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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.
11

Sensitivity studies using multi-region and open boundary conditions for terrain bottom following ocean models

Martinho, Antonio S. January 2003 (has links) (PDF)
Thesis (Ph. D. in Physical Oceanography)--Naval Postgraduate School, March 2003. / Dissertation supervisor: Batteen, Mary L. "March 2003." Includes bibliographical references (p. 167-168). Also available in print. Mode of access: World Wide Web.
12

Effects of finite amplitude bottom topography on ocean variability

Leonov, Dmitri A. Dewar, William K. January 2005 (has links)
Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. William K. Dewar, Florida State University, College of Arts and Sciences, Dept. of Oceanography. Title and description from dissertation home page (viewed Sept. 23, 2005). Document formatted into pages; contains xi, 61 pages. Includes bibliographical references.
13

A heuristic approach to the evaluation of seafloor bathymetric changes : a case study of Dundee Harbour, Eastern Scotland

Zin, Harun Shah Bin Mat January 1997 (has links)
The phenomena of seabed bathymetric changes in Dundee harbour, eastern Scotland have been investigated, by use of archive bathymetric data. The bathymetric data were available from the Dundee Port Authority, from its past annual harbour maintenance programmes during the period of 1989 to 1993. Archive bathymetric data are seen as under-utilised, after being used for their intended purposes. A methodology was therefore developed to use sequential bathymetric data to estimate the deposition and erosion of sediment over a period of time. This is in the form of a systematic procedure of processing for comparison of data from different dates. The comparison or differencing of bathymetric data in their original form cannot be directly applied. This would require each data point to be located at spatially common positions (i.e. grid points) and could be achieved only through interpolation. A procedure known as 'gridding' is instead used to prepare depths at the spatially fixed points or nodes. Six different methods of interpolation have been examined and trial computations using a common data subset for each individual method conducted. The results of the interpolation were often substantially different from one method to another. A technique known as the Blending Interpolation Technique is proposed to overcome the uncertainty in depth interpolation. Computer programs were specifically written for this study and for the visualisation of the phenomena of deposition and erosion, use was made of the available UNIRAS software package. The methodology and procedures of this study are not only applicable for an estuarine harbour environment, but are also equally applicable to any areas such as large reservoirs, lakes or coastal ports and harbours, that are continuously affected by the phenomena of sedimentation and erosion, where their estimation and quantification are of critical importance. This study, however, has demonstrated the usefulness of the Blending Interpolation Technique which is seen as a future tool to detect, monitor and quantify seabed changes, in particular where bathymetric data of the same area are available from different dates. It also serves to prolong the usefulness of archive bathymetric data kept for an area.
14

Three investigations of accretionary wedge deformation

Breen, Nancy Ann. January 1987 (has links)
Thesis (Ph. D.)--University of California, Santa Cruz, 1987. / Typescript. "These papers describe faulting and folding observed on the seafloor using SeaMARC II side-scan sonar, seismic reflection, and 3.5 kHz data"--P. 1. Includes bibliographical references.
15

Turbulent mixing near rough topography /

Carter, Glenn S. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 155-170).
16

Modeling of the Peru-Chile trench from wide-angle reflection profiles

Goebel, Vaughn 29 October 1973 (has links)
A proposed modeling technique that yields a best fit to observed wide-angle reflection profiles incorporates (1) the use of migrated vertical reflection profiles to provide topographic control, (2) ray tracing to produce theoretical wide-angle reflection profiles for hypothetical crustal sections, and (3) the iterative adjustment of crustal layer dip, thickness and velocity. The technique, applied to four successive wide angle reflection profiles located due west of Callao, Peru, and extending from 50 km west of to 80 km east of the axis of the Peru-Chile trench, suggests (1) that a 5 km thick oceanic crust thickens to 7 km at the trench axis, (2) that the oceanic plate underthrusts the continental plate, and (3) the existence of a previously undetected 7.8 km per sec oceanic layer. Migrated vertical reflection profiles show (1) a series of block faults across 20 km of the trench edge of the continental plate and (2) oceanic basement underthrusting 6 km of the trench edge of the continental plate. / Graduation date: 1974
17

Deformation in the Peru Trench, 6⁰-10⁰S

Prince, Roger Allan 28 December 1973 (has links)
Detailed surveys of several segments of the Peru Trench show that the region between 6° to 10⁰ S is an area of recent deformation. Seismic reflection records across the axis of the trench show faulting, uplift, and tilting of the sedimentary fill and the acoustic basement. Uplift of the acoustic basement beneath the trench is greatest at 7°40'S and 9°20'S where ridges are elevated above the trench floor. Turbidites occur on top of the ridge at 9°20'S and seaward of the ridge in a basin which is elevated 300 m above the main trench floor. Based upon a hemipelagic sedimentation rate of 1.7 cm/1000 yr, the age of uplift of the ridge is dated at less than 10,000 yrs. B.P. Similarly, the age of uplift of the elevated basin seaward of the ridge is dated at less than 34,000 yrs. B.P. near the ridge and at less than 53,000 yrs. B.P. at the seaward edge of the basin. The trench shoals and turns eastward as one proceeds from south to north along the axis. It divides naturally into three segments separated by the axial ridges at 7°40'S and 9°20'S. The southern segment trends N31W and has an axial depth of 6300 m; the middle segment trends N24W at 6200 m; and the northern segment trends N11W at 5800 m. The upper continental slope is characterized by submarine canyons which funnel sediments into the trench axis. The lower slope is characterized by benches. These benches may define old imbricate thrust sheets. Ridges in the axis are thought to be new imbricate thrust sheets which are forming at the boundaries between segments of the subducted lithosphere. An apparent fracture zone trending N45E enters the area from the southwest. Two turbidite basins (B1 and B2) trending N9E occur northeast of this fracture zone. Turbidite deposition ended in these basins 5100 yrs. ago. The basins intersect the trench axis just north of the ridge at 7°40'S and are presently 700 m above the trench axis. This relative difference in depth is attributed to a combination of subsidence of the trench and uplift of the oceanic plate upon initiation of thrust faulting which presumably occurred 5100 yrs. B.P. There is still insufficient data to determine the exact origin of these basins. From the regional structure, it appears that the lower continental slope of South America is underthrusting the upper continental slope along old imbricate thrust faults beneath the Peruvian continental slope. This overthrusting has caused uplift and accretion of the continental slope and shelf edge and subsidence and sediment infilling of the area between the shelf edge and the coastline. The author suggests that the seismic gap (present lack of large magnitude shallow earthquakes in this area) may be in part due to the highly fractured and deformed nature of the subducted Nazca Plate. Finally, using variable motion along old imbricate thrust faults, the imbricate thrust model provides mechanisms for reorientation of the trench and for episodic subduction of the oceanic plate beneath the trench axis. / Graduation date: 1974
18

Examining the effects of mid ocean ridge topography on 3D marine magnetometric resistivity model responses /

Lassner, Lisa A. January 1900 (has links)
Thesis (M.S.)--Joint Program in Oceanography/ Applied Ocean Science and Engineering, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 2003. / Includes bibliographical references (p. 768-69).
19

Two responses of a uniformly stratified flow over a sloping bottom to a spatially varying downwelling favorable wind /

Logvinov, Evgeny. January 2008 (has links)
Thesis (Master of Science)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution,2008. / Bibliography: p. 62-63.
20

Topographic influences on the path of the Gulf Stream

Warren, Bruce A. January 1962 (has links)
Thesis--Massachusetts Institute of Technology (Ph. D. Geology). / Photocopy of typescript, Microfilm -- 1 reel ; 35 mm.

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