Description

The OhmMapper is a capacitively-coupled resistivity meter. It uses a set of cables that are towed along the surface for its measurements unlike traditional resistivity meters which require stakes in the ground. This unique design enables you to collect data up to 10 times faster than traditional resistivity systems!

Capacitively-coupled resistivity meters are AC coupled into the ground through the capacitance of the cables to the soil. Since direct contact with the ground is not required a resistivity survey using the OhmMapper can be done over pavement, frozen ground, rock, ice, snow, caliche, or any other hard surface. The OhmMapper is perfect for environments where putting stakes in the ground is either extremely difficult, impossible, or prohibited.

The OhmMapper uses a narrow signal frequency of approximately 16 kHz, so interference from power lines and telluric ground currents aren’t a concern. It can be towed manually or by attaching the OhmMapper array to an ATV or other vehicle.  An external GPS can be used for position or the internal GPS from an Android tablet or cell phone, or even a Windows logger can be used. The OhmMapper is ideals for surveys where the desired depths of investigation is around 8 to 20, depending on the soil type. Since its creation the OhmMapper has proven itself to be the tool of choice for shallow-surface resistivity mapping.

 

Features and benefits

  • Fast, Accurate, Reliable: Fast accurate resistivity mapping up to 10 times faster than with tradition resistivity meters using metal stakes in the ground.
  • Hard Surface Surveying: Perform surveys over pavement, runways, hard rock, frozen ground, snow, and other difficult areas without the need to drill holes and plant metal electrodes.
  • Software Agnostic: Data format compatible with popular resistivity software RED2DINV & EarthImager and Golden Software’s modeling software Surfer and Voxler.
  • Reduced Noise: Narrow band AC measurements avoid noise problems with powerlines and strong telluric currents.
  • GPS Functionality: GPS logging or manual fiducial marks for accurate data positioning.
  • Easy Operation:  With no stakes to pound into the ground and no long spread cable to deploy the setup is quick and easy.
  • High Density Data: From one to five receivers possible, a complete hundred meter long psuedosection can be collected in just minutes!
  • Fast Sample Rate: Up to five receivers at 1 sample a second. Collect 1000+ point data sets in just a few minutes!
  • Large, High-Density Data Sets:  Using five OhmMapper receivers you can produce a full depth profile in a single traverse along a survey line.
  • Supports Modern Technology: Built in Bluetooth allow the OhmMapper to communicate with all Android and Windows devices, providing a real-time view of the data streaming in as well as receiver battery charges, apparent resistivity vs. time, apparent resistivity model vs. time, measured resistance vs. time, and many other parameters.
 

Technical Details

 

TYPICAL USES

  • Map and track pollution plums from landfills, containment ponds, and others.
  • Map changes in soil type for better precision agriculture information
  • Map subsurface voids and cavities
  • Detect and map structures and activity (use) areas for archaeological surveys
  • Map near-surface mining targets such as shallow Kimberlites for diamond exploration, clay for industrial use, gravel deposits
  • Map soil depth to bedrock and outline variations in bedrock structure
  • Characterize near-surface geology for any geotechnical and engineering surveys within the depth of investigation of the instrument
  • Excellent tool for academic research and teaching
 

Resources