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dc.contributor.advisorWallace, Terry C.en_US
dc.contributor.authorPearthree, Philip Arnim.
dc.creatorPearthree, Philip Arnim.en_US
dc.date.accessioned2011-10-31T17:34:50Z
dc.date.available2011-10-31T17:34:50Z
dc.date.issued1990en_US
dc.identifier.urihttp://hdl.handle.net/10150/185339
dc.description.abstractThis dissertation research assesses the behavior of young faults in central Nevada through analyses of landforms associated with these faults. Four large earthquakes have occurred since 1915 in a striking N-S belt in central Nevada; no comparable earthquakes have occurred elsewhere in the Great Basin. The frequency of large-earthquake occurrence, and temporal and spatial patterns and rates of faulting in central Nevada during the Holocene were assessed through geomorphic and geologic studies of young fault scarps. Ages of paleoseismic events were estimated primarily through analyses of fault scarp morphologies and characterization and quantification of soil development associated with alluvial surfaces. Rates of fault scarp degradation were explored through diffusion-based modeling of latest Pleistocene pluvial shoreline scarps. Morphologic scarp age depends strongly on scarp size; modest variations in local climate, particle size, and aspect are less important. Incorporating a factor that depends on scarp size almost always decreases the scatter in scarp age estimates, and is critical if only small scarps exist along a fault zone. An average of ±30% uncertainty about the mean scarp age estimate remains after these analyses. Soil development indices were calibrated using 14 Holocene to latest Pleistocene soil profiles in central Nevada whose maximum ages are constrained. Soil development indices were used to estimate ages of faulted and unfaulted alluvial surfaces along fault scarps. Soils and morphologic fault scarp age estimates for paleoseismic events are generally consistent. Temporal and spatial patterns and rates of faulting during the Holocene were evaluated using age estimates for paleoseismic events. The long-term rate of faulting is about 10 times lower than the historical rate. There were no other N-S belts of faulting during the Holocene, although scarp ages suggest that there may have been other temporal clusters of faulting. There have been spatial clusters of faulting during portions of the Holocene. The extensional deformation rate across central Nevada during the Holocene is about 0.5-0.75 mm/yr. Integrating this rate with fault-slip data from other portions of the northern Great Basin, the Holocene extensional deformation rate is 3.5-6.5 mm/yr, substantially lower than the historical deformation rate.
dc.language.isoenen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectGeology -- Nevada -- Great Britainen_US
dc.subjectGeology, Structural -- Nevadaen_US
dc.subjectFaults (Geology) -- Nevada.en_US
dc.titleGeomorphic analyses of young faulting and fault behavior in central Nevada.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc681751463en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberBull, William B.en_US
dc.contributor.committeememberBaker, Victor R.en_US
dc.contributor.committeememberChase, Clement G.en_US
dc.contributor.committeememberHendricks, David M.en_US
dc.identifier.proquest9117465en_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-06-24T18:56:27Z
html.description.abstractThis dissertation research assesses the behavior of young faults in central Nevada through analyses of landforms associated with these faults. Four large earthquakes have occurred since 1915 in a striking N-S belt in central Nevada; no comparable earthquakes have occurred elsewhere in the Great Basin. The frequency of large-earthquake occurrence, and temporal and spatial patterns and rates of faulting in central Nevada during the Holocene were assessed through geomorphic and geologic studies of young fault scarps. Ages of paleoseismic events were estimated primarily through analyses of fault scarp morphologies and characterization and quantification of soil development associated with alluvial surfaces. Rates of fault scarp degradation were explored through diffusion-based modeling of latest Pleistocene pluvial shoreline scarps. Morphologic scarp age depends strongly on scarp size; modest variations in local climate, particle size, and aspect are less important. Incorporating a factor that depends on scarp size almost always decreases the scatter in scarp age estimates, and is critical if only small scarps exist along a fault zone. An average of ±30% uncertainty about the mean scarp age estimate remains after these analyses. Soil development indices were calibrated using 14 Holocene to latest Pleistocene soil profiles in central Nevada whose maximum ages are constrained. Soil development indices were used to estimate ages of faulted and unfaulted alluvial surfaces along fault scarps. Soils and morphologic fault scarp age estimates for paleoseismic events are generally consistent. Temporal and spatial patterns and rates of faulting during the Holocene were evaluated using age estimates for paleoseismic events. The long-term rate of faulting is about 10 times lower than the historical rate. There were no other N-S belts of faulting during the Holocene, although scarp ages suggest that there may have been other temporal clusters of faulting. There have been spatial clusters of faulting during portions of the Holocene. The extensional deformation rate across central Nevada during the Holocene is about 0.5-0.75 mm/yr. Integrating this rate with fault-slip data from other portions of the northern Great Basin, the Holocene extensional deformation rate is 3.5-6.5 mm/yr, substantially lower than the historical deformation rate.


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