Softening rocks with stress-activated electric current

F. T. Freund, S. A. Hoenig, A. Braun, R. P. Dahlgren, M. Momayez, J. J. Chu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

When rocks are subjected to mechanical stress, dormant electronic defects become activated. This activation produces electron-hole pairs, which increase the electrical conductivity of rocks by releasing highly mobile defects electrons, equivalent to O- in a matrix of O2-, called positive holes and symbolized by h*. The h* charge carriers can spread from the stressed rock into surrounding unstressed rocks. Preventing the outflowof h* alters the mechanical properties of the rocks: they become softer andweaker. Ongoing studies point to a delocalization of the wave function associated with the h* charge carriers, which is far-reaching and affects many neighboring O2-. Although the number density of positive holes may be as low as 1 in 1000, essentially all O2- in the rock subvolume lose some of their electron density. This loss weakens the interatomic bonds between anions and cations, thus affecting the mechanical properties of rocks.

Original languageEnglish (US)
Title of host publicationRock Stress and Earthquakes - Proceedings of the 5th International Symposium on In-Situ Rock Stress
PublisherTaylor and Francis - Balkema
Pages839-843
Number of pages5
ISBN (Print)9780415601658
DOIs
StatePublished - Jan 1 2010
Event5th International Symposium on In-Situ Rock Stress, ISRSV 2010 - Beijing, China
Duration: Aug 25 2010Aug 27 2010

Publication series

NameRock Stress and Earthquakes - Proceedings of the 5th International Symposium on In-Situ Rock Stress

Other

Other5th International Symposium on In-Situ Rock Stress, ISRSV 2010
CountryChina
CityBeijing
Period8/25/108/27/10

ASJC Scopus subject areas

  • Geology
  • Geotechnical Engineering and Engineering Geology

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  • Cite this

    Freund, F. T., Hoenig, S. A., Braun, A., Dahlgren, R. P., Momayez, M., & Chu, J. J. (2010). Softening rocks with stress-activated electric current. In Rock Stress and Earthquakes - Proceedings of the 5th International Symposium on In-Situ Rock Stress (pp. 839-843). (Rock Stress and Earthquakes - Proceedings of the 5th International Symposium on In-Situ Rock Stress). Taylor and Francis - Balkema. https://doi.org/10.1201/9780415601658-146