In GPR surveys, electromagnetic waves of frequencies between 50MHz and 1.5GHz are transmitted into the ground or structure, The transmitted energy is reflected back to the surface when it encounters significant contrasts in dielectric properties.

With the wide range of antenna available, the GPR technique can be applied to numerous geological, environemntal and engineering applications with investigation depths from a couple of centimeters to up to ~10mbgl. The data can be collected as a series of 1D soundings, 2D traverses, or in more complex situations as a 3D volume. With this dynamic versatility, the GPR technique can be applied in a wide variety of circumstances.

Applications; Detecting underground storage tanks, mapping of shallow voids (geological and artificial), buried foundation and infrastructure mapping, stragtigraphic mapping, detection of infilled materials, assessing subsurface heterogeneity, contamination mapping…

Leaflet on Ground Penetrating Radar
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We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

The electrical properties of the subsurface vary with the ground material, the presence and saturation level of fluids, and the presence of buried objects. By employing different electrode configurations it is possible to determine the apparent resistivity at various locations and depths. Comparison with computer models makes it possible to solve for the subsurface resisitivity distribution, and hence identify any anomalous areas or features. As different rocks/objects/saturating fluids exhibit different values of electrical resistivity, it is possible to map their distribution.

The introduction of multi-electrode and computer controlled systems allow semi-automated surveys, allowing large data sets to collected more quickly and at reduced cost. Three-dimensional surveys, which are invaluable when surveying complex geological / man-made features, are now a practical and cost effective tool.

STATS Geophysical routinely employ state of the art processing software which allow forward modelling and inversions of resisitivity data using complex mathematical algorithms.

Applications; Locating buried landfills, mapping and monitoring leachate plumes, mapping and monitoring of groundwater pollution, determination of depth to bedrock, locating dissolution features, stratigraphic mapping, locating buried channels, dykes, ore bodies and other geological features, slope stability assessments, time-lapse infiltration studies, cross-hole tomography, assessment of aquifer heterogeneity…

Leaflet on Resistivity Tomography
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We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

In electromagnetic (EM) surveying, the electrical conductivity of the ground is measured as a function of depth and/or horizontal distance. Different rocks, buried structures and objects exhibit different values of electrical conductivity. Mapping variations in electrical conductivity can identify anomalous areas worthy of further geophysical or intrusive investigation.

Due to the rapid data collection methodologies utilising GPS positioning systems, the Electromagnetic Mapping method is often used as a reconnaissance style survey to rapidly characterise sites prior to intrusive investigations. With most site investigations, EM mapping can provide an overview of contamination concentrations, thickness of overburden across a site etc, and hence can be used to target any future sampling and testing strategies.

Applications; Locating dissolution features and subsurface voids, mapping and monitoring groundwater pollution, mapping saline intrusions, locating underground storage tanks and buried drums, mapping buried foundations, locating the boundaries of landfills, mapping leachate migration, determination of layer thickness and conductivities, mapping buried utilities…

Leaflet on Electromagnetic Mapping
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We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

Magnetic surveying is a passive method based on the measurement of localised perturbations to the Earth's magnetic field caused by the presence of buried ferrous targets (e.g., pipes, cables, drums, military ordnance etc.).

Magnetic surveys can be conducted with a wide range of magnetometers, which can measure the amplitude of the field to within 0.01nT. Gradiometry surveys, which determine the vertical gradient of the magnetic field, are increasingly common in environmental/engineering site investigations as they are particularly sensitive to the near-surface.

Applications; Mineral exploration, geological studies, detection of buried infill, locating landfill boundaries, mapping underground storage tanks, buried drums, piles, reinforced concrete etc.. Detection of underground pipes and other utilities, mapping land mines and unexploded ordnance, archeological studies…

We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

Geophysical techniques are NDT methodologies that rely on contrasts in physical properties to detect features in the subsurface or within structures. STATS Geophysical can advise on the correct application of individual techniques, and provide expert survey design, execution and reporting services.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

Different subsurface materials have different bulk densities. In microgravity surveying, areas of contrasting density are located by collecting surface measurements of the variation in the Earth’s gravitational field.

A gravity meter is a highly sensitive spring balance. When positioned above a dense material it records the acceleration due to gravity (g) as a relative high (a positive gravity anomaly). When positioned above a low density material (e.g. an air filled cavity) the gravity meter records a relative gravity low (or negative gravity anomaly).

Applications; Cavity detection (including bomb shelters, hidden tunnels/adits, old mine workings, natural cave systems, sinkholes and dissolution features), density determination, mineral exploration, grouting investigations…

Leaflet on Microgravity Surveying
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We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

Rapid shear stiffness (G) measurements can be made in situ using the Continuous Surface Wave System (CSWS). The method allows non-destructive evaluation of ground stiffness, and provides a profile of stiffness values with depth. In cases where the ground variation is complex, or where extremely accurate information is required, the stiffness measurements can be refined through numerical modelling techniques.

Applications; Stratigraphic mapping, Estimation of depth to bedrock including landfill base location, Soil stiffness and ground improvement verification, In-situ ground stiffness for geotechnical and civil engineering projects.…

Leaflet on Ground Siffness
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We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk

Self potentials are measurements of the difference in natural ground potentials between two points on the ground surface. They can be generated by a number of different sources including groundwater flow, mineral deposits and chemical diffusion.

Self potentials measured can vary from less than a millivolt to over one volt, and the sign of the potential is a diagnostic factor in the interpretation of SP anomalies. Although there are many sources of self potentials, the common factor among them is groundwater. The potentials are generated by the flow of water, by water acting as an electrolyte and as a solvent of different minerals, compounds, and so on.

Applications

1. Hydrogeological investigations (eg groundwater flow determination, contaminant transportation).
2. Leak detection in reservoirs and dams.
3. Landfill delineation.
4. Geothermal surveys.
5. Locating massive sulphide ore bodies.

Leaflet on Self Potential
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We are happy to advise on principles and techniques, and provide courses and seminars on geophysical theory and applications.

To discuss the benefits of a well designed and executed geophysical survey, in general terms, or for a specific site, contact STATS Geophysical.

Tel: 01727 833261; Fax: 01727 811528; email: geophysics@stats.co.uk