Seismic Refraction Tomography for Near-Surface Velocity Model Building and Statics Corrections

The present work proposes a new methodology for the construction of 2D near-surface velocity models for static corrections for terrestrial seismic data using surface refraction information. An algorithm, widely used in seismic data \ textit {wide-angle} for crustal modeling applications, was adapted for modeling and inversion of velocity and layer structure close to the surface. A methodology for the proposed workflow was evaluated on four synthetic models built with real topography information and velocity models from geophysical and geological information. Three real seismic data from 2D lines were also used. Initial models were built using traditional methods of interpreting shallow seismic refraction. Subsequently, the modeling and inversion were performed using a 2D tomography algorithm based on ray tracing to minimize the travel times of the first arrival, inverting the seismic velocities and vertical position of the refractor. For the synthetic data was observed that the algorithm obtained the smallest relative errors in most parameters of the model and in the estimation of static corrections. For the real data, a better stacking of the seismic reflections was observed in relation to traditional methods used in the stage of statics corrections in the seismic processing workflow.