Geophysical Services

3D Ground Penetrating Radar (3DGPR) is a revolutionary geophysical technique that provides detailed images of the subsurface as never seen before. By utilizing a dense array of sensors, our 3DGPR can create three-dimensional images of underground structures, allowing for precise mapping and analysis of subsurface features. The main applications of 3DGPR span across engineering, environmental, and archaeological fields, offering high-resolution subsurface imaging and precise spatial interpretation.

Key uses include:

* In essence, 3DGPR provides a volumetric view of the subsurface, transforming radar data into clear spatial models that enhance interpretation accuracy and decision-making.

Ground Penetrating Radar (GPR) is a non-destructive geophysical technique widely used to image and characterize the subsurface with high resolution. Its main applications include the detection and mapping of buried utilities and infrastructure, assessment of pavement and structural conditions, archaeological prospection to locate buried features without excavation, geotechnical investigations for identifying voids, fractures, or changes in material properties, and environmental studies to detect buried waste, tanks, or contamination zones. GPR’s versatility and precision make it an essential tool for engineering, environmental, and heritage preservation projects

The seismic refraction method is a geophysical technique that determines subsurface structure and elastic properties by analyzing the travel times of seismic waves refracted along geological layers. Seismic energy—generated by a hammer, weight drop, or small explosive—is recorded by geophones on the surface. When waves encounter layers with different velocities, part of the energy refracts along the boundary and returns to the surface, allowing the estimation of layer thicknesses, seismic velocities, and depths to interfaces. In near-surface investigations, seismic refraction is widely used for geotechnical and engineering studies, providing data on depth to bedrock, material rippability, degree of weathering, and soil stiffness. It also supports hydrogeological and environmental applications by identifying the water table, aquifer geometry, and layer boundaries. Its accuracy and cost-effectiveness make it a key tool for characterizing shallow subsurface conditions.

The Multi-channel Analysis of Surface Waves is an advanced geophysical method used to analyse the propagation of surface waves. This technique helps determine soil and rock stiffness, stratigraphy, and the shear-wave velocity profile, which is essential for evaluating ground conditions.

MASW involves generating surface waves (often by striking the ground with a hammer or using specialized vibrators) and recording the waves as they travel through the ground. Multiple geophones capture the wave signals. The data is then analyzed to extract the velocity of the surface waves at different depths, which can be used to develop a detailed profile of the subsurface materials and their mechanical properties.

Key Applications of MASW:

The downhole test method uses a seismic source at the surface and receivers in a borehole to measure P-wave and S-wave velocities in subsurface geologic layers. By analyzing the travel times, this method provides accurate, localized data on the dynamic properties of soil and rock, which is crucial for determining geomechanical parameters.

Key applications include reservoir characterization, foundation design for large structures, and earthquake-proofing studies, allowing engineers to calibrate surface seismic interpretations and design safer projects. The test involves a source on the ground surface generating seismic waves that travel into the ground and are then detected by sensors positioned at different depths within a borehole. The receivers are clamped or suspended at specific depths, and the source is triggered, recording the arrival times of the waves. The wave velocities calculated from these times are used to determine parameters such as shear modulus and Poisson’s ratio, which are vital for characterizing the subsurface.

The applications of these measurements are widespread in the civil engineering and geosciences industries, supporting projects like the design of tunnels, bridges, and dams by providing essential site-specific data for seismic response analysis and other geomechanical assessments.

The Cross-Hole technique is part (with the Down-Hole technique) of the borehole seismic surveys. The main difference between them is the location of the geophones and the seismic source. In the Cross-Hole technique the seismic source is in one borehole and the sensor (geophone) is in another adjacent borehole. Seismic waves are excited in the first borehole and recorded in the second borehole.

As a result, the seismic velocities (VP and VS) can be obtained, which can be used to compute the main dynamic elastic moduli (Poisson’s ratio, Young`s modulus, Shear Modulus and Bulk Modulus).

HVSR (also known as Nakamura method) uses ambient seismic noise to determine a site’s fundamental resonance frequency, crucial for earthquake engineering. It’s a non-invasive passive method, analyzing the ratio of horizontal to vertical ground motion spectra.

This reveals the site’s resonance frequency and potentially building resonance or shear wave velocity with additional data

Vertical Electrical Sounding (VES) is probably the original geo-electrical method from which all other methods derive. VES is a DC electrical resistivity method consisting in injecting into the ground a short electric current (using two electrodes, named A and B) and measuring the induced voltage difference between another pair of electrodes (named, M and N).

These current and voltage readings are carried out at progressively larger electrode separations (sometimes kilometers apart) to analyze the subsurface electrical properties to greater depths.

VES field data (apparent resistivities) are processed to produce a one-dimensional (1D) resistivity profile. This profile represents the variation of subsurface resistivity with depth, providing insights into geological structures and material composition.

Electrical Resistivity Tomography (ERT) is a non-invasive geophysical method that images subsurface electrical resistivity variations using electrodes placed in the ground to inject a current and measure potential differences. This technique provides a 2D or 3D model of the subsurface, revealing properties like lithology, water content, fluid composition, and the location of anomalies such as buried structures, contamination plumes, or voids.

Applications in near-surface investigations include mapping groundwater resources, environmental site assessment, geotechnical engineering, mineral exploration, and identifying buried cavities

The Induced Polarization (IP) method is a geophysical technique that measures the ability of the subsurface to retain an electrical charge after an electric current is turned off, revealing the subsurface’s “chargeability”. IP surveys involve injecting a current and monitoring the voltage decay, which indicates polarization processes, and is often combined with electrical resistivity tomography (ERT) to better differentiate materials like clays, mineral deposits, and contaminated soils. Applications in near-surface investigations include mineral exploration, hydrogeophysics, mapping landfills, and monitoring hydrocarbon-impacted zones.

The SP (Self-Potential) method measures natural electrical potential differences on the Earth’s surface to investigate subsurface conditions, a passive, non-intrusive technique driven by electrokinetic, electrochemical, and thermoelectric effects. Its primary applications in near-surface investigations include mapping groundwater flow and contaminant plumes, detecting dam and landfill leaks, monitoring remediation progress, and exploring for ore deposits.

The magnetic method uses a magnetometer to detect variations in the Earth’s magnetic field caused by differences in the magnetic susceptibility of subsurface materials, enabling the detection of ferrous objects like Unexploded Ordnance (UXO) and contaminated areas, the mapping of mineral deposits, and investigations of archaeological features. By identifying these magnetic anomalies, the method allows for the localization of subsurface utilities, landfills, and buried debris.

The micro-gravity method measures tiny variations in the Earth’s gravitational field caused by subsurface density differences. Denser materials, like compact rock, create slightly stronger gravity signals than less dense materials, such as voids or sediments. In near-surface studies, this allows detection of features like cavities, tunnels, or buried structures.

Data is collected using sensitive gravimeters at regular stations, with corrections for drift, tides, and topography. The resulting gravity anomaly maps reveal density contrasts, which can be used to locate voids, shallow mineral deposits, or archaeological remains, and to assess foundations or embankments non-invasively.