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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Subseismic description of the Slichter modes in a rotating Earth /

Peng, Zhengrong, January 1990 (has links)
Thesis (M.Sc.) -- Memorial University of Newfoundland. / Typescript. Bibliography: leaves 52-53. Also available online.
32

Analysis of multicomponent seismic data from the Hydrate Ridge, offshore Oregon

Kumar, Dhananjay, Sen, Mrinal K., Stoffa, Paul L., January 2005 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisors: Mrinal K. Sen and Paul L. Stoffa. Vita. Includes bibliographical references.
33

Seismologische Studien im gebiete der Ostalpen ... Mit 5 Karten.

Christensen, Adolf, January 1911 (has links)
Inaug.-diss.--Strassburg. / Lebenslauf. "Literatur": p. 104-105.
34

Improved teleseismic Green's functions and western Canada mantle structure and evolution

Mercier, Jean-Philippe 05 1900 (has links)
The present thesis is divided into three distinct parts and focuses both on the improvement of deconvolution technique in a teleseismic context for crustal and upper-mantle studies and on the understanding of western Canada structure and evolution through seismic imaging. The first part presents estimates of the P-component of the teleseismic-P Green's functions for three stations of the Canadian National Seismic Network (CNSN) obtained using a new deconvolution technique. Our results show evidence of the principal, first-order scattered Moho phases and, in particular, the Pp_Mp. The second part presents teleseismic receiver functions from 20 broadband three-component seismometers deployed along the MacKenzie-Liard Highway in Canada's Northwest Territories as part of the joint Lithoprobe-IRIS CAnadian NOrthwest Experiment (CANOE). These stations traverse a Paleoproterozoic suture and subduction zone that has been previously documented in detail to mantle depths using seismic reflection profiling. Our results reveal the response of the ~1.8 Ga subduction zone on both the radial and transverse component. The identification of this structure and its comparison with fine-scale mantle layering below the adjacent Slave province and from a range of Precambrian terranes provides an unambiguous connection between fossil subduction and fine-scale, anisotropic mantle layering found beneath cratons. Previous documentation of similar layering below the adjacent Slave province provides strong support for the thesis that early cratonic blocks were stabilized through processes of shallow subduction. The last part presents P- and S wave velocity models for western Canada. In this part, we focus our attention on two distinct features: 1) the transition from Phanerozoic to cratonic mantle in northwestern Canada and 2) the complex tectonic environment at the northern terminus of the Cascadia subduction zone where the plate boundary changes from convergent to transform. We find that the main transition from Phanerozoic to cratonic mantle in northwestern Canada occurs at the Cordilleran deformation front. In northern Cascadia, we have imaged and characterized the signature of the subducting Juan de Fuca plate and observed evidence of subduction beyond the northern edge of the slab. Our result show that the Anahim hotspot track is underlain by a -2% low-velocity zone. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
35

PV-Induced Forcing of Gravity Waves in a Shallow Water Model

Unknown Date (has links)
The influence of a geostrophically balanced or potential vorticity (PV) background flow on gravity wave propagation is examined using a rotating shallow water model. The system is analyzed in the context of a perturbative expansion that focuses on the dynamics of the resonances within the nonlinear terms of the system. The nonlinearity is reconstructed as a wave-wave interaction forcing on an otherwise undisturbed linear wavefield. The principal conclusion is that while the PV flow is generally undisturbed by the gravity wavefield, the gravity wavefield is forced by the geostrophic flow over moderate timescales. We numerically test these results for the interaction between a single geostrophic mode and a gravity wave, followed by propagation of a single gravity mode through a turbulent PV background. We find that the gravity mode energy is scattered into other modes of similar wavelength but different directions of propagation. The rate of dispersion is in agreement with resonant triad theory, where the rate depends primarily on the initial gravity wavenumber and background PV strength. These results are expected to have relevance to the propagation of coherent internal tides in the open ocean.} / A Dissertation Submitted to the Geophysical Fluid Dynamics Institute in Partial FulfiLlment of the Requirements for the Degree of Doctor of Philosophy. / Spring Semester, 2008. / March 26, 2008. / Gravity Waves, Shallow Water Model, Potential Vorticity, Wave Interaction, Tidal Waves / Includes bibliographical references. / Philip Cunningham, Professor Directing Dissertation; Janet Peterson, Outside Committee Member; Carol Anne Clayson, Committee Member; William K. Dewar, Committee Member; Ruby Krishnamurti, Committee Member.
36

Double-Diffusive Fingering in Porous Media

Unknown Date (has links)
Laboratory experiments were conducted on a double-diffusive fluid with components of dissolved salt and sucrose contained within a porous medium of nearly spherical glass beads. The fluid is stabilized by the faster diffuser (Sa) and destabilized by the slower diffuser (Su) arranged in such a way so that the system is finger-favorable. The experiments were conducted in a tank of depth 30 cm, with initial vertical opposing linear profiles of Sa and Su between two reservoirs, the top containing a Su solution and the bottom a Sa solution of known values. Measurements show that the Rayleigh-Darcy number experimental range is up to |Rsa|~10^5 and density ratio ranges from Rrho= 1.1 to 1.4 with spherical bead range of d = 0.01 to 0.80 cm. The finger flux for salt was Fsa~CRsa^a with a = 0.17 to 0.25 and was Fsu~CRsu^b with b = 0.12 to 0.14 for sugar. The spacing of the fingers was measured and non-dimensionalized using the height of the test reservoir. The non-dimensional spacing lambda was found to be related to the salt Rayleigh-Darcy number lambda~Rsa^m with m = -0.31 for glass bead size d = 0.05 cm and m = -0.55 for d = 0.10 cm and related to the sucrose Rayleigh-Darcy number lambda~Rsu^n with n = -0.41 for d = 0.05 cm and n = -0.69 for d = 0.10 cm, compared to the prediction of lambda~Rsa^0.5 from linear theory. / A Dissertation Submitted to the Geophysical Fluid Dynamics Institute in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Fall Semester, 2007. / April 3, 2007. / Convection, Double Diffusion, Fingering / Includes bibliographical references. / Ruby Krishnamurti, Professor Directing Dissertation; James F. Tull, Outside Committee Member; Georges Weatherly, Committee Member; Jennifer Georgen, Committee Member.
37

Wavelets-Based Analysis of Variability in the Air-Sea Fluxes

Unknown Date (has links)
Presented in this research is an examination of the energy transfer between the atmosphere and the ocean via the surface energy fluxes. Typically, air-sea processes are modeled using general circulation models (GCMs) fraught with difficulties arising from numerical approximation of the theory in an attempt to align the models with global observations. As a result, GCMs are not generally able to resolve atmosphere or ocean processes to the higher resolutions required to effectively model regional phenomena. The increase in availability of regional observations has improved regional models, and subsequently caused the gap between observations and GCM model output to become a glaring problem for small scale, localized phenomena. The use of regional models, however, requires analysis tools capable of resolving signals spanning the spectrum of both large and small scale processes while preserving temporal and spatial localization of the different phenomena. Put forth herein is a wavelets-based method for analyzing the output from a high resolution air-sea model system to examine energy transfer between the atmosphere and the ocean. The model system is comprised of observed sea surface temperature data forcing the WRF-ARW atmospheric model. Energy exchange between the atmosphere and ocean is examined through the evolution of three-dimensional surface fluxes estimated by a turbulent heat flux model. Specifically, the latent and sensible heat fluxes are separated into large and small scale variability via wavelets-based windowing. The use of wavelets-based analysis is preferred because of the need to preserve spatial and temporal localization. The end result is the characterization of each heat flux in space and time, for both large and small scale variability. Heat flux variability is then related to large and small scale changes in the atmosphere and ocean. / A Dissertation submitted to the Geophysical Fluid Dynamics Institute in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester, 2009. / December 9, 2008. / Turbulent Heat Fluxes, Surface Energy Budget, Wavelets / Includes bibliographical references. / Carol Anne Clayson, Professor Directing Dissertation; Eric Chicken, Outside Committee Member; Mark Bourassa, Committee Member; Phil Cunningham, Committee Member.
38

Adsorption of Radionuclides on Clay Minerals

Warinner, J. Ernest 01 January 1962 (has links)
No description available.
39

Seismic reflection study of the subsurface structure in western and central Ohio /

Mayhew, George H. January 1969 (has links)
No description available.
40

Seismic and hydroacoustic investigations near Ascension Island /

Hanson, Jeffrey Acton, January 1998 (has links)
Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references.

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