佘山地震基准台四分量钻孔应变仪相对标定

YRY-4型四分量钻孔应变仪观测数据基本符合自洽方程,当数据不符合自洽方程时,一个可能原因是,井下探头中元件的灵敏度发生了变化。佘山地震基准台四分量钻孔应变仪于2006年安装运行,井下探头中各元件现已出现不同程度的老化,在数据分析前必须进行实地相对标定。本文利用应变观测资料的原始值(变化值)和差分值,按照月尺度及年尺度,分别计算四元件灵敏度系数K及矫正前后C95信度指标。对比发现,在月尺度下,若观测资料质量良好,采用变化矫正效果更好,而对于"坏点"较多月份,采用差分矫正可有效去除坏点,提高C95信度指标;在年尺度下,变化矫正后C95信度指标更高。

Field relative calibration of four-component borehole strain gauge at Sheshan Seismic Station

The observation data of the YRY-4 four-component borehole strain gauge basically conforms to a self-consistent equation. When observation data does not conform to the self-consistent equation, one possible reason is that the sensitivity of the components in the downhole probe is changed. The four-component borehole strain gauge at Sheshan Seismic Station was installed in 2006 and has been operating for more than 10 years. The components in the downhole probe aged to different degrees. Therefore, a field relative calibration must be carried out before data analysis. In this paper, the sensitivity coefficient K of the four components and the reliability index of C₉₅ before and after correction are calculated by using original values and difference values of the observation data at a monthly scale and an annual scale. It is found that at the monthly scale, if the observation data is in good quality, the effect of correction on original values is better; when there are some "bad points", the correction on difference values can effectively remove the bad points and improve the reliability index of C₉₅. At the annual scale, the C₉₅ reliability index is higher after correction on original values.