Estimation of phase velocity and attenuation coefficient in gas-charged sediment

摘要

Anderson-Hampton theory describes the characteristics of gas-charged sediment,near resonance frequency,dispersion in gas-charged sediment causes abnormal high attenuation and high phase velocity.The accurate calculation of attenuation coefficient and phase velocity could estimate physical properties of gas-charged sediment.We propose a method to measure attenuation coefficient and phase velocity from two waveforms propagating at different distances.The synthetic waveform is processed by filter-cross correlation method and spectral ratio to verify validity of proposed method.The characteristics of gas-charged sediment distort waveform,which seriously reduces the accuracy of phase velocity calculation,but the estimation of attenuation is more stable.We focus on the calculation of attenuation to estimate resonance frequency by Anderson-Hampton model.