Shallow Seismic Exploration in Soil Dynamics

Methods of shallow seismic exploration of soils are continually developing and evolving. Advances in techniques and equipment for performing crosshole and downhole tests, new data on interpretation of waves in these tests, and a description of the new Spectral-Analysis-Of-Surface-Waves method for in situ site evaluation are presented. In addition some speculation with regard to a process which might be called 'Geotomography' is presented based on the current potential for automated data reduction in crosshole testing. Finally, a review of recent re-examinations of the role of the state of stress in a soil mass on the low strain amplitude dynamic properties is presented and discussed with regard to the importance of principal stress directions in elastic wave propagation.