Universität zu Köln

Moerbe, Wiebke, Yogeshwar, Pritam, Tezkan, Buelent and Hanstein, Tilman (2020). Deep exploration using long-offset transient electromagnetics: interpretation of field data in time and frequency domain. Geophys. Prospect., 68 (6). S. 1980 - 1999. HOBOKEN: WILEY. ISSN 1365-2478

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Abstract

In the framework of the Deep Electromagnetic Soundings for Mineral Exploration project, we conducted ground-based long-offset transient-electromagnetic measurements in a former mining area in eastern Thuringia, Germany. The large-scale survey resulted in an extensive dataset acquired with multiple high-power transmitters and a high number of electric and magnetic field receivers. The recorded data exhibit a high data quality over several decades of time and orders of magnitude. Although the obtained subsurface models indicate a strong multi-dimensional subsurface with variations in resistivity over three orders of magnitude, the electrical field step-on transients are well fitted using a conventional one-dimensional inversion. Due to superimposed induced polarization effects, the transient step-off data are not interpretable with conventional electromagnetic inversion. For further interpretation in one and two dimensions, a new approach to evaluate the long-offset transient-electromagnetic data in frequency domain is realized. We present a detailed workflow for data processing in both domains and give an overview of technical obstructions that can occur in one domain or the other. The derived one-dimensional inversion models of frequency-domain data show strong multi-dimensional effects and are well comparable with the conventional time domain inversion results. To adequately interpret the data, a 2.5D frequency-domain inversion using the open source algorithm MARE2DEM (Modeling with Adaptively Refined Elements for 2-D EM) is carried out. The inversion leads to a consistent subsurface model with shallow and deep conductive structures, which are confirmed by geology and additional geophysical surveys.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Moerbe, Wiebke UNSPECIFIED UNSPECIFIED UNSPECIFIED Yogeshwar, Pritam UNSPECIFIED UNSPECIFIED UNSPECIFIED Tezkan, Buelent UNSPECIFIED UNSPECIFIED UNSPECIFIED Hanstein, Tilman UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-333595
DOI:	10.1111/1365-2478.12957
Journal or Publication Title:	Geophys. Prospect.
Volume:	68
Number:	6
Page Range:	S. 1980 - 1999
Date:	2020
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1365-2478
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INDUCED-POLARIZATION; INVERSION; ALGORITHM; SYSTEM Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/33359