Seismic refraction data collected in 1985 by the USGS were used in this study to derive the P and S velocity structure of the crust beneath the Gulf of Maine. The data quality differs among instruments and is affected by surficial lateral heterogeneities, a ringy source signature and reverberations. Velocity models of the crust were computed by one-dimensional raytracing and by wavefield continuation. Pg arrivals were modeled using both techniques to derive the P velocity of the upper 5-15 km of the crust and give very similar results. Strong Sg arrivals were also observed, and computed S amplitudes generated from P-S conversion for different scenarios show that the observed S wave is generated at the basement top. Two small sediment basins are indicated in the Central Plutonic Zone and two faults are suggested in the Fault Zone and the Central Plutonic Zone, respectively. Beneath the sediments the layering is uniform with dips of less than 2° and a fairly laterally homogeneous velocity structure, in spite of lateral variations in reflectivity. P and S velocities increase from 5.3 and 2.8 km/s, respectively, at the basement to 6.4 and 3.7 km/s at 10 km depth. A laterally discontinuous low velocity zone is indicated at 6-10 km depth which might be caused by laccolithic granitic intrusions. However, magnetic and gravity data do not show indications for felsic intrusions where the low velocity zones are observed. Velocity differences among some instruments suggest anisotropy in the upper 6 km of the crust, as observed in onshore Maine. These instruments indicate velocities parallel to the structural grain of the Appalachians of 6.1-6.4 km/s and velocities transverse to the grain of 5.8-6.1 km/s in the depth range 2-6 km. Cashes Ledge granite, a site of an intense magnetic high, has a reduced velocity compared to surrounding rocks and might extend to at least 10 km depth. Poisson's ratio for the upper crust ranges from 0.23-0.26. To derive the velocity structure of the middle and lower crust, wide-angle reflections interpreted to be PmP and SmS were modeled by one-dimensional raytracing. In addition synthetic seismograms were computed using the WKBJ method to constrain possible middle and lower crust velocity models by their PmP and SmS amplitudes. Recorded PmP and SmS wide-angle reflections have quite different amplitudes and travel-times among instruments suggesting a heterogeneous lower crust. The crust below 10 km depth has an average P velocity of 6.5-6.8 km/s and an average S velocity of 3.7-3.9 km/s. Most instruments indicate a Poisson's ratio of around 0.25 between 10 km depth and Moho and one instrument suggests a Poisson's ratio of 0.28. Hence, the middle and/or lower crust under the Gulf of Maine is heterogeneous and represents average crust modified by mafic intrusions, probably during Mesozoic extension. Moho depth is indicated between 30 and 37 km depth. Wide-angle reflections coming from 28 km depth as indicated by two instruments are interpreted to come from the top of a lower crustal intrusion. This interpretation is supported by an observed mismatch between the models giving a thickness of 28 km and the reflection data. Although it represents a different geological terrane, the velocity and thickness of the crust beneath the central Gulf of Maine is very similar that onshore Maine. / Graduation date: 1991

In this thesis anomalous downcore shallowing of paleomagnetic inclinations is interpreted to be caused by sediment compaction. Thus, compaction-induced inclination shallowing may influence tectonic reconstructions that are based on inclinations from deep-sea sediment cores. Progressive downcore shallowing of the remanent inclination was observed in a 120-m section of Plio- Pleistocene sediments at Deep Sea Drilling Project (DSDP) site 578 in the northwest Pacific. Near the top of the section the average inclination corresponds to the expected geocentric axial dipole value of 53° but shallows downcore by about 6° to 8°. In sediments spanning the same time interval of neighboring site 576, no inclination shallowing was observed. This second site has considerably lower sedimentation rates, and the Plio- Pleistocene is represented by a 26-m sedimentary section. The inclination shallowing at site 578 was correlated to a downhole decrease in porosity, and these results are interpreted to suggest that both the downhole inclination shallowing and decrease of porosity in site 578 were caused by sediment compaction. Microscopic models demonstrate that sediment compaction may lead to inclination shallowing of the magnetic remanence. Furthermore, it is shown that inherent initial within-sample dispersion of the magnetic moments will transform any form of microscopic mechanism to an equation of a standardized form: tan (I-ΔI) = (1-a ΔV) tan I, where I is the inclination of the ambient field, ΔI is the inclination shallowing, a is a constant and ΔV the compaction. Paleomagnetic inclinations of Cretaceous DSDP sediments from the Pacific plate are known to be systematically shallower than predicted from paleolatitudes of hot spot reconstructions. Published paleomagnetic data were reexamined and the shallow Cretaceous inclinations explained as a result of sediment compaction. The Cretaceous data are used to estimate the parameter a. The resulting a values are comparable to those of previous studies of compaction-induced inclination shallowing, both from laboratory experiments and the considerably younger deep-sea sediments at site 578. Values of the parameter a suggest that it might be controlled by sediment lithology with greater shallowing for clayey than calcareous sediments. / Graduation date: 1991

Thesis (M.S. in Engineering)--University of Texas at Austin, 2003. / Title from title screen; viewed on 02/13/07. "Project report prepared for the Minerals Management Service, under the MMS/OTRC cooperative research agreement, 1465-01-99 CA-31003, task order 18217, MMS project 421." "August 2003." "OTRC Library Number: 8/03B121." Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 75-78).

An optimization methodology, algorithms, and computer program for cable/lumped-body deployment system are developed for the design and installation of sonar packages in deep ocean ranges. In addition, a methodology and algorithms for the control of the system are proposed. A penalty function is developed in terms of the system parameters and the dynamic constraints are set up for the optimization of cable/lumped-body deployment system. Deployment procedures and segmentations characterized by their initial and terminal condition are proposed. Alternating Direction (ADM) and Modified Alternating Direction (MADM) methods are employed for the optimum search. The optimization algorithms are then implemented on a desk-top computer. The objective of the search is to achieve the optimum vessel speed and cable pay-out rate that result in the minimum penalty value. Numerical examples are presented to test the robustness of the algorithm (ADM) and the compute program capabilities. The results are compared to those of the MADM method and the entire space search. During actual installation, it is anticipated that randomness in the excitation will cause sonar packages to miss the exact target locations. Thus a continuous correction in the controllable parameters is necessary. Three alternative types of control algorithms are presented for these reasons. / Graduation date 1993

This study investigates the hydrodynamic variations along the Gao-ping Submarine Canyon influence by the topography effects. The data used in this study were collected from two cruises of field observations using research vessel OR3. Instruments applied include sb-ADCP¡Bbm-ADCP¡Bmoored-ADCP¡BCTD and several vertical strings of temperature loggers. Parameters recorded include flow velocities, water temperature and tidal elevation. The analysis method is enlightenment by the case study in the Monterey Canyon of California. The results show that (1) the current speed in the lower layer is faster than that of upper layer, which is explained due to v-shape of topography and bottom-trapped effect of internal tide. This result is consistent with previous studies. (2) In flood tide, the currents flowed into the Canyon from deep water to shallower. The baroclinic kinetic energy decreased to 0.2 at the turning point of canyon axis at 230m water, whichwas caused mainly by bottom friction. On the other hand, the baroclinic kinetic energy increased to 0.47 at 250m water in ebb tide when there was less influence of bottom friction. (3) In comparison the effects of bottom slope and area of cross section of the canyon, the baroclinic kinetic energy dissipation was mainly occurred at up slope flow during the flood tide. The change of the canyon width had less influence. During the ebb, the baroclinic kinetic energy was mainly due to the change of canyon width in the region shallower then the 230m of the second turning of the canyon. (4) The loss of kinetic energy during flooding up slope current can be verified by the changes of water mass temperature. Cold bottom was raised to upper layer when there was large drop of kinetic energy. There was likely a conversion of kinetic energy to potential energy. No upwelled cold water detected during ebb current with increase of kinetic energy.

Internal tide is generated in the interface of density stratification by some hydrodynamic disturbance. The major mechanisms are borotrophic tidal current oscillated at the edge of the continental shelf, submarine canyons, ridges or sills. The resulting disturbance generated has the same motion cycle of tidal period. There were internal tides reported in the Kaoping Submarine Canyon. The generation sites and mechanisms, however, are not clear. This study analysis four cruises of field observed data using ship mounted ADCP and CTD, and moored temperature strings and current meters. The results showed: (1) The phase of M2 tidal current increase toward the canyon head, with minimum value at the canyon mouth. This result implies that the internal tide was generated near the canyon mouth and propagated up canyon with the thermocline decreasing toward the shallower water. (2) The internal tide generated at the canyon mouth propagated, through some mechanisms, at the upper layer density interface about 150m instead of beaming near the bottom layer where the current and topography interact. (3) The vertical variations of tidal ellipse and phase based on bottom mounted ADCP support the results of ship mounted observations, the internal tidal energy propagates near the interface of 150m below the surface.

This study presents the first reconstruction of pollution history of Polychlorinated biphenyls (PCBs) in Taiwan coast. Six sediment cores were collected from Gaoping submarine canyon and its adjacent area to investigate the distribution and source recognition of PCBs. The concentrations of PCBs in the cores from Gaoping canyon ranged 0.155--2.281 ng/g dry wt, whereas the maximum concentrations of PCBs reached 21.0 and 2.93 ng/g dry wt, respectively, in the cores from the northern and sourthern continental shelf of Gaoping canyon. The toxicological effects assessed by sediment quality guidelines (SQGs), show that only 2-10cm in core L27 exceeded the guideline value suggested by Förstner (6 ng/g), which indicated the sediment in this area had been polluted seriously and should not be disturbed. Overall, compared with studies in the world, the sediment PCB concentrations in Kao-Ping coastal areas were relatively low. Hierarchical Cluster Analysis identified the source of PCBs in the study area was a mixture of Aroclor 1016, Aroclor 1242 and Aroclor 1260. Similarity in vertical variations of total concentrations of PCBs among the six cores was observed and the trend is consistent with the history of the PCB usage in Taiwan. The drastic decrease in PCB concentrations around the late 1980s, clearly demonstrates the effectiveness of the ban of PCBs use in 1980 in Taiwan.

Inaug.-diss.--Munich. / Lebenslauf. "Quellennachweis": p. 159-160.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Anthony J. Healey. Includes bibliographical references (p. 57-59). Also available online.