Key technology and application of DRY-1B capacitive component borehole strain gauge

This paper briefly describes the theoretical basis of the DRY-1B capacitive component drilling strain gauge (drilling strain gauge). It discusses critical technologies such as micro-displacement sensing, noise reduction, temperature control, performance testing, and calibration. The strain gauge achieved high resolution (≥5×10−11ε), wideband (10–100 Hz optional), extensive dynamic range (≥1×10−3ε), 24-bit AD recording, low power consumption (< 3W), and other technical indicators. Its performance is better than the United States PBO and Japan borehole strain gauge of the same period, and it is an international leading long-term observation instrument for crustal movement, which can basically meet the observation requirements of creep movement with slow accumulation of long-term strain and seismic and volcanic activity with a rapid change of short-term strain. Since 2008, through the application of more than 20 geostress stations, the borehole strain gauge has recorded a large amount of strain information, such as crustal deformation, fault activity, co-seismic strain wave, strain step, and ore pressure activity. Based on the results of the self-consistency test of strain monitoring data of the geostress station in the Beichangshan Mountain and the analysis of seismic mapping capacity of the Turkey earthquake, it is found that the strain curves of the 1#+3# and 2#+4# capacitance sensors at the Beichangshan Mountain stress station are generally stable, and the correlation coefficient R2 is 0.95. The annual variation rate of the differential strain of 1#–3# and 2#–4# elements is 10−8 magnitude, which reflects that the shear stress is dominant in the Long Island area and the stress environment of seismic activity is relatively high. The strain gauge was used to observe the apparent co-seismic strain response of Turkey’s M 7.8 and M 7.5 earthquakes on February 6, 2023. In particular, it obtained the M 7.8 main seismic surface wave period of 50–60 s, presenting an out-facing wave anomaly. Theoretically, the strain wave generated by the M 0.74 earthquakes within 100 km can be distinguished, and the application demonstration effect has been achieved. The borehole strain gauge has good popularization value and application prospects in geodynamics research and internal dynamic geological disaster monitoring.