This approach uses the final output of 2D Vs profile from the current typical inversion approach as input to the second phase of the inversion based on a different forward modeling scheme than previously used (Fig. 1). Considering the lateral variation is largely smeared during the dispersion analysis because of the layered-earth-model assumption, the main objective with this approach would be to recover the smearing effect as much as possible by adopting another scheme accounting for the local variation of Vs. This scheme may use the Vs structure provided by the previous output of the 2D Vs profile as an initial starting model to account for the local variations observed within an individual field record to update a certain part of the 2D Vs model, mostly likely corresponding to the surface location of the receiver spread used during data acquisition. This update process can be continued in an iterative manner to accomplish an improved outcome. Development of a forward-modeling scheme to accurately account for various types of local variations—like phase and amplitude difference between receiver locations—will be the key issue for this approach to be successful as well as the optimization technique to improve the local Vs model. Inevitably, this approach will be computationally intensive. Any successful case of this type has not been reported yet.