Waveform tomography for areas of complex near surface

Hussain I. Hammad, Gary F. Margrave

We test the capability of waveform tomography in resolving a model in an area of very challenging near surface geology. The complex near surface of the model makes it difficult to image a low relief structure at depth. The goal of the inversion is to recover the near surface compressional velocity and to detect some indication of the of the low relief structure. We inverted the data using the a multi scale technique and the efficient approach of Sirgue and Pratt (2004). The resulting models contain substantially higher resolution than the initial models. We also compare statics provided by the estimated models. The statics of the estimated models agree with the statics of the true model to within +/- 15ms in most regions in the model. This statics correction is sufficient for a subsequent residual statics solution to be effective.