Estimation of near-surface quality factors by constrained inversion of Rayleigh-wave attenuation coefficients

摘要: Abstract Quality factors (Q) of near-surface materials are as important velocities the in many applications. Only phase information surface-wave data is utilized when high-frequency (≥ 2 Hz) routinely inverted to determine shear (S)-wave velocities. Amplitude can be used quality materials. Given S-wave velocity, compressional (P)-wave and Rayleigh-wave velocities, it feasible solve for factor QS P-wave QP (for some specific velocity models) down 30 m below ground surface settings by inverting attenuation coefficients a layered earth model. seismic an exponential function coefficients. When calculating from changes amplitude, this nonlinear nature would result that small variations amplitude cause huge This suggests (attenuation coefficients) normally possess large errors could eventually transfer model (quality factors); therefore, constraints (or priori information) on models necessary. Because inversion system problem unstable, regularization parameter must introduced into algorithm stabilize inversion. These characteristics allow us constrained regularized linear system. Usually, set meet defined obtained solving Based system, smooth selected solution using L-curve method. approach trade-off between misfit length. Several real-world examples demonstrate importance finding acceptable realistic empirical data.