Geophysical Services

Ground Pentrating Radar (GPR)
GPR works by sending a pulse of energy down into the subsurface and recording the
strength and time required for a reflected signal to return. Reflections are produced
when the energy pulse enters into materials with differing electrical conduction
properties. GPR is very effective for locating USTs, utilities, piping, burials,
foundations and other subsurface objects to significant depths.

Electromagnetic (EM) Terrain Conductivity and Induction
EM conductivity and induction investigations are a rapid and cost effective way to map
landfills, locate USTs and buried drums/waste, as well as map shallow
groundwater contamination.

Subterra Geoservices uses the Geonics EM31DL Terrain Conductivity Meter to measure soil
conductivity and the Geonics EM61-MKII system for precision metal detection.

The devices are non-intrusive and can be carried or towed. The geophysical data is
collected simultaneously with real-time Differentially-corrected Global Positioning
System (DGPS) coordinates. The data is contoured and presented to show the
interpreted subsurface features (anomalies) as in the example shown. The final data
maps can be presented in a variety of file formats allowing direct import into popular
GIS and CAD programs such as ArcView® or AutoCad®.

Borehole Video Logging
Subterra Geoservices utilizes the GeoVision Jr. Heavy Duty down-hole video camera
system to provide real-time visual investigations of boreholes and wells of all diameters
to depths up to 1000 feet. Video is viewed live on site, recorded digitally, and can be
burned to a DVD for delivery to the client.
• view and inspect water and monitoring wells, vertical and horizontal boreholes
• find and view fractures, voids, caves, water inflow, cross or inter-bed water flows,
sand, gravel, and grout
• inspect piping, mines, caves, bridges, dams and foundations
• locate and identify obstructions or lost items