引言应用地震波到时进行地震或地球成像的研究需要对背景噪声之上的到时进行检测。全球地震台网各台站之间的噪声水平在某些频带上的差别能够超过60dB(见图1),按地震波检波阈值计算,这种差别就是4个以上震级的地震到时的差别。因此,噪声水平是地震台站选址的一个非常重要的标准 INTRODUCTION The application of seismic waves to seismic or earth imaging studies requires the detection of the arrival time above background noise. The difference in the noise levels between stations at global seismograph stations over some bands can exceed 60 dB (see Figure 1), calculated as the seismic wave detection threshold, which is the difference between the time of arrival of more than 4 earthquakes. Therefore, the noise level is a very important criterion for the site selection of a seismic station