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Electric potential changes prior to shear fracture in dry and saturated rocks

Yoshida, S; Clint, OC; Sammonds, PR; (1998) Electric potential changes prior to shear fracture in dry and saturated rocks. Geophysical Research Letters , 25 (10) 1577 - 1580. 10.1029/98GL01222. Green open access

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Abstract

Electric potential changes before shear rupture were measured using Darley Dale sandstone (quartz-rich) and Icelandic basalt (quartz-free) on both dry specimens and in the presence of pore fluid. We find that electric potential changed markedly just prior to dynamic rupture in dry and saturated sandstones and saturated basalt but we did not detect precursory signals in dry basalt. The absence of signals in dry basalt provides strong evidence that the piezoelectric effect and electrokinetic effect are dominant sources for precursory signals. Moreover we find that the amplitude of the precursory signals due to electrokinetic effect in saturated sandstone were as large as the coseismic signals. We propose that this signal is caused by accelerating evolution of dilatancy as cracks grow in the rock before rupture, resulting in water flow into the dilatant region with an electric current produced concurrently.

Type: Article
Title: Electric potential changes prior to shear fracture in dry and saturated rocks
Open access status: An open access version is available from UCL Discovery
DOI: 10.1029/98GL01222
Publisher version: http://dx.doi.org/10.1029/98GL01222
Language: English
Additional information: Copyright 1998 by the American Geophysical Union
Keywords: Earth preceding earthquakes, Physical-properties, Permeability, Compression, Emission, Field
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Inst for Risk and Disaster Reduction
URI: http://discovery.ucl.ac.uk/id/eprint/59842
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