多通道相关分析用于宽频带地震仪自噪声检测

将多通道相关分析方法用于宽频带地震仪的自噪声检测,测量分析了Reftek 130、130 B和130 S三种地震数据采集器的自噪声检测结果以及14套Reftek 130 S连接Guralp CMG-3T地震计的自噪声一致性检测结果,同时给出了地震计的三轴正交性估计.结果表明:Reftek数据采集器设置为普通增益时在0.3 Hz以上频段自噪声高于Guralp CMG-3T地震计自噪声,设置为32倍高增益时在测量频段远低于地震计自噪声;测量的多台Guralp CMG-3T地震计自噪声结果在不同频段一致性差异较大,垂直向分量0.3 Hz以下频段可作为一致性比对参考频段,采集配置选择普通增益时0.3~2 Hz频段可作为数据采集器一致性比对参考频段;Guralp CMG-3T地震计三轴正交性误差估计平均在0.5°以内.

Applying multiple channel correlation technique in the self-noise measurement of broadband seismographs

We apply the multiple channel correlation technique in the self-noise measurements of broadband seismographs, measure and analyze the self-noise results of three types of data-loggers from Trimble company including Reftek 130, 130B and 130S, also we get the self-noise results for 14 sets of seismographs comprised of Reftek 130S data-loggers and Guralp CMG-3T seismometers and evaluate axes-orthogonality errors of seismometers' three components. Our results show that when Reftek dataloggers are configured as the unity sampling option, data-loggers' self-noises are higher than those of CMG-3T seimsometers in frequency band larger than 0.3 Hz and conversely for frequency band smaller than 0.3 Hz; while for the high-gain sampling option, the dataloggers' self-noises are smaller than those of seismometers within all tested frequency band. There exist large vaiations for self-noise evaluation of multiple Guralp CMG-3T seismometers in different frequency bands, the self-noise results from vertical component in frequency band lower than 0.3 Hz can be used as the reference standard for CMG-3T seismometers consistency check and 0.3~2 Hz frequency band can be used as the referecne standard for Reftek data-loggers when unity sampling option is adopted. The average axes-orthogonality errors of CMG-3T seismometers are less than 0.5 degree.