Seismic Refraction Tomography

Refraction tomography bases on the classic seismic refraction studies. Classical refraction gives good results in the ground with relatively low variable structure and layers (which differ significantly in velocities of seismic waves). In contrast, tomography can localize more complex structures where seismic wave velocities change in different directions gradually. Such places are fault zones, areas of karst, voids. Refraction tomography uses `first breaks` of refraction P-waves. The result of refraction tomography is determining velocity field in the tested ground.