Mechanisms and rates of strength recovery in laboratory fault zones.

dc.contributor.advisorDewers, Thomas A.,en_US
dc.contributor.authorMuhuri, Sankar Kumar.en_US
dc.date.accessioned2013-08-16T12:18:24Z
dc.date.available2013-08-16T12:18:24Z
dc.date.issued2001en_US
dc.description.abstractThe results of this investigation may be applied to explain observations of rapid strengthening along large, active crustal fault zones such as parts of the San Andreas Fault system in California and the Nojima fault in Japan. Presence of fault seals in clean hydrocarbon reservoirs with minor clay content as in several North Sea fields may also be a manifestation of similar deformation processes.en_US
dc.description.abstractMechanisms and rates of strength recovery in laboratory fault zones were investigated in this research with the aid of several experimental designs. It was observed that wet faults recover strength in a time-dependent manner after slip due to operative creep processes. Subsequent loading results in unstable failure of a cohesive gouge zone with large associated stress drops. The failure process is similar to that observed for intact rocks. Dry laboratory faults in contrast do not recover strength and slip along them is always stable with no observable drop in stress.en_US
dc.description.abstractStrengthening in laboratory faults proceeds in a manner that is a logarithmic function of time. The recovery is attributable to fluid mediated mechanisms such as pressure solution, crack sealing and Ostwald ripening that collectively cause a reduction in porosity and enhance lithification of an unconsolidated gouge. Rates for the individual deformation mechanisms investigated in separate experimental setups were also observed to be a non-linear function of time. Pressure solution and Ostwald ripening are especially enhanced due to the significant volume fraction of fine particles within the gouge created due to cataclasis during slip.en_US
dc.description.abstractThe life cycle of a typical fault zone consists of repeated catastrophic seismic events during which much of the slip is accommodated interspersed with creep during the inter-seismic cycle. Fault strength is regenerated during this period as a result of several time-dependent, fluid assisted deformation mechanisms that are favored by high stresses along active fault zones. The strengthening is thought to be a function of the sum total of the rates of recovery due to these multiple creep processes as well as the rate of tectonic loading.en_US
dc.format.extentxiv, 184 leaves :en_US
dc.identifier.urihttp://hdl.handle.net/11244/383
dc.noteSource: Dissertation Abstracts International, Volume: 62-10, Section: B, page: 4428.en_US
dc.noteAdviser: Thomas A. Dewers.en_US
dc.subjectFaults (Geology)en_US
dc.subjectGeophysics.en_US
dc.subjectFault zones.en_US
dc.subjectFault gouge.en_US
dc.subjectGeology.en_US
dc.thesis.degreePh.D.en_US
dc.thesis.degreeDisciplineConoco Phillips School of Geology and Geophysicsen_US
dc.titleMechanisms and rates of strength recovery in laboratory fault zones.en_US
dc.typeThesisen_US
ou.groupMewbourne College of Earth and Energy::Conoco Phillips School of Geology and Geophysics
ou.identifier(UMI)AAI3028811en_US

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