GPR-Seismic-Metal Detection-Gravel Exploration-Environmental Sites-Geologic Mapping
Our projects span the globe, from Alaska to Antarctica to Africa. We've employed ground penetrating radar, seismic tools, and other geophysical methods to contaminated sites, concrete imaging, geological mapping, snow and ice thickness, and additional diverse range of subsurface imaging solutions.
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.
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.
Seismic refraction surveys to estimate depth to bedrock
Logic Geophysics conducted seismic refraction surveys in southeast Alaska. We used a sledgehammer source in conjunction with Geometrics Geode survey equipment to perform the work. Seismic data were ground-truthed with excavations to provide reliable results. Our knowledge of Alaskan sites and logistics allowed us to execute the project at a remote location in winter with less than 2 weeks notice. We successfully completed the project safely and on-time, meeting all project objectives.
Finding gravel in the Arctic using capacitively-coupled resistivity
On Alaska's North Slope, we conducted over 100 miles of surveys using resistivity tools as part of gravel exploration projects. We work closely with a engineers and drillers to find unidentified gravel deposits with non-invasive geophysical tools. Geophysical gravel exploration has proven quicker, cheaper, and more reliable for finding gravel in Arctic conditions than conventional methods alone. All project work has been completed safely and on time at temperatures down to -52F.
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.
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.
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.
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.”
EM61 surveys at an archaeological site in Anchorage, Alaska
We used Geonics EM61 to survey a previous World War II military site in Anchorage, Alaska. In spite of difficult terrain and vegetation, we completed the project successfully and delineated the locations of buried debris in a timely manner. All work was accomplished safely and below budget.
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 and EM61 surveys at a remote oil and gas production facility in Alaska
Equipment and personnel traveled by small aircraft to a remote landing strip at an Alaskan oil and gas production facility. We conducted both EM61 and GPR surveys to identify buried HDPE lines and metallic debris. All work was completed safely, on-time, and on-budget.
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.
Locating buried utilities with GPR
Locating buried utilities in an urban environment on an active roadway requires particular attention to safety. Traffic control blocked one lane of the road to allow surveys to proceed with safe operating conditions. Two different sets of GPR antennas, at 500-MHz and 200-MHz, with a high-voltage transmitter, provided imaging of buried utilities and conduit down to 14 feet below ground surface.
Seismic 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.
Using ground-penetrating radar to find buried objects on an Alaskan glacier
We used ground-penetrating radar at a remote site on a glacier in the central Alaska Range to find multiple objects buried in snow. Buried objects were located quickly using the GPR antennas pulled behind the operator in a sled, and then partially excavated where possible for positive identification. Equipment and personnel were flown to the site in a single-engine plane equipped with skis landing directly on the snow-covered glacier. All work was conducted safely and efficiently.
Estimating soil properties and permafrost conditions using resistivity tools
At project sites along the Dalton Highway north of Fairbanks, Alaska, we used capacitively-coupled resistivity tools to estimate the lithology and moisture structure of the underlying permafrost. We pulled the equipment array using snowmachines and human-power, depending on terrain, snow conditions, and vegetation. This project supported a geotechnical investigation for roadway realignment. All work was completed safely, on time, and on budget at remote field sites.
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.
Locating utilities with ground-penetrating-radar (GPR) at the Anchorage International Airport, Anchorage, Alaska
Ground-penetrating-radar surveys were conducted with an emphasis on safety and accuracy in an urban, restricted area during concurrent aviation operations. Gridded data collection occurred with both 500-MHz antennas and 200-MHz antennas to provide imaging down to approximately 15 feet below ground surface. Data processing and interpretation were accomplished onsite to provide site markings immediately for follow-on drilling operations.
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.
Ground-penetrating-radar surveys to find buried pipes in Anchorage, Alaska
We conducted GPR surveys in Anchorage, Alaska to find buried pipes for an engineering and construction investigation. Traffic control was conducted as part of the data collection in an urban environment. Gridded GPR data provided imaging of linear features associated with the main storm drain and tie-in pipes. Imaging down to 12 feet below ground surface was possible with 200-MHz antennas and a powerful GPR transmitter. The project was completed safely, on time, and on budget.
Ground-penetrating-radar surveys of an historic cemetery in Lake Clark National Park
Logic Geophysics mobilized to a remote site in Lake Clark National Park, Alaska, to conduct GPR surveys of an historic cemetery for the National Park Service. 500-MHz GPR antennas provided imaging down to about 6 feet below ground surface, to locate burials located on the site. A few markers remained on the surface, but we identified data anomalies likely correlated with additional unmarked graves. NPS is using our results to help manage this cultural heritage site.
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.
Environmental site investigation at Point Lonely, Alaska (BEM Systems, US DoD)
Electromagnetic surveys were conducted with Geonics EM-61-MK2A, to delineate buried tanks, drums, and other debris at a site investigation and remediation project at Point Lonely, Alaska. Our geophysical surveys and subsequent on-site data processing and interpretation revealed the presence of a buried jeep in an old landfill and multiple buried drums throughout the site. Immediate on-site digs were conducted to remove debris, and the area was resurveyed to support the remediation objectives.
Providing subsurface clearance for drilling operations (Port of Anchorage, Arcadis)
At the Port of Anchorage, ground-penetrating-radar data were used to delineate subsurface features such as fuel lines, electric lines, water lines, and other utilities. Borehole locations were based on our expert interpretation of the radar data. Throughout the 2 month project we cleared 43 borehole locations for drilling operations with a 100% success rate.
Measuring snow depth at Alaskan glaciers (United States Geological Survey)
Over 200 miles of ground-penetrating-radar data were collected from helicopters and by towing the radar system behind snowmachines, on foot, and on skis, at glaciers throughout Alaska, including Gulkana Glacier; Wolverine Glacier; Eklutna Glacier; Lemon Creek Glacier; and Taku Glacier. We processed and interpreted the radar data in conjunction with ground-truth data collected via snow pits and cores. The project provided insights into snow accumulation and redistribution processes on these glaciers and others.