Geophysical ground investigations include a number of methods for mapping the ground without digging or drilling. The methods are based on the use of physical signals (acoustic, electromagnetic, gravimetric) that are sent through the ground and then read off with suitable sensors. The properties of the ground will determine how the signals move in the ground, whether they are reflected, attenuated or deflected. Once the results have been processed and interpreted, they can be used to derive important geotechnical parameters such as depth to rock, type of soil or zones of weakness.
With geophysics you can cover large areas in a short time. Geotechnical drilling or sampling provides more accurate information, but is limited to one point and is expensive in comparison. With a combination of the two, the boreholes can be used to calibrate the geophysical results, and the mapping is both precise, comprehensive and efficient.
Read more about the different methods:
Remote sensing and geospatial analysis
Remote imaging methods from terrestrial, airborne or satellite-based platforms are used to map, monitor, and measure phenomena on the Earth's surface. These methods can be used for settlement and deformation monitoring in urban areas, surveying rock slides and making engineering geology evaluations.
NGI uses many different types of remote sensing datasets to, combined with geospatial analyses and visualisation, provide insight into geotechnical and geoscientific projects.