Frequency Domain Finite Difference Modelisation of Wave Propagation with Topography

P184 FREQUENCY DOMAIN FINITE DIFFERENCE MODELISATION OF WAVE PROPAGATION WITH TOPOGRAPHY 1 INTRODUCTION Many seismic techniques aim at identifying deep geological structures. Waves coming from these areas must therefore be clearly recorded and recognized. Unfortunately they may be modified by near-surface structures. Moreover other waves traveling through superficial layers often pollute the desired signal. These waves are currently reflected scattered or converted leading to an energetic « ground roll ». In order to understand complex superficial phenomena and therefore cancel in records effects of the superficial propagation we have to determine the near-surface structure. We simulate the wavefield propagation in