Diane E. Moore
David A. Lockner
Virginia G. Toy
John Townend
Rupert Southerland
Carolyn Boulton
2014
<p><span>Principal slip zone gouges recovered during the Deep Fault Drilling Project (DFDP-1), Alpine Fault, New Zealand, were deformed in triaxial friction experiments at temperatures, </span><i>T</i><span>, of up to 350°C, effective normal stresses,<span> </span></span><i>σ<sub>n</sub></i><span>′, of up to 156 MPa, and velocities between 0.01 and 3 µm/s. Chlorite/white mica-bearing DFDP-1A blue gouge, 90.62 m sample depth, is frictionally strong (friction coefficient,<span> </span></span><i>μ</i><span>, 0.61–0.76) across all experimental conditions tested (</span><i>T</i><span> = 70–350°C,<span> </span></span><i>σ<sub>n</sub></i><span>′ = 31.2–156 MPa); it undergoes a transition from positive to negative rate dependence as<span> </span></span><i>T</i><span><span> </span>increases past 210°C. The friction coefficient of smectite-bearing DFDP-1B brown gouge, 128.42 m sample depth, increases from 0.49 to 0.74 with increasing temperature and pressure (</span><i>T</i><span> = 70–210°C,<span> </span></span><i>σ<sub>n</sub></i><span>′ = 31.2–93.6 MPa); the positive to negative rate dependence transition occurs as<span> </span></span><i>T</i><span><span> </span>increases past 140°C. These measurements indicate that, in the absence of elevated pore fluid pressures, DFDP-1 gouges are frictionally strong under conditions representative of the seismogenic crust.</span></p>
application/pdf
10.1002/2013GL058236
en
AGU
Frictional properties of exhumed fault gouges in DFDP-1 cores, Alpine Fault, New Zealand
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