Jordskanner

Jordskanner, or ground scanner, is a non-invasive geophysical instrument used to detect and map subsurface features and interfaces. It enables archaeologists, engineers, and surveyors to identify objects, voids, or stratigraphic changes without excavation. The term covers several sensing modalities that probe the electrical, magnetic, or acoustic properties of the ground.

Common methods include ground-penetrating radar (GPR), electrical resistivity tomography (ERT), magnetometry, and seismic methods. GPR transmits radio waves into the ground and records reflections from buried interfaces, producing cross-sectional images called radargrams. ERT measures ground resistivity by injecting electrical current and recording surface potentials to build a resistivity tomogram. Magnetometers detect magnetic anomalies caused by ferrous objects or burned features, while seismic approaches illuminate deeper structures by analyzing the travel times of seismic waves.

Most jordskannere are handheld or vehicle-mounted and combine a transmitter, a receiver, a data logger, and positioning tools such as GPS. Data are processed with specialized software to produce two- or three-dimensional representations and to enhance resolution through filtering and migration. Field surveys follow systematic transects and require calibration and site knowledge.

Applications include archaeology, cultural heritage recording, utility mapping, construction planning, geotechnical investigations, and environmental studies. Depth and resolution depend on technology and soil conditions; GPR offers high-resolution results near the surface in dry or non-conductive soils but is limited in saturated clays. Interpretation requires expertise to distinguish accidental from natural features.