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Fault Gouge Properties Study |
Kevin Brown, Achim Kopf, and
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| Clays and water play an important
role in controlling the amount of stress build-up and release at subduction
zones and other plate boundaries. We investigate the physical properties
of gouges, clay dominated fault materials, as they undergo deformation.
The speed at which fault ruptures occur ranges from rapid (seismic)
to ultra slow (aseismic). Our work concentrates on the activity of plate
interfaces at the slower end of this continuum. |
| One key finding is that the overall
weakness of active subduction plate boundaries can be easily accounted
for by the intrinsic weakness of clays in contact with pore fluids that
are ubiquitous along subduction faults. As a result, pore pressure values required for fault rupture do not need
to be as high as previously estimated (based on values of friction from
Byerlee's law). |
| Another interesting result is the apparent lack of onset of unstable slip
associated with the smectite to illite reaction. This reaction was initially
touted as the reason for onset of seismogenesis in subduction zones.
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| Experimental systems descriptions:
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