| Using a Near-Bed Sediment Flux Sensor to Measure Wave Formed Bedform Migrations and Formation Processes |
OCT 2007 |
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| Authors:
Peter A. Traykovski; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
 | My research program focuses on identifying and quantifying sediment erosion, transport, and deposition processes on the continental shelf through state of the art observational techniques in both fine grained and sandy environments. In sandy environments, my goal is to understand the detailed interactions and feedbacks between hydrodynamics, bedforms, and the resulting sand transport. In fine-grained environments, I have been investigating the role fluid mud flows as a depositional mechanism in ... |
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| Shallow Seabed Methane Gas Could Pose Coastal Hazard |
30 MAY 2006 |
3 pages |
| Authors:
Angus I. Best; Michael D. Richardson; Bernard P. Boudreau; Alan G. Judd; Ira Leifer; Anthony P. Lyons; Christopher S. Martens; Danial L. Orange; Simon J. Wheeler; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS SEAFLOOR SCIENCES DIRECTORATE
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 | Abnormally high levels of methane gas in seafloor sediments could pose a major hazard to coastal populations within the next 100 years through their impact on climate change and sea level rise. Marine scientists have known for many years that biogenic methane (CH4) is generated in shallow seabed sediments on continental margins, especially in rapidly deposited muddy sediments with high organic matter content. Grassy sediments are found in river deltas, ... |
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| Mine Burial Experiments at the Martha's Vineyard Coastal Observatory |
03 FEB 2004 |
8 pages |
| Authors:
Peter Traykovski; Michael D. Richardson; John A. Goff; Larry Mayer; Roy Wilkens; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOSCIENCES DIV
|
| Several experiments to measure the burial of seafloor mines by scour and fill have been conducted at the Woods Hole Oceanographic Institution Martha's Vineyard Coastal Observatory (MVCO). Two sets of mine scour burial experiments were conducted during the winters of 2001-2002 and 2002-2003 with a single optically instrumented mine in the field of view of a rotary sidescan sonar. Sixteen mines were deployed from October 2003 to April of 2004, ... |
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| Uncertainty in Acoustic Mine Detection Due to Environmental Variability |
2004 |
11 pages |
| Authors:
Peter C. Chu; Nick A. Vares; Ruth E. Keenan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA NAVAL OCEAN ANALYSIS AND PREDICTION LAB
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| Uncertainty in acoustic bottom target detection due to environmental variability for a shallow sea (30 m water depth) is investigated using the Navy's Comprehensive Acoustic Simulation System/Gaussian Ray Bundle model for a generic Very High Frequency (VHF) forward looking sonar. The effects of imprecise bottom type and wind speed data are evaluated to determine the impact of this variability on bottom target detection. The acoustic uncertainty due to the wind ... |
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| Assessment of Electrical Resistivity Anomalies Caused by Freshwater Discharge Across the Continental Shelf: Seeps Off North Carolina |
11 MAR 2003 |
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| Authors:
Robert L. Evans; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF GEOLOGY AND GEOPHYSICS
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| To determine the impact that fresh water discharge across the continental shelf has on the electrical resistivity structure of bottom sediments and, by so doing, to use electrical measurements to constrain the regional hydrology and the exchange of continentally derived groundwater with the ocean. The strength and spatial distribution of resistivity anomalies caused by fresh water will be used to assess the likelihood of false target identification in mine counter ... |
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| Spatial and Temporal Variability in Bottom Roughness: Implications to High Frequency Subcritical Penetration and Backscatter |
20 SEP 2002 |
9 pages |
| Authors:
Kevin L. Williams; Darrell R. Jackson; Eric I. Thorsos; Dajun Tang; Kevin B. Briggs; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Quantitative prediction of high frequency, low grazing angle penetration into, and scattering from, sand sediments requires knowledge of the roughness of the water/sand interface. Since the sediment roughness evolves due to hydrodynamic and biological processes, concurrent, co-located measurement of roughness and acoustic penetration/backscattering is essential for testing acoustic models or using such models to determine the likelihood of buried target detection. Here, we examine both roughness and acoustic measurements carried ... |
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| Empirical Predictions of Seafloor Properties Based on Remotely Measured Sediment Impedance |
2002 |
11 pages |
| Authors:
Michael D. Richardson; Kevin B. Briggs; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
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| Numerous acoustic systems have been developed over the past 25 years for remote classification of the seabed. Many systems use inversions of echo returns to estimate seafloor impedance and then use empirical relationships to predict other seabed properties from values of impedance. New regressions are presented, separately for siliciclastic and carbonate sediments, which allow prediction of sediment grain size, porosity, bulk density, percent sand and gravel, and sound speed ratio ... |
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| The Use of Field Screening or Rapid Sediment Characterization (RSC) tools for Sediment Assessments |
AUG 2001 |
8 pages |
| Authors:
Victoria J. Kirtay; Sabine E. Apitz; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
| The primary goals of a sampling and analysis plan for an Ecological Risk Assessment (ERA) or a sediment site assessment are to identify potential contaminant sources and to delineate areas of concern. However, traditional sampling and analysis approaches do not always provide the information necessary to support the decision-making process in a cost- and time-effective manner. Site assessments performed in the marine environment are often hindered due to the complexity ... |
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| Vertical Effective Stresses from Multi-Piezometer Array System (MPAS) pore Pressure Measurement at the Coastal Oil-Spill Simulation Facility |
22 DEC 1999 |
30 pages |
| Authors:
Glen R. Andersen; S. P. Gonzales; TEXAS ENGINEERING EXPERIMENT STATION COLLEGE STATION
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| This report describes and examines the excess pore water pressures generated in a sand bed subjected to gravity water waves as measured by piezometer probes of the Multi-Piezometer Array System (MPAS). Experiments were conducted a medium-sized wave tank (2.1 m wide, 2.4 m deep, and 30 m long), floored by 1 m of uniform, saturated, medium dens to dense fine sand covered by 1.2 m ... |
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| Harvesting Energy from Redox Potential Gradients in Sediments and Soils |
DEC 1999 |
3 pages |
| Authors:
Clare E. Reimers; RUTGERS - THE STATE UNIV NEW BRUNSWICK NJ INST OF MARINE AND COASTAL SCIENCE
|
| Pairs of platinum mesh or graphite fiber electrodes, one embedded in marine sediment (anode), the other in proximal seawater (cathode), have been used to harvest low levels of power from natural, microbe established, voltage gradients at marine sediment-seawater interfaces. The sustained power harvested has been on the order of 0.01 W/m(2) of electrode geometric area but is dependent on electrode design, sediment composition, and temperature. It is proposed that the ... |
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| The ABCS Program for the Analysis of Echo Sounder Returns for Acoustic Bottom Classification |
AUG 1999 |
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| Authors:
Paul A. Clarke; L. J. Hamilton; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION MELBOURNE (AUSTRALIA)
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| An echo sounder can be used to indicate the type of sediment on the sea floor through analysis of the returned echo's shape and energy characteristics. This document describes the ABCS program written to analyze echo sounder ping returns for simple shape and energy statistics, with the intention to investigate which statistics are important in characterizing the seabed. ABCS was written in Visual Basic ... |
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| Development of a Portable Innovative Contaminated Sediment Dredge |
SEP 97 |
69 pages |
| Authors:
Trimbak M. Parchure; Charles N. Sturdivant; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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| The Cooperative Research and Development Agreement (CRDA) document was signed to undertake development of a portable innovative contaminated sediment dredge. Three major problems are associated with dredging of contaminated sediments: (1) The contaminated sediment are mostly fine and highly compacted, and specialized devices are needed for cutting and loosening them before transporting, (2) the dredged fine sediments are vertically resuspended and dispersed easily within the entire water column and adversely ... |
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| Numerical Modeling of Steady-State Plow/Soil Interaction |
AUG 97 |
177 pages |
| Authors:
Theodore A. Shugar; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
|
| A numerical model of steady-state plow/soil interaction in support of cable burial operations on the seafloor was developed. Coupled field equations for equilibrium of an elasto-plastic medium and pore water diffusion in the presence of rigid surfaces contacting and sliding through fully saturated soil were solved in two dimensions. Time histories of unit plow forces contained distinct transient and steady-state phases reminiscent of total plow force histories recorded in the ... |
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| Bottom Scattering Strengths Measured in Deep and Shallow Water Using the Deep Towed Acoustics/Geophysics System |
30 APR 97 |
25 pages |
| Authors:
Joseph Jeffery; Peter M. Ogden; NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS SYSTEMS BRANCH
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| The Deep Towed Acoustics/Geophysics System (DTAGS) has been used for some years by Naval Research Laboratory investigators to examine the structure of ocean bottom sediments. With the replacement of the DTAGS horizontal array by a vertical array, it became possible to use the system to measure bottom scattering strengths in both deep and shallow water. The first DTAGS scattering measurements with the vertical array were taken in two general locations: ... |
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| Enhancing Shallow Seismic Reflection Profiles Using Nonlinear Correlation: Applications to the New Jersey Margin |
APR 97 |
4 pages |
| Authors:
Gregory S. Mountain; Peter Buhl; LAMONT-DOHERTY EARTH OBSERVATORY PALISADES NY
|
| Some older Multichannel Seismic data recorded on the shallow continental shelf do not properly image the upper few 100 m. This is due to a large (approx. 200 m) minimum source receiver offset. Nonlinear Correlation, used successfully for other seismic processing was not able to correct the data. The use of a short (Approx. 30 m) minimum source receiver offset produces excellent seismic images of the upper sediments. |
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| High Resolution Seismic Surveying for Pleistocene Sequence Stratigraphy New Jersey Continental Shelf and Upper Slope in Support of Strataform |
27 MAR 97 |
5 pages |
| Authors:
Gregory Mountain; Peter Buhl; Kenneth Miller; LAMONT-DOHERTY EARTH OBSERVATORY PALISADES NY
|
| This contract provided support to plan, acquire, and process high resolution multichannel seismic reflection data offshore New Jersey during cruise 270 of the R/V Oceanus. This was part of the STRATAFORM initiative that seeks geologic and geophysical data on the continental terrace at temporal and spatial scales ranging from 0.1 to 100000 yrs and .01 to 1000 m. Our cruise objectives were to collect high resolution reflection images of stratal ... |
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| Continental Borderlands Shear Structure from Seafloor Compliance Measurements |
NOV 96 |
8 pages |
| Authors:
John A. Hildebrand; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| Shear properties are poorly known for shallow water sediments because of the difficulty of making direct measurements. Deformation from low frequency waves provides information about deep structure and from high frequency waves provides information about shallow structure. Seismic reflection profiles of several major faults in this area have revealed that they are actively deforming young sediments. As the sediments are uplifted or compressed, their pore-water content may be significantly altered; ... |
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| ULF/VLF Noise on Basalt and Sediment (NOBS) |
OCT 96 |
10 pages |
| Authors:
Leroy M. Dorman; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| This experiment undertook a comparison between noise and seismic signal fields on seafloor of two different structural types. Arrays of newly constructed ONR OBS's were deployed on the flanks of the Gorda Ridge, Juan De Fuca Ridge, and in the Cascadia Basin. These instruments made simultaneous observations of seafloor noise, in addition to some earthquakes. The primary question addressed was 'Is seafloor noise smaller at hard-bottom (basalt) seafloor sites than ... |
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| Bottom Grain Gas and Roughness Technique (BOGGART) Version 3.0: Bottom Backscatter Model User's Guide |
04 JUN 96 |
46 pages |
| Authors:
Frank A. Boyle; Nicholas P. Chotiros; TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS
|
| A user's guide has been developed for BOGGART, a model for acoustic backscatter from marine sediments, developed at Applied Research Laboratories, The University of Texas at Austin (ARL:UT), with support from the Naval Research Laboratory at Stennis Space Center (NRL/SSC). The model, named for bottom grain gas and roughness technique, computes the total backscattering strength as an incoherent sum of contributions from three components. They are (1) scattering from sediment ... |
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| The Form of Organic Matter in the Muddy Sediments Near Eckernfoerde Bay, Germany |
31 MAR 96 |
11 pages |
| Authors:
Yoko Furukawa; UNIVERSITY OF SOUTHERN MISSISSIPPI STENNIS SPACE CENTER CENTER FOR MARINE SCI ENCE
|
| Organic matter (OM) is one of the most important components in the seafloor sediments in Eckemfoerde Bay, Germany. The GM accounts for up to 10 weight % of sediments in some parts of the Bay. Because GM is relatively low in density and often hydrophilic, its role in defining the sediment structure and microfabric can be significant. Therefore, it is important to understand the form of GM in the sediments. ... |
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| Bottom Classification by QTC View Near the Dry Tortugas |
MAR 96 |
70 pages |
| Authors:
Bill Collins; Brad Prager; QUESTER TANGENT CORP SIDNEY (BRITISH COLUMBIA) MARINE TECHNOLOGY CENTRE
|
| The research described in this report represents an important step forward in the development of seabed classification technology. First, it represents the application of the QTC VIEW technology to a new seabed environment. The data sets analyzed here involve reef seabeds which have not previously been studied. Second, they represent a consistent effort to compare the results obtained by using two different frequencies of sounder over the same seabed type. ... |
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| Multiple Scatter Theory of Ocean Sediments II |
FEB 96 |
5 pages |
| Authors:
Nicholas P. Chotiros; TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS
|
| The long term goals are to develop a new model of acoustic bottom backscatter from sandy sediments, based on a multiple scattering theory approach, and hence, properly explain observed phenomena, including Lambert's rule and frequency dependence of backscattering strength, particularly at shallow grazing angles, for which current theories are at a loss. |
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| Geoacoustic Study of Delaware Atlantic Coast from Cape Henlopen to Fenwick Island |
NOV 95 |
354 pages |
| Authors:
Richard G. McGee; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS LAB
|
| A comprehensive geoacoustic study has been performed for a 3-mile- wide area offshore of the Delaware coast between Cape Henlopen and Fenwick Island for the purpose of defining the limits of available granular materials. The work was performed in support of the U.S. Army Engineer District, Philadelphia's, feasibility study for shore protection solutions for the Atlantic coast of Delaware. Specifically, the objective of this investigation was to quantify the bottom ... |
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| Sediment Classification and Bathymetry Data Acquired from the AN/UQN-4 Depth Sounder in Support of MTEDS |
25 OCT 95 |
55 pages |
| Authors:
Robert A. Altenburg; Karl W. Rehnn; Nicholas P. Chotiros; TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS
|
| A realtime system for the measurement of the bottom reflection coefficient using the AN/UQN-4 depth sounder was developed. Data provided by the system is transferred to the MTEDS database system where it is made available to the Acoustic Sediment Classification System (ASCS). In addition to the bottom reflection coefficient, the system also provides time and ship's position from a built-in GPS receiver, and depth data for the MTEDS database. Three ... |
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| Material Properties Related to Navigation and Dredging: Summary Report for Technical Area 2 |
SEP 95 |
81 pages |
| Authors:
Lyndell Z. Hales; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
|
| This report summarizes research conducted by the Dredging Research Program, Technical Area 2, Material Properties Related to Navigation and Dredging. Goals of Technical Area 2 were to develop new instrumentation and technology for more thorough subsurface investigations at dredging projects and to refine descriptors for better communication of knowledge from Corps geotechnical engineers to dredging contractors. |
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| Selected Topics in Coastal and Ocean Technology |
01 AUG 95 |
114 pages |
| Authors:
Scott A. Jenkins; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
|
| This final report details research in three major areas: (1) sedimentation control in harbors and waterways. (2) wave structure interaction for a novel tetrahedron sandbag structural concept and (3) tactical oceanography involving development of an optimum glide theory for low speed submarine operations. The sedimentation control research focused on understanding the mechanics of bed shear strength and explored new methods to elevate the bottom shear stress to induce erosion of ... |
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| A Technique to Assess the Characteristics of Bottom and Subbottom Marine Sediments |
MAR 95 |
178 pages |
| Authors:
Richard G. McGee; Robert F. Ballard Jr.; David D. Caulfield; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
|
| This report presents the theoretical concept, assembly, and field testing of a waterborne seismic acoustic impedance technique which has been developed to characterize bottom and subbottom sediments as they relate to removal by dredging. This method, developed under the Dredging Research Program (DRP), provides estimates of in situ density and soil type in a rapid, cost effective manner using digital acoustic subbottom profiling methodology. In situ densities obtained by the ... |
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| Design Guide for Pile-Driven Plate Anchors |
MAR 95 |
57 pages |
| Authors:
James Forrest; Robert Taylor; Lora Bowman; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
|
| A user guide is presented for designing and installing plate anchors in the sea bottom using conventional pile driving techniques. This permits use of low cost, highly efficient, mooring anchors to meet a broad range of mooring requirements, including hurricane moorings for ships or other floating structures. This technique is particularly appropriate for heavily congested or confined areas. The anchors are suitable for various bottom deposits, including soft organic silts, ... |
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| Tidal Constituent Database. West Coast of the United States and Eastern North Pacific Ocean |
JAN 95 |
12 pages |
| Authors:
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
|
| This technical note describes a database of tidal elevation boundary condition information generated in support of the 'Long-Term Fate of Dredged Material Disposed in Open Water' research of the Dredging Research Program (DRP) , being conducted at the U.S. Army Engineer Waterways Experiment Station. The database, described in detail by Hench and others (1994), allows the user to manually generate time series of tidal elevations or to use a program ... |
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| High-Frequency Acoustic Scattering from Sediment Interface Roughness and Volume Inhomogeneities |
05 DEC 94 |
156 pages |
| Authors:
Kevin B. Briggs; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| High-frequency acoustic and geoacoustic data from five experiment sites with different sediment types are compared with predictions from the composite roughness model to ascertain the relative contribution of interface roughness and sediment volume scattering. Model fits to backscattering data from silty sediments indicate that volume scattering predominates, but measured bottom roughness was sufficient to explain the backscattering measured from a rippled, sandy sediment. Fluctuations in sediment porosity and sound velocity ... |
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| RECOVERY, A Mathematical Model to Predict the Temporal Response of Surface Water to Contaminated Sediments |
NOV 94 |
63 pages |
| Authors:
Jean M. Boyer; Steven C. Chapra; Carlos E. Ruiz; Mark S. Dortch; ARMY FOREIGN SCIENCE AND TECHNOLOGY CENTER CHARLOTTESVILLE VA
|
| RECOVERY is a PC-based screening-level model to assess the impact of contaminated bottom sediments on surface waters. The analysis is limited to organic contaminants with the assumption that the water column is well mixed. The contaminant is assumed to follow linear, reversible, equilibrium sorption and first-order decay kinetics. The physical representation of a system by RECOVERY consists of a well-mixed water column (i.e., zero- dimensional) underlain by a vertically stratified ... |
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| A Waterborne Seismic Reflection Survey of Three Tributaries in Boston Harbor, Massachusetts |
AUG 94 |
235 pages |
| Authors:
Keith J. Sjostrom; Rodney L. Leist; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB
|
| A waterborne seismic reflection and side scan sonar survey of three tributaries to Boston Harbor, Massachusetts, is reported. The geophysical studies were performed in the Mystic and Chelsea Rivers, Reserved Channel, and the Inner Confluence Area in order to characterize and quantify bottom and subbottom sediments in support of proposed channel deepening. Two high resolution subbottom profiling systems with specially designed data acquisition and analysis software packages were utilized to ... |
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| Installation of Vertical Strip Drains to Increase Storage Capacity of Craney Island Dredged Material Management Area |
MAY 94 |
72 pages |
| Authors:
Timothy D. Stark; Thomas A. Williamson; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB
|
| This study investigates the feasibility of installing vertical strip drains to increase the storage capacity of the Craney Island Dredged Material Management Area. The installation of vertical strip drains in the disposal area is technically feasible and will accelerate consolidation of the dredged fill and underlying marine clay. This consolidation will result in a rapid increase in storage capacity and soil shear strength. The shear strength gain will allow the ... |
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| Multiple Scatter Theory of Ocean Sediments |
25 APR 94 |
7 pages |
| Authors:
Nicholas P. Chotiros; TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS
|
| The long term goal was to develop a new model of acoustic bottom backscatter from sandy sediments, based on a multiple scattering theory approach, and, hence, properly explain observed phenomena, including Lambert's rule and frequency dependence of backscattering strength, particularly at shallow grazing angles, for which current theories are at a loss. |
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| Descriptions of WHOI Sediment Cores. Volume 8 |
MAY 93 |
|
| Authors:
P. B. Mills; J. E. Broda; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| The report contains visual descriptions and smear slide analyses for several suites of cores received in the geological samples collection of the Woods Hole Oceanographic Institution between mid-1984 and late 1989. Approximately 220 sample localities from the North Atlantic. South Atlantic, Mediterranean and Pacific Oceans are represented. Charts of ships tracks for cruises included in this report and updated computer listings of all cores in the W.H.O.I. collection are also ... |
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| Environmental Effects of Dredging. Determining the Developmental Status of Sediment Toxicity Bioassays |
DEC 92 |
13 pages |
| Authors:
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB
|
| This technical note describes events in the generic development of sediment toxicity bioassays for the evaluation of dredged material under section 103 of the Marine Protection, Research, and Sanctuaries Act of 1972 (Public Law 92- 532) and section 404(b)(1) of the Federal Water Pollution Control Act of 1972 (Public Law 92-500), as amended. This technical note was written for four reasons. The first was to facilitate determining the technical progress ... |
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| Characterization of the Bottom Sediment Velocity-Depth Relationship for the Somali Basin and the Arabian Sea |
JUN 92 |
148 pages |
| Authors:
Nelson J. LeTourneau; NAVAL OCEANOGRAPHIC OFFICE STENNIS SPACE CENTER MS
|
| In the study and modeling of sound propagation of the ocean bottom, one of the most important parameters is the velocity of sound versus depth in the bottom. To provide this parameter in the Somali Basin and the Arabian Sea, each area was sampled with velocity-depth measurements by the wide-angle bottom reflection method. Sediment surface sound velocity and bottom water sound velocity were collected as supporting data. From these data, ... |
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| Deep-Tow Acoustics/Geophysics System Compressional Velocity Database |
MAY 92 |
22 pages |
| Authors:
M. M. Rowe; J. F. Gettrust; NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS
|
| This technical note describes the Deep-Tow Acoustics/Geophysics System (DTAGS) compressional velocity database, a compilation of compressional velocity functions derived from DTAGS deep-tow multichannel seismic data. Three geologically distinct areas are represented by the velocity functions included in this database: thick turbidites on the Bermuda Rise, fine grained terrigenous sediments containing methane hydrate on the Blake Outer Ridge, and thin sediments overlying young basement near the Juan de Fuca Ridge. Horizontal ... |
|
| Seabed-Structure Interaction: Workshop Report and Recommendations for Future Research Held in Metairie, Louisiana on 5-6 November 1991 |
FEB 92 |
28 pages |
| Authors:
R. H. Bennett; NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS
|
| Intrinsic to the topic of Seabed-Structure Interaction (S-SI) of objects coupled with the seafloor is the dynamics of the 'system.' The dynamics involve environmental forcing of the object and the seabed, the fundamental properties of the geological material, the size an shape of the object, and the time-dependent processes associated with the coupling of the water column, seabed, and the object. Thus, the most crucial S-Sl research problems to address ... |
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| Geotechnical Properties of Periplatform Carbonate Sediments |
JUL 90 |
|
| Authors:
Dawn L. Lavoie; NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS
|
|
| Experiments and Analysis of Data on Shear Wave Propagation in Shallow Water Sediments |
01 JUN 90 |
|
| Authors:
George H. Sutton; RONDOUT ASSOCIATES INC STONE RIDGE NY
|
| This research is to determine the physical parameters that control acoustic propagation in shallow water and their relationship to geological structure and processes to improve acoustic monitoring capability. Specific objectives were to develop instrumentation, field, procedures, and data inversion methods required for efficient high resolution determination of elastic parameters of bottom sediments as functions of depth and location, and to evaluate effects of lateral heterogeneity and anisotropy. Bottom mounted sources ... |
|
| Compressional Wave/Shear Wave Seismo-Acoustic Probe |
30 APR 90 |
|
| Authors:
Thomas E. Owen; SOUTHWEST RESEARCH INST SAN ANTONIO TX
|
| The prototype seismo-acoustic probe represents the first version of a self-penetrating seabed probe system designed to measure the compressional and shear wave parameters of the seabed sediment. Several new and untried technical features and operating concepts were incorporated in this design to achieve the desired measurement objectives. Taking these broad factors into account, the basic probe system design has good technical merit and a very good potential for becoming a ... |
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| Dynamic Soil-Structure Interaction Behavior on the Seafloor |
AUG 88 |
|
| Authors:
Philip J. Valent; Richard H. Bennett; Wayne A. Dunlap; NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS
|
| Dynamic Soil-Structure Interaction (S-SI) behavior on the seafloor describes the coupling of a structure and the seabed and their combined response to the influence of waves and currents and the material properties of the seafloor. S-SI problems are significant to the Navy when structures placed on the seafloor must be recovered promptly, maintain position (such as no lateral movement), maintain stability (such as not bury or tilt), and not be ... |
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| Use of Seabed Drifters for Locating and Monitoring Dredged Material Placement Sites. Environmental Effects of Dredging |
MAR 88 |
12 pages |
| Authors:
James E. Clausner; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB
|
| The purpose of this note provides information on using seabed drifters (SBDs) to help locate optimum sites for placing dredged material, for both nearshore berms (feeder berms) and offshore mounds (stable berms). In addition, guidance is given for using SBI)s to monitor potential sediment transport pathways at existing dredged material placement sites. Some of the information provided is based on results from DUCK 85 and SUPERDUCK, two large coastal processes ... |
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| Shallow Seismic Experiments Using Shear Waves |
JAN 88 |
|
| Authors:
R. D. Stoll; G. M. Bryan; R. Flood; D. Chayes; P. Manley; LAMONT-DOHERTY GEOLOGICAL OBSERVATORY PALISADES NY
|
| During the summer of 1986, a series of seismo-acoustic experiments was carried out in shallow water off the New Jersey shore. The purpose of these experiments was to measure the geoacoustic properties of the ocean sediments that comprise the upper few hundred meters of the sediment column. Seismic sources and receivers were deployed at or very near the bottom in order to excite shear waves in the sediment and minimize ... |
|
| A Lee Wave Model for Deep-Sea Mudwave Activity |
88 |
|
| Authors:
Roger D. Flood; LAMONT-DOHERTY GEOLOGICAL OBSERVATORY PALISADES NY
|
| Mudwaves, with wavelengths up to 6 km and heights up to 100 m, are commonly found in the deep sea where steady, sediment-laden currents are present; their internal structure suggests that they have migrated with time. Lee waves appear to be generated in the density gradient above the sinusoidal mudwave topography; the near-bottom flow field associated with the lee waves creates a cross-wave asymmetry in bottom current velocity. A model ... |
|
| Velocity and Attenuation Profiles in the Monterey Deep-Sea Fan |
DEC 87 |
|
| Authors:
Richard K. Brienzo; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| Data obtained during a refraction experiment is used to estimate velocity and attenuation profiles in an area of thick sediments (2.5 -3 km). A vertical hydrophone array was deployed at mid-depth in 2800 meters of water. Estimates of velocity as a function of depth, and attenuation as a function of frequency and depth are obtained from an analysis of the pressure time series generated by the explosive charges and received ... |
|
| Low Frequency Seismo-Acoustic Propagation in a Sloping Ocean Environment: Measured Results and Numerical Predictions |
NOV 87 |
|
| Authors:
Hassan B. Ali; L. D. Bibee; Mona J. Authement; Ralph A. Stephen; Jeff Becklehimer; NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY NSTL STATION MS
|
| As part of continuing program to investigate the characteristics of acoustic propagation and ambient noise in the very low frequency regime (20 Hz and less). Ninety -seven experiments were conducted off the Southeastern coast of the U.S. (Cape Fear) in 1985. Preliminary results of the Cape Fear data analysis have already shed some light on seismo-acoustic propagation. At the source-receiver ranges thus far considered, considerable penetration into the bottom is ... |
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| Particle Flux in the Western Black Sea in the Present and over the Last 5,000 Years: Temporal Variability, Sources, Transport Mechanisms |
SEP 87 |
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| Authors:
Bernward J. Hay; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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| The particle flux in the present and over the last 5,000 years was investigated in the western Black Sea in a comparative study with samples from time-series sediment traps and laminated core sediments. The particle flux varies considerably seasonally and regionally. Dominant particle sources are biogenic and terrigenous matter. The relative importance in the particle supply varies seasonally and can be grouped into three phases: Phase I (June-October; coccolithophorid production); ... |
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| Selected Papers on Ocean-Seismo Acoustics Low-Frequency Underwater Acoustics Based on the SACLANTCEN Contributions to a Symposium Held by SACLANTCEN on 10-14 June 985 |
JUN 86 |
109 pages |
| Authors:
Tuncay Akal; Johathan M. Berkson; SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)
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| CONTENTS: Time dependence of infrasonic ambient seafloor noise on a continental shelf; The use of Love waves to determine the geoacoustic properties of marine sediments; Medium induced low frequency fluctuations in acoustic transmission loss; Directional measurements of low frequency acoustic backscattering from the seafloor; Shear properties of ocean sediments determined from numerical modelling of Scholte wave data; Evaluation of low frequency bottom backscattering strength vs grazing angle by means of ... |
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*OCEAN BOTTOM SOILS
