Dissertations / Theses: 'Structure of the upper mantle'

1

Mangino, Stephen George. "Eurasian crust and upper mantle structure." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627166.

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Gaherty, James B. "Structure and anisotropy of the upper mantle." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/53007.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1995.
Includes bibliographical references (p. 171-180).
by James B. Gaherty.
Ph.D.

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Wagner, Lara Suzanne. "Investigations of Upper Mantle Structure using Broadband Seismology." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1204%5F1%5Fm.pdf&type=application/pdf.

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4

Katzman, Rafael. "Structure and dynamics of the Pacific upper mantle /." Woods Hole, Mass. : Massachusetts Institute of Technology, Woods Hole Oceanographic Institution, Joint Program in Oceanography/Applied Ocean Science Engineering, 1998. http://hdl.handle.net/1912/1834.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998.
"February 1998." "Doctoral dissertation." Includes bibliographical references (p. 189-198).

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Katzman, Rafael 1963. "Structure and dynamics of the Pacific upper mantle." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/59643.

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6

Lombardi, Denis. "Alpine crustal and upper-mantle structure from receiver functions /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17508.

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Hertzog, Justin Tyler. "The Upper Mantle Seismic Structure Beneath Northeastern North America." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3401.

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Thesis advisor: John E. Ebel
Thesis advisor: John C. Hepburn
Using the seismic refraction technique with a least squares inversion methodology, arrival time data from 1985 to the present are analyzed to delineate, with improved spatial resolution, the upper mantle P-velocity structure throughout northeastern North America (NENA). A total of one hundred and sixty-eight earthquakes are analyzed utilizing over one hundred seismic stations throughout NENA. Seismic data analyzed between 200 - 400 km, 400 - 600 km, and 600+ km throughout NENA are used to study the increase in velocity with depth in the upper mantle. A jackknife analysis was carried out to put constraints on the uncertainties of the velocity measurements. The P-wave velocity of the upper mantle through the New England Appalachians is found to be uniformly 7.94 - 8.07 km/s at depths down to 75 km. Upper mantle Pn velocities throughout the southeastern Grenville Province show velocities ranging from 8.15 km/s to 8.54 km/s as epicentral distances increase. Uncertainties of P velocities range from 0.01- 0.12 km/s. Based on laboratory measurements of simulated upper mantle conditions and the orogenic history of the Grenville Province and northern Appalachians, upper mantle mineral compositions of eclogite (Grenville Province) and pyroxenite (northern Appalachians) are proposed to be the factor controlling seismic velocity variation in the upper mantle. Variations in upper mantle temperatures between the Grenville Province and northern Appalachians are ruled out as affecting the difference in upper mantle velocities between southeastern Canada and New England
Thesis (MS) — Boston College, 2013
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Geology and Geophysics

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Tilmann, Frederik Jan. "The seismic structure of the upper mantle beneath Hawaii." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624534.

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Saunders, Paul Nicholas. "The lithospheric structure of western Turkey : crustal deformation in an extending region." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336353.

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Villagomez, Diaz Darwin R. 1973. "Crustal and upper mantle structure beneath the Galapagos arechipelago from seismic tomography." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/11071.

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xv, 151 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
To explain the origin of several distinct aspects of the Galápagos volcanic hotspot, such as the broad geographical extent of recent volcanism and the unusual pattern of geochemical anomalies, we conducted seismic tomography studies of the upper mantle and crust beneath the Galápagos Archipelago. The studies combine measurements of group and phase velocities of surface waves and delay times of body waves. We find that upper mantle seismic velocities are lower than those beneath other regions of comparable age in the Pacific and consistent with an excess temperature of 30 to 150°C and ∼0.5% melt. We attribute the excess temperature and presence of melt to an upwelling thermal mantle plume. Crustal seismic velocity is up to 25% lower than that of very young crust at the East Pacific Rise (EPR) and is comparable to that of Hawaii, which we attribute to heating by increased intrusive activity above the Galápagos plume and the construction of a highly porous volcanic platform. In addition, we find that the Galápagos hotspot is underlain by a high-velocity region whose thickness varies from 40 to 100 km. The tomographic images reveal that the upwelling mantle plume tilts northward (towards the nearby Galápagos Spreading Center) as it rises and then spreads laterally when it reaches the bottom the lid. The lid, which we attribute to residuum from melting, is thickest where it is farthest from the spreading center, suggesting that ridge processes may affect the generation and amount of thinning of the residuum layer. In addition, the thickness of the lid correlates well with the geographical pattern of geochemical anomalies of erupted lavas, suggesting that the lid may control the final depth of decompression melting. We conclude that many of the distinct characteristics of the Galápagos can be attributed to the interaction of the upwelling plume with the lid and the nearby ridge. We further suggest that the ridge affects the geometry of plume upwelling in the upper mantle and also the pattern of lateral spreading of the plume due to its effect on the thickness of the residuum layer. This dissertation includes previously published co-authored material.
Committee in charge: Dr. Douglas R. Toomey, Chairperson; Dr. Eugene Humphreys, Member; Dr. Emilie Hooft Toomey, Member; Dr. Paul Wallace, Member; Dr. John Conery, Outside Member

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Harrison, A. J. "Crustal and upper mantle structure of the Taupo Volcanic Zone, New Zealand." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603773.

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The Taupe Volcanic Zone (TVZ) is a major Pliocene-Quaternary NNE-SSW orientated volcano-techonic complex, in central North Island, New Zealand. It is a region characterised by voluminous rhyolitic eruptions, high natural heat flow, intense shallow seismic activity and active NW-SE extension. The central portion of the TVZ is regarded as the most frequently active and productive silicic volcanic system on Earth, yet to date no direct evidence for the source for the magmatisim has been found. In February and December 2001, as part of the NIGHT (North Island GeopHysical Transect) experiment, a total of ten 500 kg land slots were fired into an NW-SE array that ran the width of central North Island, New Zealand. An additional passive array of broad-band and short-period instruments centred on the TVZ recorded local and teleseismic earthquakes for six and a half months. Forward and inverse modelling of this active and shallow (< 10 km) earthquake data shows low-velocity (2.0-3.5 km/s) volcanic sediments reaching a maximum thickness of 3 km beneath the central TVZ. Underlying these sediments to 16 km depth are velocities of 5.0-6.5 km/s, interpreted as quartzo-fieldspathic crust. East and west of the TVZ, these velocities are observed to depths of 30 and 23 km respectively. Beneath the TVZ, material with P-wave velocities of 6.9-7.3 km/s are observed to ~30 km depth and are interpreted as heavily intruded or underplated lower crust. Modelling of deep (> 40 km) earthquake events originating near the top of the subducting Pacific plate, reveals a low-velocity region (LVR) (Vp of 7.4-7.8 km/s) overlying a northwest dipping high-velocity structure that coincides with the Wadati-Benioff zone.

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Hansen, Samantha E. "Crustal and upper mantle structure of the Red sea and Arabian Peninsula /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.

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Gilligan, Amy Rebecca. "Imaging the structure of the crust and upper mantle in central Asia." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708358.

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Stankiewicz, Jacek Maciej. "Receiver function analysis of crustal and upper mantle structure beneath Southern Africa." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/4226.

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15

Silvennoinen, H. (Hanna). "3D structure of the crust and upper mantle beneath Northern Fennoscandian shield." Doctoral thesis, University of Oulu, 2015. http://urn.fi/urn:isbn:9789526210681.

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Abstract The crustal and upper mantle structures of the Shield on the regional scale were investigated using the data of the POLENET/LAPNET passive seismic array and the previously published models of active and passive seismic experiments in the study area. This area is centred in northern Finland and it extends to surrounding areas in Sweden, Norway and northwestern Russia. The bedrock there is mostly of the Archaean origin and the lithosphere of the region was reworked by two orogenies during Palaeoproterozoic. One of the results of the thesis was a new map of the Moho depth of the study area, for which new estimates of the crustal thickness were obtained using receiver function method and complemented by published results of receiver function studies and controlled source seismic profiles. The map differs from the previously published maps in two locations, where we found significant deepening of the Moho. The 3D structure of the upper mantle was studied using teleseismic traveltime tomography method. The resulting model shows high seismic velocities below three cratonic units of the study area, which may correspond to non-reworked fragments of cratonic lithosphere and a low velocity anomaly separating these cratonic units from each other. The regional scale studies were complemented by two smaller scale studies in upper crust level using combined interpretation of seismic profiling and gravity data. These studies were centred on Archaean Kuhmo Greenstone Belt in eastern Finland and central Lapland in northern Finland located in the crust reworked during Palaeoproterozoic. Both areas are considered as prospective ones for mineral exploration. Both studies demonstrate the advantage of gravity data inversion in studying 3D density structure of geologically interesting formations, when the Bouguer anomaly data is combined with a priori information from petrophysical and seismic datasets.

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16

Larson, Angela Marie. "S-wave velocity structure beneath the Kaapvaal Craton from surface-wave inversions compared with estimates from mantle xenoliths." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34200.

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Results from two-station surface-wave inversions across the Archean Kaapvaal craton of southern Africa are compared with seismic velocities estimated from approximately 100 mantle xenoliths brought to the surface in kimberlite pipes. As the xenoliths represent a snapshot of the mantle at the time of their eruption, comparison with recently recorded seismic data provides an opportunity to compare and contrast the independently gained results. These cratonic xenoliths from the southern Kaapvaal, all less than 100Ma in age, have been analyzed geothermobarometrically to obtain the equilibrium P-T conditions of the cratonic mantle to about 180km depth [James et al 2004]. Seismic velocity-depth and density-depth profiles calculated on the basis of these P-T data and the mineral modes of the xenoliths are used to produce theoretical surface-wave dispersion curves and to generate roughly the upper 200km of a starting/reference model. A regionally-developed crustal structure [Niu and James 2002] was used for the crust and 300km of mantle values taken from PREM filled in down to 500km depth. This composite model was used as the starting/reference model for a Neighbourhood Algorithm surface-wave inversion using fundamental-mode Rayleigh-wave phase velocities for 16 paths within the Kaapvaal Craton from five events. The velocity structures found by that inversion are consistent with those derived from the xenolith data. Hence the velocity structure (i.e. thermal structure) of the mantle to a depth of 180km beneath the Kaapvaal craton is basically the same today as it was 80-90Ma. Further, synthetics runs show that for this surface-wave dataset, there is no strong low-velocity zone at depths shallower than at least 200km.
Master of Science

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17

Reeg, Heidi Alison. "Seismic structure of the crust and upper mantle of the Sierra Nevada, California." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1460872.

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18

Pilidou, Sylvana Demetriou. "Upper mantle shear-wave velocity and anisotropy structure beneath the North-Atlantic : a seismic image of the Iceland mantle plume." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615904.

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19

Schutt, Derek Leigh. "Aspects of upper mantle structure in the Yellowstone Swell, Wyoming Craton, and Yavapai Province /." view abstract or download file of text, 2000. http://wwwlib.umi.com/cr/uoregon/fullcit?p9998046.

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Thesis (Ph. D.)--University of Oregon, 2000.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 93-100). Also available for download via the World Wide Web; free to University of Oregon users.

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20

Zelt, Colin Andrew. "Seismic structure of the crust and upper mantle in the Peace River Arch region." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29327.

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The Peace River Arch (PRA) is a regional ~E-W trending geological structure within the Western Canada Sedimentary Basin whose Phanerozoic history of vertical movements is anomalous with respect to the basin as a whole. Four intersecting ~300-km-long reversed refraction lines within the PRA region in northwestern Alberta and northeastern British Columbia have been interpreted for crustal and upper mantle P-wave velocity structure. The data have been analyzed using a new two-dimensional ray-trace forward modelling algorithm to match travel times and amplitudes of first and coherent later arrivals. An inversion of first arrival travel times along a fan shot profile has been performed to constrain crustal thickness northwest of the arch in a region not sampled by the in-line profiles. 5-waves and the observed spectra of the refraction data have been analyzed to infer a regional Poisson's ratio and Q structure, respectively. The consistency of the seismic models with the observed Bouguer gravity data was studied. The new algorithm for tracing rays and calculating amplitudes in two-dimensional media is based on a simple, layered, large-block velocity model parameterization in which velocity is an analytic function of position. This allows for computationally efficient ray tracing. The user's ability to specify kinematically-similar ray families permits practical and rapid forward modelling of refraction data. In addition, the routine allows for 5-wave propagation, converted phases, multiple and surface reflections, approximate attenuation, head waves, a simulation of smooth layer boundaries, and a reverse ray-direction amplitude calculation. Amplitude calculations are based on zero- and first-order asymptotic ray theory. The main attributes of the routine are illustrated with several examples. The major features of the interpreted structural model of the PRA region are (1) weak to moderate lateral variations in crustal structure with no evidence of significant layering or thick low-velocity zones within the crust, (2) an average sub-basement RMS crustal velocity of 6.6 km/s, average upper mantle velocity of 8.25 km/s and average crustal thickness of 40 km, (3) a high-velocity (> 7.0 km/s) lower crust of 5 to 10 km thickness, (4) westward crustal thinning north of the arch, (5) regional variations in structure that appear related to the N-S Precambrian trends as revealed by aeromagnetic data, including crustal thickness, upper crustal and upper mantle velocities and P[sub m]P character, and (6) subtle variations in structure that may be associated with the E-W trending Devonian axis of the PRA, including a shallowing of high lower-crustal velocities, thickening of the crust, and an anisotropic P[sub m]P character beneath the arch and along-axis low-amplitude P[sub n] arrivals. A high-velocity lower crust and localized shallowing of high lower-crustal velocities are commonly observed in continental rift zones. These features and the ~E-W trend of the arch perpendicular to the ancient western margin suggest that the PRA originated as a Paleozoic failed-rift. The results of supplementary studies show (1) an average crustal Poisson's ratio of 0.25, (2) Q increases with depth from ~500 to ~1000 in the crust and is ~1000 in the upper mantle, and (3) a seismic-gravity relationship that suggests that localized velocity anomalies of the refraction models are not associated with density anomalies. Also, extended-listen-time processing of a 10-km-long industry Vibroseis reflection line coincident with one of the refraction lines shows prominent dipping events that correlate with the zero-offset two-way travel time of a strong intracrustal reflector and the crust-mantle boundary of the refraction model. A series of reflections over 1.5 s terminating at the refraction Moho indicates a complex, possibly layered crust-mantle transition zone of 5 km thickness.
Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate

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21

VanDecar, John Callaway. "Upper-mantle structure of the Cascadia subduction zone from non-linear teleseismic travel-time inversion /." Thesis, Connect to this title online; UW restricted, 1991. http://hdl.handle.net/1773/6804.

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22

DuPass, Mary K. 1961. "Upper mantle shear velocity structure of east Africa, the Arabian shield, and the eastern Mediterranean." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/558112.

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23

Bray, Trevor David. "The determination of the velocity structure in the upper mantle by seismic travel time inversion." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359809.

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24

Bastow, Ian David. "Upper-mantle seismic structure in a region of incipient continental break-up : northern Ethiopian rift." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417311.

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25

Reid, Fiona J. L. "Velocity and attenuation structure of the mantle : constraints from differential properties of shear waves." Thesis, University of Oxford, 1999. http://ora.ox.ac.uk/objects/uuid:83796f01-c45f-4d84-9c4c-04e084ac135f.

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Although much progress has been made in determining the three dimensional distribution of seismic wave velocities in the Earth, substantially less is known about the three dimensional distribution of intrinsic attenuation. In this study variations in attenuation and shear velocity of the Earth's mantle are constrained using measurements of differential travel time and attenuation. The data are broadband displacement SH seismograms filtered to have energy in the period range 8 to 20 s. Broadband data are used as they should allow a more accurate estimation of body wave attenuation to be made. The seismograms are obtained from over 600 globally distributed earthquakes of magnitude, Mw, 5.5 or greater. Two new methods for determining differential travel times and differential t* values from multiple S phases are presented. The first of these, referred to as the "waveform fitting method" is used to analyse approximately 4300 SS and S waveforms and around 1000 SSS and SS waveforms resulting in differential SS-S and SSS-SS travel times, and corresponding values of differential attenuation represented by t*. The second method, referred to as the "spectral ratio method" is used to analyse approximately 3200 SS and S and around 900 SSS and SS waveforms. The differential travel times and t* values are inverted to obtain models of the lateral variation of shear velocity and lateral variation of q(mu) where q(mu) =1/Q(mu). The models explain the data well but have limited depth resolution. The velocity models show good correlation with previous studies, in particular, low velocities are observed underlying spreading ridges and convergent margins and high velocities are observed under continental regions. The q(mu) model shows shield regions to be less attenuating than PREM, with ridges appearing as highly attenuating features. Models of shear velocity and attenuation are also obtained by combining the body wave dataset of this study with the surface wave datasets of Van Heijst (1997) and Selby (1998).

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26

Neves, Fernando Antonio Pereira da Silveira. "Velocity structure of upper mantle discontinuities from global waveform inversion of wide-angle land seismic data." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627449.

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27

Elsenbeck, James R. "Influence of grain size evolution and water content on the seismic structure of the oceanic upper mantle." Thesis, Online version of original thesis, 2007. http://hdl.handle.net/1912/1821.

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28

Heuer, Barbara. "Lithospheric and upper mantle structure beneath the western Bohemian Massif obtained from teleseismic P and S receiver functions." Potsdam : Geoforschungszentrum [u.a.], 2006. http://www.diss.fu-berlin.de/2006/401/index.html.

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29

Biryol, Cemal Berk. "COMPLEX RUPTURE PROCESSES OF THE SOLOMON ISLANDS SUBDUCTION ZONE EARTHQUAKE AND SUBDUCTION CONTROLLED UPPER MANTLE STRUCTURE BENEATH ANATOLIA." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194681.

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This dissertation explores subduction zone-related deformation both on short time scales in the form of subduction zone earthquakes and over larger time and geographical scales in the form of subduction rollback or detachment of the subducting lithosphere. The study presented here is composed of two parts. First, we analyzed the source-rupture processes of the April 1, 2007 Solomon Islands Earthquake (Mw=8.1) using a body-wave inversion technique. Our analysis indicated that the earthquake ruptured approximately 240 km of the southeast Pacific subduction zone in two sub-events.In the second part of this study, we used shear-wave splitting analysis to investigate the effects of the subducting African lithosphere on the upper-mantle flow field beneath the Anatolian Plate in the Eastern Mediterranean region. Our shear-wave splitting results are consistent with relatively uniform southwest-directed flow towards the actively southwestward-retreating Aegean slab. Based on spatial variations in observed delay times we identified varying flow speeds beneath Anatolia and we attribute this variation to the differential retreat rates of the Aegean and the Cyprean trenches.Finally, we used teleseismic P-wave travel-time tomography to image the geometry of the subducting African lithosphere beneath the Anatolia region. Our tomograms show that the subducting African lithosphere is partitioned into at least two segments along the Cyprean and the Aegean trenches. We observed a gap between the two segments through which hot asthenosphere ascends beneath the volcanic fields of western Anatolia. Our results show that the Cyprean slab is steeper than the Aegean slab. We inferred that this steep geometry, in part, controls the flow regime of asthenosphere beneath Anatolia causing variations in flow speeds inferred from shear-wave splitting analysis.

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El-Haddadeh, B. R. H. "Seismological investigation of the crust and upper mantle structure of the British Isles using teleseismic travel time data." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372598.

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31

Dewberry, Shawn Robert. "Crustal and upper mantle structure for the Pacific Northwest from an analysis of short-period teleseismic network data /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/6795.

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32

Kato, Mamoru. "Upper-mantle velocity structure beneath the western Philippine Sea plate from body waves, surface waves, and SCS reverberations." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11183.

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33

Delph, Jonathan, and Jonathan Delph. "Crustal and Upper Mantle Structure of the Anatolian Plate: Imaging the Effects of Subduction Termination and Continental Collision with Seismic Techniques." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/622908.

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The neotectonic evolution of the eastern Mediterranean is intimately tied to interactions between the underthrusting/subducting slab along the southern margin of Anatolia and the overriding plate. The lateral variations in the subduction zone can be viewed as a temporal analogue of the transition between continuous subduction and subduction termination by continent-continent collision. By investigating the lateral variations along this subduction zone in the overriding plate, we can gain insight into the processes that precede continent collision. This dissertation summarizes the results of three studies that focus on different parts of the subduction margin: 1) In the west, where the development of a slab tear represents the transition between continuous and enigmatic subduction, 2) In the east, where continent-continent collision between the Arabian and Eurasian Plate is leading to the development of the third largest orogenic plateau on earth after complete slab detachment, and 3) In central Anatolia, where the subducting slab is thought to be in the processes of breaking up, which is affecting the flow of mantle material leading to volcanism and uplift along the margin. In the first study, we interpret that variations in the composition of material in the downgoing plate (i.e. a change from the subduction of oceanic material to continental material) may have led to the development of a slab tear in the eastern Aegean. This underthrusting, buoyant continental fragment is controlling overriding plate deformation, separating the highly extensional strains of western Anatolia from the much lower extensional strains of central Anatolia. Based on intermediate depth seismicity, it appears that the oceanic portion of the slab is still attached to this underthrusting continental fragment. In the second study, we interpret that the introduction of continental lithosphere into the north-dipping subduction zone at the Arabian-Eurasian margin led to the rollback and eventual detachment of the downgoing oceanic lithosphere attached to the Arabian Plate. After detachment, high rates of exhumation in the overriding plate are recorded due to the removal of the oceanic lithosphere and accompanying rebound of the Arabian continental lithosphere. In the third study, we image a transitional stage between the complete slab breakoff of the second study and the continuous subduction slab of the first study. We interpret that trench-perpendicular volcanism and ~2 km of uplift of flat-lying carbonate rocks along the southern margin of Turkey can be attributed to the rollback and ongoing segmentation of the downgoing slab as attenuated continental material is introduced into the subduction zone. Combining these three studies allows us to understand the terminal processes of a long-lived subduction zone as continental material is introduced.

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Bianchi, Irene <1981&gt. "Velocity structure and seismic anisotropy in the crust and upper mantle from Receiver Function analysis: three case studies in Italy." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2614/.

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The research for this PhD project consisted in the application of the RFs analysis technique to different data-sets of teleseismic events recorded at temporary and permanent stations located in three distinct study regions: Colli Albani area, Northern Apennines and Southern Apennines. We found some velocity models to interpret the structures in these regions, which possess very different geologic and tectonics characteristics and therefore offer interesting case study to face. In the Colli Albani some of the features evidenced in the RFs are shared by all the analyzed stations: the Moho is almost flat and is located at about 23 km depth, and the presence of a relatively shallow limestone layer is a stable feature; contrariwise there are features which vary from station to station, indicating local complexities. Three seismic stations, close to the central part of the former volcanic edifice, display relevant anisotropic signatures with symmetry axes consistent with the emplacement of the magmatic chamber. Two further anisotropic layers are present at greater depth, in the lower crust and the upper mantle, respectively, with symmetry axes directions related to the evolution of the volcano complex. In Northern Apennines we defined the isotropic structure of the area, finding the depth of the Tyrrhenian (almost 25 km and flat) and Adriatic (40 km and dipping underneath the Apennines crests) Mohos. We determined a zone in which the two Mohos overlap, and identified an anisotropic body in between, involved in the subduction and going down with the Adiratic Moho. We interpreted the downgoing anisotropic layer as generated by post-subduction delamination of the top-slab layer, probably made of metamorphosed crustal rocks caught in the subduction channel and buoyantly rising toward the surface. In the Southern Apennines, we found the Moho depth for 16 seismic stations, and highlighted the presence of an anisotropic layer underneath each station, at about 15-20 km below the whole study area. The moho displays a dome-like geometry, as it is shallow (29 km) in the central part of the study area, whereas it deepens peripherally (down to 45 km); the symmetry axes of anisotropic layer, interpreted as a layer separating the upper and the lower crust, show a moho-related pattern, indicated by the foliation of the layer which is parallel to the Moho trend. Moreover, due to the exceptional seismic event occurred on April 6th next to L’Aquila town, we determined the Vs model for two station located next to the epicenter. An extremely high velocity body is found underneath AQU station at 4-10 km depth, reaching Vs of about 4 km/s, while this body is lacking underneath FAGN station. We compared the presence of this body with other recent works and found an anti-correlation between the high Vs body, the max slip patches and earthquakes distribution. The nature of this body is speculative since such high velocities are consistent with deep crust or upper mantle, but can be interpreted as a as high strength barrier of which the high Vs is a typical connotation.

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35

Monna, Stephen [Verfasser], and Torsten [Akademischer Betreuer] Dahm. "Insights on the upper-mantle structure of the Central-Western Mediterranean from seismic tomography : three study cases / Stephen Monna. Betreuer: Torsten Dahm." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1037822153/34.

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Darold, Amberlee, and Amberlee Darold. "Resolving Upper Mantle Seismic Structure Beneath the Pacific Northwest and Inferred Plume-Lithosphere Interactions During the Steens-Columbia River Flood Basalt Eruptions." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12365.

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Cenozoic tectonics of the Pacific Northwest (PNW) and the associated mantle structures are remarkable, the latter revealed by EarthScope seismic data. In this thesis we model teleseismic body waves constrained by ambient-noise surface waves and teleseismic receiver function analysis in order to recover better-controlled higher resolution images of the PNW continuously from the surface of the crust to the base of the upper mantle. We focus on and have clearly imaged two major upper mantle structures: (1) the high-velocity Farallon slab (the "Siletzia curtain") extending vertically beneath the Challis-Kamloops-Absaroka volcanic flareup (~53-47 Ma) of western Idaho and central Washington; and (2) a high-velocity anomaly beneath the Wallowa Mountains of northeast Oregon associated with the main Columbia River flood basalts source region. The proximity of these two structures along with the tectono-magmatic history of the PNW leads us to reexamine the origin of the Columbia River Basalts ~ 16 Ma. This thesis includes co-authored material submitted for publication.

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Dündar, Süleyman [Verfasser]. "Imaging of the crustal, lithospheric and upper mantle structure beneath the westernmost Mediterranean region using P- and S- receiver function methods / Süleyman Dündar." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1026265835/34.

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38

Heuer, Barbara [Verfasser]. "Lithospheric and upper mantle structure beneath the western Bohemian Massif obtained from teleseismic P and S receiver functions / Geoforschungszentrum Potsdam in der Helmholtz-Gemeinschaft. Barbara Heuer." Potsdam : Geoforschungszentrum, 2006. http://d-nb.info/98226769X/34.

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Dündar, Süleyman [Verfasser]. "Imaging of the crustal, lithospheric and upper mantle structure beneath the westernmost mediterranean region using P- and S-receiver function methods / Süleyman Dündar. Deutsches GeoForschungsZentrum GFZ." Potsdam : Deutsches GeoForschungsZentrum GFZ, 2011. http://nbn-resolving.de/urn:nbn:de:kobv:b103-11121.

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Nunn, Ceri. "Tomographic images of the crust and upper mantle beneath the Tibetan Plateau : using body waves, surface waves and a joint inversion." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708398.

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Münch, Thomas Willi Christian [Verfasser]. "3D Simultaneous Inversion for Seismic Structure and Local Hypocenters in Germany under Consideration of Seismic Anisotropy in the Upper Mantel / Thomas Willi Christian Münch." Kassel : Universitätsbibliothek Kassel, 2009. http://d-nb.info/1007955066/34.

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42

Chai, Mu. "Physical properties of mantle silicates under upper mantle pressures /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/6805.

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Frederiksen, Andrew William. "Seismic imaging of the Canadian upper mantle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq61090.pdf.

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44

Montagner, Jean-Paul. "Etude de la structure profonde de la terre a partir des ondes de surface de longue periode." Paris 6, 1986. http://www.theses.fr/1986PA066188.

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Differentes methodes d'inversion de la vitesse de ces ondes sont appliquees a plusieurs regions du globe: ocean pacifique, afrique, ocean indien. La regionalisation suivant l'age du fond oceanique montre que des heterogeneites laterales de vitesse existent jusqu'a au moins 400 km de profondeur et que la correlation entre la tectonique de surface et la structure profonde est meilleure sous l'ocean pacifique que sous l'ocean indien

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Sommacal, Silvano, and silvano sommacal@anu edu au. "Computational petrology: Subsolidus equilibria in the upper mantle." The Australian National University. Research School of Earth Sciences, 2004. http://thesis.anu.edu.au./public/adt-ANU20050415.151025.

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Processes that take place in the Earths mantle are not accessible to direct observation. Natural samples of mantle material that have been transported to the surface as xenoliths provide useful information on phase relations and compositions of phases at the pressure and temperature conditions of each rock fragment. In the past, considerable effort has been devoted by petrologists to investigate upper mantle processes experimentally. Results of high temperatures, high pressure experiments have provided insight into lower crust-upper mantle phase relations as a function of temperature, pressure and composition. However, the attainment of equilibrium in these experiments, especially in complex systems, may be very difficult to test rigorously. Furthermore, experimental results may also require extrapolation to different pressures, temperatures or bulk compositions. More recently, thermodynamic modeling has proved to be a very powerful approach to this problem, allowing the deciphering the physicochemical conditions at which mantle processes occur. On the other hand, a comprehensive thermodynamic model to investigate lower crust-upper mantle phase assemblages in complex systems does not exist. ¶ In this study, a new thermodynamic model to describe phase equilibria between silicate and/or oxide crystalline phases has been derived. For every solution phase the molar Gibbs free energy is given by the sum of contributions from the energy of the end-members, ideal mixing on sites, and excess site mixing terms. It is here argued that the end-member term of the Gibbs free energy for complex solid solution phases (e.g. pyroxene, spinel) has not previously been treated in the most appropriate manner. As an example, the correct expression of this term for a pyroxene solution in a general (Na-Ca-Mg-Fe2+-Al-Cr-Fe3+-Si-Ti) system is presented and the principle underlying its formulation for any complex solution phase is elucidated.¶ Based on the thermodynamic model an algorithm to compute lower crust-upper mantle phase equilibria for subsolidus mineral assemblages as a function of composition, temperature and pressure has been developed. Included in the algorithm is a new way to represent the total Gibbs free energy for any multi-phase complex system. At any given temperature and pressure a closed multi-phase system is at its equilibrium condition when the chemical composition of the phases present in the system and the number of moles of each are such that the Gibbs free energy of the system reaches its minimum value. From a mathematical point of view, the determination of equilibrium phase assemblages can, in short, be defined as a constrained minimization problem. To solve the Gibbs free energy minimization problem a Feasible Iterate Sequential Quadratic Programming method (FSQP) is employed. The systems Gibbs free energy is minimized under several different linear and non-linear constraints. The algorithm, coded as a highly flexible FORTRAN computer program (named Gib), has been set up, at the moment, to perform equilibrium calculations in NaO-CaO-MgO-FeO-Al2O3-Cr2O3-Fe2O3- SiO2-TiO2 systems. However, the program is designed in a way that any other oxide component could be easily added.¶ To accurately forward model phase equilibria compositions using Gib, a precise estimation of the thermodynamic data for mineral end-members and of the solution parameters that will be adopted in the computation is needed. As a result, the value of these parameters had to be derived/refined for every solution phase in the investigated systems. A computer program (called GibInv) has been set up, and its implementation is here described in detail, that allows the simultaneous refinement of any of the end-member and mixing parameters. Derivation of internally consistent thermodynamic data is obtained by making use of the Bayesian technique. The program, after being successfully tested in a synthetic case, is initially applied to pyroxene assemblages in the system CaO-MgO-FeO-Al2O3-SiO2 (i.e. CMFAS) and in its constituent subsystems. Preliminary results are presented.¶ The new thermodynamic model is then applied to assemblages of Ca-Mg-Fe olivines and to assemblages of coexisting pyroxenes (orthopyroxene, low Ca- and high Ca clinopyroxene; two or three depending on T-P-bulk composition conditions), in CMFAS system and subsystems. Olivine and pyroxene solid solution and end-member parameters are refined, in part using GibInv and in part on a trial and error basis, and, when necessary, new parameters are derived. Olivine/pyroxene phase relations within such systems and their subsystems are calculated over a wide range of temperatures and pressures and compare very favorably with experimental constraints.

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Ghods, Abdolreza. "Melt migration modeling in partially molten upper mantle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0024/NQ50169.pdf.

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Hall, Paul S. "Free and forced convection in earth's upper mantle /." View online ; access limited to URI, 2003. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3115631.

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Sommacal, Silvano. "Computational petrology : subsolidus equilibria in the upper mantle /." View thesis entry in Australian Digital Theses Program, 2004. http://thesis.anu.edu.au/public/adt-ANU20050415.151025/index.html.

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Papadimitriou, Panayotis. "Etude de la structure du manteau supérieur de l'Europe et modélisation des ondes de volume engendrées des séismes égéens." Paris 7, 1988. http://www.theses.fr/1988PA077133.

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On construit un modèle de vitesse qui correspond a la structure du manteau supérieur de l'Europe en utilisant des stations européennes les ondes de volume p et pp et des séismes qui ont lieu dans le domaine égéen. Pour cela on utilise la méthode des faisceaux gaussiens. Il est alors possible pour des séismes dont D<30**(O) de déterminer leur mécanisme au foyer et leur intensité

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Zheng, Yingcai. "Imaging upper mantle discontinuities and Earth's small-scale heterogeneities /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.

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Dissertations / Theses on the topic 'Structure of the upper mantle'

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