Universität zu Köln

Fadavi Asghari, Shiva ORCID: 0000-0003-0436-3469 (2025). Three-Dimensional Inversion of Controlled-Source Radiomagnetotelluric Data: Application on a Waste-Site in Cologne, Germany. PhD thesis, Universität zu Köln.

PDF (PhD thesis) Thesis_NoSignature.pdf Bereitstellung unter der CC-Lizenz: Creative Commons Attribution Non-commercial. Download (353MB)

Abstract

The focus of this thesis is the development and application of the controlled-source RMT (CSRMT) method in order to obtain 3D inversion results of tensor CSRMT by using two perpendicularly located transmitters. This research was conducted in the framework of a DFG funded project in which the universities of Cologne and St. Petersburg cooperate. The focus of this project under the title of "Interpretation of controlled-source radiomagnetotelluric data in the frequency range of 1 kHz - 1 MHz using multidimensional conductivity models", is on applying the extended dipole transmitters for multidimensional interpretation of far-field CSRMT data. The major novelty in this thesis is using two perpendicularly located horizontal electric dipoles (HED) as controlled-sources to provide a full tensor of CSRMT data that was interpreted using 3D inversion algorithm of ModEM. Two surveys were accomplished in Russia and Germany, and the acquired RMT and CSRMT data are interpreted using 2D and 3D algorithms developed for MT inversion. The first survey was carried out near Alexandrovka village in the Kaluga region, at about 180 km southwest of Moscow, Russia. The area is the Moscow State University test site and has already been investigated using different geophysical methods e.g. DC, IP, seismic, magnetics for many years. Alexandrovka has relatively simple morphology of pre- Quaternary layers. Additional borehole data is available at several locations. The survey layout consists of 8 profiles with 40 m separation and 20 m inter-station distance along the profiles. Two perpendicularly located HED transmitter lines, were being used as CSRMT sources. The acquired RMT and CSRMT data from a total of 175 site locations are then processed and inverted using 2D and 3D algorithms. The obtained models, confirm the geological structure available from previous studies and indicate good agreement with the borehole results. The second survey was carried out in a waste-site in Cologne, Germany. The same as the first measurement, both RMT and CSRMT data was acquired along 13 profiles over a total of 177 stations using two perpendicularly located HED transmitter lines with a length of 265 and 580 m. The aim was to determine the boundary and depth of the landfill. The results successfully reveal the geometry of the landfill and strongly agree with the results from other geophysical methods such as ERT, that were carried out at the same location.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Fadavi Asghari, Shiva shiva.fadavi@gmail.com orcid.org/0000-0003-0436-3469 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-785733
Date:	2025
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Institute for Geophysics and Meteorology
Subjects:	Earth sciences
Uncontrolled Keywords:	Keywords Language Electromagnetic English CSRMT English waste-site English conductivity English
Date of oral exam:	23 June 2025
Referee:	Name Academic Title Tezkan, Bülent Prof. Dr. Becken, Michael Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/78573