GeoSearchesFull-service geophysics · Nationwide & worldwide · Est. 2000
We run non-intrusive geophysics — GPR, electromagnetics, resistivity, seismic, magnetics, LiDAR and more — so you know what’s in the ground before you dig, core or pour.
Methods & equipment
Each measures a different physical property of the ground — dielectric contrast, conductivity, elastic velocity, magnetic susceptibility, density, thermal conductivity. Combining two or three is often what turns an ambiguous anomaly into an answer. Instruments are owned and operated in-house, not hired in for the day.
Dielectric contrast imaging from millimeter resolution in concrete to tens of feet in favorable ground.
Conductivity mapping for metal, plumes, fill boundaries and bulk ground change — fast over large areas.
Multi-electrode imaging that sections the ground by resistivity — the standard for layered geology and groundwater.
Elastic wave methods for engineering properties and deep structure.
Seismic surveys in detail →Site classification, MASW & ReMi →
Passive methods that need no source. Magnetics finds ferrous mass; gravity finds what isn't there.
Magnetic surveys in detail →Microgravity in detail →Abandoned oil & gas wells →
Millimeter capture of what is actually there, as a registered point cloud you can measure, section and hand straight to a designer.
A service in its own right, inside buildings and out. Heat gives a defect away long before anything has to be opened up, lifted or cut.
How quickly the ground carries heat away decides how much current a buried cable can carry. Assume it and the feeder is either undersized or paid for twice.
Where a hole already exists, we log it — and use it to tie the surface geophysics to ground truth.
Industries
The physics is the same everywhere. The question isn't. These are the sectors we work for most, and the thing each one is usually trying not to hit.
Geotechnical characterization, seismic site class, depth to bedrock and design-stage subsurface data.
Scanning before coring and cutting, utility clearance before excavation, as-built verification.
Tanks, drums, waste cells, fill boundaries, plume delineation and Phase II support.
Road and bridge condition, infrastructure asset mapping, cemetery and archaeological work.
Network locating and mapping, damage prevention, GIS record improvement.
Seismic site classification, soil thermal resistivity for feeder sizing, slab and void verification, utility clearance across very large footprints.
Abandoned well screening before pile layout, geotechnical characterization and foundation-depth data across solar and wind acreage.
Seismic acquisition, site characterization and pipeline route survey, onshore and remote.
Overburden thickness, old workings, structure and resource delineation.
Pavement layer thickness, bridge deck delamination, runway and rail bed assessment.
Pre-purchase due diligence, subsidence investigation and expert evidence.
Applications
Eight recurring problems, plus the drill clearance work that runs alongside all of them.
Before you core, cut or drill, we map what's inside the slab and mark it on the surface.
Condition and thickness data across pavements without closing them for coring.
Designating buried utilities across a site, marked to the APWA color code and delivered survey-ready.
Larger-area work where the target isn't a utility and the records don't exist.
A pile driven into a forgotten casing is a very bad day. Wells sunk before anyone kept records appear on no map — and solar and wind sites cover a great deal of ground in exactly the country where those wells were drilled.
Soluble ground fails without warning at the surface. The void is there long before the collapse, and it is findable long before that.
Where a building loses heat, takes water or hides a fault, thermal imaging finds it without opening anything up. Interiors and exteriors, at ground level or flown.
What was built is rarely quite what was drawn. A registered point cloud settles the argument before anyone fabricates to the wrong dimension.
ASCE 7-22 changed the basis of this work. Site class is now determined by shear-wave velocity alone; standard penetration resistance and undrained shear strength are no longer an acceptable basis. Three classes were added — BC, CD and DE — and Class A and B can only be assigned from velocity measured on site. If nobody measures, the structural engineer designs to the conservative default, and on a large slab that shows up directly in steel tonnage.
We measure Vs30 — the harmonic mean shear-wave velocity over the top 100 ft (30 m) — without a borehole, usually in a single day on site. MASW uses an active source and Rayleigh-wave dispersion for resolution through the shallow section. ReMi is passive, reading ambient traffic and plant noise, so it works on loud urban and industrial sites and reaches deeper. Run together they extend the dispersion curve at both ends and better constrain the profile.
Deliverable: shear-wave velocity profile, Vs30, and site class to ASCE 7-22 / IBC in a signed report for the structural engineer and the permit set. Data center programs are the busiest source of this work right now — large footprints, fast schedules, and a seismic design that governs a great deal of steel.
Before a rig sets up, we clear the footprint. Boreholes hit things — services, tanks, old foundations, mine workings — and the cost of finding out with a drill string is never just the drill string.
ASCE 38 · Subsurface utility engineering
Utility information comes in four quality levels. We produce three. The fourth needs a vacuum truck.
Existing records and utility owner information, compiled and reconciled.
QL-D plus surveyed above-ground features — manholes, valve boxes, meters.
Geophysical designation of horizontal position, with depth where the method supports it.
Plan and elevation from exposing the utility. Outside our scope — we designate the dig points.
What you receive
Marks on the ground wash off. What you keep is the drawing — every line attributed to a quality level, every depth stated, and the one thing you actually asked answered on its face.
Drawings are issued as PDF and, where the project needs it, as CAD or GIS for direct import. Both examples are illustrative — real deliverables carry the site, the date, the instrument and the operator.
Case study 01
Antigua is karst. The limestone beneath it dissolves, and where it dissolves it leaves voids that give no warning at the surface until something drops through.
A runway laid during the Second World War, still carrying private and cargo traffic seventy years later. Sound pavement on soluble rock is a particular kind of problem: the surface stays intact while the ground under it goes hollow, and the first symptom is usually the failure itself.
An operating airfield. Coring a grid across the pavement was never realistic — and coring only ever tells you about the holes you drill. Between them, the ground is an assumption.
Ground-penetrating radar with a low-frequency antenna working across roughly 80 to 250 MHz. Low frequency trades resolution for penetration, which is the right trade when the target is a void meters down rather than rebar in a slab. Continuous survey lines along and across the pavement gave coverage between the points a drilling program would have sampled.
Voids and developing sinkholes were located and mapped beneath the pavement. The runway was repaired and redesigned on the strength of the survey rather than on assumption — and stayed open while the work was scoped.
The same problem sits under any pavement, slab or yard built on soluble ground: limestone, gypsum, old workings. The instrument changes with the site. The argument doesn't — you cannot core your way to a void map.
Case study 02
A Confederate officers' prison stood on Johnson's Island in Sandusky Bay. The men who died there were buried in thin soil over bedrock, under wooden headboards that did not last.
Around twelve thousand Confederate officers passed through the prison camp during the war. Those who died there were buried beside it, in ground where bedrock sits close enough to the surface to prevent burial at the customary depth. The first markers were wooden headboards. By 1890, when citizens of Georgia paid for 206 marble headstones, the original positions were already a matter of inference.
You cannot excavate to find graves. Not here, not anywhere. The question was where the burials actually lay, and the only acceptable answer was one that disturbed nothing — which left exactly one class of method.
Ground-penetrating radar, run across the cemetery and deliberately beyond the fence line rather than only within it. Graves are a subtle target: the signature is the disturbed soil of the shaft and the contrast between backfill and undisturbed ground, not the remains themselves. Shallow bedrock helps as much as it hinders, because a grave cut into rock leaves a boundary the radar can follow.
267 sets of remains were located — sixty-one more than the 206 markers accounted for, and found both inside the iron fence and beyond it, in ground that had not been treated as part of the cemetery for well over a century.
The boundary was realigned to bring them inside it, and the headstones were replaced against the survey rather than against the old assumption. Two granite monuments were dedicated on 21 June 2003. One carries the map produced from the survey. The other records how the work was done, in a sentence that reads: two hundred sixty-seven sets of remains of those who died in the prison camp from 1862 to 1865 have been located through the use of non invasive ground penetrating radar.
Where excavation is unacceptable rather than merely inconvenient — cemeteries, consecrated ground, archaeology, anywhere a mistake cannot be undone — geophysics is not the cheaper option. It is the only one. The deliverable here outlived the invoice by some margin.
ASCE 7-22 · IBC · V̄s30
ASCE 7-22 changed how this works. Site class is now determined by shear-wave velocity alone — blow counts and undrained shear strength are no longer an acceptable basis — and three new classes were added between the old ones. If nobody measures the velocity, the structural engineer designs to a conservative default.
Data center programs are driving most of this work — very large footprints, compressed schedules, and a seismic design that governs a lot of structure. The same requirement lands on warehousing, manufacturing, healthcare and any project reaching for a permit under the current code.
Two of the nine classes can only be reached by measuring velocity on site. Without data, the default assumption applies; with it, the engineer designs to what the ground actually is.
Deliverable: shear-wave velocity profile, V̄s30, and site class to ASCE 7-22 / IBC in a report for the structural engineer and the permit set. No borehole, no coring, nothing left in the ground — most sites are a single day.
The other number a data center asks for
Site class sizes the structure. Thermal resistivity sizes the power. Both get asked for at the same stage of a data center program, and both are measurements rather than assumptions.
Every buried feeder and duct bank depends on the ground around it carrying heat away. Where it can't, the cable runs hot and its ampacity falls. Design on a guessed value and you either undersize the feeder or pay for copper you never needed — and on a campus with megawatts of underground distribution, that margin is not small.
Resistivity rises sharply as soil dries, so the design case is the dry case. We measure across moisture content to produce the dry-out curve, not a single fair-weather number.
Deliverable: thermal resistivity in °C·cm/W and K·m/W by location and depth, dry-out curves, and a recommendation on whether native soil will serve or engineered backfill is required.
The company
The company dates from 2000. The experience behind it runs to forty-five years in geophysics, nationally and internationally, on four continents and counting.
We are a full-service geophysical company. That means we are not tied to one instrument and one answer — we select the method from the question, the target depth and the ground, and combine methods when a single dataset would leave the result ambiguous.
Almost every survey is non-intrusive, and all are non-destructive. Nothing is excavated, nothing cored, nothing left in the ground. The one exception is thermal resistivity testing, which inserts a slim needle probe and withdraws it on completion. Knowing the ground before you commit to a design is cheaper than discovering it mid-project. That has been the whole argument since 2000, and it has not needed updating.
Sister company
Terradocs turns project details into a sendable proposal, scope or safety document — standards-referenced, priced from your own rate table, and carrying the limitations language that protects your firm.
terradocs.ai →Where we work
Four offices across the United States and three overseas. Crews mobilise nationally and internationally, and have acquired data on four continents.
United States
International
Data acquired across North America, Europe, Africa, the Middle East, the Far East and Latin America.
Get a survey scoped
Tell us the site, the ground and what you're trying to find. Most scopes get quoted on the phone, and the right method usually becomes obvious in that call.
(844) 300-6GPR