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GEONICS EM-31 TERRAIN CONDUCTIVITY METER |
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 EMS uses non-invasive techniques where appropriate to help define and delineate contaminant plumes or source material of contamination.
A Geonics® EM-31 Terrain Resistivity/Conductivity Meter (EM-31) is used to map subsurface anomalies that affect resistivity/conductivity including brine spills, buried metal objects, etc. The EM-31 is capable of automatically downloading conductivity data as well as spatial data into a hand-held computer. Spatial data is collecting using a global positioning system (GPS). The GPS is capable of receiving differential GPS readings from local beacons or satellite stations resulting in a sub-meter accuracy of the survey locations.
EM-31 surveys are accomplished using traverses along the ground surface and collecting conductivity readings using a manual trigger, or a programmed time or distance interval. The EM-31 collects conductivity data of two general types simultaneously during a survey. A “conductivity” data reading recorded the response from the instrument transmitter measures the general conductance of the slice of earth approximately 15-20 feet below the instrument and an “in-phase” signal component response is recorded to indicate heightened sensitivity to surficial or buried metal objects, if present.
This data is recorded and subsequently mapped using specialized software programs to indicate anomalous readings which indicate areas that should be investigated further by analytical or invasive techniques. |
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