地震计方位角偏差校正方法对剪切波分裂结果的影响OA

Seismometer orientation misalignment significantly affects the accuracy of shear wave splitting measurements;however,the reliability of different correction methods still requires systematic verification.Taking the MW7.0 earthquake that occurred on September 1,2016,off the east coast of North Island,New Zealand and recorded at station 8H.EP02 in the Pamir Plateau as a case study,five methods were adopted for seismometer orientation misalignment correction:global minimum transverse energy,multi-event P-wave polarization analysis,P-wave principal component analysis,Rayleigh surface wave correlation,and long-period particle motion.This study compares the impacts of different methods on shear wave splitting parameters(fast wave polarization direction and delay time).All five methods effectively determined the seismometer orientation misalignment with maximum differences not exceeding 4°;the differences in time delay results obtained using different methods were small,within 0.01 s;the differences in fast-wave polarization directions did not exceed 3°.Further systematic tests using an orientation misalignment of±20° revealed that the global minimum transverse energy and multi-event P-wave polarization analyses achieved optimal performance.Considering calculation accuracy and efficiency,the multi-event P-wave polarization analysis method should be prioritized in practical applications.These findings underscore the importance of seismometer misorientation correction in shear wave splitting studies for reliable anisotropy characterization.