Studying converted waves in shallow marine environment

For many years, waves converted from compressional to shear mode have been successfully applied in hydrocarbon exploration to image and characterize the subsurface. Since shear‐waves propagate with a velocity that is dependent on the shear modulus and are thus directly related to the shear strength of the sediment, they are very useful for geotechnical purposes. Generally, P‐wave reflection amplitudes contain S‐wave information but Riedel et al. (2001) showed that these reflections are not very sensitive to this. An alternative approach is to obtain S‐wave information directly from converted waves. However, it is not clear whether these waves can be applied for geotechnical aims. The main focus will be on understanding the dependence of mode conversion on the seismic properties. In this study, we investigate the possibility of acquiring converted waves in marine unconsolidated sediments. From our numerical experiments we found that the conversion is maximal at two angles where the smallest angle appears to be more favorable in the environment of interest. Furthermore, we show how and where converted waves can be observed on a seismogram and the optimum field configuration to acquire them.