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What is Applied Geophysics about?

The research group of Prof. Bülent Tezkan focuses on Applied Geophysics. This field of work utilises geophysical measurement methods in order to find mineral deposits of resources such as oil, gas, or metal ore, in the upper 10 km of the Earth's crust. The increasingly important applications in environmental geophysics also belong to the applied geophysics. They explore the uppermost 1000 m, for example, in the context of disposal and contaminated sites or ground water. The last group belonging to the applied geophysics are the engineer geophysics, which play an important role in the preparation of large building measures.

Although these are in the narrow sense the applied geophysics, applied research is of course conducted in all sections of the geophysics, from air chemistry to seismology, just to name two examples.

For survey, the applied geophysics use

  • artificially induced seismic waves in seismics,
  • gravity anomalies through disruptions in rock density in gravimetry,
  • and the magnetisation of rock in magnetics.

With so-called geoelectric and electromagnetic techniques, the electrical conductivity is investigated, which enables conclusions on the geological structure of the subsurface (boundaries of deposits, etc.). In field measurements, profiles of the Earth's surface are taken plane or lengthwise, or otherwise taken from drill holes. Depending on measurement technique and the goal of the measurements, the field measurements can also be conducted from air plane, helicopter, or ship. Geophysics and geologists work closely together when interpreting the results. 

Within the research group, electromagnetic methods for detecting disposal sites, oil and gas deposits, and contaminated sites are designed and improved. Out of the wide range of techniques, the magnetotelluric is applied, which enables the sounding of the upper layers of the Earth down to tens of kilometers depth, by measuring slowly varying natural electric and magnetic fields. For depths down to a few kilometers - in special cases down to 25 km - the LOTEM technique (LOTEM = long-offset transient electromagnetics) is applied, which measures transients. These are temporal disruptions of the magnetic field, which occur on the polarity reversal of strong currents (up to 100 Ampere), which are fed into the earth at a distance of several kilometers. The research group also improves the radiomagnetotelluric technique (RMT) with which the uppermost meters down to 20 m can be surveyed. This technique delivers good results for the sounding of deposits and contaminated areas and uses commercial myriametric-wave transmitters, which are for example is use for communication. Finally, the research group has recently begun working on the Geo-Radar technique, which can also be applied for the uppermost meters.

Overall goal of the research group is to improve the field measuring techniques, the data analysis, and the data presentation for the above mentioned techniques. Here, even for geophysical techniques with long existing instrumentation, there is still a large need for action; both the transition from laboratory to field measurements for instruments and the transition from program development to field application for software is inmost cases everything but easy and straightforward.