Frequency Dependence of Q in the Crust and Upper Mantle of China and Surrounding Regions, from Computations of Lg Q and the Attenuation of High- Frequency P-Waves

摘要

Starting with fundamental-mode Rayleigh-wave attenuation coefficient values predicted by previously determined frequency-independent model of shear- wave Q we have obtained frequency-dependent Q models that explain both the measured values of yr as well as of Lg coda Q and its frequency dependence at 1 Hz (Q and n respectively) for China and some adjacent regions. The process combines trial-and-error selection of a model for the depth distribution of the frequency parameter for Q with a formal inversion for the depth distribution of Q at 1 Hz. Fifteen of the derived models have depth distributions that are constant, or nearly constant, between the surface and a depth of 30 km. Distributions that vary with depth are necessary to explain the remaining seven models.