3-D seismic reflection methods have been established as the predominant seismic method for exploration scale purposes. While this is true for exploration scale surveys the same is not yet true for near-surface seismic reflection investigations. While the benefits of employing 3-D methods have been documented they are still yet to be fully adopted by the near-surface community. There are a number of reasons for this; primary among them is the difficulty in planting large numbers of geophones. Adding to this is the cost involved with the increased amount of equipment required. Additional concerns arise because planning a 3-D survey requires more consideration that a 2- D survey. While both must address the same basic questions such as depth to target and resolution, planning a 3-D survey must take additional requirements, such as azimuth, into consideration as part of the design.
The University of Kansas geophysics group has developed a portable, automated seismic data acquisition system, known as the autojuggie, for efficient ultra-shallow seismic imaging. The autojuggie is capable of quickly performing non-invasive, high-resolution 2-D or 3-D seismic surveys by deploying a dense array of geophones. Early tests involved geophones mounted to a board (Steeples et al., 1999a). Following the success of these initial tests, a linear design of 72 geophones was implemented for automated 2- D subsurface imaging (Steeples et al., 1999b; Spikes et al., 2005). Further development of the autojuggie allowed a 2- D array of single component (vertical) geophones to be deployed simultaneously in a 3-D survey mode (Tsoflias et al., 2006). The instrumentation of the autojuggie consists of a rigid steel platform used for positioning, planting, and transporting geophones; a hydraulically controlled mechanism for decoupling the geophones from the platform during seismic-data recording; and a 2-D array of geophones. A significant development in the design of the autojuggie was a mechanism that allows the planted geophones to automatically decouple from the rigid platform, thus eliminating the interference of complex seismic modes generated by the planting instrumentation. Automatically planted, stand-alone geophones were shown to be capable of recording the same quality of seismic data as hand-planted geophones, for only a small fraction of the time and effort required to acquire conventional ultrashallow 3-D. In its current form the autojuggie is capable of deploying 220 geophones at 0.5 m x 0.5 m spacing over a 9.5 m x 5.0 m area in a matter of a few minutes. The autojuggie has successfully been applied to several studies within the Lawrence, KS area. It has been used in the investigation of a shallow water table and lithology (Sloan, 2008) as well as adapted with metal base plates for conducting seismic reflection investigations on pavement systems (Miller et al., 2009). The autojuggie provides a method for performing cost effective and efficient high resolution seismic reflection surveys.
There are numerous publications within the refereed literature pertaining to exploration scale 3-D seismic reflection.
