Comparison of Strain Observation Data of Different Borehole Strain in the Same Site

This paper studies the observation data of different borehole strain gauges in the same site at Yixian Station, analyze the reliability of the four-component borehole strain and its correlation with body strain, and then analyze the response of different borehole strain observations to special events. The result shows that: 1) The 4-component borehole strain observation at Yixian Station is not very self-consistent and requires field relative calibration; when performing relative calibration, the selection of difference value data is beneficial to improve the reliability of the data; 2) The Pearson correlation coefficient of S₁+S₃ and body strain is slightly higher than that of S₂+S₄ and body strain; 3) In terms of response to special events, the volume strain and the four-component borehole strain show tensile changes due to pumping disturbance, and the variation is higher than the volume strain. The correlation coefficient between volume strain and S₁+S₃ is higher than volume strain and S₂+S₄. In terms of co-seismic response, the co-seismic response of different borehole strains is consistent, and the correlation coefficient is related to the magnitude of the earthquake.