Reliability analysis of component strain and volume strain at Dongping seismic station and comparison of influence of special events

Abstract

In this paper, the reliability analysis of the YRY-4 borehole component strain observation data at Dongping seismic station is carried out through the four-component self-check and the relative calibration internal accuracy analysis. The data of the two instruments are compared by combining the sliding correlation calculation and the internal accuracy of the tidal factor. It is proved that the two surface strain correlation of the YRY-4 borehole component strain is high, and the correlation coefficient is close to 1. The relative calibration internal accuracy is high, which is consistent with the overall trend of the volume strain data. The observation environment of the two instruments is consistent, and the operation is stable, the data are normal and reliable. However, there are also inconsistencies in the curves of rainfall and site interference in special periods. For the two special cases, compared by correlation calculation and S transform, the results show that, due to the large difference in drilling conditions, the correlation between the two instrument data during rainfall period is poor, close to 0. During the site interference period, the two observation systems were affected, and the interference signals appeared synchronously in the frequency domain, which affected the data curve shape and the accuracy of the tidal factor, but the strain correlation between the two instruments reached 0.91 during the interference period. Comprehensive analysis shows that the two sets of instrument observation systems of component strain and volume strain at Dongping seismic station are reliable and stable.

Keywords

• component borehole strain
• volume strain
• reliability analysis
• special events
• rainfall interference
• site interference