Our projects span the globe, from Alaska to Antarctica to Africa.  We've employed ground-penetrating radar, seismic tools, resistivity, IP, and other geophysical methods for contaminated sites, concrete imaging, geological mapping, snow and ice thickness, and additional diverse range of subsurface imaging solutions.

3D Magnetotelluric Surveys at a Remote Site in Alaska

We deployed a crew of 3 plus a helicopter pilot to a remote site providing our own camp and logistics. The crew stayed on site for 23 days collecting MT data in a 3D grid. The data processing revealed features of interest with amazing data quality. All the work was completely safely and on time.

Gravity surveys for mineral exploration

2-D gravity profiles were collected over a mineral deposit at a remote site in Alaska. We conducted the data processing on site in order to determine if additional 3D surveys were warranted. We recommended based on the response not to continue with the gravity, as there was not a clear correlation between the existing boreholes and the gravity response. But the core was beautiful! I suspect this negative results was due to the thin layers of the deposit.

Gravity surveys to delineate a fault near Anchorage, Alaska

We conducted a land-based gravity survey outside Anchorage in winter conditions to provide insight into potential faulting near the site. Data processing included corrections for snow depth and density, measured on site. All work was completed safely, on-time, and on-budget with 10% more data than the project specification. Profile and gridded data of the complete Bouguer anomaly provided visualization of the data results.

Sea ice surveys for the Port of Nome

We collected GPR data over several miles of sea ice outside the port of Nome in preparation for drilling activities. Data were processed to provide a color-coded map integrated into the client’s GIS platform for manipulation and viewing of the data set. This data set provided for enhanced safety of the drilling crew over just drilling holes, as the GPR data collected information at sub-foot resolution.

Seismic surveys to estimate soil properties at Moose Creek Dam
We performed downhole surveys using a borehole geophone and a sledgehammer on the end of a weighted plank to estimate shear wave and compressional wave velocities in the material below the dam. MASW surveys at the same locations provided a check of shear-wave velocities produced from the downhole surveys. Reprocessing of the data using a refraction workflow also produced 2-D sections of compressional wave velocities. All work was completed on-time despite adverse weather conditions.

Delineating the lateral and vertical extent of waste in an abandoned landfill in northern Alaska

Logic Geophysics surveyed 14 acres of a relic landfill using low-frequency GPR to estimate the waste volume. We were also able to provide additional site information including identifying subsurface ice and ash layers. All operations were completely safely and on time in a remote area.

EM31 and GPR surveys of a contaminated site

A contaminated site was surveyed using GPR and EM31 combined to provide information about contaminant location and subsurface lithology. We conducted the work quickly and safely at a remote site, dealing with challenging site conditions as well as wildlife hazards (encroaching bears causing temporary egress from the survey area). Results were successfully integrated with a soil boring campaign to inform a remediation strategy.

Locating buried utilities at a U.S. Coast Guard facility

200-MHz and 500-MHz ground penetrating radar antennas provided subsurface imaging down to approximately 14 feet below ground surface.  The 500-MHz GPR antennas provided imaging of very near-surface (<2 feet deep) utilities as well as enhanced resolution in the upper 6 feet of the subsurface profile.  Dozens of utilities were successfully located in this large (over an acre) gridded survey requiring integrated operations with traffic control and multiple military and civilian agencies in a team effort to provide timely data collection and results.

Seismic refraction surveys to estimate depth to bedrock and bedrock quality

We provided seismic surveys using an explosive source (Betsy gun) and long arrays to provide imaging of seismic velocities down to 200 feet below surface. Results correlated extremely well with available borehole data. The information gained will be used in design and reconstruction of roadway. All work was completed safely and on-time.

EM61 and GPR surveys at a Formerly Used Defense Site in the western Aleutians, Alaska

Logic deployed personnel and equipment to the western Aleutians via aircraft and landing craft as part of a site investigation team at a Formerly Used Defense Site (FUDS).  EM61 and GPR data were processed on-site to guide excavation and sampling efforts in real-time.  In spite of the extremely remote location and difficult weather conditions, geophysical work was completed early and under budget, promoting the timely success of the overall project. 

Detecting void spaces beneath asphalt at Fairbanks International Airport

166 miles of survey distance were completed using a GPR system towed behind a vehicle. All data collection on the runways and taxiway was completed at night while integrated with aviation operations on the airport. Our aviation experience promoted safe and efficient operations during the data collection, enabling us to finish early and below budget. Subsequent data processing and interpretation revealed void locations underneath the surveyed asphalt.

Using low-frequency GPR to measure ice thickness near Haines, Alaska

25-MHz GPR antennas provided imaging of ice thickness at a mountain glacier outside Haines, Alaska.  Logic Geophysics’ personnel were based in a remote camp and site access was provided via helicopter.  In spite of difficult travel conditions and weather, we completed the work safely, on-time, and below budget, as evidence of our unique expertise in remote sites and “extreme geophysics.” 

Estimating depth to bedrock at a road site outside Haines, Alaska

Radar methods are often more accurate and quicker than seismic methods for depth-to-bedrock surveys, where the site conditions are amenable.  We used low-frequency GPR (25 MHz and 50 MHz) to look for the overburden/bedrock interface along a road in southeastern Alaska.   

Cemetery surveys in Nome, Alaska, to identify unmarked grave locations

We surveyed over 5 acres of cemetery and tundra to detect and locate unmarked human burials.  Surveys were conducted in cemetery areas with known burials as well as on tundra where no known burials were previously thought to exist.  Our work was able to locate data anomalies likely associated with human remains and provide real-world coordinates for georeferencing of burials.  The results from this project will be used for management of the Nome cemetery, and important societal and cultural resource in Alaska.

Locating rebar, conduit, and post-tensioning cable in concrete with GPR

We provided GPR imaging services at 32 coring locations in a concrete pad.  Using high-frequency GPR, we were able to quickly and accurately estimate the locations and depths of the rebar, conduit, and PT-cable, keeping the overall project on time.  On-site marking of objects within the concrete occurred immediately after data collection.  With this methodology, we saved the overall project from costly and potentially life-threatening mistakes.

GPR investigations of an ice tunnel and permafrost

GPR tools provided imaging of mass ground ice thickness and depth to frozen sediments.  Profiles within a tunnel were accomplished on the tunnel floor, walls, and roof to define mass ice thickness and geometry.  Data were processed on-site for immediate interpretation of ice thickness to provide recommended drilling locations.  Work was accomplished safely, on-time, and under budget in cold, hazardous conditions.

Seismic reflection imaging to map subsurface geology and help manage water quality in Benin, Africa (Geoscientists Without Borders)

In conjunction with Geoscientists Without Borders, over 8 km of near-surface seismic data were recorded in Coutonou, Benin in 2013 using a manual (sledgehammer) source.  Interpreted data mapped the primary hydrogeologic units of the Godomey aquifer system. Electrical and electromagnetic methods were also used to image the freshwater-saltwater contact and develop a hydrogeologic model. Results were shared with the city's groundwater management agency to manage groundwater pumping from the Godomey aquifer and reduce saltwater intrusion.

Ice and snow surveys on the North Slope of Alaska using GPR

Logic Geophysics managed a large-scale, ground-penetrating-radar project on the North Slope of Alaska for imaging snow and ice thicknesses over approximately 5000 miles of survey transects.  We provided classroom and on-site training for all GPR personnel before acquisition, managed personnel and equipment throughout the project during 24/7 operations, and provided daily quality control for collected data in accordance with project objectives.

Ground penetrating radar (GPR) surveys of roads and bridges on the North Slope of Alaska

Ground-penetrating-radar surveys were accomplished with 500-MHz antennas and 200-MHz antennas to provide imaging down to approximately 15 feet below ground surface.  Data processing and interpretation revealed subsurface features of interest relevant to engineering design and construction on the roads and bridges, including rebar structure and accreting ice layers.  Our results exceeded the project's data quality standards in an safe, on-time performance during rigorous working conditions down to -14F.

Where gravel is gold: Successful gravel exploration in northern Alaska using electrical resistivity

Proof-of-Concept testing for gravel exploration with surface-based geophysical methods was completed in 2017 on the North Slope of Alaska.  In this environment, gravel is scarce, demand is high, and traditional geologic method are largely unsuccessful.  Our project used IRIS Syscal Pro Resistivity meter and borehole data to succesfully correlate subsurface resistivity structure with gravel deposits.  Project was completed successfully demonstrating a 70% success rate for gravel exploration with our survey design.  Remote site required helicopter daily helicopter deployment and a bear guard, and safe operations were a priority at all times.

Two for one: EM-31 surveys of a contaminated site in Alaska

We conducted EM-31 surveys at a contaminated remote site in Alaska to delineate both subsurface metal and subsurface contamination, where present.  Data were collected on a grid to compensate for positioning errors caused vegetation canopy reducing GPS signal quality. All project objectives were met in a safe, on-time, on-budget performance.

Multi-offset ground penetrating radar (GPR) surveys for imaging snow thickness and snow-water equivalent

Multi-offset ground-penetrating radar data provide the optimal tool to analyze subsurface radar velocity, and therefore provide the most rigorous depth estimates as compared to other techniques.  We used multi-offset radar data and proprietary processing algorthms to analyze snow depth and water content at a remote site in the Canadian Arctic during temperatures as low as -54F.

Ground penetrating radar (GPR) surveys for highways in Alaska (Alaska Department of Transportation)

312-miles of ground-penetrating-radar data were collected over roads and highways in Anchorage, Palmer, and Wasilla, and on the Kenai Peninsula in 2015 for Alaska DOT. Two different frequencies were deployed simultaneously using Sensors & Software industry-leading "Spidar" acquisition system.  Data processing and interpretation provided asphalt thickness; base course and sub-base thicknesses; locations of utilities, traffic loops, and culverts; and unusual subsurface features potentially associated with road subsidence.  Direct comparison of Spidar results with Air-horn system results showed a 10% increase in accuracy using the Spidar system.