• Mapping Subsurface Voids

    Mapping Subsurface Voids

    ESP provided next-day response for the evaluation of potential voids associated with a storm drain pipe beneath a four-lane highway in western North Carolina. ESP collected closely spaced GPR data and processed the data in 3D to show the depth and lateral extent of the void. The client used the results to select grouting locations for repair.

  • Delineate Abandoned Landfill

    Delineate Abandoned Landfills

    ESP provided geophysical studies to characterize an old landfill that was the site of a planned development. We collected electromagnetic induction data to map the lateral extent of the buried waste and identify likely areas of municipal solid waste versus land clearing/inert debris.

  • Depth to Bedrock Studies

    Depth to Bedrock Studies

    Seismic refraction services can help map the approximate depth to rock for building expansion projects. Compressional wave velocity models are combined with boring data to show the approximate depth to weathered rock and bedrock. The results can be used to estimate the quantity of rock removal for site development.

  • Remote Scour Monitoring

    Remote Scour Monitoring

    ESP provided consulting to a state DOT to select and install a remote scour monitoring system. We researched and purchased the recommended system, fabricated mounting brackets and installed the system, and provided real-time data presentation that automatically uploaded the data to a customized web site for real-time display.

  • Bedrock Fracture Characterization

    Bedrock Fracture Characterization

    ESP provides geophysical services for industrial groundwater contamination projects, including lineament analyses, resistivity studies, and borehole televiewer logging. The results can indicate the likely locations and orientations of groundwater-bearing fractures that could control off-site contaminant migration.

  • Seismic Site Class Studies

    Seismic Site Class Studies

    Surface wave seismic studies are used to develop shear wave velocities for determining the site class designation. The seismic data is collected and processed using the Multi-Channel Analysis of Surface Waves (MASW) method. In many cases, the results have been used to improve the site class over that determined from Split Spoon Testing (SPT) data.

  • Locating Abandoned USTs

    Locating Abandoned USTs

    ESP has performed numerous geophysical studies to locate abandoned USTs for NCDOT and other clients. Typical services include review of historical aerial photographs, collection of electromagnetic induction data using an EM61 to locate buried metal objects, and GPR imaging of anomalies to identify buried USTs.

  • Void Studies for Bridge Construction

    Void Studies for Bridge Construction

    Geophysical services can help characterize select subsurface conditions for a planned bridge construction. In one instance, the planned location of the bridge was adjacent to a large sinkhole. ESP collected 2D electrical resistivity imaging, micro-gravity, and GPS data to identify possible subsurface voids.

ESP’s geophysical services are proven to help solve problems and add value to environmental and engineering projects. The goals of our geophysical studies are to reduce risk and lower design and construction costs.

Example Geophysical Services:

  • Locating underground storage tanks (USTs)
  • Collecting surface wave seismic data for IBC site class
  • Delineating buried waste such as municipal landfills
  • Exploring the extent of sinkholes and karst features
  • Mapping dam seepage paths
  • Locating voids
  • Mapping lake sediment thickness
  • Locating steel reinforcement and PT cables
  • Evaluating groundwater-bearing fractures and aquifers
  • Mapping depth to bedrock

Typical Geophysical Methods:

  • Ground-Penetrating Radar (GPR)
  • Electromagnetic induction (EM)
  • Seismic refraction
  • Surface wave seismic (MASW)
  • Seismic reflection
  • Electrical Resistivity Imaging (ERI)
  • Induced Potential (IP)
  • Self-Potential (SP)
  • Micro-gravity
  • Magnetometer and gradiometer
  • Borehole geophysics
  • Overwater/underwater geophysics