Seismic wave testing has become increasingly popular in site investigation. This is due to the fact that the principles involved are becoming more accepted and that the equipment are becoming more available and reliable. This dissertation presents the required theory behind one seismic test in particular, the Continuous Surface Wave (CSW) method of seismic testing. The attributes of seismic testing are presented along with a summary of various testing methods. The dissertation also demonstrates that the author developed his own system for completing this test and demonstrated that he successfully used it to measure the stiffness of two soil profiles. The author compared the stiffness as measured using the CSW method with the strength as measured using the Dynamic Cone Penetrometer (DCP) for two soil profiles, and the in situ profile was compared to a compacted profile. The author demonstrated that the in situ profile had a higher stiffness than the same soil after it was thoroughly compacted and that the DCP results concur. This was caused by the in situ profile being structured and the compacted profile not. / Dissertation (MSc)--University of Pretoria, 2006. / Civil Engineering / MSc / Unrestricted