Early-arrival waveform inversion for near-surface velocity and anisotropic parameters: inversion of synthetic data

Early-arrival waveform inversion for near-surface velocity and anisotropic parameters: inversion of synthetic data

Xukai Shen

Abstract:

I test different inversion parametrizations of vertical velocity and anisotropic parameter $\epsilon$ . A model space parametrized by the squares of vertical and horizontal velocity results in vertical velocity and $\epsilon$ updates with opposite signs. On the other hand, a model space parametrized by the logarithm of the vertical velocity squared and $\epsilon$ has more reasonable updates, as well as better data matching. However, ambiguity does exist in the inversion results between vertical velocity and $\epsilon$ . I clearly demonstrate these findings using a synthetic example.