oa Challenges and Strategies for Near-Surface Modeling for Static Corrections

Understanding the geology is vital in modeling the near-surface. The geophysical implications are<br>rapidly varying vertical and lateral velocities, complete with velocity inversions. Modeling strategies<br>include elevation correction with sand dune term, and use of refraction statics and tomography. The<br>modeling challenges include shingling, acquisition geometry, long wavelength and imaging of complex<br>structures.<br>Shingling is a near-surface generated en-echelon effect due to shallow inversions, outcropping<br>refractors, multiple fast thin refractors, or interference. Shingling creates medium and long wavelength<br>anomalies due to poor definition of the layer velocity field. Strategies for model building include picking<br>a consistent refractor and averaging all shallow layers as a single weathering layer.