A new waveform inversion workflow: Application to near-surface velocity estimation in Saudi Arabia

Abstract

Waveform inversion is the most theoretically accurate near-surface velocity estimation tool. It is able to solve for complex near-surface velocity structure where conventional ray-based methods fail. If errors in the initial model are too large, waveform inversion will fail to converge to the correct model. This convergence problem is particularly true for large near-surface velocity contrasts and velocity inversions. In such cases, first break traveltimes will become discontinuous and ray-based methods will be unable to reconstruct the velocity. We propose to address this issue with a new inversion workflow that adds a wave-equation traveltime inversion step prior to waveform inversion. The performance of our approach is evaluated on both synthetic and field data.