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Weathering resistance of carbonate fault mirrors promotes rupture localization
Author(s) -
Goldberg R.,
SimanTov S.,
Emmanuel S.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl067788
Subject(s) - geology , weathering , carbonate , induced seismicity , slip (aerodynamics) , fault (geology) , dolostone , breccia , dissolution , carbonate rock , strike slip tectonics , mineralization (soil science) , seismology , petrology , geochemistry , sedimentary rock , materials science , chemistry , physics , metallurgy , thermodynamics , soil water , soil science
Fractured rocks in fault zones regain their mechanical strength through a process called healing. A central pathway for healing involves the dissolution and reprecipitation of minerals in the fault zone which cements the fractured rocks during interseismic periods. However, some faults contain highly polished surfaces—coated in a thin nanoparticle layer—along which slip is localized. Crucially, these surfaces show little evidence of postseismic mineralization and healing. Here we use atomic force microscopy to show that naturally polished rocks from carbonate fault zones are resistant to dissolution, in stark contrast to the reactive minerals that make up the fault breccia. Our results suggest that the low reactivity of the nanoparticle layer could retard healing, helping to maintain the localization of the fault zone between seismic slip events. As fault localization affects seismic motion, the geochemical reactivity of fault mirrors could be an important control on seismicity along faults.