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Titel |
A critical discussion of the electromagnetic radiation (EMR) method to determine stress orientations within the crust |
VerfasserIn |
M. Krumbholz, M. Bock, S. Burchardt, U. Kelka, A. Vollbrecht |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1869-9510
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Digitales Dokument |
URL |
Erschienen |
In: Solid Earth ; 3, no. 2 ; Nr. 3, no. 2 (2012-11-26), S.401-414 |
Datensatznummer |
250000997
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Publikation (Nr.) |
copernicus.org/se-3-401-2012.pdf |
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Zusammenfassung |
In recent years, the electromagnetic radiation (EMR) method has been used to
detect faults and to determine main horizontal stress directions from
variations in intensities and directional properties of electromagnetic
emissions, which are assumed to be generated during micro-cracking. Based on
a large data set taken from an area of about 250 000 km2 in Northern
Germany, Denmark, and southern Sweden with repeated measurements at one
location during a time span of about 1.5 yr, the method was systematically
tested. Reproducible observations of temporary changes in the signal
patterns, as well as a strongly concentric spatial pattern of the main
directions of the magnetic component of the EMR point to very low frequency (VLF) transmitters as
the main source and hence raise serious concerns about the applicability of
the method to determine recent crustal stresses. We conclude that the EMR
method, at its current stage of development, does not allow determination of
the main horizontal stress directions. |
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