Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/1212
AuthorsHeikamp, H.* 
Nover, G.* 
TitleThe electrical signature of rock samples exposed to hydrostatic and triaxial pressures
Issue DateApr-2001
Series/Report no.44/2
URIhttp://hdl.handle.net/2122/1212
KeywordsElectrical impedance spectroscopy
fracturing
carbonate
amphibolite
pressure
Subject Classification04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods 
04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism 
AbstractThe electrical signature of sedimentary (carbonate) and crystalline rock samples was studied in hydrostatic and triaxial pressure experiments up to 300 MPa. The aim was to establish a relation between an electrical signal stimulated by an external pressure acting on the sample and the mechanical stability of the rock. Natural open fractures tend to be closed under hydrostatic pressure conditions, whereas in triaxial pressure experiments new fractures are generated. These contrary processes of either decrease or increase in crack density and geometry, cause a decrease or increase in the inner surface of the sample. Such pressure induced variations in pore geometry were investigated by an interpretation and modelling of the frequency dependence of the complex electrical conductivity. In a series of hydrostatic pressure experiments crack-closure was found in the electrical signature by a decrease of the model capacitor C being related to crack geometry. This capacitor increases in the triaxial experiments where new fractures were formed.
Appears in Collections:Annals of Geophysics

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