group velocity of Rayleigh waves from the cross correlation of the ambient seismic noise between two seismic stations and figured out the group velocity＇ space situation.The results show that the signal noise ratio（SNR）increases proportional to the added times,but the results from different days are similar to one another.Synchronously the arrival-time is stable too and there is no obvious change when the typhoon occurred.It is found that the velocity of the surface wave is in 2.9～3.1km/s in Fujian Province,which is close to that of the observation.