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dc.contributor.advisorBeck, Susan
dc.contributor.authorRyan, James
dc.creatorRyan, James
dc.date.accessioned2018-05-21T19:42:57Z
dc.date.available2018-05-21T19:42:57Z
dc.date.issued2018
dc.identifier.urihttp://hdl.handle.net/10150/627728
dc.description.abstractLocal earthquake locations and teleseismic receiver functions can provide insight into the structure of orogenic crust. This dissertation summarizes three studies that focus on using locations of local earthquakes, determination of crustal velocity models, and calculation of teleseismic receiver functions to better understand parts of two Cordilleran orogenic systems. In the southern Sierra Nevada of North America, we used broadband seismic data from a temporary network to locate 131 local earthquakes, ranging in depth from 3.1 to 47.1 km, which occurred between June 2005 and May 2006. This catalog of earthquakes improves on those reported by regional catalogs for this period, locating more events and more accurately determining their depth. These small earthquakes cluster into two distinct groups and occur above a Moho that shows a sharp, high-amplitude character at < 40 km depth to the northeast but deepens and becomes more diffuse and low-amplitude to the southwest. These earthquakes provide information on where the localized foundering of lithosphere and upwelling of asthenosphere may be occurring in the southern Sierra Nevada. In the second study, we analyzed local earthquakes from a 2-year broadband seismic deployment in the north-central and central Andes (between latitudes ~10°-20°S) and found the crustal events were constrained mainly to the upper ~10 km. Based on the shallow depths of the crustal earthquakes we interpret the mid and lower crust to be ductile, a rheology consistent with the Andean Low Velocity Zone located at a depth of ~15-25 km that is identified across the Central Andean Plateau. For our third study we used receiver functions to provide a more detailed map of crustal thickness than previously available for the central Andes in northwest Bolivia and southern Peru. Overall, the high elevations have thick crust, with crustal thicknesses of >70 km beneath the Altiplano and Western Cordillera, and lower elevations have thinner ~40 km thick crust beneath the active deformation front. However, there are two isolated areas of thinner than expected crust beneath the >4 km high peaks of the Cordillera Real that we suggest are due to climate induced exhumation. We also identified mid-crustal conversions in the receiver function stacks that correspond with the basal décollement in the Subandean fold and thrust belt and the top of a low velocity zone corresponding to the previously mentioned Andean Low Velocity Zone.en_US
dc.language.isoen_USen_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.subjectCordilleraen_US
dc.subjectCrustal structureen_US
dc.subjectSeismologyen_US
dc.subjectTectonicsen_US
dc.titleInvestigating Cordilleran Crustal Structure Through Use of Local Crustal Earthquakes and Teleseismic Receiver Functionsen_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberZandt, George
dc.contributor.committeememberRichardson, Randall
dc.contributor.committeememberBennett, Richard
dc.contributor.committeememberDeCelles, Peter
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-05-21T19:42:57Z


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