The seismic reflection method has only recently been developed into a practical tool for evaluating shallow environmental sites at depths from 2 to 100 meters. Field configuration, seismic sources, and data processing for shallow seismic reflection data differ significantly from practices used in petroleum exploration. Steeples and Miller [1993] review the principles behind shallow seismic reflection profiling. Miller [1992] discusses the importance of using appropriate signal processing for shallow seismic reflection data. Some seismic data processing steps required for petroleum exploration, such as migration, are often unnecessary for shallow reflection data [ Black et al. 1994]. Hasbrouck [1991] explores the feasibility of using hammer-impact shear-wave sources and transverse geophones for shallow seismic reflection studies.
The success of a shallow seismic reflection survey can depend on the choice of seismic source. Miller et al. [1992] present field comparisons of shallow seismic sources at a site in California. The sources included a sledgehammer and steel plate, various shotguns fired into the ground or discharged in a water-filled hole, small explosive charges, and a electrical sparker source fired in a saltwater-filled hole with a trash bag liner. Rechtien et al. [1993] describe a high-frequency borehole sparker source suitable for tomographic investigations of shallow subsurface features.