A Review of the Calculation Formula for the Four-component Borehole Strainmeter and Application to Earthquake Cases

作者：SU Kaizhi

摘要：Based on the principle formula for the four-component strainmeters, we can directly obtain the specific plane strain, shear strain and azimuthal angle of the principal strain, and the maximum and minimum principal strains calculated afterwards are the indirect result. The problems of practicality of the sensitivity coefficients A and B of plane strain and shear strain are then discussed. Based on this idea, we analyzed the observation data of several fourcomponent borehole strainmeters near the epicenter of the Yiliang MS5. 7 earthquake in 2012 and the Ludian MS6. 5 earthquake in 2014 in the Zhaotong area, Yunnan Province. The results show that the analysis based on the perspective of plane strain and shear strain has an obviously better effect than that based on the component readings, and can directly peel off the respective abnormality of the plane strain and shear strain. In addition, the correlation coefficient curves between measured data of two plane strains show significant anomalies which often occur several days before and during the earthquake.

發文機構：Institute of Crustal Dynamics

關鍵詞：Four-componentboreholestrainmeterLudianMS6.5EARTHQUAKEYiliangMS5.7EARTHQUAKEPlaneSTRAINABNORMALITYShearSTRAINABNORMALITYSELF-TESTofdataSTRAINanomaly

分類號： P[天文地球]