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Progressive microscopic damage associated with fault growth
Author(s) -
Tamarkin T.,
OugierSimonin A.,
Zhu Wenlu
Publication year - 2012
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 - 10.1029/2012gl052487
Subject(s) - differential stress , brittleness , geology , fault (geology) , fracture (geology) , stress (linguistics) , materials science , stress intensity factor , intensity (physics) , seismology , deformation (meteorology) , fracture mechanics , composite material , geotechnical engineering , linguistics , philosophy , physics , quantum mechanics
It is known that microstuctural damage precedes macroscopic fracture in rocks during brittle failure. The quantitative relationship between the grain‐scale damage and fault growth is not yet clearly understood, partly due to the unstable nature of the faulting process. A lateral relaxation path was devised so that a rock sample can be deformed to failure by increasing differential stress along with decreasing effective mean stress. Porous rocks subjected to such a loading path exhibit a rather stable fault growth. Microstructural damage was analyzed on samples deformed to various post‐yielding stages before macroscopic faulting emerges. The intensity of microcracking is strain rate and effective pressure dependent. At peak stress, no spatial correlation among the regions with high crack intensities was observed. Beyond peak stress, the overall crack intensity increases and the regions with high crack intensities coalesce to form a macroscopic fracture. These results provide constraints for a better understanding of fault rupture.