Surface Geophysics
OVERVIEW

Surface geophysics is often the most cost-effective way to characterize subsurface features at the beginning of the planning process, to avoid costly change orders and delays, and to provide site-specific data for value engineering decisions.
Delta Geophysics uses various geophysical techniques to provide subsurface imaging solutions for environmental, geologic, mining, and engineering applications. These techniques are non-invasive and typically used early in the project life-cycle to provide a focus point for more expensive and disruptive methods such as test drilling, soil probes, and excavation. Surface geophysics include seismic, magnetic, resistivity, electromagnetic, gravity and GPR methods that are applied to locate and mark-out underground utilities and storage tanks, determine depth to bedrock, locate water wells identify anomalous soil conditions, map geological features, located underground faults and fractures, produce depth-to-bedrock maps, and provide other site characterization data used by engineering, geologic, mining, and geotechnical firms.
Opposed to test wells, test borings or test pits, geophysical data provides widespread coverage over a site. Instead of a data point every 250 feet, you have a data point every 20 feet, every 10 feet or even every 2 feet! Instead of randomly drilling and hoping to encounter a fracture, conduct a geophysical survey and locate fracture trends and locations to target test wells. Rather than accidentally digging into an underground utility, underground storage tank or an abandoned foundation during routine operations, determine the location of these features ahead of time and plan the project accordingly! Instead of hitting a large rock ridge in the middle of site excavation or utility installation, plan for these added excavation costs ahead of time! The advantage of surface geophysical techniques is that they can minimize the use of more expensive invasive techniques while proving continuous coverage between these isolated data points.
That being said, geophysics is not magic – results are uniquely site dependent and much benefit can be gained by calibrating geophysical data to site conditions using selected test borings or other invasive methods.
Delta Geophysics will look at your project, determine the optimum suite of tools and surveys required to meet you objectives, and provide you with a cost proposal to conduct the work. You consider the alternative costs and make a decision. How much does a dry well cost – does this probability offset the cost of conducting geophysical investigations? What is the extent of contamination – will a geophysical survey provide information that will significantly reduce the number of delineation wells/test borings required? How many underground tanks are located on the property and where exactly are they? How much rock must be blasted for excavation – is available data sufficient and reliable? Is there a sinkhole under the proposed building location – could there be cavities below test hole depth? Is the detention basin likely to increase sink activity because of its planned location? Where is the best place to drill the monitoring wells? These are typical questions that geophysics will address, in many cases in an extremely cost effective manner.
We would be delighted to consult with you to learn your goals and objectives, evaluate how geophysical methods might help you meet these objectives in a cost effective manner, and offer a proposal to integrate geophysical surveys with your planned geotechnical investigations. We have helped hundreds of clients with site and mitigation design and value the opportunity to use our extensive experience to assist you in an ethical and straight-forward manner.
APPLICATION

SURFACE GEOPHYSICAL APPLICATIONS

• Precision Utility Locating (Old Subsurface Utility Locating)
• Locate Underground Storage Tanks (old UndergroundStorageTanks)
• Locate Pipes, Utility CableS AND LINES
• Locate Concrete Structures
• Map Landfill Boundaries
• Locate Pits and Trenches (old Waste Burial Trench Mapping)
• Delineate Leach Fields/Septic Tanks (old Septic System and Tank)
• Delineate Excavated and Backfilled Areas (old landfill delineation & Waste Burial Trench Mapping)
• Map Soil Stratigraphy
• Map Bedrock Topography
• Map Subsurface Voids and Cavities (old VoidsTunnels)
• Characterize Archaeological Sites
• Map Soil and Groundwater Contamination (old contaminant plumes)
• Sediment Deposition Determinations
• Reservoir Construction
• Pre- and Post Dredging Surveys
• Bedrock Profiling
• Characterize Subsurface Hydrogeology (new Borehole Logging)
• Map Buried Channel Deposits
• Map Geologic Structure
• Conduct Groundwater Exploration (old Groundwater Resource Investigations)
• Locate Conductive fault and Fracture Zones
• Locate Buried Drums (Old Buried Drums & New Buried Metal Targets)
• Detect Buried Ordinance (New Buried Metal Targets)
• Locate Abandoned Wells (old Abandoned WellLocating)
• Clear Drilling Locations (
• Test Elastic Properties of Sediments and Bedrock
• Map pathways of groundwater flow
• Bridge Scour Surveys
• Delineate Sinkhole Activity (new Karst Terrain)
• Characterize Karst Geology (new Karst Terrain)
• Clear Drilling and Excavation Locations (new UST datasheet)
BENEFIT

Delta Geophysics provides interpreted data that allows our clients to create a robust subsurface model early in a project. Let Delta apply their years of varied experience to provide you with the extra level of knowledge that will help make your geotechnical and environmental decisions today hold up tomorrow.
DELTA GEOPHYSICS USES THE FOLLOWING METHODS TO INVESTIGATE AND MAP KARST FEATURES:
Surface Wave Seismic
Seismic Tomography
3-D Seismic
Resistivity Profiling
Ground Penetrating Radar
Electromagnetic Induction
Micro Gravity