利用厦门—连城临时测线记录提取面波格林函数

Extracting Rayleigh Wave Green′s Functions from the Records of Temporary Seismic Stations along the Xiamen-Liancheng Line

本文利用沿厦门—连城测线布设的20个临时观测台的记录,结合近年发展起来的利用噪声提取面波格林函数的技术,提取了这20个临时观测点两两间的面波格林函数。结果表明,40天的噪声数据完全可以得到信噪比较高的面波格林函数,这可能和该测线与海岸线近似垂直,能量主要由沿海传向内陆有关。根据所有射线每天的面波格林函数随时间推移的变化,指出S04观测点在此次临时观测期间存在1.5～2.0s的授时误差,这可很好的解释爆破观测中出现的震中距与波形到时的颠倒现象;并且,利用爆破记录的观测到时验证了"华南地区近震走时表"在该地区的适用性。

In this paper, we used the records of 20 broad-band seismographs span along the line from Xiamen to Liancheng cities to extract Rayleigh wave Green＇s functions between two floating observation stations with cross-correlation method developed these years. The result shows that high SNR Green＇s function of Rayleigh wave could be completely obtained from the seismic noise data of 40 days. It may be related to the fact that the floating measure line is almost vertical to the coastline and most of the power spread inland from the coast. According to the time running change of Rayleigh wave Green＇s function of all radial lines each day, we presented that S04 station has about 1.5-2 s or more time error during the temporary observation, which could well explain the reversal phenomenon between the epicentral distance and wave arrival occurred in real blast observations. Finally, we validated the applicability of the South China near earthquake traveltime table in the region using the arrived time recorded by blast observation.