Geophysical investigation techniques provide subsurface information without digging or drilling. They can reveal important geotechnical properties such as bedrock depth and rock quality, as well as reservoirs of water or oil, metal objects or contaminants.
If present-day geophysical investigations are integrated with traditional geotechnical investigations and their data, highly detailed, continuous and comprehensive models can be produced for application within numerous areas.
Remote imaging, conducted by terrestrial, airborne or satellite-based platforms have the ability to accurately image the Earth's surface with high resolution. This can be used for settlement and deformation monitoring, surveying rock slides and making engineering geology evaluations.
State-of-the-art remote sensing techniques at NGI include radar, optical image analysis and Lidar and GigaPan measurements. As with geophysical technologies, the best results are often achieved by integration with the more traditional geotechnical Methods.
The gigapan gives an overview panorama of the target and at the same time allows the user to zoom in onto a small spot in the image with an incredible resolution.
Geographical information systems (GIS)
GIS are computer-based systems for recording, modelling, analysing and presenting geographically referred data. This data is a digital representation of phenomena from the real world.
A GIS database contains two types of data:
- Location-related data such as roads, elevations, boreholes, etc.
- Associated property data.
GIS is also the best tool for integrating results from geophysical investigations, remote sensing and other location-related information.
Reduces project costs and timeframes
Use of geophysical investigation techniques, remote sensing and GIS help to considerably reduce total project costs and timeframes. Use of such solutions can further reduce the risks of offshore drilling decisions, for example, or the risks of discovering large archaeological remains in the middle of a construction project or the early detection of regional subsidence.
Services relating to geophysics, remote sensing and GIS
NGI's specialist competence in geophysics, remote sensing and GIS covers various methods and equipment for
- surveying geotechnical design parameters on land
- investigating and monitoring areas subject to rock slides
- investigating reservoirs of oil and gas (link to rock physics)
- modelling rock slide paths
- surveying risks in transport and data management
Broad-based scientific expertise, not only in geophysics, remote sensing and GIS, but also in instrumentation and development of new equipment, geology, geomechanics, rock slide hazard surveys, laboratory testing and numerical modelling help to create a unique professional environment, where ideas can be realised from one day to the next.
Research and development
NGI has played an important role in the development of seismic, electrical and electromagnetic methods in the last few decades. Since 2008, NGI has prioritised research and development of remote sensing techniques and has become an advanced user of new accurate sensors and methods in this field. An internal, strategic research programme (link to SP Remote Mapping and Warning R&D programme), in progress from 2011 to 2013, focused on improvement and integration of various techniques in geophysics and remote sensing which are vital to NGI's most important geotechnical services.
New concepts have been developed by modelling, analysing and testing new sensor technology, geophysical laboratory work, design, assembly of prototypes and field testing. Focus is on development and further development of hardware and software and on integrating techniques from geophysics, remote sensing and GIS in geotechnical projects.
The projects include the geotechnical use of helicopter resistivity scanning, advanced processing of geological LiDAR and InSAR, satellite-based rock slide mapping, risk analysis of soil and rock slides and avalanches, rock quality resistivity mapping, integrated resistivity interpretation for quick clay and other geotechnical purposes, 3D resistivity mapping and cluster-based EM inversion.