Power Plant Expansion

Subsurface Evaluations, Inc. (SEI), performed a seismic refraction/reflection survey on south Florida power plant on July 6-10, 2005. The purpose of the seismic refraction/reflection survey was to map the limestone subsurface to a depth of at least 100 feet.  The objective of the survey was to look for structural weakness in the subsurface in the form of faults and/or karst features.

The power plant expansion site was in a state of dynamic change during the time of data acquisition.  A virtual army of construction vehicles operating during normal working hours prevented seismic surveying during the day. Large pumps, unable to be turned off, were running in an effort to remove groundwater from an excavated area of the foundation footprint. This ambient seismic noise encountered during the day was dramatically reduced at night, thus data acquisition became strictly a night-time operation.

Night-time operations and additional filtering during processing allowed SEI to overcome the unusually high cultural noise encountered on the site. Using the latest refraction inversion software, SEI was able to identify possible voids in the shallow limestone. Additionally, surfaces that appeared irregular or highly undulated were also delineated as they may represent areas of karst activity. Following the survey, based on the seismic profiles, the client was able to position a drill rig above interpreted features for further testing and ground-truthing.