What Is EM Equipment Used For in Environmental & Geophysical Surveys?

February 9, 2026

Electromagnetic (EM) equipment plays a critical role in modern environmental, geotechnical, agricultural, and utility investigations. By measuring variations in ground conductivity and detecting buried metal objects, EM instruments allow professionals to “see” below the surface without digging, drilling, or disturbing the ground. This non-invasive capability makes EM equipment invaluable for site characterization, environmental assessments, utility investigations, and land management projects.

At Environmental Equipment + Supply, EM equipment in the rental fleet focuses on two primary applications: ground conductivity surveying and metal detection. Instruments such as the EM31-MK2, EM38-MK2, and EM61-MK2 are widely used by environmental consultants, engineers, and surveyors who need accurate subsurface data quickly and efficiently.

Understanding Electromagnetic (EM) Surveying

Electromagnetic surveying works by transmitting an electromagnetic field into the ground and measuring the response. Changes in soil composition, moisture content, salinity, buried objects, or contaminants affect how the ground conducts electricity. EM instruments measure these changes and display them as conductivity or in-phase data.

Unlike traditional resistivity methods, EM equipment:

  • Requires no electrodes

  • Does not need direct ground contact

  • Can operate over asphalt, gravel, sand, or frozen ground

  • Allows continuous data collection while walking a site

This makes EM surveys significantly faster and more flexible than many other geophysical methods.

Ground Conductivity Equipment: Mapping What Lies Below

Ground conductivity meters are used to identify subsurface features associated with changes in soil or material properties. These instruments are especially useful for locating:

  • Buried pipes and utilities

  • Trenches and backfilled excavations

  • Landfill boundaries

  • Groundwater contamination

  • Saline intrusion

  • Changes in soil type or moisture content

EM31-MK2 Ground Conductivity Meter

The EM31-MK2 is an updated version of the industry-standard EM31 and is designed for environmental and engineering site characterization. It uses a patented electromagnetic inductive technique to measure apparent conductivity and in-phase response without electrodes or ground contact.

With an effective depth of exploration of approximately six meters, the EM31-MK2 is ideal for:

  • Locating buried utilities and pipes

  • Mapping geological variations

  • Identifying groundwater contaminant plumes

  • Delineating landfill edges, trenches, and spill areas

One of the key advantages of the EM31-MK2 is its speed and precision. Surveys can be conducted rapidly, with continuous data readout and collection as the operator traverses the site. Small changes in conductivity are measured with high accuracy, making subtle subsurface features easier to identify than with conventional resistivity methods.

The in-phase component is particularly valuable for detecting shallow buried metal, hazardous waste, or metallic structures that may not be visible at the surface. Modern upgrades, including Bluetooth data transfer and removable data loggers, improve efficiency and streamline post-processing.

EM38-MK2: Shallow Conductivity and Agricultural Applications

The EM38-MK2 is designed for high-resolution, shallow subsurface investigations. Measuring both quadrature-phase (conductivity) and in-phase (susceptibility) responses, it is especially well suited for:

  • Agricultural soil salinity surveys

  • Mapping saline intrusion

  • Monitoring groundwater pollution

  • Identifying buried foundations

  • Determining topsoil thickness

With two receiver coils offering different effective depth ranges, the EM38-MK2 provides flexibility for near-surface investigations. The instrument can also be operated in different orientations to adjust depth sensitivity, making it adaptable to a wide range of site conditions.

Lightweight and only about one meter long, the EM38-MK2 allows operators to cover large areas quickly while maintaining excellent lateral resolution. Bluetooth connectivity enables wireless data transmission to a field computer or tablet, and GPS integration allows data to be spatially referenced for accurate mapping.

Because it does not require grounded electrodes, the EM38-MK2 is particularly efficient for agricultural and environmental surveys where speed, repeatability, and minimal site disturbance are critical.

Metal Detection with EM Equipment

While ground conductivity meters are ideal for mapping soil and subsurface variations, some applications require locating metal objects directly, including non-magnetic metal. This is where metal-specific EM systems excel.

EM61-MK2 Metal Detector

The EM61-MK2 is designed specifically for detecting buried metal objects, including both ferrous and non-ferrous targets. It is commonly used for:

  • Locating buried drums

  • Identifying unexploded ordnance (UXO)

  • Detecting buried scrap metal or waste

  • Environmental site remediation

  • Brownfield and landfill investigations

The EM61-MK2 advances traditional EM metal detection by incorporating multiple time gates, which improve target characterization and sensitivity. Earlier time gates allow detection of smaller targets that may not be visible using standard methods, while mid-range time gates maintain compatibility with legacy EM61 data sets.

Additional features include:

  • Real-time graphical data display

  • High-capacity data storage for extended surveys

  • Optional integrated GPS for precise positioning

  • Improved ergonomics with a lighter backpack design

  • Optional high-power output for increased depth of exploration

These capabilities make the EM61-MK2 a powerful tool for environmental professionals who need confidence in locating buried metal hazards before excavation or remediation begins.

Choosing the Right EM Equipment

Selecting the right EM instrument depends on the project goals and subsurface conditions.

Use ground conductivity equipment when you need to:

  • Map subsurface features or boundaries

  • Identify changes in soil or groundwater conditions

  • Locate buried pipes or trenches

  • Conduct rapid, non-invasive site assessments

Use metal detection EM equipment when you need to:

  • Locate buried metal objects or drums

  • Identify non-magnetic metallic waste

  • Characterize hazardous sites prior to excavation

  • Support environmental remediation planning

In many cases, combining conductivity surveys with metal detection provides the most complete understanding of subsurface conditions.

Why Rent EM Equipment?

EM instruments are sophisticated tools that require proper selection and application. Renting EM equipment allows project teams to:

  • Access professional-grade geophysical instruments without large capital investment

  • Match the instrument to the specific project scope

  • Scale equipment needs based on workload

  • Ensure access to modern, well-maintained systems

For short-term investigations or specialized surveys, rental is often the most cost-effective and flexible solution.

EM Equipment Rentals from Environmental Equipment + Supply

Environmental Equipment + Supply provides a trusted rental source for electromagnetic equipment used in environmental, geotechnical, agricultural, and utility applications. From ground conductivity meters like the EM31-MK2 and EM38-MK2 to advanced metal detection systems such as the EM61-MK2,  Environmental Equipment + Supply helps professionals get the right equipment for accurate subsurface investigations.

Whether you’re mapping conductivity variations, locating buried pipes, or identifying metal hazards, Environmental Equipment + Supply’s knowledgeable team can help you select the appropriate EM solution for your project. With dependable equipment and expert support, Environmental Equipment + Supply makes complex geophysical surveys more efficient and reliable.

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