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Natural electromagnetic radiation (EMR) and its application in structural geology and neotectonics

Greiling, Reinhard O.; Obermeyer, H.

Abstract:
Natural electromagnetic radiation (EMR) impulses are emitted from rocks under stress. Electromagnetic emission may start during crystal deformation prior to and during the nucleation phase of nanocracks. The emission direction is either parallel with or normal to the crack surfaces. The EMR magnetic component is measured by the sensor or aerial of an instrument, the Cerescope, at frequencies from 5 to 50 kHz. Measurements at the surface show directions of recent stresses remarkably well. A calibration of EMR intensity in terms of stress magnitude is possible in tunnels, where the overburden pressure can be calculated. Two examples from the Upper Rhine Graben and NW India show EMR line measurements. In both cases, stress concentrations at fault or bedding surfaces can be detected. These surfaces
can be regarded as tectonically active. Two further examples of EMR determinations in tunnels give more detailed information on the regional stress field. The example from the Swiss Jura fold-and-thrust belt shows directional results, with different directions beneath and above the regional detachment horizon at the base of the belt. The example from central Scandinavia shows a late Caledonian shear zone as a boundary between two recent stress domains, and gives absolute values of stress.



Originalveröffentlichung
DOI: 10.1007/s12594-010-0015-y
Scopus
Zitationen: 24
Web of Science
Zitationen: 22
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2010
Sprache Englisch
Identifikator ISSN: 0016-7622, 0974-6889
KITopen-ID: 1000015390
Erschienen in Journal of the Geological Society of India
Band 75
Heft 1
Seiten 265 - 275
Nachgewiesen in Web of Science
Scopus
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