Robust Attenuation Estimation of Microseismic Waves in Geotechnical Engineering

Accurate calculation of microseismic wave attenuation in engineering remains challenging because of the high noise levels and short durations of microseismic signals. The conventional methods applied to the calculation of microseismic wave attenuation are often very ineffective and do not yield good attenuation patterns. Hence, this study improves conventional algorithms and uses body wave data to calculate the quality factor Q value, including both regression analysis and spectral ratio methods. A fixed-length S-window is adopted, and a multitaper spectral algorithm is employed to optimize spectral estimation. The improved method is applied to process microseismic data obtained from two projects. The results demonstrate that the magnitude of the Q values is consistent with the geological conditions on site. Compared to the results before improvement, the optimized results exhibit high stability and significantly improved resolution of the Q values. The results also show a pronounced minimum in Q over the analyzed frequency range, indicating strong frequency-dependent behavior. The improved method provides more stable Q estimates for short-duration records affected by noise and limited spectral resolution.