Velocity model inversion using parametric curves: Geophys

The use of parametric curves to define velocity models in seismic traveltime tomography is proposed. This approach provides increased flexibility in shaping the velocity models because it allows inversion for both velocity and grid point adjustments. The method is applied to a data set generated from a 1-D profile having sharp discontinuities. The results are compared with those obtained from other methods currently in use for traveltime tomography. It is found that large gradients and discontinuities can be retrieved with improved accuracy and that instabilities caused by non-optimal prior selection of the inversion grid can be avoided. The results appear to be robust when the sizes of both data and model space are reduced which makes the method appealing for the solution of large-scale tomographic problems. Key words: crustal models, model parameterization, seismic inversion