Seismic Anisotropy, Intermediate-Depth Earthquakes, and Mantle Flow in the Chile-Argentina Flat-Slab Subduction Zone

Persistent Link:
http://hdl.handle.net/10150/195670
Title:
Seismic Anisotropy, Intermediate-Depth Earthquakes, and Mantle Flow in the Chile-Argentina Flat-Slab Subduction Zone
Author:
Anderson, Megan Louise
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © 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.
Abstract:
Subduction zone structure and kinematics are topics of ongoing investigation with broadband seismology. Recent advances in experimental observations of mantle materials at high temperatures and pressure, expanded broadband seismic datasets, new seismic analysis methods, and advances in computational modeling are ever increasing our capacity for synthesized investigation of tectonic environments. With the resulting expanded capability for interpretation, the geophysical community is in a position to build more refined and detailed models of subduction zone processes. This study takes part in these advances by refining structural observations of the subducting slab and making new observations of mantle kinematics in a part of the South American subduction zone in Chile and Argentina (between 30 degrees and 36 degrees S). First, I investigate the utility of multiple-event earthquake relocation algorithms for accurate locations using a regional dataset for seismic events in Nevada and then I apply the observations resulting from this study in the determination of new Wadati-Benioff zone seismicity hypocenter locations for the study area in South America. I interpolate new contours of the top of the subducting slab from this seismicity that, when interpreted with focal mechanism solutions for these events, are consistent with its deformation due to slab pull. I use shear wave splitting of teleseismic earthquake waves and s-waves from local earthquakes to characterize mantle strain within the mantle wedge and within and below the subducting slab. From these observations, I conclude that mantle flow in subduction zones is quite responsive to local changes in slab geometry as well as the thermal state of and shear stresses in the mantle wedge.
Type:
text; Electronic Dissertation
Keywords:
seismology; South America; subduction; anisotropy; seismic location; mantle
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Zandt, George
Committee Chair:
Zandt, George

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleSeismic Anisotropy, Intermediate-Depth Earthquakes, and Mantle Flow in the Chile-Argentina Flat-Slab Subduction Zoneen_US
dc.creatorAnderson, Megan Louiseen_US
dc.contributor.authorAnderson, Megan Louiseen_US
dc.date.issued2005en_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.description.abstractSubduction zone structure and kinematics are topics of ongoing investigation with broadband seismology. Recent advances in experimental observations of mantle materials at high temperatures and pressure, expanded broadband seismic datasets, new seismic analysis methods, and advances in computational modeling are ever increasing our capacity for synthesized investigation of tectonic environments. With the resulting expanded capability for interpretation, the geophysical community is in a position to build more refined and detailed models of subduction zone processes. This study takes part in these advances by refining structural observations of the subducting slab and making new observations of mantle kinematics in a part of the South American subduction zone in Chile and Argentina (between 30 degrees and 36 degrees S). First, I investigate the utility of multiple-event earthquake relocation algorithms for accurate locations using a regional dataset for seismic events in Nevada and then I apply the observations resulting from this study in the determination of new Wadati-Benioff zone seismicity hypocenter locations for the study area in South America. I interpolate new contours of the top of the subducting slab from this seismicity that, when interpreted with focal mechanism solutions for these events, are consistent with its deformation due to slab pull. I use shear wave splitting of teleseismic earthquake waves and s-waves from local earthquakes to characterize mantle strain within the mantle wedge and within and below the subducting slab. From these observations, I conclude that mantle flow in subduction zones is quite responsive to local changes in slab geometry as well as the thermal state of and shear stresses in the mantle wedge.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectseismologyen_US
dc.subjectSouth Americaen_US
dc.subjectsubductionen_US
dc.subjectanisotropyen_US
dc.subjectseismic locationen_US
dc.subjectmantleen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorZandt, Georgeen_US
dc.contributor.chairZandt, Georgeen_US
dc.contributor.committeememberBeck, Susan L.en_US
dc.contributor.committeememberChase, Clemen_US
dc.contributor.committeememberDucea, Mihaien_US
dc.contributor.committeememberDecelles, Peteren_US
dc.identifier.proquest1257en_US
dc.identifier.oclc137354654en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.