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通过对地震噪声及其与区域气象条件的相关分析给出了宽频带地震台站CAD的主要特征。传感器场地(在地表下80m处的封闭洞穴内)的质量,为宽频带地震台站监测较小地震事件提供了理想的条件。通过对15个月内长度各为15min的噪声序列的分析,对较小地震事件的监测能力的研究已经完成。通过给定每天的噪声估计值,分析了噪声振幅随季节的变化;利用每天4个采样值,对地震噪声的短周期变化进行了研究,并与外部气象条件进行了比较。研究结果表明:这一台站与位于坚实基岩上的典型地震台站的特征是相似的,并且三个分量的特性也是没有区别的。对若干频谱成份的分析显示,地脉动与大气扰动的相对激发程度可相差一个量级以上。噪声振幅频谱与大气压的短周期变化有明显的反相关性。尽管对传感器场地没有直接的冲击,但高频噪声与外部风速有直接的关系。未观察到频谱曲线形状(指总体上或对于特定频率)与大气参数的相关性。
The main features of CAD for broadband seismic stations are given through the correlation analysis of seismic noise and regional meteorological conditions. The quality of the sensor site (within a closed caverns 80m below the surface of the earth) provides the ideal conditions for the monitoring of small earthquakes by broadband seismic stations. A study of the monitoring of smaller earthquakes has been completed through the analysis of 15-minute noise sequences over a 15-month period. By giving a daily noise estimate, the variation of noise amplitude with the seasons is analyzed. Using the daily sampling data, the short-period variation of seismic noise is studied and compared with the external weather conditions. The results show that the characteristic of this station is similar to that of a typical seismic station located on a solid bedrock, and the characteristics of the three components are also indistinguishable. Analysis of several spectral components shows that the relative excitation of ground pulsations and atmospheric disturbances can differ by more than one order of magnitude. There is a significant inverse correlation between the noise amplitude spectrum and short-term atmospheric pressure changes. Although there is no direct impact on the sensor site, high-frequency noise is directly related to external wind speed. No correlation was observed with the spectral shape of the spectrum (either overall or for a specific frequency) with atmospheric parameters.