Geophysical mapping.

Geophysical mapping

A large part of Sweden is covered by soil or water that hides our bedrock. With different geophysical methods we are able to look down in the ground, from a few meters to several kilometers. SGU uses different methods to measure physical properties in both soil and bedrock to draw conclusions about geological structures and processes.

Geophysical surveys are an important part of mapping bedrock, soil and groundwater. Geophysics is also used for specific problem settings such as; bedrock conditions before an underground construction, mapping of natural resources, risk analysis of landslides, detection of groundwater magazines and mapping of contaminated sites.

Basic mapping routine at SGU involves measuring earth’s magnetic field from airplanes. This method allows large areas to be measured quickly. Gamma radiation and electromagnetic fields are measured at the same time to give more information about the surface and bedrock properties. SGU also carries out gravity measurements all over Sweden. The geophysical mapping aims to give a full representation of how the physical properties vary over Sweden and connect this with other geodata.

SGU is also responsible for measurement and documentation of how the earth’s magnetic field varies in time and space, and does forecasts over how it will change. Seismic surveys together with georadar and resistivity measurements are important methods when investigating, for example; groundwater magazines, quaternary deposits and soil depth. Bedrock samples collected during bedrock mapping are measured in laboratories to establish physical properties. These bedrock samples are in many ways the link between geology and geophysics.

Data from SGUs geophysical surveys are used by many operators in society, for example prospecting and construction companies, organizations and governmental agencies as well as universities and colleges.

Last reviewed 2020-09-22