Summary
The spatial extent of the dilatant zone and its time variations associated with preseismic fault creep are very sensitive to the dilatant constitutive law. For a power law of the form γ=δ·I n/22 (where γ is dilatant strain, δ is a constant andI 2 is the deviatoric stress invariant) the ratio of dilatant scale to depth of faulting is significantly less than unity forn=2 (‘microcrack dilatancy’), about unity forn=1 (‘joint dilatancy’), and much larger than unity forn=1/2 (‘sand pile dilatancy’). Consequently it is necessary to establish thein situ nature of the dilatant process in order to understand the onset, distribution and development of crustal dilatant regions.
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Nur, A. A note on the constitutive law for dilatancy. PAGEOPH 113, 197–206 (1975). https://doi.org/10.1007/BF01592910
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DOI: https://doi.org/10.1007/BF01592910