Welcome to the Applied Geophysics Group
Applied geophysics at Frankfurt University deal with concepts and performance of measurements, data processing and interpretation.
The Working Group Applied Geophysics mainly focusses on the detection of conductivity structures in the Earth’s interior. The conductivity is strongly related to rock and soil properties like porosity, fluid or melt content as well as physical parameters like temperature. Therefore the knowledge of the conductivity distribution within the Earth contributes to our understanding of its structures and processes within. The methods used by the Working Group highlight the depth range of a few decimetres down to several hundred kilometres.
We use the magnetotelluric and the geoelectric method to investigate the conductivity distribution:
In magnetotellurics time variations of the natural electromagnetic field are observed at the Earth’s surface within the period range of 0.0001-100000 seconds. The field variations result from external sources (lightening, ionospheric and magnetospheric current systems) and are superposed by secondary fields from induced electrical currents within the subsurface. Thus the analysis of the observed data allows inferring the electrical conductivity distribution at depths depending on the period (skindepth).
In geoelectrics currents are injected into the ground and the potential field distribution is observed nearby. The conductivity distribution within the subsurface influences the distribution of the electrical currents and therefore the observed potential differences. The depth of investigation depends on the distance between current source and potential measurements.