Prof. Dr. Andreas Hördt

Technische Universität Braunschweig
Institute of Geophysics and extraterrestrial Physics (IGEP)
Mendelssohnstr. 3
D-38106 Braunschweig
Phone: +49 531 391 5218
E-Mail: a.hoerdt@tu-braunschweig.de
Website: www.igep.tu-bs.de

Researcher’s Career

  • Managing Director of the Institute of Geophysics and extraterrestrial Physics (IGEP), TU Braunschweig
  • Professor of Applied Geophysics, TU Braunschweig
  • Temporary Professor of Applied Geophysics, Institute of Geology, Universität Bonn
  • Assistant Professor, Universität zu Köln
  • Postdoc, Universität zu Köln
  • Dr. rer. nat., Universität zu Köln
  • Dipl. Geophysics, Universität zu Köln

Mission Statement

We advance electrical and magnetic methods in the field of Applied Geophysics. Our aim is an improved investigation of the subsurface of the Earth, with a variety of applications in geosciences, such as groundwater research, exploration for resources, environmental sciences, permafrost and tectonics.

Research

Spectral induced polarization

Spectral induced polarization measures the complex, frequency-dependent impedance of the subsurface. The aim is to estimate hydraulic parameters, important for many applications in groundwater research. We study method in the laboratory, at the field scale, and theoretically by developing models to understand the relationships between hydraulic and electric properties.

Spectral induced polarization measurements in the field, credits: IGEP
Electrical image of the subsurface, credits: IGEP

Capacitive resistivity

Capacitive resistivity determines the electrical impedance of the subsurface without direct contact to the ground. In the frequency range between 100 Hz and 100 kHz, the electrical permittivity of water ice displays a characteristic frequency dependence. We exploit this information for terrestrial permafrost studies, and potentially during space missions for the investigation of small planetary bodies.

Three-component borehole magnetometry

We measure Earth’s magnetic field in boreholes. Whereas conventional methods determine only the total field, we are able to measure all three components. This requires an extremely precise determination of the sensor orientation, for which we use fiber optic gyros and sophisticated software. From the data, we can determine the rock magnetization which is important for plate tectonics and ore exploration.

Selected Publications

  • S. Ehmann, A. Hördt, M. Leven, and C. Virgil: Paleomagnetic inclination and declination from three-component borehole magnetometer data – New insights from logging in the Louisville seamounts J. Geophys. Res. Solid Earth, 120, 2015, doi:10.1002/2014JB011531.
  • C. Virgil, S. Ehmann, A. Hördt, M. Leven, and E. Steveling: Reorientation of three-component borehole magnetic data. Geophys.Prospect., 63, pp. 225-242, 2015, doi:10.1111/1365-2478.12175.
  • K. Bairlein, A. Hördt, and S. Nordsiek: The influence of the sample preparation on induced polarization spectra of unconsolidated sediments. Near Surface Geophysics, 12, pp. 667-677, 2014, doi: 10.3997/1873-0604.2014023.
  • M. Bücker and A. Hördt: Long and short narrow pore models for membrane polarization, Geophysics, 78, E299-E314, 2013.
  • M. Bücker and A. Hördt: Analytical modelling of membrane polarization with explicit parameterization of pore radii and the electrical double layer, Geoph. J. Int., 2013, doi: 10.1093/gji/ggt136.