Sample records for submarine base bangor

  1. Evaluation of Freshwater Aquatic Resources and Stormwater Management at U.S. Naval Submarine Base, Bangor, Washington

    National Research Council Canada - National Science Library

    May, Christopher


    Surface and storm water conditions on the Naval Submarine Base (NSB), Bangor, Washington, are evaluated, and recommendations are made to improve water quality and enhance the ecological integrity of aquatic resources located on the base...

  2. Trident Biological Surveys: Naval Submarine Base Bangor, Washington (1979, 1980 & 1981) Summary Report. Supplement 3 (United States)


    Relationships in the Eastern Oyster (Crassostrea virginica) to Detect Heavy Metal Pollution, Water Research, vol 7, p 451 -460, 1973 43Jenkins, DW...Metal Pollution, Water Research, vol 7, p 451 -460, 1973. 86 43. Jenkins, DW, Biological Monitoring of Toxic Trace Metals: Biological Monitoring and...when water temperatures are favorably warm (usually about 67 degrees Farenheit ). For normal growth of oyster larvae during the fast several weeks of

  3. Management of demand based inventory aboard submarine tenders servicing attack (SSN) submarines


    Ross, Timothy Joseph


    Approved for public release; distribution is unlimited. This thesis examines the computation of inventory levels based on demand history aboard Submarine Tenders that use the Shipboard Automated Data Processing System (SUADPS) for inventory control. The focus of the thesis was the workload and supply effectiveness issues associated with the processing of the SUADPS levels setting program. The objective of the thesis was to determine the effect on supply effectiveness and stock churn if the...

  4. 75 FR 1546 - Television Broadcasting Services; Bangor, ME (United States)


    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; Bangor, ME AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Commission has before it a petition for rulemaking filed by...

  5. Submarine hydrodynamics

    CERN Document Server

    Renilson, Martin


    This book adopts a practical approach and presents recent research together with applications in real submarine design and operation. Topics covered include hydrostatics, manoeuvring, resistance and propulsion of submarines. The author briefly reviews basic concepts in ship hydrodynamics and goes on to show how they are applied to submarines, including a look at the use of physical model experiments. The issues associated with manoeuvring in both the horizontal and vertical planes are explained, and readers will discover suggested criteria for stability, along with rudder and hydroplane effectiveness. The book includes a section on appendage design which includes information on sail design, different arrangements of bow planes and alternative stern configurations. Other themes explored in this book include hydro-acoustic performance, the components of resistance and the effect of hull shape. Readers will value the author’s applied experience as well as the empirical expressions that are presented for use a...

  6. From nuclear submarines to graduate medical education: applying David Marquet’s intent-based leadership model


    Fernandez-Salvador, Camilo; Oney, Rebecca; Song, Sungjin A.; Camacho, Macario


    L. David Marquet, a decorated Navy Captain, transformed an underperforming submarine crew by empowering his subordinates to be leaders and reach their full potential. He called this intent-based leadership (IBL). What would happen if Marquet’s model were implemented in Graduate Medical Education (GME)? In this letter to the editor, we summarize the potential of the IBL model in graduate medical education as opposed to the traditional leader-follower method. IBL harnesses human productivity to...

  7. Submarine Medicine Team (United States)

    Federal Laboratory Consortium — The Submarine Medicine Team conducts basic and applied research on biomedical aspects of submarine and diving environments. It focuses on ways to optimize the health...

  8. A biodetrital coral mound complex: Key to early diagenetic processes in the mississippian bangor limestone (United States)

    Haywick, D.W.; Kopaska-Merkel, D. C.; Bersch, M.G.


    The Bangor Limestone is a Mississippian (Chesterian) shallow marine carbonate formation exposed over a large portion of the Interior Low Plateaus province of northern Alabama. It is dominated by oolitic grainstone and skeletal wackestone and packstone, but in one outcrop near Moulton, Alabama, the Bangor contains a five m thick, 25 m wide, oolitebiodetrital moundtidal flat succession. This sequence is interpreted as a 4th order sea level cycle. Four petrofacies (oolite, mound, skeletal and mudstone/dolomicrite) and four diagenetic phases (iron oxide, fibrous calcite cement, calcite spar cement and dolomite) are distinguished at the study site. Iron oxide, a minor component, stained and/or coated some ooids, intraclasts and skeletal components in the oolite petrofacies. Many of the allochems were stained prior to secondary cortical growth suggesting a short period of subaerial exposure during oolite sedimentation. The oolite petrofacies also contains minor amounts of fibrous calcite cement, a first generation marine cement, and rare infiltrated micrite that might represent a second phase of marine cement, or a first phase of meteoric cement (i.e., "vadose silt") (Dunham 1969). Intergranular pore space in all four petrofacies is filled with up to three phases of meteoric calcite spar cement. The most complete record of meteoric cementation is preserved within coralline void spaces in the mound petrofacies and indicates precipitation in the following order: (1) non-ferroan scalenohedral spar, (2) ferroan drusy spar (0.1-0.4 wt% Fe2+) and (3) non-ferroan drusy spar. The first scalenohedral phase of meteoric cement is distributed throughout the oolite and mound petrofacies. The ferroan phase of meteoric calcite is a void-filling cement that is abundant in the mound petrofacies and less common in the skeletal and mudstone/dolomicrite petrofacies. Non-ferroan drusy calcite is pervasive throughout the Bangor Limestone at the Moulton study site. Growth of the fourth

  9. SSN 774 Virginia Class Submarine (SSN 774) (United States)


    Report: The VIRGINIA Class Submarine Program continues to deliver submarines within cost, ahead of schedule , with improved quality and with...baseline schedule threshold set ten years earlier, in 1994. June 20, 2006: USS TEXAS, which was essentially the second lead ship of the class , is the first...factored for the VIRGINIA Class based on weight. Public and private shipyard data was used, as well as the maintenance schedule provided in the CARD, Rev E

  10. Low cost submarine robot


    Ponlachart Chotikarn; Werapong Koedsin; Boonlua Phongdara; Pattara Aiyarak


    A submarine robot is a semi-autonomous submarine robot used mainly for marine environmental research. We aim todevelop a low cost, semi-autonomous submarine robot which is able to travel underwater. The robot’s structure was designedand patented using a novel idea of the diving system employing a volume adjustment mechanism to vary the robot’s density.A light weight, flexibility and small structure provided by PVC can be used to construct the torpedo-liked shape robot.Hydraulic seal and O-rin...

  11. Low cost submarine robot

    Directory of Open Access Journals (Sweden)

    Ponlachart Chotikarn


    Full Text Available A submarine robot is a semi-autonomous submarine robot used mainly for marine environmental research. We aim todevelop a low cost, semi-autonomous submarine robot which is able to travel underwater. The robot’s structure was designedand patented using a novel idea of the diving system employing a volume adjustment mechanism to vary the robot’s density.A light weight, flexibility and small structure provided by PVC can be used to construct the torpedo-liked shape robot.Hydraulic seal and O-ring rubbers are used to prevent water leaking. This robot is controlled by a wired communicationsystem.

  12. Evaluation of the Bangor Dyslexia Test (BDT) for use with Adults. (United States)

    Reynolds, Andrea Elaine; Caravolas, Markéta


    The Bangor Dyslexia Test (BDT) is a short, easy-to-administer screener for use with a broad age range, which has been in use in the UK for over three decades. A distinctive feature of the battery is its focus on skills requiring aspects of verbal and phonological processing without, however, measuring literacy skills per se. Despite its longstanding existence and usage, there has been no evaluation of the psychometric properties of the battery as an adult dyslexia screener. We examined the psychometric properties of the BDT and evaluated its capacity to discriminate between adults with and without dyslexia. A large archival sample of university students with dyslexia (n = 193) and students with no reported literacy difficulties (n = 40) were compared on the BDT as well as on literacy and cognitive measures. Statistical analyses revealed the BDT to be a reliable (α = .72) and valid dyslexia screening tool with the capacity to effectively identify adults at risk of the disorder with an overall classification rate of 94% (sensitivity 96.4% and specificity 82.5%). In addition, higher indices of dyslexia risk on the BDT were associated with lower scores on standardized measures of literacy. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Index of Submarine Medical Officer’s Qualification Theses 1944-1974 (United States)



  14. Ra Tracer-Based Study of Submarine Groundwater Discharge and Associated Nutrient Fluxes into the Bohai Sea, China: A Highly Human-Affected Marginal Sea (United States)

    Liu, Jianan; Du, Jinzhou; Yi, Lixin


    Nutrient concentrations in coastal bays and estuaries are strongly influenced by not only riverine input but also submarine groundwater discharge (SGD). Here we estimate the SGD and the fluxes of the associated dissolved inorganic nitrogen (DIN), phosphorus (DIP), and silicon (DSi) into the Bohai Sea based on a 226Ra and 228Ra mass balance model. This procedure shows that in the Bohai Sea the average radium activities (dpm 100 L-1) are 42.8 ± 6.3 (226Ra) and 212 ± 41.7 (228Ra) for the surface water and 43.0 ± 6.1 (226Ra) and 216 ± 38.4 (228Ra) for the near-bottom water. According to the 228Ra/226Ra age model, the residence time in the Bohai Sea is calculated to be 1.7 ± 0.8 yrs. The mass balance of 226Ra and 228Ra suggests that the yearly SGD flux into the whole Bohai Sea is (2.0 ± 1.3) × 1011 m3 yr-1, of which the percentage of submarine fresh groundwater discharge (SFGD) to the total SGD is approximately (5.1 ± 4.1)%. However, the DIN and DSi fluxes from SFGD constitute 29% and 10%, respectively, of the total fluxes from the SGD. Moreover, nutrient loads, which exhibit high DIN/DIP from SGD, especially the SFGD, may substantially contribute to the nutrient supplies, resulting in the occurrence of red tide in the Bohai Sea.

  15. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin


    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  16. A new model for turbidity current behavior based on integration of flow monitoring and precision coring in a submarine canyon (United States)

    Symons, William O.; Sumner, Esther J.; Paull, Charles K.; Cartigny, Matthieu J.B.; Xu, Jingping; Maier, Katherine L.; Lorenson, Thomas; Talling, Peter J.


    Submarine turbidity currents create some of the largest sediment accumulations on Earth, yet there are few direct measurements of these flows. Instead, most of our understanding of turbidity currents results from analyzing their deposits in the sedimentary record. However, the lack of direct flow measurements means that there is considerable debate regarding how to interpret flow properties from ancient deposits. This novel study combines detailed flow monitoring with unusually precisely located cores at different heights, and multiple locations, within the Monterey submarine canyon, offshore California, USA. Dating demonstrates that the cores include the time interval that flows were monitored in the canyon, albeit individual layers cannot be tied to specific flows. There is good correlation between grain sizes collected by traps within the flow and grain sizes measured in cores from similar heights on the canyon walls. Synthesis of flow and deposit data suggests that turbidity currents sourced from the upper reaches of Monterey Canyon comprise three flow phases. Initially, a thin (38–50 m) powerful flow in the upper canyon can transport, tilt, and break the most proximal moorings and deposit chaotic sands and gravel on the canyon floor. The initially thin flow front then thickens and deposits interbedded sands and silty muds on the canyon walls as much as 62 m above the canyon floor. Finally, the flow thickens along its length, thus lofting silty mud and depositing it at greater altitudes than the previous deposits and in excess of 70 m altitude.

  17. Submarines, spacecraft and exhaled breath. (United States)

    Pleil, Joachim D; Hansel, Armin


    important concern is a suite of products from chemical reactions among oxidizing compounds with biological chemicals such as amines, thiols and carbonyls. SAMAP Meeting We (Armin and Joachim) attended the 2011 SAMAP conference in Taranto, Italy (10-14 October), which occurred just a few weeks after the IABR meeting in Parma, Italy (11-15 September 2011). It was held at the Officers' Club of the Taranto Naval Base under the patronage of the Italian navy; the local host was Lucio Ricciardi of the University of Insubria, Varese, Italy. At the 2011 SAMAP meeting, the theme was air-independent propulsion (AIP), meaning the capability of recharging the main batteries of the submarine without the need to surface. Only a few navies (e.g. US, UK, France, Russia, China) have historically had this capability using nuclear-powered submarines that can function underwater for extended periods of time (months). Most navies operate submarines with conventional diesel-electric propulsion, wherein diesel-powered generators charge battery banks which then drive an electric motor connected to the propeller. The batteries are charged while the boat is on the surface or during snorkelling, when the boat is submerged a few meters below the surface and a snorkel tube is extended to the surface. The period between battery charges can vary from several hours to one or two days depending on the power requirements and the nature of the mission. The process is necessary for breathing air revitalization (flushing out accumulated contaminants) and for the operation of the diesel engines. However, during this period the submarine is vulnerable to detection. Since the 1940s there have been various attempts to develop a power generation system that is independent of external air (AIP). To this end hydrogen peroxide was initially used and later liquid oxygen (LOX). Currently, most AIP submarines use fuel cell technology (LOX and hydrogen) to supplement the conventional diesel-electric system in order to

  18. Geomorphic process fingerprints in submarine canyons (United States)

    Brothers, Daniel S.; ten Brink, Uri S.; Andrews, Brian D.; Chaytor, Jason D.; Twichell, David C.


    Submarine canyons are common features of continental margins worldwide. They are conduits that funnel vast quantities of sediment from the continents to the deep sea. Though it is known that submarine canyons form primarily from erosion induced by submarine sediment flows, we currently lack quantitative, empirically based expressions that describe the morphology of submarine canyon networks. Multibeam bathymetry data along the entire passive US Atlantic margin (USAM) and along the active central California margin near Monterey Bay provide an opportunity to examine the fine-scale morphology of 171 slope-sourced canyons. Log–log regression analyses of canyon thalweg gradient (S) versus up-canyon catchment area (A) are used to examine linkages between morphological domains and the generation and evolution of submarine sediment flows. For example, canyon reaches of the upper continental slope are characterized by steep, linear and/or convex longitudinal profiles, whereas reaches farther down canyon have distinctly concave longitudinal profiles. The transition between these geomorphic domains is inferred to represent the downslope transformation of debris flows into erosive, canyon-flushing turbidity flows. Over geologic timescales this process appears to leave behind a predictable geomorphic fingerprint that is dependent on the catchment area of the canyon head. Catchment area, in turn, may be a proxy for the volume of sediment released during geomorphically significant failures along the upper continental slope. Focused studies of slope-sourced submarine canyons may provide new insights into the relationships between fine-scale canyon morphology and down-canyon changes in sediment flow dynamics.

  19. Managing integrity of submarine gas pipeline based on the application of ASME B31.8-S standard

    Energy Technology Data Exchange (ETDEWEB)

    Wisianto, A. [Pertamina, West Java (Indonesia)


    Pertamina operates the East Java Gas Pipeline (EJGP) in Indonesia. The pipeline, which consists of offshore and onshore sections, began operation in 1994. This paper addressed the benefit of pipeline integrity management (PIM) for both onshore and offshore operations. Pertamina has considered adopting the ASME B31.8S onshore guideline for its submarine pipelines. The standard contains both technical and non-technical aspects, as well as a structured methodology which can help the operator in developing a comprehensive PIM and conducting remedial work. The intention of PIM is to prevent integrity problems from creating a significant impact on public safety, the environment and business operations. Pertamina has gathered data, identified potential hazards, performed risk assessments, surveys and engineering analysis in order to achieve high reliability, life extension, optimum cost and minimum lifecycle cost. A corrosion survey conducted by Pertamina on the EJGP revealed that the external corrosion protection is still in good condition and the remaining lifetime of the anode is more than 30 years. However, an in-line inspection will be conducted in the near future to increase the confidence level of corrosion protection. 10 refs., 2 tabs., 5 figs.

  20. Are tilt measurements useful in detecting tsunamigenic submarine landslides?


    Sascha Brune; Andrey Babeyko; Stephan V. Sobolev


    Large submarine landslides can generate dangerous tsunamis. Because of their long-period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land-based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like ...

  1. SCICEX: Submarine Arctic Science Program (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  2. The Submarine, 1776-1918

    National Research Council Canada - National Science Library

    Uhlig, Frank


    When, on 11 April 1900, the U.S. Navy thought the Holland, named for its designer, that little submarine joined a fleet consisting of two armored cruisers, six monitors, seven first and second-class battleships, and seventeen each...

  3. 78 FR 53109 - Security Zones; Naval Base Point Loma; Naval Mine Anti-Submarine Warfare Command; San Diego Bay... (United States)


    ... at Naval Base Point Loma to support the construction of a new Naval fuel pier. In addition to the... security zone for the Naval Base Point Loma Fuel Pier construction and the establishment of a security zone... program during the construction phase of the new fuel pier. The extended security zone at Naval Base Point...

  4. Submarine Information Organization and Prioritization and Submarine Officer of the Deck Experience (United States)


    The Submarine Review, 58-64. Shobe, K. (2002, May). Information organization and modeling of the submarine officer of the deck and sonar operator...Technical Report 01Oct00 - 31Sep02 SUBMARINE INFORMATION ORGANIZATION AND PRIORITIZATION AND SUBMARINE OFFICER OF THE DECK EXPERIENCE 51001 1) Katharine K

  5. Enhancing Submarine Operational Relevance: A Leadership Challenge

    National Research Council Canada - National Science Library

    Daigle, Jr, Michael J


    .... This vision of submarine operations must change. As the military continues to shift to operations focused on joint capabilities, the submarine force must break from the closed, protective, and risk averse culture of its past and push forward...

  6. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  7. Relationship between work stress and health in submariners

    Directory of Open Access Journals (Sweden)

    Nan-nan JIANG


    Full Text Available Objective To explore the relationship between work stress and health in submariners. Methods In April 2008, 272 submariners trained in a navy base were selected as study subjects by random group sampling method, and tested by primary personal information questionnaire, self-rated health measurement scale (SRHMS, self-developed submariners' work stressors questionnaire, and work stress self-rated scale. Physical health, mental health and social health of submariners were analyzed, and scores were compared with the norm of reference scores. Correlations were analyzed respectively between 10 items of submariners' general information (including age, length of military service, education degree, years at the present post, times of receiving awards, on-duty hours, off-duty hours, hours of sleep, lost days of leave, positive attitude to work and their physical health score, mental health score, social health score, total health score, as well as between 15 submariners' work stressors (including workrelated risks, diet problems, high temperature, humidity and noise in workplace, shortage of clean clothes, illness, losing contact with outside, lack of information about the task, lacking supports from family members, relationship problems, lack of involvement in task decisions, boring and dull work, on duty, heavy work, high quality of work, coping with unexpected threat and their physical health score, mental health score, social health score and total health score. Results No significant difference was found between submariners' SRHMS total score and the normal referenced score (t=0.56, P>0.05, but the physical health score and mental health score were significantly lower than normal referenced scores respectively (t=–2.172, P<0.05; t=–3.299, P<0.01, and the social health score was significantly higher than normal referenced score (t=9.331, P<0.001. The age, length of military service, years at present post of submariners were related

  8. Submarine groundwater discharge and nutrient loadings in Tolo Harbor, Hong Kong using multiple geotracer-based models, and their implications of red tide outbreaks. (United States)

    Luo, Xin; Jiao, Jiu Jimmy


    Multiple tracers, including radium quartet, (222)Rn and silica are used to quantify submarine groundwater discharge (SGD) into Tolo Harbor, Hong Kong in 2005 and 2011. Five geotracer models based on the end member model of (228)Ra and salinity and mass balance models of (226)Ra, (228)Ra, (222)Rn, and silica were established and all the models lead to an estimate of the SGD rate of the same order of magnitude. In 2005 and 2011, respectively, the averaged SGD based on these models is estimated to be ≈ 5.42 cm d(-1) and ≈2.66 cm d(-1), the SGD derived DIN loadings to be 3.5 × 10(5) mol d(-1) and 1.5 × 10(5) mol d(-1), and DIP loadings to be 6.2 × 10(3) mol d(-1) and 1.1 × 10(3) mol d(-1). Groundwater borne nutrients are 1-2 orders of magnitude larger than other nutrient sources and the interannual variation of nutrient concentration in the embayment is more influenced by the SGD derived loadings. Annual DIP concentrations in the harbor water is positively correlated with the precipitation and annual mean tidal range, and negatively correlated with evapotranspiration from 2000 to 2013. Climatologically driven SGD variability alters the SGD derived DIP loadings in this phosphate limited environment and may be the causative factor of interannual variability of red tide outbreaks from 2000 to 2013. Finally, a conceptual model is proposed to characterize the response of red tide outbreaks to climatological factors linked by SGD. The findings from this study shed light on the prediction of red tide outbreaks and coastal management of Tolo Harbor and similar coastal embayments elsewhere. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Submarine landslides on the north continental slope of the South China Sea (United States)

    Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping


    Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.

  10. North American Submarine Cable Association (NASCA) Submarine Cables (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data show the locations of in-service and out-of-service submarine cables that are owned by members of NASCA and located in U.S. territorial waters. More...

  11. Submarine geothermal resources (United States)

    Williams, D.L.


    Approximately 20% of the earth's heat loss (or 2 ?? 1012 cal/s) is released through 1% of the earth's surface area and takes the form of hydrothermal discharge from young (Pleistocene or younger) rocks adjacent to active seafloor-spreading centers and submarine volcanic areas. This amount is roughly equivalent to man's present gross energy consumption rate. A sub-seafloor geothermal reservoir, to be exploitable under future economic conditions, will have to be hot, porous, permeable, large, shallow, and near an energy-deficient, populated land mass. Furthermore, the energy must be recoverable using technology achievable at a competitive cost and numerous environmental, legal and institutional problems will have to be overcome. The highest-temperature reservoirs should be found adjacent to the zones of the seafloor extension or volcanism that are subject to high sedimentation rates. The relatively impermeable sediments reduce hydrothermal-discharge flow rates, forcing the heat to be either conducted away or released by high-temperature fluids, both of which lead to reservoir temperatures that can exceed 300??C. There is evidence that the oceanic crust is quite permeable and porous and that it was amenable to deep (3-5 km) penetration by seawater at least some time in the early stages of its evolution. Most of the heat escapes far from land, but there are notable exceptions. For example, in parts of the Gulf of California, thermal gradients in the bottom sediments exceed 1??C/m. In the coastal areas of the Gulf of California, where electricity and fresh water are at a premium, this potential resource lies in shallow water (< 200 m) and within sight of land. Other interesting areas include the Sea of Japan, the Sea of Okhotsk and the Andaman Sea along the margins of the western Pacific, the Tyrrhenian Sea west of Italy, and the southern California borderland and west flank of the Juan de Fuca Ridge off the west coast of the United States. Many questions remain to be

  12. Submarine canyons off Madras Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Submarine canyons off the coast of Madras, Tamil Nadu, India were studied during cruise of @iINS Kistna@@ as part of the IIOE programme They consist of hill-like projections and V-shaped valleys Their other features are also reported...

  13. Submarine fans: A critical retrospective (1950–2015

    Directory of Open Access Journals (Sweden)

    G. Shanmugam


    Full Text Available When we look back the contributions on submarine fans during the past 65 years (1950–2015, the empirical data on 21 modern submarine fans and 10 ancient deep-water systems, published by the results of the First COMFAN (Committee on FANs Meeting (Bouma et al., 1985a, have remained the single most significant compilation of data on submarine fans. The 1970s were the “heyday” of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal elements of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean (Bay of Bengal, and the East Sea (Korea. The Annot Sandstone (Eocene–Oligocene, exposed at Peira-Cava area, SE France, which served as the type locality for the “Bouma Sequence”, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite-fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970–2015, are discussed using modern and ancient systems. They are: (1 the classic submarine fan model with attached lobes, (2 the detached-lobe model, (3 the channel-levee complex without lobes, (4 the delta-fed ramp model, (5 the gully-lobe model, (6 the suprafan lobe model, (7 the depositional lobe model, (8 the fan lobe model, (9 the ponded lobe model, (10 the nine models based on grain size and sediment source, (11 the four fan models based on tectonic settings, (12 the Jackfork debrite model, (13 the basin-floor fan model, (14 supercritical and subcritical fans, and (15 the three types of fan reservoirs. Each model is unique

  14. Simulation of Wave-Plus-Current Scour beneath Submarine Pipelines

    DEFF Research Database (Denmark)

    Eltard-Larsen, Bjarke; Fuhrman, David R.; Sumer, B. Mutlu


    A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed and suspen...

  15. SCICEX: Submarine Arctic Science Program, Version 1 (United States)

    National Aeronautics and Space Administration — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  16. An ongoing large submarine landslide at the Japan trench (United States)

    Nitta, S.; Kasaya, T.; Miura, S.; Kawamura, K.


    This paper deals with an active submarine landslide on a landward trench slope in the Japan trench. Studied area is located on the upper terrace ranging from 400 to 1200 m in water depth, off Sendai, northeast Japan. We have surveyed in detail the seabed topography using a multi narrow beam (hereafter MBES) and a subbottom profiler (hereafter SBP) during the cruise MR12-E02 of R/V Mirai. The survey lines were 12 lines in N-S, and 3 lines in E-W, and situated in the region from 141°45'E, 37°40'N to 142°33'E, 38°32'N. Moreover, we used multi-channel seismic profile by the cruise KR04-10 of R/V Kairei in the interpretation of the SBP results. In general, horseshoe-shaped depressions of about 100 km wide along the trench slope are arrayed along the Japan trench. It has thought that they were formed by large submarine landslides, but we could not understand critically the relationship between the depressions and the submarine landslides. Based on the survey results, we found signals of an active submarine landslide in the depression as follows. 1) We observed arcuate-shaped lineaments, which are sub-parallel to a horseshoe-shaped depression. The lineaments concentrate in the south region from 38°N at about 20 km wide. These lineaments are formed by deformation structures as anticlines, synclines and normal fault sense displacements. 2) Most of the synclines and anticlines are not buried to form the lineaments. 3) Normal faults cutting about 1 km deep are observed in a multi-channel seismic profile. The normal faults are located just below the arcuate-shaped lineaments, and are tilted eastward being the downslope direction. It indicates a large submarine landslide. We concluded that the arcuate-shaped lineaments were generated by surface sediment movement with the submarine landsliding. We think that the submarine landslide of about 20 km wide and about 1 km thick move continuously down the landward trench slope. This would be the formation process of the horseshoe

  17. Submarine landslides: advances and challenges (United States)

    Locat, Jacques; Lee, Homa J.


    Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine mass movements. Except for the occurrence of turbidity currents, the aquatic environment (marine and fresh water) experiences the same type of mass failure as that found on land. Submarine mass movements, however, can have run-out distances in excess of 100 km, so their impact on any offshore activity needs to be integrated over a wide area. This great mobility of submarinemass movements is still not very well understood, particularly for cases like the far-reaching debris flows mapped on the Mississippi Fan and the large submarine rock avalanches found around many volcanic islands. A major challenge ahead is the integration of mass movement mechanics in an appropriate evaluation of the hazard so that proper risk assessment methodologies can be developed and implemented for various human activities offshore, including the development of natural resources and the establishment of reliable communication corridors. Key words : submarine slides, hazards, risk assessment, morphology, mobility, tsunami. Le dveloppement rcent de techniques de levs hydrograhiques pour les fonds marins nous a permis d'atteindre une qualit ingale dans la cartographie et la description des glissements sous marins. l'exception des courants de turbidit, on retrouve dans le domaine aquatique les mmes types de mouvements de terrain que sur terre. Par contre, les glissements sous-marins peuvent atteindre des distances excdant 100 km de telle sorte que leur impact sur les activits offshore doit tre pris en compte sur degrandes tendues. La grande mobilit des glissements sous-marins n'est pas encore bien comprise, comme pour le cas des coules dedbris cartographies sur le cne du Mississippi ainsi que pour les grandes avalanches rocheuses sous-marines retrouves au pourtour des les volcaniques. Un dfi majeur

  18. Did a "lucky shot" sink the submarine H.L. Hunley? (United States)

    Lance, Rachel M; Warder, Henry; Bass, Cameron R Dale


    The H.L. Hunley was the first submarine to be successful in combat, sinking the Union vessel Housatonic outside Charleston Harbor in 1864 during the Civil War. However, despite marking a milestone in military history, little is known about this vessel or why it sank. One popular theory is the "lucky shot" theory: the hypothesis that small arms fire from the crew of the Housatonic may have sufficiently damaged the submarine to sink it. However, ballistic experiments with cast iron samples, analysis of historical experiments firing Civil War-era projectiles at cast iron samples, and calculation of the tidal currents and sinking trajectory of the submarine indicate that this theory is not likely. Based on our results, the "lucky shot" theory does not explain the sinking of the world's first successful combat submarine. Published by Elsevier B.V.

  19. Improved OTEC System for a Submarine Robot (United States)

    Chao, Yi; Jones, Jack; Valdez, Thomas


    An ocean thermal energy conversion (OTEC), now undergoing development, is a less-massive, more-efficient means of exploiting the same basic principle as that of the proposed system described in "Alternative OTEC Scheme for a Submarine Robot" (NPO-43500), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 50. The proposed system as described previously would be based on the thawing-expansion/freezing-contraction behavior of a wax or perhaps another suitable phase-change material (PCM). The power generated by the system would be used to recharge the batteries in a battery- powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. At one phase of its operational cycle, the previously proposed system would utilize the surface ocean temperature (which lies between 15 and 30 C over most of the Earth) to melt a PCM that has a melting/freezing temperature of about 10 C. At the opposite phase of its operational cycle, the system would utilize the lower ocean temperature at depth (e.g., between 4 and 7 C at a depth of 300 m) to freeze the PCM. The melting or freezing would cause the PCM to expand or contract, respectively, by about 9 volume percent. The PCM would be contained in tubes that would be capable of expanding and contracting with the PCM. The PCM-containing tubes would be immersed in a hydraulic fluid. The expansion and contraction would drive a flow of the hydraulic fluid against a piston that, in turn, would push a rack-and-pinion gear system to spin a generator to charge a battery.

  20. Similarities between rivers and submarine channels (United States)

    Balcerak, Ernie


    Scientists have long known that the width and depth of rivers follows a power law relationship with discharge. They have also noticed that submarine channels appear to be similar to terrestrial rivers, but there have not been many systematic comparisons of the relationships between submarine channel morphology and discharge. Konsoer et al. compared the width, depth, and slope of 177 submarine channels to those of 231 river cross sections. They found that submarine channels are up to an order of magnitude wider and deeper than the largest terrestrial rivers, but they exhibit a similar power law relationship between width and depth. For submarine channels that were similar in size to rivers, the authors found that submarine channels tend to be 1 to 2 orders of magnitude steeper than rivers. The authors also inferred values for sediment concentration in the turbidity currents in the channels and combined this with estimated mean flow velocities to look for a relationship between discharge and morphology in the channels. They found that like rivers, the width and depth of the submarine channels follow a power law scaling with discharge. (Journal of Geophysical Research-Earth Surface, doi:10.1029/2012JF002422, 2013)

  1. The ASTARTE Paleotsunami and Mass Transport Deposits data bases - web-based references for tsunami and submarine landslide research around Europe (United States)

    De Martini, Paolo Marco; Patera, Antonio; Orefice, Simone; Paris, Raphael; Völker, David; Lastras, Galderic; Terrinha, Pedro; Noiva, João; Smedile, Alessandra; Pantosti, Daniela; Hunt, James; Gutscher, Marc-Andre; Migeon, Sébastien; Papadopoulos, Gerassimos; Triantafyllou, Ioanna; Yalciner, Ahmet C.


    EU project ASTARTE aims at developing a higher level of tsunami hazard assessment in the North East Atlantic, Mediterranean and Connected seas (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative work of 26 institutes from 16 countries and links together the description of past tsunamigenic events, the identification and characterization of tsunami sources, the calculation of the impact of such events, and the development of adequate resilience and risks mitigation strategies ( Within ASTARTE two web-based data bases on Paleotsunami and Mass Transport Deposits in the NEAM areas were created with the purpose to be the future information repositories for tsunami research in Europe.The aim is to integrate every existing official scientific reports and peer reviewed papers on these topics and update on new entries every 6-12 months, hosting information and detailed data, that are crucial e.g for tsunami modeling. A relational database managed by ArcGIS for Desktop 10.x software has been implemented. One of the final goals of the project is the public sharing of the archived datasets through a web-based map service that will allow visualizing, querying, analyzing, and interpreting all datasets. The interactive map service will be hosted by ArcGIS Online and will deploy the cloud capabilities of the portal. Any interested users will be able to access the online GIS resources through any Internet browser or specific apps that run on desktop machines, smartphones, or tablets and will be able to use the analytical tools, key tasks, and workflows of the service.We will present the data bases structure and topics as well as their ArcGIS Online version. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for

  2. Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii (United States)

    Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.


    Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii.New hydrological insights for the regionEstimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron (220Rn,t1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

  3. Calciclastic submarine fans: An integrated overview (United States)

    Payros, Aitor; Pujalte, Victoriano


    Calciclastic submarine fans are rare in the stratigraphic record and no bona fide present-day analogue has been described to date. Possibly because of that, and although calciclastic submarine fans have long intrigued deep-water carbonate sedimentologists, they have largely been overlooked by the academic and industrial communities. To fill this gap we have compiled and critically reviewed the existing sedimentological literature on calciclastic submarine fans, thus offering an updated view of this type of carbonate slope sedimentary system. Calciclastic submarine fans range in length from just a few to more than 100 km. Three different types can be distinguished: (1) Coarse-grained, small-sized (depression associated with tectonic structures, an inherited topography, or large-scale mass failures.

  4. Aspects of Propeller Developements for a Submarine

    DEFF Research Database (Denmark)

    Andersen, Poul; kappel, Jens Julius; Spangenberg, Eugen


    Design and development of propellers for submarines are in some ways different from propellers for surface vessels. The most important demand is low acoustic signature that has priority over propeller efficiency, and the submarine propeller must be optimized with respect to acoustics rather than...... efficiency. Moreover the operating conditions of a submarine propeller are quite different. These aspects are discussed as well as the weighing of the various propeller parameters against the design objectives. The noise generated by the propeller can be characterized as thrust noise due to the inhomogeneous...... wake field of the submarine, trailing-edge noise and noise caused by turbulence in the inflow. The items discussed are demonstrated in a case study where a propeller of the Kappel type was developed. Three stages of the development are presented, including a design of an 8-bladed propeller where...

  5. Russia's Submarine Force: Determinants and Prospects

    National Research Council Canada - National Science Library

    Tully, John


    ... the determinants of these events, The Russian Federation inherited a huge submarine fleet from the Soviet Union, Due to the changing conditions in the world and in Russia, its future status is in doubt...

  6. Submarine landslides: processes, triggers and hazard prediction. (United States)

    Masson, D G; Harbitz, C B; Wynn, R B; Pedersen, G; Løvholt, F


    Huge landslides, mobilizing hundreds to thousands of km(3) of sediment and rock are ubiquitous in submarine settings ranging from the steepest volcanic island slopes to the gentlest muddy slopes of submarine deltas. Here, we summarize current knowledge of such landslides and the problems of assessing their hazard potential. The major hazards related to submarine landslides include destruction of seabed infrastructure, collapse of coastal areas into the sea and landslide-generated tsunamis. Most submarine slopes are inherently stable. Elevated pore pressures (leading to decreased frictional resistance to sliding) and specific weak layers within stratified sequences appear to be the key factors influencing landslide occurrence. Elevated pore pressures can result from normal depositional processes or from transient processes such as earthquake shaking; historical evidence suggests that the majority of large submarine landslides are triggered by earthquakes. Because of their tsunamigenic potential, ocean-island flank collapses and rockslides in fjords have been identified as the most dangerous of all landslide related hazards. Published models of ocean-island landslides mainly examine 'worst-case scenarios' that have a low probability of occurrence. Areas prone to submarine landsliding are relatively easy to identify, but we are still some way from being able to forecast individual events with precision. Monitoring of critical areas where landslides might be imminent and modelling landslide consequences so that appropriate mitigation strategies can be developed would appear to be areas where advances on current practice are possible.

  7. Estimating the empirical probability of submarine landslide occurrence (United States)

    Geist, Eric L.; Parsons, Thomas E.; Mosher, David C.; Shipp, Craig; Moscardelli, Lorena; Chaytor, Jason D.; Baxter, Christopher D. P.; Lee, Homa J.; Urgeles, Roger


    The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating individual events as well as the open time intervals before and after the observed sequence of landslides. For observed sequences of submarine landslides, we typically only have the age date of the youngest event and possibly of a seismic horizon that lies below the oldest event in a landslide sequence. We use an empirical Bayes analysis based on the Poisson-Gamma conjugate prior model specifically applied to the landslide probability problem. This model assumes that landslide events as imaged in geophysical data are independent and occur in time according to a Poisson distribution characterized by a rate parameter λ. With this method, we are able to estimate the most likely value of λ and, importantly, the range of uncertainty in this estimate. Examples considered include landslide sequences observed in the Santa Barbara Channel, California, and in Port Valdez, Alaska. We confirm that given the uncertainties of age dating that landslide complexes can be treated as single events by performing statistical test of age dates representing the main failure episode of the Holocene Storegga landslide complex.

  8. Submarine Landslides at Santa Catalina Island, California (United States)

    Legg, M. R.; Francis, R. D.


    Santa Catalina Island is an active tectonic block of volcanic and metamorphic rocks originally exposed during middle Miocene transtension along the evolving Pacific-North America transform plate boundary. Post-Miocene transpression created the existing large pop-up structure along the major strike-slip restraining bend of the Catalina fault that forms the southwest flank of the uplift. Prominent submerged marine terraces apparent in high-resolution bathymetric maps interrupt the steep submarine slopes in the upper ~400 meters subsea depths. Steep subaerial slopes of the island are covered by Quaternary landslides, especially at the sea cliffs and in the blueschist metamorphic rocks. The submarine slopes also show numerous landslides that range in area from a few hectares to more than three sq-km (300 hectares). Three or more landslides of recent origin exist between the nearshore and first submerged terrace along the north-facing shelf of the island's West End. One of these slides occurred during September 2005 when divers observed a remarkable change in the seafloor configuration after previous dives in the area. Near a sunken yacht at about 45-ft depth where the bottom had sloped gently into deeper water, a "sinkhole" had formed that dropped steeply to 100-ft or greater depths. Some bubbling sand was observed in the shallow water areas that may be related to the landslide process. High-resolution multibeam bathymetry acquired in 2008 by CSU Monterey Bay show this "fresh" slide and at least two other slides of varying age along the West End. The slides are each roughly 2 hectares in area and their debris aprons are spread across the first terrace at about 85-m water depth that is likely associated with the Last Glacial Maximum sealevel lowstand. Larger submarine slides exist along the steep Catalina and Catalina Ridge escarpments along the southwest flank of the island platform. A prominent slide block, exceeding 3 sq-km in area, appears to have slipped more than

  9. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K.


    Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

  10. The Enemy Below - The Global Diffusion of Submarines and Related Technology

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, K G


    The end of the Cold War seemed to create a more peaceful international environment. September 11 reminded us of the dangers of complacency. Indeed, even before September 11 US forces had intervened in a number of wars and crises, including Panama, the Persian Gulf War, Somalia, Rwanda, Bosnia, Kosovo, several Taiwan Straits crises, the North Korea nuclear weapons crisis, and most recently Afghanistan. US ability to intervene in remote areas of the world is often dependent on the Navy's ability to project power ashore. As a result, US ability to influence events in crisis situations, especially between or among nuclear powers, may become more difficult along with our ability to conduct littoral warfare. Although the numbers of potentially hostile submarines have declined with the end of the Cold War, US anti-submarine warfare capabilities have also declined. Moreover, foreign submarines and related technologies are likely to diffuse globally. New technologies like Air Independent Propulsion (AIP), improved weapons and sensors will make conventional submarines more dangerous, and the spread of nuclear submarines even to a few more countries raise political, military, environmental, and safety concerns. Submarines are one of the key weapon systems used alone or in combination with other weapon systems such as coastal defense missiles, aircraft, and other sea-based missile platforms to deny US ability to project power ashore, Thus, other countries who wish to deny the US the ability to interfere with their regional or even global ambitions may emphasize the acquisition and/or development of submarines. As the world become more multipolar over the longer term, as the Chinese believe it will, countries such as Russia, China. etc., may be able to acquire the submarine capabilities to challenge us not just regionally, but in blue waters. To the extent that our alliance relationships require US naval access or superiority to sustain them, then our erstwhile friendly

  11. Influence of stiffness constant of stern bearing on vibration and acoustic radiation of whole submarine

    Directory of Open Access Journals (Sweden)

    WANG Lucai


    Full Text Available [Objectives] This paper studies the influence of the stiffness constant of a stern bearing on the vibration and acoustic radiation of a whole submarine.[Methods] Based on the form of SUBOFF, a whole submarine model is established in which the structures of the propeller and shaft are first formed in solid elements. Through calculating and comparing the structural vibration and acoustic radiation driven by a vertically excited force, the influence of the elastic coefficient of the stern bearing on the vibroacoustic of the overall submarine structure is mainly considered. [Results] It is demonstrated that the reduction of the elastic coefficient of the stern bearing leads to the convergence of structural vibration and acoustic radiation to the second order overall bending modal frequency, and the frequency gradually becomes lower, which can benefit the vibroacoustic reduction of submarines at frequencies higher than the second order overall bending modal frequency. [Conclusions] These results provide a reference for the acoustic design of submarine structures.

  12. Submarine landslide and tsunami hazards offshore southern Alaska: Seismic strengthening versus rapid sedimentation (United States)

    Sawyer, Derek E.; Reece, Robert S.; Gulick, Sean P. S.; Lenz, Brandi L.


    The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high-sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure. This conclusion is supported by shear strength outside of the fan that follow an active margin trend. More broadly, seismically active margins with wet-based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking.

  13. Research on Big Data Attribute Selection Method in Submarine Optical Fiber Network Fault Diagnosis Database

    Directory of Open Access Journals (Sweden)

    Chen Ganlang


    Full Text Available At present, in the fault diagnosis database of submarine optical fiber network, the attribute selection of large data is completed by detecting the attributes of the data, the accuracy of large data attribute selection cannot be guaranteed. In this paper, a large data attribute selection method based on support vector machines (SVM for fault diagnosis database of submarine optical fiber network is proposed. Mining large data in the database of optical fiber network fault diagnosis, and calculate its attribute weight, attribute classification is completed according to attribute weight, so as to complete attribute selection of large data. Experimental results prove that ,the proposed method can improve the accuracy of large data attribute selection in fault diagnosis database of submarine optical fiber network, and has high use value.

  14. Addressing submarine geohazards through scientific drilling (United States)

    Camerlenghi, A.


    Natural submarine geohazards (earthquakes, volcanic eruptions, landslides, volcanic island flank collapses) are geological phenomena originating at or below the seafloor leading to a situation of risk for off-shore and on-shore structures and the coastal population. Addressing submarine geohazards means understanding their spatial and temporal variability, the pre-conditioning factors, their triggers, and the physical processes that control their evolution. Such scientific endeavour is nowadays considered by a large sector of the international scientific community as an obligation in order to contribute to the mitigation of the potentially destructive societal effects of submarine geohazards. The study of submarine geohazards requires a multi-disciplinary scientific approach: geohazards must be studied through their geological record; active processes must be monitored; geohazard evolution must be modelled. Ultimately, the information must be used for the assessment of vulnerability, risk analysis, and development of mitigation strategies. In contrast with the terrestrial environment, the oceanic environment is rather hostile to widespread and fast application of high-resolution remote sensing techniques, accessibility for visual inspection, sampling and installation of monitoring stations. Scientific Drilling through the IODP (including the related pre site-survey investigations, sampling, logging and in situ measurements capability, and as a platform for deployment of long term observatories at the surface and down-hole) can be viewed as the centre of gravity of an international, coordinated, multi-disciplinary scientific approach to address submarine geohazards. The IODP Initial Science Plan expiring in 2013 does not address openly geohazards among the program scientific objectives. Hazards are referred to mainly in relation to earthquakes and initiatives towards the understanding of seismogenesis. Notably, the only drilling initiative presently under way is the

  15. MVAC Submarine cable, impedance measurements and analysis

    DEFF Research Database (Denmark)

    Arentsen, Martin Trolle; Pedersen, Morten Virklund; Expethit, Adrian


    Due to environmental concerns an increase in off-shore windfarms has been observed in recent years, leading to an increased demand for three-core-wire-armoured submarine cables. However, the IEC Standard 60287 used to calculate the ampacity of these cables is widely recognized as being not accurate...

  16. German Submarine Offensives and South African Countermeasures

    African Journals Online (AJOL)


    'Good Hunting': German Submarine Offensives and South African. Countermeasures off the South African Coast during the Second World. War, 1942-1945. Evert Kleynhans. •. Abstract .... wolf packs south, Dönitz had hoped to cause a diversionary effect whereby the Allies would be forced to split their defensive forces ...

  17. Submarine Telecommunication Cables in Disputed Maritime Areas

    NARCIS (Netherlands)

    van Logchem, Youri


    There are a considerable number of maritime areas where no boundary exists, or where a boundary is delimited only in part. This article deals with the issue of submarine telecommunication cables, which are sometimes placed on the seabed or buried in the subsoil of areas that are claimed by multiple

  18. Oceanographic studies supporting the assessment of deep-sea disposal of defueled decommissioned nuclear submarines (United States)

    Ross Heath, G.; Rea, David K.; Ness, Gordon; Dale Pillsbury, R.; Beasley, Thomas M.; Lopez, Carlos; Talbert, Daniel M.


    Based on criteria developed by the international Atomic Energy Agency (IAEA), potential disposal sites for defueled, decommissioned nuclear submarines appear to exist in deep water south of the Mendocino Fracture Zone within 200 nautical miles of the United States Oceanographic measurements in the water column and at the sea floor in a study area (W-N) at 39 5°N, 127 5°W will allow the operational and radiological consequences of deep-sea disposal to be compared with land burial of old submarines. The W-N studies also are yielding new data that will provide insights to the deposition and early diagenesis of distal hemipelagic sediments

  19. Monitoring of the nuclear submarine Komsomolets

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde E.; Flo, Janita K.; Liebig, Penny L. [Institute of Marine Research, P. O. Box 1870 Nordnes, N-5817 Bergen (Norway); Gaefvert, Torbjoern; Rudjord, Anne Liv [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Oesteraas (Norway); Gwynn, Justin P. [Norwegian Radiation Protection Authority, The Fram Centre, N-9296 Tromsoe (Norway)


    The Soviet nuclear submarine Komsomolets sank on the 7 April 1989, 180 km southwest of Bear Island in the Norwegian Sea to a depth of about 1655 m. The submarine contains one nuclear reactor containing long-lived radionuclides such as cesium-137 ({sup 137}Cs) along with other fission and activation products, in addition to 2 mixed uranium/plutonium nuclear warheads containing weapons grade plutonium. Although several model studies have shown that a radioactive leakage from Komsomolets will have insignificant impact on fish and other marine organisms, there are still public concerns about the condition of the submarine and the potential for radioactive leakage. In order to document the contamination levels and to meet public concerns, monitoring of radioactive contamination in the area adjacent to the submarine has been ongoing since 1993. Samples of bottom seawater and sediments have been collected annually by the Institute of Marine Research (IMR) and have been analysed for {sup 137}Cs and plutonium-239,240 ({sup 239,240}Pu). So far, activity concentrations in the samples have been comparable to levels found in other samples from the Norwegian and Barents Seas. During sampling from R/V 'G. O. Sars' in April 2013, an area of about 1 km{sup 2} of the seabed around Komsomolets was mapped to precisely locate the submarine using a Kongsberg EM302 multibeam echo sounder, a Simrad EK60 single beam echo sounder and an Olex 3D bottom-mapping system. For sediment sampling, a Simrad MST342 mini-transponder was attached to a Smoegen box corer to allow for precise positioning of the corer. With the aid of the Kongsberg HiPAP (High Precision Acoustic Positioning) system, 4 box cores were collected around the submarine at a distance of 10 to 20 m. In addition, one box core was collected from a reference station about 100 m upstream of the submarine. Surface sediments and sediment cores were collected from the box cores taken at each sampling location. Sediment cores

  20. Chemical environments of submarine hydrothermal systems (United States)

    Shock, Everett L.


    Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to approximately 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such

  1. Phase 1 Final Report: Titan Submarine (United States)

    Oleson, Steven R.; Lorenz, Ralph D.; Paul, Michael V.


    The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase 1 for 2014. The proposal stated the desire to investigate what science a submarine for Titan's liquid hydrocarbon seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (100 kg), it was found that a submersible platform can accomplish extensive science both above and below the surface of the Kraken Mare. Submerged science includes mapping using side-looking sonar, imaging and spectroscopy of the lake, as well as sampling of the lake's bottom and shallow shoreline. While surfaced, the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 km inland. This imaging requirement pushed the landing date to Titan's next summer period (2047) to allow for lighted conditions, as well as direct-to-Earth communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid, sediment, and chemical interactions. An estimated 25 Mb of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system.The baseline 90-day mission would be to sail submerged and surfaced around and through Kraken Mare investigating the shoreline and inlets to evaluate the sedimentary interaction both on the surface and then below. Depths of Kraken have yet to be sensed (Ligeia to the north is thought to be 200 m (656 ft) deep), but a maximum depth of 1,000 m (3,281 ft) for Kraken Mare was assumed for the design). The sub would spend 20 d at the interface between Kraken Mare and Ligeia Mare for clues to the drainage of

  2. Miocene Current-Modified Submarine Fans (United States)

    Arce Perez, L. E.; Snedden, J.; Fisher, W. L.


    In the southwestern Gulf of Mexico, new and newly reprocessed seismic data has revealed a series of large bedforms, with set thicknesses of 130 to 250 meters. These exhibit hummocky, oblique and shingled to parallel seismic clinoform reflections. This seismic package has a paleowater depth of 450 meters. Those shingled seismic reflections in offshore east Mexico are interpreted as contourite drift deposits. These Miocene-age contourites may be related to strong ocean bottom currents that modified submarine fans and transported sediment to the north. Those contourites were identified on older seismic data, but are better imaged and interpreted on this new data. Plans are to map out and investigate the origin and extent of fans and contourites that extends over a large area of the Gulf of Mexico. In the Early Miocene several submarine fans systems were formed by the sediment input related to orogenic activity in Mexico. Submarine fan development persisted into the Middle Miocene due to continued uplift and erosion of the Mexican landmass. Initial, contourites are small and close proximity to the deep-water fan. In the Late Miocene time, contourite drift field reached its maximum extent in the Mexican deepwater area, anchored on its southern end by a submarine mound. This mounded submarine fan is located in the offshore northeast Veracruz and can be linked to increased uplift and erosion of the Trans-Mexican volcanic belt. In the Miocene-Pliocene, the large contourite drift begins to diminish in size and scale and is moribund by the Pliocene, with establishment of oceanic circulation similar to the present day. This research is important to understand more about the Gulf of Mexico and also for the Miocene timeframe that is a key phase in the earth's history. The role of the change in bottom water flow during progressive closure of the equatorial seaway separating North and South America will also be investigated.

  3. Post-eruptive Submarine Terrace Development of Capelinhos, Azores (United States)

    Zhongwei Zhao, Will; Mitchell, Neil; Quartau, Rui; Tempera, Fernando; Bricheno, Lucy


    Erosion of the coasts of volcanic islands by waves creates shallow banks, but how erosion proceeds with time to create them and how it relates to wave climate is unclear. In this study, historical and recent marine geophysical data collected around the Capelinhos promontory (western Faial Island, Azores) offer an unusual opportunity to characterize how a submarine terrace developed after the eruption. The promontory was formed in 1957/58 during a Surtseyan eruption that terminated with extensive lava forming new rocky coastal cliffs. Historical measurements of coastline position are supplemented here with coastlines measured from 2004 and 2014 Google Earth images in order to characterize coastline retreat rate and distance for lava- and tephra-dominated cliffs. Swath mapping sonars were used to characterize the submarine geometry of the resulting terrace (terrace edge position, gradient and morphology). Limited photographs are available from a SCUBA dive and drop-down camera deployments to ground truth the submarine geomorphology. The results reveal that coastal retreat rates have decreased rapidly with the time after the eruption, possibly explained by the evolving resistance to erosion of cliff base materials. Surprisingly, coastline retreat rate decreases with terrace width in a simple inverse power law with terrace width. We suspect this is only a fortuitous result as wave attenuation over the terrace will not obviously produce the variation, but nevertheless it shows how rapidly the retreat rate declines. Understanding the relationship between terrace widening shelf and coastal cliff retreat rate may be more widely interesting if they can be used to understand how islands evolve over time into abrasional banks and guyots.

  4. Simple models for the simulation of submarine melt for a Greenland glacial system model (United States)

    Beckmann, Johanna; Perrette, Mahé; Ganopolski, Andrey


    Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid-1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with high-resolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters), which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating

  5. Health and environmental risk assessment associated with a potential recovery of the Russian submarine K-27

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, A.; Amundsen, I.; Brown, J.E.; Dowdall, M.; Standring, W. [Norwegian Radiation Protection Authority/CERAD CoE (Norway); Bartnicki, J. [Norwegian Meteorological Institute/CERAD CoE (Norway); Karcher, M. [O.A.Sys - Ocean Atmosphere Systems GmbH (Germany); Lind, O.C.; Salbu, B. [Norwegian University of Life Sciences/CERAD CoE (Norway)


    The nuclear submarine K-27 is one of several objects with spent nuclear fuel (SNF) which has been dumped in the Arctic. It contained two liquid metal reactors (LMRs) of 70 MW maximum thermal power each and used Pb-Bi as the coolant. The reactors were loaded with 180 kg of U-235 at an enrichment of 90 %. In September 1981, the submarine was sunk in the shallow waters of Stepovoy Fjord at an estimated depth of 30 m. Concerns have been expressed by various parties regarding the issue of dumped nuclear waste in the Kara Sea and in particular the submarine K-27. To address these concerns and to provide a better basis for evaluating possible radiological impact (especially as a consequence of a potential recovery of the submarine), an environmental impact assessment has been undertaken. The study is based on construction of different hypothetical accident scenarios and evaluating possible associated consequences for human and the environment. In general, three main scenarios seem probable and thus appropriate for consideration. One is the 'zero- alternative', i.e. investigate the current and future impact assuming no interventions. The second considers an accidental scenario involving the raising of the submarine and the third an accidental scenario related to the transportation of the submarine to shore for defueling. With regards to the accidental scenarios related to raising and transportation of the submarine, two alternatives can be considered depending on where and how a hypothetical accident will take place and whether the subsequent releases occur under water or at the water surface. The issue of an uncontrolled chain reaction occurring as a result of a potential recovery of the submarine will be included in the assessment. The work includes application of state of the art 3D hydrodynamic and atmospheric dispersion models to investigate the transport, distribution and fate of relevant radionuclides following a hypothetical accident in aquatic and

  6. Age of the Shirshov submarine ridge basement (Bering Sea) based on the results of investigation of zircons using the U-Pb SHRIMP method (United States)

    Sukhov, A. N.; Chekhovich, V. D.; Lander, A. V.; Presnyakov, S. L.; Lepekhina, E. N.


    The Shirshov Ridge holds an important position in the structure of the Bering Sea Basin. Stretching from north to south for over 500 km, it divides the Bering Sea into two deep water basins, the Aleutian and Komandorsky basins. The age of oceanic crust of the Aleutian basin based on linear magnetic anomalies is conventionally considered Early Cretaceous, of the Komandorsky basin — Miocene, according to the K-Ar dating of the basalts (9.8 Ma) exposed in 191 deep water drill borehole. Rocks belonging to the basement of the Shirshov Ridge were dredged during the 29th cruise of research vessel Dmitrii Mendeleev and are represented by amphibolitic gabbro whose composition is similar to that of gabbroids of mid-oceanic ridges. The age of metamorphism based on the results of K-Ar dating of amphibole is 47 ± 5 Ma. The U-Pb zircon dating method was used to determine the age of gabbro. Zircons were extracted from a ˜5 kg combined amphibolitic gabbroid sample, and the age of zircons was determined using a SHRIMP-II sensitive high resolution secondary ion microprobe (Center of Isotopic Studies, A.P. Karpinskii Russian Geological Research Institute, St. Petersburg). The average concordant age value for the 25 determinations performed based on 20 points for 18 grains is 72 ± 1.4 Ma (Late Campanian). For 5 grains, the measured age values are within the range of 88 ± 3.5 Ma to 126.5 ± 4.5 Ma. Given the western vergence of the thrust structure of the Shirshov Ridge, the acoustic basement of the Shirshov Ridge is most probably a complexly deformed oceanic crust of the Aleutian Trench, which most likely dates from the Early to Late Cretaceous.

  7. An Automatic Procedure for the Quantitative Characterization of Submarine Bedforms

    Directory of Open Access Journals (Sweden)

    Massimo Di Stefano


    Full Text Available A model for the extraction and quantitative characterization of submarine landforms from high-resolution digital bathymetry is presented. The procedure is fully automated and comprises two parts. The first part consists of an analytical model which extracts quantitative information from a Digital Elevation Model in the form of objects with similar parametric characteristics (terrain objects. The second part is a rule-based model where the terrain objects are reclassified into distinct landforms with well-defined three dimensional characteristics. For the focus of this work, the quantitative characterization of isolated dunes (height greater than 2 m is used to exemplify the process. The primary metrics used to extract terrain objects are the flatness threshold and the search radius, which are then used by the analytical model to identify the feature type. Once identified as dunes, a sequence of spatial analysis routines is applied to identify and compute metrics for each dune including length, height, width, ray of curvature, slope analysis for each stoss and lee side, and dune symmetry. Dividing the model into two parts, one scale-dependent and another centered around the shape of the landform, makes the model applicable to other submarine landforms like ripples, mega-ripples, and coral reefs, which also have well-defined three-dimensional characteristics.

  8. Fin propulsion on a human-powered submarine (United States)

    Anderson, Iain A.; Pocock, Benjamin; Harbuz, Antoni; Algie, Cam; Vochezer, Daniel; Chao, Ryan; Lu, Benjamin


    Nearly all surface and underwater vessels are driven by screw propulsion; ideal for coupling to rotary engines and well understood after over a century of development. But most aquatic creatures use fins for swimming. Although there are sound evolutionary reasons why fish have fins and not propellers, they are nevertheless agile, fast and efficient. Although fish-like robots such as the MIT Robotuna are providing good insight into fin-based swimming there are advantages for using humans in the experimental device. Like an airplane test pilot they can write crash reports. We present preliminary observations for the human powered finned submarine: Taniwha. The sub participated in the 2nd European International Submarine races in Gosport UK where it received a trophy for "Best Non-Propeller Performance". Two sets of Hobie Mirage fin drives fixed to the upper and lower rear surfaces of the sub are pedaled by the pilot. The pilot also has two levers at the front, one to pitch a pair of dive planes and one for yawing a large rudder. Good speed, we estimate to be greater than 6 m/s is possible with these fins although we haven't explored their full potential. Straying too near the surface or bottom can lead to an instability, synonymous to a stall, such that control is lost. The mechanism for this will be discussed and solutions offered. Fish are 400 million years in front of us but one day we'll catch them.

  9. Are tilt measurements useful in detecting tsunamigenic submarine landslides? (United States)

    Brune, Sascha; Babeyko, Andrey Y.; Sobolev, Stephan V.


    Large submarine landslides can generate dangerous tsunamis. Because of their long-period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land-based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like slide location, volume, and velocity. We exemplify our method by applying it to the Storegga slide west of Norway and other tsunamigenic landslide events. The parameter which can be most robustly estimated from tiltmeter array measurements is the product of slide volume and its velocity (slide tsunamigenic potential). This parameter also controls the amplitude of the generated tsunami wave. The inversion accuracy of this parameter and the estimated tsunami height near the coast depends on the noise level of tiltmeter measurements, distance of the tiltmeters from the slide, and slide tsunamigenic potential itself. The tsunamigenic potential of the most dangerous slides like Storegga can be estimated well by tiltmeters at the coast if the effective noise level does not exceed 50 nrad.

  10. Feasibility study of submarine diesel exhaust valve interspace coating application

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, W.; Zhou, M.; Bibby, D.; Huang, J.


    This document described a feasibility study conducted to evaluate surface coating systems applied to the surface of a diesel exhaust valve interspace on a VICTORIA Class submarine. A series of laboratory studies were conducted to determine the physical characteristics of the coatings, which will be subjected to high service temperatures, diesel exhaust gas, and seawater. The valves were made of Q1N steel castings. The surface coatings were designed to provide corrosion resistance and thermal protection to the valves. As part of the study, a survey was conducted on various state-of-the-art surface coating systems. Coatings were rated on their ability to protect the Q10 steel surface from corrosion, high temperatures and seawater. An additional requirement was that the coatings should not produce high amounts of hydrogen. Plating trials were conducted with a nickel-based alloy (Ni-Cu-P) placed on Q1N steel substrates with a hypophosphite reducing agent. The results of X-ray diffraction (XRD) analyses suggested that the coatings can also be used to protect the external surfaces of various submarine components. 54 refs., 4 tabs., 10 figs.

  11. Psychological Implications for Submarine Display Design (United States)


    This paper addresses a number of psychological issues pertaining to display design . We review the literature comparing 3-D and 2-D displays and...perceptual, cognitive and ecological factors that are relevant to display design for submarine environments. The Generative Transformational visual perception is outlined and the relevance of transformational theory to display design is discussed. The paper also discusses a number of

  12. Topology Model of the Flow around a Submarine Hull Form (United States)


    resistance and flow noise arising from flow-structure interaction, it is necessary to test the shape of the submarine , which includes the length-to...UNCLASSIFIED Topology Model of the Flow around a Submarine Hull Form S.-K. Lee Maritime Division Defence Science and Technology Group DST-Group–TR...3177 ABSTRACT A topology model constructed from surface-streamer visualisation describes the flow around a generic conventional submarine hull form at

  13. A Lanchester model of submarine attack on a carrier battlegroup


    Eagle, James N.


    A Lanchester model is developed for a battlegroup ASW engagement. Two variations are included. In the first, long-range missile firing submarines, short-range missile or torpedo firing submarines, and submarines firing only torpedoes distribute their attack uniformly over battlegroup escort ships and carriers. In the second variation, the attack is concentrated on the carriers. supported by the Naval War College NA

  14. Meta-Analysis of Data from the Submarine Ventilation Doctrine Test Program

    National Research Council Canada - National Science Library

    Hoover, J


    .... The Submarine Ventilation Doctrine Test Program was developed to address submarine-specific issues regarding the use of ventilation systems to control smoke and heat movement, maintain habitability...

  15. Australia’s Submarine Design Capabilities and Capacities: Challenges and Options for the Future Submarine (United States)


    General Dynamics Electric Boat Corporation EMC electromagnetic compatibility EMF electromagnetic field EMI electromagnetic interference EPCM flow-induced radiated noise Own-sensor performance degradation Note: Risks can be reduced for given designs using scale models...Acoustic analysis Addresses the total radiated noise signature of submarine designs Radiated noise that an enemy might detect Self-noise that that

  16. North Sea submarine cable disruptions and fishing activity

    NARCIS (Netherlands)

    Hintzen, N.T.; Machiels, M.A.M.


    At the North Sea seafloor, numerous submarine cables are positioned that connect telecommunication networks between countries. Worldwide, human activities cause most of the cable disruptions with fisheries accounting for nearly half of all reported faults. Due to a recent increase of submarine cable

  17. The 1929 Grand Banks submarine landslide revisited (United States)

    Schulten, Irena; Mosher, David C.; Krastel, Sebastian; Piper, David J. W.; Kienast, Markus


    On November 18th, 1929 a large submarine landslide occurred along the St. Pierre Slope of the southwestern Grand Banks of Newfoundland, as a result of a Mw 7.2 earthquake. This submarine landslide led to the first recognition of naturally-occurring submarine turbidity currents and is one of the few landslides known to have generated a tsunami. The event caused 28 causalities in Newfoundland and severe infrastructural damage. Earlier investigations of the area identified widely distributed shallow mass failures (15 - 20 m high escarpments), but no evidence of a larger headscarp. It is difficult to conceive, therefore, how this distributed shallow failure that rapidly evolved into a turbidity current would have generated a tsunami. It is hypothesised in this study that a deeper rooted sediment failure ( 500 m), involving faulting and mass-rotation, was involved in the sediment failure and this displacement generated the tsunami. In order to test this hypothesis, the volume and kinematics of the 1929 slope failure are analysed by means of recently acquired high resolution seismic reflection and multibeam swath bathymetry data, in addition to a significant volume of legacy data. The data allow determination of: 1) the dimension of the failure area, 2) the thickness and volume of failed sediment on St. Pierre Slope, 3) fault patterns and displacements, and 4) styles of sediment failure involved. Shallow (20 m high) sinuous escarpments and a number of faults are observed along the upper St. Pierre Slope (500 - 2 500 m water depth). The uppermost and largest of these escarpments shows association with a fault system. Preliminary results, therefore, indicate a complex sediment failure pattern along the St. Pierre Slope, possibly involving a deep-seated decollement and mobilization of a large volume of surficial sediment through retrogressive failure. Causes for the tsunami are yet to be determined.

  18. Multivariable Control System Design for a Submarine, (United States)


    perturbations applied to the nominal point were identical in all cases (see table 2.3). The comparisons show excellent correlation between the...Open Loop Singular Values for the 5 and 1S Knot Linear Modelo *~~* b % % V’ , * % ~ .%~ C 9 ~ V. --.- V. V.-.--.--46..- S. 77’ Model S20R5 20- 10- -0...without imparting a pitch angle to the submarine and provides an excellent example of both the usefulness of w(t) as a state variable and the

  19. Hydrogen isotope systematics of submarine basalts (United States)

    Kyser, T.K.; O'Neil, J.R.


    The D/H ratios and water contents in fresh submarine basalts from the Mid-Atlantic Ridge, the East Pacific Rise, and Hawaii indicate that the primary D/H ratios of many submarine lavas have been altered by processes including (1) outgassing, (2) addition of seawater at magmatic temperature, and (3) low-temperature hydration of glass. Decreases in ??D and H2O+ from exteriors to interiors of pillows are explained by outgassing of water whereas inverse relations between ??D and H2O+ in basalts from the Galapagos Rise and the FAMOUS Area are attributed to outgassing of CH4 and H2. A good correlation between ??D values and H2O is observed in a suite of submarine tholeiites dredged from the Kilauea East Rift Zone where seawater (added directly to the magma), affected only the isotopic compositions of hydrogen and argon. Analyses of some glassy rims indicate that the outer millimeter of the glass can undergo lowtemperature hydration by hydroxyl groups having ??D values as low as -100. ??D values vary with H2O contents of subaerial transitional basalts from Molokai, Hawaii, and subaerial alkali basalts from the Society Islands, indicating that the primary ??D values were similar to those of submarine lavas. Extrapolations to possible unaltered ??D values and H2O contents indicate that the primary ??D values of most thoteiite and alkali basalts are near -80 ?? 5: the weight percentages of water are variable, 0.15-0.35 for MOR tholeiites, about 0.25 for Hawaiian tholeiites, and up to 1.1 for alkali basalts. The primary ??D values of -80 for most basalts are comparable to those measured for deep-seated phlogopites. These results indicate that hydrogen, in marked contrast to other elements such as Sr, Nd, Pb, and O, has a uniform isotopic composition in the mantle. This uniformity is best explained by the presence of a homogeneous reservoir of hydrogen that has existed in the mantle since the very early history of the Earth. ?? 1984.

  20. Particle sedimentation and diffusive convection in submarine clouds (United States)

    Carazzo, G.; Jellinek, M.; Turchyn, A. V.


    The longevity of submarine plumes generated by the release of hydrothermal fluids during crustal rupturing or by the rapid cooling of an erupting lava flow constrains the input of crustal-derived elements into the deep-ocean. Decades of observations of episodic "event plumes" suggest that a key process governing the dynamics of a submarine cloud spreading out laterally from a buoyant rising plume is the production of internal layering. Here, we use geological data on submarine clouds and a new experimental apparatus producing at laboratory scale turbulent, hot particle-laden plumes and clouds to show that this layering occurs where particle diffusive convection driven by the differential diffusion of heat and small mineral precipitates gives rise to a large scale double diffusive instability. We show that this "particle diffusive convection" can extend the longevity of an event plume to two years after its emplacement, allowing iron-sulfide minerals to dissolve and deliver iron to the deep-ocean. The very long residence time imposed by diffusive convective effects does not allow iron-oxide minerals to dissolve but may lead to the formation of iron-rich sediments at large distances from the point of emission. We develop a new theoretical model that includes both sedimentation and dissolution processes to quantify the potential amount of iron produced by the dissolution of iron-sulfide minerals settling through the cloud by diffusive convection. A key prediction is that hydrothermal systems could provide 75% of the global budget of dissolved iron in the deep-ocean. The consideration of scale-basin variations suggests that the Southern Hemisphere is probably the most impacted by hydrothermal iron, consistent with observations and global ocean models. Photographs showing the typical evolution of a lab-scale turbulent, hot particle-laden plume. At stage 1, the buoyant plume reaches a level of neutral buoyancy and spreads out laterally forming a neutrally buoyant cloud

  1. Disposal of Russian nuclear submarines and surface ships; Deutsch-russisches Gemeinschaftsprojekt zur Entsorgung russischer Atom-U-Boote

    Energy Technology Data Exchange (ETDEWEB)

    Klammt, Jens-Uwe; Menger, Bernd; Mietann, Detlef [Energiewerke Nord GmbH, Rubenow (Germany)


    A German contribution to the initiative of the Global G8 Partnership against the Proliferation of Weapons of Mass Destruction is a project for the disposal of decommissioned nuclear submarines of the Russian Northern Sea Fleet. The Federal Republic of Germany makes available a total of 600 million euro for this purpose for the period of 2003 to 2014. Since 2003, a long-term store has been under construction in the Saida Bay in the Murmansk region for land-based storage of mothballed reactor sections from decommissioned nuclear submarines and components of nuclear surface ships with a total of 178 storage positions, the necessary infrastructure included. At the present time, 33 mothballed reactor sections of disassembled nuclear submarines are stored there. Work is also under way to build and equip a center for conditioning, treatment, and long-term storage of radioactive waste from the northwestern region of Russia, which will be commissioned in 2014. This waste management center is a key item in Russian plans for the establishment of radiologically safe conditions in the region. Germany financed the disassembly of 20 submarines into reactor sections fit for storage. Extensive assistance was provided in improving the material technical basis of the shipyard commissioned to dispose of the nuclear submarines. (orig.)

  2. Flow dynamics around downwelling submarine canyons

    Directory of Open Access Journals (Sweden)

    J. M. Spurgin


    Full Text Available Flow dynamics around a downwelling submarine canyon were analysed with the Massachusetts Institute of Technology general circulation model. Blanes Canyon (northwestern Mediterranean was used for topographic and initial forcing conditions. Fourteen scenarios were modelled with varying forcing conditions. Rossby and Burger numbers were used to determine the significance of Coriolis acceleration and stratification (respectively and their impacts on flow dynamics. A new non-dimensional parameter (χ was introduced to determine the significance of vertical variations in stratification. Some simulations do see brief periods of upwards displacement of water during the 10-day model period; however, the presence of the submarine canyon is found to enhance downwards advection of density in all model scenarios. High Burger numbers lead to negative vorticity and a trapped anticyclonic eddy within the canyon, as well as an increased density anomaly. Low Burger numbers lead to positive vorticity, cyclonic circulation, and weaker density anomalies. Vertical variations in stratification affect zonal jet placement. Under the same forcing conditions, the zonal jet is pushed offshore in more uniformly stratified domains. The offshore jet location generates upwards density advection away from the canyon, while onshore jets generate downwards density advection everywhere within the model domain. Increasing Rossby values across the canyon axis, as well as decreasing Burger values, increase negative vertical flux at shelf break depth (150 m. Increasing Rossby numbers lead to stronger downwards advection of a passive tracer (nitrate, as well as stronger vorticity within the canyon. Results from previous studies are explained within this new dynamic framework.

  3. Submarine Tailings Disposal (STD—A Review

    Directory of Open Access Journals (Sweden)

    Bernhard Dold


    Full Text Available The mining industry is a fundamental industry involved in the development of modern society, but is also the world’s largest waste producer. This role will be enhanced in the future, because ore grades are generally decreasing, thus leading to increases in the waste/metal production ratio. Mine wastes deposited on-land in so-called tailings dams, impoundments or waste-dumps have several associated environmental issues that need to be addressed (e.g., acid mine drainage formation due to sulphide oxidation, geotechnical stability, among others, and social concerns due to land use during mining. The mining industry recognizes these concerns and is searching for waste management alternatives for the future. One option used in the past was the marine shore or shallow submarine deposition of this waste material in some parts of the world. After the occurrence of some severe environmental pollution, today the deposition in the deep sea (under constant reducing conditions is seen as a new, more secure option, due to the general thought that sulphide minerals are geochemically stable under the reduced conditions prevailing in the deep marine environment. This review highlights the mineralogical and geochemical issues (e.g., solubility of sulphides in seawater; reductive dissolution of oxide minerals under reducing conditions, which have to be considered when evaluating whether submarine tailings disposal is a suitable alternative for mine waste.

  4. Submarine melt rates under Greenland's ice tongues (United States)

    Wilson, Nat; Straneo, Fiametta; Heimbach, Patrick; Cenedese, Claudia


    The few remaining ice tongues (ice-shelf like extensions) of Greenland's glaciers are undergoing rapid changes with potential implications for the stability of the ice sheet. Submarine melting is recognized as a major contributor to mass loss, yet the magnitude and spatial distribution of melt are poorly known or understood. Here, we use high resolution satellite imagery to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues: Ryder Glacier, Petermann Glacier and Nioghalvfjerdsbræ (79 North Glacier). We find that submarine plus aerial melt approximately balance the ice flux from the grounded ice sheet for the first two while at Nioghalvfjerdsbræ the total melt flux exceeds the inflow of ice indicating thinning of the ice tongue. We also show that melt rates under the ice tongues vary considerably, exceeding 60 m yr-1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. Using derived melt rates, we test simplified melt parameterizations appropriate for ice sheet models and find the best agreement with those that incorporate ice tongue geometry in the form of depth and slope.

  5. Environmental assessment of submarine power cables

    Energy Technology Data Exchange (ETDEWEB)

    Isus, Daniel; Martinez, Juan D. [Grupo General Cable Sistemas, S.A., 08560-Manlleu, Barcelona (Spain); Arteche, Amaya; Del Rio, Carmen; Madina, Virginia [Tecnalia Research and Innovation, 20009 San Sebastian (Spain)


    Extensive analyses conducted by the European Community revealed that offshore wind energy have relatively benign effects on the marine environment by comparison to other forms of electric power generation [1]. However, the materials employed in offshore wind power farms suffer major changes to be confined to the marine environment at extreme conditions: saline medium, hydrostatic pressure... which can produce an important corrosion effect. This phenomenon can affect on the one hand, to the material from the structural viewpoint and on the other hand, to the marine environment. In this sense, to better understand the environmental impacts of generating electricity from offshore wind energy, this study evaluated the life cycle assessment for some new designs of submarine power cables developed by General Cable. To achieve this goal, three approaches have been carried out: leaching tests, eco-toxicity tests and Life Cycle Assessment (LCA) methodologies. All of them are aimed to obtaining quantitative data for environmental assessment of selected submarine cables. LCA is a method used to assess environmental aspects and potential impacts of a product or activity. LCA does not include financial and social factors, which means that the results of an LCA cannot exclusively form the basis for assessment of a product's sustainability. Leaching tests results allowed to conclude that pH of seawater did not significantly changed by the presence of submarine three-core cables. Although, it was slightly higher in case of broken cable, pH values were nearly equals. Concerning to the heavy metals which could migrate to the aquatic medium, there were significant differences in both scenarios. The leaching of zinc is the major environmental concern during undersea operation of undamaged cables whereas the fully sectioned three-core cable produced the migration of significant quantities of copper and iron apart from the zinc migrated from the galvanized steel. Thus, the tar

  6. What threat do turbidity currents and submarine landslides pose to submarine telecommunications cable infrastructure? (United States)

    Clare, Michael; Pope, Edward; Talling, Peter; Hunt, James; Carter, Lionel


    The global economy relies on uninterrupted usage of a network of telecommunication cables on the seafloor. These submarine cables carry ~99% of all trans-oceanic digital data and voice communications traffic worldwide, as they have far greater bandwidth than satellites. Over 9 million SWIFT banks transfers alone were made using these cables in 2004, totalling 7.4 trillion of transactions per day between 208 countries, which grew to 15 million SWIFT bank transactions last year. We outline the challenge of why, how often, and where seafloor cables are broken by natural causes; primarily subsea landslides and sediment flows (turbidity currents and also debris flows and hyperpycnal flows). These slides and flows can be very destructive. As an example, a sediment flow in 1929 travelled up to 19 m/s and broke 11 cables in the NE Atlantic, running out for ~800 km to the abyssal ocean. The 2006 Pingtung earthquake triggered a sediment flow that broke 22 cables offshore Taiwan over a distance of 450 km. Here, we present initial results from the first statistical analysis of a global database of cable breaks and causes. We first investigate the controls on frequency of submarine cable breaks in different environmental and geological settings worldwide. We assess which types of earthquake pose a significant threat to submarine cable networks. Meteorological events, such as hurricanes and typhoons, pose a significant threat to submarine cable networks, so we also discuss the potential impacts of future climate change on the frequency of such hazards. We then go on to ask what are the physical impacts of submarine sediment flows on submerged cables? A striking observation from past cable breaks is sometimes cables remain unbroken, whilst adjacent cables are severed (and record powerful flows travelling at up to 6 m/s). Why are some cables broken, but neighbouring cables remain intact? We provide some explanations for this question, and outline the need for future in

  7. Risk assessment in submarine outfall projects: the case of Portugal. (United States)

    Mendonça, Ana; Losada, Miguel Ángel; Reis, Maria Teresa; Neves, Maria Graça


    Submarine outfalls need to be evaluated as part of an integrated environmental protection system for coastal areas. Although outfalls are tight with the diversity of economic activities along a densely populated coastline being effluent treatment and effluent reuse a sign of economic prosperity, precautions must be taken in the construction of these structures. They must be designed so as to have the least possible impact on the environment and at the same time be economically viable. This paper outlines the initial phases of a risk assessment procedure for submarine outfall projects. This approach includes a cost-benefit analysis in which risks are systematically minimized or eliminated. The methods used in this study also allow for randomness and uncertainty. The input for the analysis is a wide range of information and data concerning the failure probability of outfalls and the consequences of an operational stoppage or failure. As part of this risk assessment, target design levels of reliability, functionality, and operationality were defined for the outfalls. These levels were based on an inventory of risks associated with such construction projects, and thus afforded the possibility of identifying possible failure modes. This assessment procedure was then applied to four case studies in Portugal. The results obtained were the values concerning the useful life of the outfalls at the four sites and their joint probability of failure against the principal failure modes assigned to ultimate and serviceability limit states. Also defined were the minimum operationality of these outfalls, the average number of admissible technical breakdowns, and the maximum allowed duration of a stoppage mode. It was found that these values were in consonance with the nature of the effluent (tourist-related, industrial, or mixed) as well as its importance for the local economy. Even more important, this risk assessment procedure was able to measure the impact of the outfalls on

  8. Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress (United States)


    propulsion technology first occurred many years ago: To help jumpstart the UK’s nuclear - powered submarine program, the United States transferred to the UK a... nuclear - powered attack submarines (SSNs), nuclear - powered cruise missile submarines (SSGNs), and nuclear - powered ballistic missile submarines (SSBNs). 2...2 In the designations SSN, SSGN, SSBN, and SSBN(X), the SS stands for submarine, N stands for nuclear - powered (meaning the ship is

  9. Submarine landside in the Bussol Graben: Structural and formation features (United States)

    Baranov, B. V.; Lobkovsky, L. I.; Dozorova, K. A.; Rukavishnikova, D. D.


    Analysis of geophysical data obtained during a study of the insular slope in the central Kuril‒Kamchatka Trench during projects Kuriles-2005 and Kuriles-2006 promoted by the Presidium of the Russian Academy of Sciences revealed a large submarine landslide in this area. The landslide, located at the bottom of the transverse valley confined to the Bussol l Graben, resulted from the failure of the northeastern wall of a graben composed of sedimentary material. It exceeds 35 km3 in size, representing one of the large submarine landslides discovered to date on the slope of the Kuril‒Kamchatka Trench in submarine canyonfan environments.

  10. Simple models for the simulation of submarine melt for a Greenland glacial system model

    Directory of Open Access Journals (Sweden)

    J. Beckmann


    Full Text Available Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid-1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with high-resolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters, which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume

  11. Biomonitoring of physiological status and cognitive performance of underway submariners undergoing a novel watch-standing schedule (United States)

    Duplessis, C. A.; Cullum, M. E.; Crepeau, L. J.


    Submarine watch-standers adhere to a 6 hour-on, 12 hour-off (6/12) watch-standing schedule, yoking them to an 18-hr day, engendering circadian desynchronization and chronic sleep deprivation. Moreover, the chronic social crowding, shift work, and confinement of submarine life provide additional stressors known to correlate with elevated secretory immunoglobulin A (sIgA) and cortisol levels, reduced performance, immunologic dysfunction, malignancies, infections, gastrointestinal illness, coronary disease, anxiety, and depression. We evaluated an alternative, compressed, fixed work schedule designed to enhance circadian rhythm entrainment, sleep hygiene, performance, and health on 10 underway submariners, who followed the alternative and 6/12 schedules for approximately 2 weeks each. We measured subjects" sleep, cognitive performance, and salivary biomarker levels. Pilot analysis of the salivary data on one subject utilizing ELISA suggests elevated biomarker levels of stress. Average PM cortisol levels were 0.2 μg/L (normal range: nondetectable - 0.15 μg/L), and mean sIgA levels were 562 μg/ml (normal range: 100-500 μg/ml). Future research exploiting real-time salivary bioassays, via fluorescent polarimetry technology, identified by the Office of Naval Research (ONR) as a future Naval requirement, allows researchers to address correlations between stress-induced elaboration of salivary biomarkers with physiological and performance decrements, thereby fostering insight into the underway submariner"s psychoimmunological status. This may help identify strategies that enhance resilience to stressors. Specifically, empirically-based modeling can identify optimal watch-standing schedules and stress-mitigating procedures -- within the operational constraints of the submarine milieu and the mission --that foster improved circadian entrainment and reduced stress reactivity, enhancing physiological health, operational performance, safety, and job satisfaction.

  12. Submarine thermal springs on the Galapagos Rift (United States)

    Corliss, J.B.; Dymond, J.; Gordon, L.I.; Edmond, J.M.; Von Herzen, R. P.; Ballard, Richard D.; Green, K.; Williams, D.; Bainbridge, A.; Crane, K.; Van Andel, T. H.


    The submarine hydrothermal activity on and near the Galápagos Rift has been explored with the aid of the deep submersible Alvin. Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of seawater; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galápagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis

  13. A model for tidewater glacier undercutting by submarine melting (United States)

    Slater, D. A.; Nienow, P. W.; Goldberg, D. N.; Cowton, T. R.; Sole, A. J.


    Dynamic change at the marine-terminating margins of the Greenland Ice Sheet may be initiated by the ocean, particularly where subglacial runoff drives vigorous ice-marginal plumes and rapid submarine melting. Here we model submarine melt-driven undercutting of tidewater glacier termini, simulating a process which is key to understanding ice-ocean coupling. Where runoff emerges from broad subglacial channels we find that undercutting has only a weak impact on local submarine melt rate but increases total ablation by submarine melting due to the larger submerged ice surface area. Thus, the impact of melting is determined not only by the melt rate magnitude but also by the slope of the ice-ocean interface. We suggest that the most severe undercutting occurs at the maximum height in the fjord reached by the plume, likely promoting calving of ice above. It remains unclear, however, whether undercutting proceeds sufficiently rapidly to influence calving at Greenland's fastest-flowing glaciers.

  14. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of upward looking sonar draft data collected by submarines in the Arctic Ocean. It includes data from both U.S. Navy and Royal Navy...

  15. Virtual Reality Training System for a Submarine Command Center

    National Research Council Canada - National Science Library

    Maxwell, Douglas B


    The invention as disclosed is a system that uses a combined real and virtual display interaction methodology to generate the visual appearance of submarine combat control rooms and allow interaction...

  16. Studies on submarine control for periscope depth operations


    Tolliver, John V.


    Approved for public release; distribution in unlimited. Requirements for submarine periscope depth operations have been increased by integration with carrier battle groups, littoral operations, and contributions to joint surveillance. Improved periscope depth performance is therefore imperative. Submarine control personnel rely on a large number of analog gauges and indications. An integrated digital display system could enhance the ergonomics of the human control interface and display add...

  17. Exercise Aboard Attack Submarines: Rationale and New Options (United States)


    experience loss of physical fitness while underway. Bennett and co-workers (2) noted a 7% reduction of maximal oxygen consumption in non-exercising...Inc. designed and built a comprehensive resistance exercise device to help counteract muscle deconditioning during long term space flights (the SX... Physical activity aboard nuclear submarines as measured by pedometry. Groton: Naval Submarine Medical Research Laboratory, Report 1053, 1985, p. 12

  18. The development of permafrost bacterial communities under submarine conditions (United States)

    Mitzscherling, Julia; Winkel, Matthias; Winterfeld, Maria; Horn, Fabian; Yang, Sizhong; Grigoriev, Mikhail N.; Wagner, Dirk; Overduin, Pier P.; Liebner, Susanne


    Submarine permafrost is more vulnerable to thawing than permafrost on land. Besides increased heat transfer from the ocean water, the penetration of salt lowers the freezing temperature and accelerates permafrost degradation. Microbial communities in thawing permafrost are expected to be stimulated by warming, but how they develop under submarine conditions is completely unknown. We used the unique records of two submarine permafrost cores from the Laptev Sea on the East Siberian Arctic Shelf, inundated about 540 and 2500 years ago, to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry. Combined with geochemical analysis, we quantified total cell numbers and bacterial gene copies and determined the community structure of bacteria using deep sequencing of the bacterial 16S rRNA gene. We show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions. Pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw. Millennia after inundation by seawater, bacteria stratify into communities in permafrost, marine-affected permafrost, and seabed sediments. In contrast to pore water chemistry, the development of bacterial community structure, diversity, and abundance in submarine permafrost appears site specific, showing that both sedimentation and permafrost thaw histories strongly affect bacteria. Finally, highest microbial abundance was observed in the ice-bonded seawater unaffected but warmed permafrost of the longer inundated core, suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming.

  19. Cardiometabolic Health in Submariners Returning from a 3-Month Patrol

    Directory of Open Access Journals (Sweden)

    Heath G. Gasier


    Full Text Available Confined space, limited exercise equipment, rotating shift work and reduced sleep may affect cardiometabolic health in submariners. To test this hypothesis, 53 male U.S. Submariners (20–39 years were studied before and after a 3-month routine submarine patrol. Measures included anthropometrics, dietary and physical activity, biomarkers of cardiometabolic health, energy and appetite regulation, and inflammation. Before deployment, 62% of submariners had a body fat % (BF% ≥ 25% (obesity, and of this group, 30% met the criteria for metabolic syndrome. In obese volunteers, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR, leptin, the leptin/adiponectin ratio, and pro-inflammatory chemokines growth-related oncogene and macrophage-derived chemokine were significantly higher compared to non-obese submariners. Following the patrol, a significant mean reduction in body mass (5% and fat-mass (11% occurred in the obese group as a result of reduced energy intake (~2000 kJ during the patrol; and, independent of group, modest improvements in serum lipids and a mean reduction in interferon γ-induced protein 10 and monocyte chemotactic protein 1 were observed. Since 43% of the submariners remained obese, and 18% continued to meet the criteria for metabolic syndrome following the patrol, the magnitude of weight loss was insufficient to completely abolish metabolic dysfunction. Submergence up to 3-months, however, does not appear to be the cause of obesity, which is similar to that of the general population.

  20. Solution of Supplee's submarine paradox through special and general relativity

    CERN Document Server

    Vieira, R S


    In 1989 Supplee described an apparent relativistic paradox on which a submarine seems to sink in a given frame while floating in another one. If the submarine density is adjusted to be the same as the water density (when both of them are at rest) and then it is put to move, the density of the submarine will become higher than that of the water, thanks to Lorentz contraction, and hence it sinks. However, in the submarine proper frame, is the water that becomes denser, so the submarine supposedly should float and we get a paradox situation. In this paper we analyze the submarine paradox in both a flat and a curved spacetime. In the case of a flat spacetime, we first show that any relativistic force field in special relativity can be written in the Lorentz form, so that it can always be decomposed into a static (electric-like) and a dynamic (magnetic-like) part. Taking into account the gravitomagnetic effects between the Earth and the water, a relativistic formulation of Archimedes principle can be established, ...

  1. Deep water velocities and particle displacements induced by acoustic-gravity waves from submarine earthquakes (United States)

    Oliveira, T. C. A.; Kadri, U.


    An uplift of the ocean bottom caused by a submarine earthquake can generate Acoustic-Gravity Waves (AGW), progressive compression-type waves that travel at near the speed of sound in water. The role of AGW for oceans hydrodynamics has recently became a topic of increasing scientific interest. Kadri [Deep ocean water transport by acoustic-gravity waves, J.Geo. Res. Oceans, 119, (2014)] showed theoretically that AGW can contribute to deep ocean currents and circulation. We analyze and simulate the fundamental AGW modes generated by a submarine earthquake. We consider the first five AGW modes and show that they may all induce comparable temporal variations in water particle velocities at different depths in regions far from the epicenter. Results of temporal variations of horizontal and vertical fluid parcel velocities induced by AGW confirm chaotic flow trajectories at different water depths. A realistic example based on the 2004 Indian Ocean earthquake shows that vertical water particle displacements of O(10-2 ) m can be generated at 1 Km depth in a 4 km water depth ocean. We show that the velocity field depends on the presence of the leading AGW modes. Each AGW mode becomes evanescent at a critical time, at which energy is transferred to the next higher modes. Consequently, the main pattern of the velocity field changes as the leading mode change. As an example, for a reference point located at 1000 Km from the epicenter, the first five AGW become evanescent after 1.6, 4.6, 7.7, 10.8 and 13.8 hours, respectively. Our analysis and simulations shed light on the spatio-temporal evolution of the deep water velocities and particle displacements induced by AGW that radiate during submarine earthquakes. Thus, this work is a contribution to understand the role of high moment magnitude submarine earthquakes in deep water mixing mechanism.

  2. Deformation microstructures and timing of a large submarine landslide drilled offshore Martinique (IODP Exp. 340) (United States)

    Guyard, H.; Le Friant, A.; Brunet, M.; Boudon, G.; Emmanuel, L.; Caron, B.; Villemant, B.; Feuillet, N.


    Flank-instabilities constitute a recurrent process in the long-term evolution of many volcanoes. A very large submarine landslide deposit (~2100 km2, ~300 km3) drilled southwest Martinique island during the IODP Exp. 340 in 2012 is likely associated with one (or more) major volcanic flank collapse of Mount Pelée during the Late Pleistocene. A recent study revealed that this D1/D2 deposit is emergent in its central part, frontally confined, and mainly comprises remobilized seafloor sediments rather than debris avalanche material from the volcanic edifice (Brunet et al., subm). Here, we investigate the sedimentary microstructures and timing of deformation from the central (Hole 1400B, ~37 km from the coastline) and distal (Hole 1399A, ~70 km from the coastline) units of the D1/D2 deposit, in order to better understand the emplacement dynamics of such potentially tsunamigenic submarine landslides. High resolution CT-Scan analyses were continuously performed on more than 300 m of sediment cores, in order to characterize and distinguish the internal architecture and the complex deformation features of the sediments at each drilling site. The establishment of the stratigraphy, based on δ18O measurements and AMS 14C dating, is still in progress and may confirm the possible link between the submarine landslide deposits and the flank collapse scars observed on the subaerial part of Martinique. These new insights into the timing and emplacement processes of this large submarine landslide will have important implications for tsunami hazards. ReferenceBrunet, M., Le Friant, A., Boudon, G., Lafuerza, S., Talling, P., Hornbach, M., Lebas, E., Guyard, H., and IODP Expedition 340 science party, submitted. Composition, geometry and emplacement dynamics of a large volcanic island landslide offshore Martinique: from volcano flank-collapse to seafloor sediment failure? Geochemistry, Geophysics, Geosystems.

  3. Did a submarine landslide contribute to the 2011 Tohoku tsunami?

    KAUST Repository

    Tappin, David R.


    Many studies have modeled the Tohoku tsunami of March 11, 2011 as being due entirely to slip on an earthquake fault, but the following discrepancies suggest that further research is warranted. (1) Published models of tsunami propagation and coastal impact underpredict the observed runup heights of up to 40 m measured along the coast of the Sanriku district in the northeast part of Honshu Island. (2) Published models cannot reproduce the timing and high-frequency content of tsunami waves recorded at three nearshore buoys off Sanriku, nor the timing and dispersion properties of the waveforms at offshore DART buoy #21418. (3) The rupture centroids obtained by tsunami inversions are biased about 60 km NNE of that obtained by the Global CMT Project. Based on an analysis of seismic and geodetic data, together with recorded tsunami waveforms, we propose that, while the primary source of the tsunami was the vertical displacement of the seafloor due to the earthquake, an additional tsunami source is also required. We infer the location of the proposed additional source based on an analysis of the travel times of higher-frequency tsunami waves observed at nearshore buoys. We further propose that the most likely additional tsunami source was a submarine mass failure (SMF—i.e., a submarine landslide). A comparison of pre- and post-tsunami bathymetric surveys reveals tens of meters of vertical seafloor movement at the proposed SMF location, and a slope stability analysis confirms that the horizontal acceleration from the earthquake was sufficient to trigger an SMF. Forward modeling of the tsunami generated by a combination of the earthquake and the SMF reproduces the recorded on-, near- and offshore tsunami observations well, particularly the high-frequency component of the tsunami waves off Sanriku, which were not well simulated by previous models. The conclusion that a significant part of the 2011 Tohoku tsunami was generated by an SMF source has important implications for

  4. ROV Tiburon Investigation of Hawaiian Submarine Canyons (United States)

    Paull, C. K.; Greene, H. G.; Caress, D. W.; Clague, D. A.; Ussler, W.; Maher, N. M.


    MBARI conducted ROV dives around the Hawaiian Islands during an expedition of the R/V Western Flyer and Tiburon in the spring of 2001. Eight ROV dives were made to investigate five major submarine canyons offshore of Oahu, Molokai, and Hawaii in up to 3,434 m water depths. Four of these canyons are located off the windward (northern) side of these islands where onshore canyons are also well developed. Those canyons located offshore of Molokai and Oahu incise the head scars of the giant Nuuanu and Wailai submarine landslides. ROV observations and sediment and rock outcrop sampling were made in these canyons to determine their origin and present-day activity. The fifth canyon investigated is located on the leeward (southern) side of Molokai. The canyons along the windward side expose extensive stratigraphic sections that reveal the history of the islands' formation. In composite, these sections contain marine pillow basalt overlain by a substantial sequence of alternating subaerial lava flows, rounded boulder conglomerates, shallow water carbonates, and hyaloclastites that indicate coastal and marine deposition. These sequences illustrate the accretion and subsequent subsidence of the islands' flanks. These canyons also have morphologically distinct upper and lower sections. The upper reaches of the canyons are incised into the shallow water marine facies and contain broad axial channels through which active sediment transport is occurring. In contrast, the morphology of the lower canyons are strongly influenced by the giant landslides that massively altered the northern flanks of the Hawaiian chain. The lower canyons contain plunge pools and steep headwall scarps that are generally comprised of mechanically competent subaerial lava flows. The presence of multiple plunge pools with differentially eroded head scarps suggests retrogressive erosion (bottom-up process) with headward advancement of the various heads. Undercutting of the headwalls also produce periodic

  5. Draft environmental impact statement for construction and operation of the proposed Bangor Hydro-Electric Company`s second 345-kV transmission tie line to New Brunswick

    Energy Technology Data Exchange (ETDEWEB)



    This Draft Environmental Impact Statement (DEIS) was prepared by the US Department of Energy (US DOE). The proposed action is the issuance of Presidential Permit PP-89 by DOE to Bangor Hydro-Electric Company to construct and operate a new international transmission line interconnection to New Brunswick, Canada that would consist of an 83.8 mile (US portion), 345-kilovolt (kV) alternating current transmission line from the US-Canadian border at Baileyville, Maine to an existing substation at Orrington, Maine. The principal environmental impacts of the construction and operation of the transmission line would be incremental in nature and would include the conversion of forested uplands (mostly commercial timberlands) and wetlands to right-of-way (small trees, shrubs, and herbaceous vegetation). The proposed line would also result in localized minor to moderate visual impacts and would contribute a minor incremental increase in the exposure of some individuals to electromagnetic fields. This DEIS documents the purpose and need for the proposed action, describes the proposed action and alternatives considered and provides a comparison of the proposed and alternatives routes, and provides detailed information on analyses of the environmental consequences of the proposed action and alternatives, as well as mitigative measures to minimize impacts.

  6. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. II. Nutrient loading, submarine light, and seagrasses (United States)

    Buzzelli, Christopher; Doering, Peter; Wan, Yongshan; Sun, Detong


    Short- and long-term changes in estuarine biogeochemical and biological attributes are consequences of variations in both the magnitude and composition of freshwater inputs. A common conceptualization of estuaries depicts nutrient loading from coastal watersheds as the stressor that promotes algal biomass, decreases submarine light penetration, and degrades seagrass habitats. Freshwater inflow depresses salinity while simultaneously introducing colored dissolved organic matter (color or CDOM) which greatly reduces estuarine light penetration. This is especially true for sub-tropical estuaries. This study applied a model of the Caloosahatchee River Estuary (CRE) in southwest Florida to explore the relationships between freshwater inflow, nutrient loading, submarine light, and seagrass survival. In two independent model series, the loading of dissolved inorganic nitrogen and phosphorus (DIN and DIP) was reduced by 10%, 20%, 30%, and 50% relative to the base model case from 2002 to 2009 (2922 days). While external nutrient loads were reduced by lowering inflow (Q0) in the first series (Q0 series), reductions were accomplished by decreasing the incoming concentrations of DIN and DIP in the second series (NP Series). The model also was used to explore the partitioning of submarine light extinction due to chlorophyll a, CDOM, and turbidity. Results suggested that attempting to control nutrient loading by decreasing freshwater inflow could have minor effects on water column concentrations but greatly influence submarine light and seagrass biomass. This is because of the relative importance of Q0 to salinity and submarine light. In general, light penetration and seagrass biomass decreased with increased inflow and CDOM. Increased chlorophyll a did account for more submarine light extinction in the lower estuary. The model output was used to help identify desirable levels of inflow, nutrient loading, water quality, salinity, and submarine light for seagrass in the lower CRE

  7. From submarine to lacustrine groundwater discharge (United States)

    Lewandowski, Jörg; Meinikmann, Karin; Pöschke, Franziska; Nützmann, Gunnar; Rosenberry, Donald O.


    Submarine groundwater discharge (SGD) and its role in marine nutrient cycling are well known since the last decade. The freshwater equivalent, lacustrine groundwater discharge (LGD), is often still disregarded, although first reports of LGD are more than 50 years old. We identify nine different reasons why groundwater has long been disregarded in both freshwater and marine environments such as invisibility of groundwater discharge, the size of the interface and its difficult accessibility. Although there are some fundamental differences in the hydrology of SGD and LGD, caused primarily by seawater recirculation that occurs only in cases of SGD, there are also a lot of similarities such as a focusing of discharge to near-shore areas. Nutrient concentrations in groundwater near the groundwater–surface water interface might be anthropogenically enriched. Due to spatial heterogeneity of aquifer characteristics and biogeochemical processes, the quantification of groundwater-borne nutrient loads is challenging. Both nitrogen and phosphorus might be mobile in near-shore aquifers and in a lot of case studies large groundwater-borne nutrient loads have been reported.

  8. Design and analysis of submarine radome (United States)

    Sandeep, C. Satya; Prasad, U. Shiva; Suresh, R.; Rathan, A.; Sravanthi, G.; Govardhan, D.


    Radomes are the electromagnetic windows that protect microwave sub-systems from the environmental effects. The major requirement of radome is its transparency to microwaves and for most of the cases mechanical properties are also equally important. Radome for underwater applications has to withstand high water pressure of the order of 45 bars. Composite materials owing to their high strength to weight ratio, high stiffness and better corrosion resistance are potential source for under water applications. The concept of 'tailoring' the material properties to suit the radome is obtained by selecting proper reinforcement, resin matrix and their compositions. The mechanical properties of composite material, evaluated by testing specimens as per ASTM standards, are utilized in designing the radome. The modulus properties calculated using classical theories of composite materials and compared with test results. ANSYS a Finite Element software package used to analyse the problem. As the cross sectional thickness of radome varies, the complexity in fabrication is overcome by adopting matched die techniques. The radome design and finite element analysis validation concluded by conducting the pressure test on radome. On the design a modal analysis is also carried to check for the natural frequency, So that resonance does not occur if the natural frequency of the radome coincides with the excitation frequency of the submarine Clinical information system (CIS) for UNRWA is a computerized distributed application that used in clinics which follows the United Nations Relief and Works Agency (UNRWA) to manage the clinical requirements and services.

  9. Submarine landslides of the Southern California Borderland (United States)

    Lee, H.J.; Greene, H. Gary; Edwards, B.D.; Fisher, M.A.; Normark, W.R.


    Conventional bathymetry, sidescan-sonar and seismic-reflection data, and recent, multibeam surveys of large parts of the Southern California Borderland disclose the presence of numerous submarine landslides. Most of these features are fairly small, with lateral dimensions less than ??2 km. In areas where multibeam surveys are available, only two large landslide complexes were identified on the mainland slope- Goleta slide in Santa Barbara Channel and Palos Verdes debris avalanche on the San Pedro Escarpment south of Palos Verdes Peninsula. Both of these complexes indicate repeated recurrences of catastrophic slope failure. Recurrence intervals are not well constrained but appear to be in the range of 7500 years for the Goleta slide. The most recent major activity of the Palos Verdes debris avalanche occurred roughly 7500 years ago. A small failure deposit in Santa Barbara Channel, the Gaviota mudflow, was perhaps caused by an 1812 earthquake. Most landslides in this region are probably triggered by earthquakes, although the larger failures were likely conditioned by other factors, such as oversteepening, development of shelf-edge deltas, and high fluid pressures. If a subsequent future landslide were to occur in the area of these large landslide complexes, a tsunami would probably result. Runup distances of 10 m over a 30-km-long stretch of the Santa Barbara coastline are predicted for a recurrence of the Goleta slide, and a runup of 3 m over a comparable stretch of the Los Angeles coastline is modeled for the Palos Verdes debris avalanche. ?? 2009 The Geological Society of America.

  10. Submarine landslides in Arctic sedimentation: Canada Basin (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.


    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  11. “Hello, HELLO! Anyone there? - on the need to assess the tsunami risk to global submarine telecommunications infrastructure (United States)

    Dominey-Howes, D.; Goff, J. R.


    National economies are increasingly dependent on the global telecommunications system - and in particular, its submarine cable infrastructure. Submarine cable traffic represents about 30% of global GDP so the cost of losing, or even simply slowing, communications traffic is high. Many natural hazards are capable of damaging and destroying this infrastructure but tsunamis are the most significant threat, particularly in waters >1000 m deep. Submarine cables and their shore-based infrastructure (the anchor points), are at risk from direct and indirect tsunami-related effects. During the 2004 Indian Ocean Tsunami in India and Indonesia, cables were broken (direct effect) as the tsunami eroded supporting sediments, and were further damaged by floating/submerged objects and intense nearshore currents. Shore-based infrastructure was also directly damaged in India, Indonesia, and the Maldives. The 1929 Grand Banks earthquake generated a submarine landslide and tsunami off Newfoundland which broke 12 submarine telegraph cables. In 2006, an earthquake in Taiwan generated submarine landslides and a tsunami. These landslides caused one of the largest disruptions of modern telecommunications history when nine cables in the Strait of Luzon were broken disabling vital connections between SE Asia and the rest of the world. Although electronic traffic in and out of Australia was slowed, it did not cease because >70% of our traffic is routed via cables that pass through Hawaii. This is extremely significant because Hawaii is an internationally recognised bottleneck or “choke point” in the global telecommunications network. The fact that Hawaii is a choke point is important because it is regularly affected by numerous large magnitude natural hazards. Any damage to the submarine telecommunications infrastructure routed through Hawaii could result in significant impacts on the electronic flow of data and voice traffic, negatively affecting dependent economies such as Australia

  12. NSMRL: A Small Command with A Huge Presence for the Submarine Force

    National Research Council Canada - National Science Library

    Daniel, J. C; Lamb, Jerry


    "To protect the health and enhance the performance of our warfighters through focused submarine, diving and surface research solutions" is the mission of the Naval Submarine Medical Research Laboratory (NSMRL...

  13. Submarine springs and coastal karst aquifers: A review (United States)

    Fleury, Perrine; Bakalowicz, Michel; de Marsily, Ghislain


    SummaryThis article reports on current knowledge of coastal karst aquifers, in which conduit flow is dominant, and its aim is to characterise the functioning of these systems which are closely linked to the sea. First, earlier and recent studies of these aquifers are discussed. On the basis of their findings, it can be shown that two essential mechanisms are involved in the functioning of these systems, i.e., aquifer discharge through submarine springs and saline intrusion through conduits open to the sea. Then, the conditions that give rise to these aquifers are described and particular emphasis is placed on the influence of deep karstification when the sea level falls. The base-level variations are attributed to the glaciations or, in the specific case of the Mediterranean, to the salinity crisis in the Messinian period. It is this inherited structure, sometimes containing very deep conduits below sea level, that today conditions the aquifer flow. The flow in the conduits open to the sea depends on the hydraulic head gradient between the aquifer and the sea and is therefore a function of the water density and head losses in the aquifer. This survey of coastal karst aquifers has revealed some common characteristics that show the development and/or functional capacity of their karstic drainage networks. A classification of such systems into three categories is proposed with the aim of assisting in the decision-making concerning potential exploitation of water resources in coastal regions.

  14. Conduct and Support of Amphibious Operations from United States Submarines in World War II (United States)


    twelfth war patrol of the Gato class submarine (See photos 1 and 2). They made history as the only Americans to conduct an offensive landing on a...Naval History Vol. 2, no. 1 (April 1, 2003), 1. 4 This monograph features five Gato class submarines, and three V-class submarines, but also addresses...1993), 67. 6 Photo 2: USS Barb (SS 220), representing the five Gato class submarines that participated in Operation Torch. Barb’s crew also

  15. Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress (United States)


    Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress Ronald O’Rourke Specialist in Naval...Affairs April 5, 2016 Congressional Research Service 7-5700 R41129 Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine...Replacement (SSBN[X]) Ballistic Missile Submarine Program Congressional Research Service Contents Introduction

  16. Process sedimentology of submarine fan deposits - new perspectives (United States)

    Postma, George


    To link submarine fan process sedimentology with sand distribution, sand body architecture, texture and fabric, the field geologist studies sedimentary facies, facies associations (fan elements) and stratigraphy. Facies analysis resides on factual knowledge of modern fan morphodynamics and physical modelling of en-masse sediment transport. Where do we stand after 55 years of submarine research, i.e. the date when the first submarine fan model was launched by Arnold Bouma in 1962? Since that date students of submarine fans have worked on a number of important, recurring questions concerned with facies analysis of submarine successions in outcrop and core: 1. What type of sediment transport produced the beds? 2. What facies can be related to initial flow conditions? 3. What is the significance of grain size jumps and bounding surface hierarchy in beds consisting of crude and spaced stratification (traction carpets)? Do these point to multi flow events or to flow pulsations by one and the same event? 4. What facies associations relate to the basic elements of submarine fans? 5. What are the autogenic and allogenic signatures in submarine fans? Particularly in the last decade, the enormous technical advancement helped to obtain high-quality data from observations of density flows in modern canyons, deep basins and deep-water delta slopes (refs 1,2,3). In combination with both physical (refs 4,5) and numerical modelling (ref 6) these studies broke new ground into our understanding of density flow processes in various submarine environments and have led to new concepts of submarine fan building by super- and subcritical high-density flow (ref 7). Do these new concepts provide better answers to our recurrent questions related to the morphodynamics of submarine fans and prediction of sand body architecture? In discussing this open question, I shall 1. apply the new concepts to a modern and ancient example of a channel-lobe-transition-zone (ref 8); 2. raise the problem of

  17. Navy Columbia Class (Ohio Replacement) Ballistic Missile Submarine (SSBN[X]) Program: Background and Issues for Congress (United States)


    nuclear deterrent force, or “triad,” which also includes land-based intercontinental ballistic missiles (ICBMs) and land-based long-range bombers. At any...any vessel owned, operated, or controlled by the Department of Defense that carries operational intercontinental ballistic missiles . Precedents for...Navy Columbia Class (Ohio Replacement) Ballistic Missile Submarine (SSBN[X]) Program: Background and Issues for Congress Ronald O’Rourke

  18. Origin of the Easter Submarine Alignment: morphology and structural lineaments

    Directory of Open Access Journals (Sweden)

    Cristián Rodrigo


    Full Text Available The Easter submarine alignment corresponds to a sequence of seamounts and oceanic islands which runs from the Ahu-Umu volcanic fields in the west to its intersection with the Nazca Ridge in the east, with a total length of about 2.900 km and a strike of N85°E. Recent bathymetric compilations that include combined satellite derived and shipboard data (Global Topography and multibeam bathymetric data (from NGDC-NOAA are interpreted both qualitatively and quantitatively by using a morphological analysis, which was comprised of the determination of bathymetric patterns, trends in lineations and structures; height measurements, computation of basal areas and volumes of seamounts, in order to establish clues on the origin of this seamount chain and to establish relationships with the regional tectonics. In the study region 514 seamounts were counted, of which 334 had a basal area less than the reference seamount (Moai. In general, the largest seamounts (>1000 m in height tend to align and to have a larger volume, with an elongation of their bases along the seamount chain. On the other hand, smaller seamounts tend to be distributed more randomly with more circular bases. As a consequence of the morphological analysis, the best possible mechanism that explains the origin of the seamount chain is the existence of a localized hotspot to the west of the Salas y Gómez Island. The corresponding plume would contribute additional magmatic material towards the East Pacific Rise through canalizations, whose secondary branches would feed intermediate volcanoes. It is possible that within the Easter Island region there would be another minor contribution through fractures in the crust, due to the crustal weakening that was produced by the Easter Fracture Zone.

  19. US Navy Submarine Sea Trial of NASA developed Multi-Gas Monitor (United States)

    Mudgett, Paul D.; Manney, Joshua A.; Smith, Matthew J.; O'Connor, Sara Jane; Pilgrim, Jeffrey S.


    During a successful 2 year technology demonstration of the tunable diode laser spectroscopy (TDLS) based Multi-Gas Monitor (MGM) on the International Space Station (ISS), we began discussing with the US Navy the possibility of conducting a sea trial of an MGM on a submarine. The sea trial would also include a gas chromatography/differential mobility spectrometer based Air Quality Monitor (AQM), which is used operationally on ISS for volatile organic compound analysis. AQM preparation and results will be the subject of a separate paper. The Navy's interest in testing NASA equipment in general relates to their ongoing search for better air monitoring technology. NASA's goal is studying submarines as closed environment analogs to spacecraft. MGM's core technology was developed by Vista Photonics Inc. using Small Business Innovation Research (SBIR) grants and expanded for various applications using NASA program funding. The MGM measures oxygen, carbon dioxide, ammonia and water vapor in ambient air, displays concentrations with temperature and pressure, and stores 30 second moving averages. The sea trial involves collocating the instrument with the Central Atmosphere Monitoring System (CAMS Mk II) of the submarine, connecting it to rack power prior to departure, and letting it run during the entire 90 day patrol. All data is stored within MGM, with no connection to the vessel data bus. Crew intervention is limited to checking MGM periodically to see that it is working and power cycling if necessary. After the trial is over, the unit with its data will be retrieved. Post sea trial calibration check and data analysis are planned and results will be compared with both CAMS Mk II data and results from MGM's ISS technology demonstration. Since the sea trial itself has been delayed, this paper describes the preparation of MGM for the sea trial and also provides a summary of the latest data from the ISS MGM technology demonstration.

  20. A submarine volcanic eruption leads to a novel microbial habitat. (United States)

    Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia


    Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.

  1. Does calving matter? Evidence for significant submarine melt (United States)

    Bartholomaus, Timothy C.; Larsen, Christopher F.; O’Neel, Shad


    During the summer in the northeast Pacific Ocean, the Alaska Coastal Current sweeps water with temperatures in excess of 12 °C past the mouths of glacierized fjords and bays. The extent to which these warm waters affect the mass balance of Alaskan tidewater glaciers is uncertain. Here we report hydrographic measurements made within Icy Bay, Alaska, and calculate rates of submarine melt at Yahtse Glacier, a tidewater glacier terminating in Icy Bay. We find strongly stratified water properties consistent with estuarine circulation and evidence that warm Gulf of Alaska water reaches the head of 40 km-long Icy Bay, largely unaltered. A 10–20 m layer of cold, fresh, glacially-modified water overlies warm, saline water. The saline water is observed to reach up to 10.4 °C within 1.5 km of the terminus of Yahtse Glacier. By quantifying the heat and salt deficit within the glacially-modified water, we place bounds on the rate of submarine melt. The submarine melt rate is estimated at >9 m d−1, at least half the rate at which ice flows into the terminus region, and can plausibly account for all of the submarine terminus mass loss. Our measurements suggest that summer and fall subaerial calving is a direct response to thermal undercutting of the terminus, further demonstrating the critical role of the ocean in modulating tidewater glacier dynamics.

  2. Submarine Construction in Germany (U-Bootbau in Deutschland), (United States)


    the IKL sister firm, Maschinenbau Gabler GmbH, also founded by Prof. Gabler, which, unlike IKL (involved solely in development), is a hardware...snorkels, radar masts, as well as wharf and dockside connections, for IKL and various submarine yards. Moreover, Maschinenbau Gabler is engaged in

  3. Dissolved Nutrients from Submarine Groundwater in Flic en Flac ...

    African Journals Online (AJOL)

    Abstract—The aim of this study was to investigate dissolved nutrients in a submarine groundwater discharge (SGD) in Flic en Flac lagoon on the west coast of the volcanic island of Mauritius. The SGD enters Flic en Flac lagoon through a thin blanket of unconsolidated sediment through a fracture system and is concentrated ...

  4. Dissolved Nutrients from Submarine Groundwater in Flic en Flac ...

    African Journals Online (AJOL)

    The aim of this study was to investigate dissolved nutrients in a submarine groundwater discharge (SGD) in Flic en Flac lagoon on the west coast of the volcanic island of Mauritius. The SGD enters Flic en Flac lagoon through a thin blanket of unconsolidated sediment through a fracture system and is concentrated along the ...

  5. Sedimentary characteristics of samples collected from some submarine canyons

    NARCIS (Netherlands)

    Bouma, Arnold H.

    Oriented rectangular cores of 20.3 × 30.5 cm and 45.7 cm high have been collected in a number of submarine canyons off southern California (U.S.A.) and off the southern tip of Baja California (Mexico) for a detailed study of their sedimentary structures. By applying several methods, mainly X-ray

  6. 'Good Hunting': German submarine offensives and South African ...

    African Journals Online (AJOL)

    The first German submarine offensive in South African waters during 1942, Operation Eisbär, was aimed at striking a devastating blow to shipping off the South African coast. By the end of December 1942, an estimated 310 864 tons of shipping had been sunk through Operation Eisbär and the first U-cruiser operation alone.

  7. Cost Estimation Lessons Learned for Future Submarine Acquisition Programs (United States)


    North Carolina and New Mexico 30 General Dynamics Electric Boat “U.S. Navy Awards General Dynamics $14 Billion Contract for Eight Virginia- Class...NAVSEA Program Executive officer, Submarines PMO 450, June 1995. “New SSN Program Life Cycle Cost Estimate.” Naval Center for Cost Analysis: GE-1300

  8. Exploring the submarine Graham Bank in the Sicily Channel

    Directory of Open Access Journals (Sweden)

    Mauro Coltelli


    Full Text Available In the Sicily Channel, volcanic activity has been concentrated mainly on the Pantelleria and Linosa islands, while minor submarine volcanism took place in the Adventure, Graham and Nameless banks. The volcanic activity spanned mostly during Plio-Pleistocene, however, historical submarine eruptions occurred in 1831 on the Graham Bank and in 1891 offshore Pantelleria Island. On the Graham Bank, 25 miles SW of Sciacca, the 1831 eruption formed the short-lived Ferdinandea Island that represents the only Italian volcano active in historical times currently almost completely unknown and not yet monitored. Moreover, most of the Sicily Channel seismicity is concentrated along a broad NS belt extending from the Graham Bank to Lampedusa Island. In 2012, the Istituto Nazionale di Geofisica e Vulcanologia (INGV carried out a multidisciplinary oceanographic cruise, named “Ferdinandea 2012”, the preliminary results of which represent the aim of this paper. The cruise goal was the mapping of the morpho-structural features of some submarine volcanic centres located in the northwestern side of the Sicily Channel and the temporary recording of their seismic and degassing activity. During the cruise, three OBS/Hs (ocean bottom seismometer with hydrophone were deployed near the Graham, Nerita and Terribile submarine banks. During the following 9 months they have recorded several seismo-acoustic signals produced by both tectonic and volcanic sources. A high-resolution bathymetric survey was achieved on the Graham Bank and on the surrounding submarine volcanic centres. A widespread and voluminous gas bubbles emission was observed by both multibeam sonar echoes and a ROV (remotely operated vehicle along the NW side of the Graham Bank, where gas and seafloor samples were also collected.

  9. Effectiveness of Unmanned Surface Vehicles in Anti-submarine Warfare with the Goal of Protecting a High Value Unit (United States)


    author and do not reflect the official policy or position of the Department of Defense or the U.S. Government . IRB Protocol number ____N/A...Communication SOA Speed of Advance SSK Diesel Electric Submarine TDZ Torpedo Danger Zone UAV Unmanned Aerial Vehicle USV Unmanned Surface Vehicle UUV...sensors. Agent-based models can perform non-linear behavior patterns , capture organizational dynamics, and provide valuable insights about real-world

  10. Seismic site response of submarine slope offshore southwestern Taiwan

    Directory of Open Access Journals (Sweden)

    Jing-Yi Lin


    Full Text Available Widely distributed Bottom-Simulating Reflectors (BSRs have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In order to clarify the link between seismic site response and sedimentary properties of submarine slope, we evaluate the response of seafloor sediments in regard to passive dynamic loads. The local site effect produced by shallow marine sediments was characterized by estimating the horizontal-to-vertical (H/V spectral ratios of data recorded by the short-period Ocean Bottom Seismometers (OBSs. The results show that the maximal H/V ratios appeared in the range of 3.66 - 9.28 Hz, suggesting that the fundamental frequency is dominated by the effect related to the very shallow sediments. For most stations, the H/V ratios estimated based on the earthquakes and noise records were characterized by different patterns. Relatively broad H/V pattern was obtained when the signals were extracted from earthquakes. This phenomenon may be related to soil nonlinearity when a stronger motion applies. In comparison with the available geological structures and bulk density distribution obtained from coring experiments, we found a relatively higher fundamental frequency of about 8 - 9 Hz for the more rigid material, such as mud diapir and folding axes. For most of the area along the slope, the fundamental frequency shows a relatively low value, about 6 - 8 Hz. Finally, when a site is characterized by thick or lowest bulk density sedimentary layer, we observed a fundamental frequency lower than 5 Hz, which is the lowest in our assessment.

  11. Analysis of Submarine Landslides and Canyons along the U.S. Atlantic Margin Using Extended Continental Shelf Mapping Data (United States)

    Chaytor, J. D.; Brothers, D. S.; Ten Brink, U. S.; Hoy, S. K.; Baxter, C.; Andrews, B.


    U.S. Geological Survey (USGS) studies of the U.S. Atlantic continental slope and rise aim to understand the: 1) the role of submarine landslides in tsunami generation, and 2) the linkages between margin morphology and sedimentary processes, particularly in and around submarine canyon systems. Data from U.S. Extended Continental Shelf (ECS) and numerous subsequent mapping surveys have facilitated the identification and characterization of submarine landslides and related features in fine detail over an unprecedented spatial extent. Ongoing analysis of USGS collected piston cores, sub-bottom and multichannel seismic (MCS) reflection profiles, and an extensive suite of legacy MCS data from two landslides, the Southern New England landslide zone and the Currituck Landslide, suggest that the most recent major landslide events are pre-Holocene, but that failures were complex and most likely multi-phase, at times resulting in extensive overlapping debris deposits. Piston core records plus visual observations of the seafloor from recent TowCam deployments and NOAA Ship Okeanos Explorer ROV dives reveal ongoing development of colluvial wedge-style debris aprons at the base of scarps within these landslides, showing that these regions continue to evolve long after the initial failure events. Multibeam bathymetry data and MCS profiles along the upper slope reveal evidence for vertical fluid migration and possible seabed gas expulsion. These observations underscore the need to reevaluate the sources of pore fluid overpressure in slope sediments and their role in landslide generation. ECS and more recent multibeam mapping have provided the opportunity to investigate the full extent of submarine canyon morphology and evolution from Cape Hatteras up to the US-Canadian EEZ, which has led to better understanding of the important role of antecedent margin physiography on their development. Six submarine canyon systems along the margin (Veatch, Hydrographer, Hudson, Wilmington

  12. Submarine fiber cable network systems cost planning considerations with achieved high transmission capacity and signal quality enhancement (United States)

    Rashed, Ahmed Nabih Zaki


    This paper has presented theoretically the comparison between three types of fibers which are investigated extensively: plastic clad silica (PCS), polystyrene (PS) and perfluorinated graded index polymer optical fibers (PF GI-POF) for high speed undersea cable systems. Based on experimental data, both the deep ocean water temperature and pressure are tailored as functions of the water depth. It is taken into account the estimation of the total cost of the submarine fiber cable system for transmission techniques under study. The system capacity as well as the spectral losses, and the dispersion effects are parametrically investigated over wide range ranges of the set of affecting parameters {wavelength, ocean depth (and consequently the ocean pressure and temperature), and the chemical structure}. The results show that PCS has the optimum performance in compared with other fibers. Therefore PCS fiber is the most appropriate candidate among all types of fibers for high speed local submarine communication systems.

  13. Gas Hydrate Formation Amid Submarine Canyon Incision: Investigations From New Zealand's Hikurangi Subduction Margin (United States)

    Crutchley, G. J.; Kroeger, K. F.; Pecher, I. A.; Mountjoy, J. J.; Gorman, A. R.


    We investigate gas hydrate system dynamics beneath a submarine canyon on New Zealand's Hikurangi subduction margin using seismic reflection data and petroleum systems modeling. High seismic velocities just above the base of gas hydrate stability (BGHS) indicate that concentrated gas hydrates exist beneath the canyon. Two-dimensional gas hydrate formation modeling shows how the process of canyon incision at this location alters the distribution and concentration of gas hydrate. The key modeling result is that free gas is trapped beneath the gas hydrate layer and then "captured" into a concentrated gas hydrate deposit as a result of a downward-shift in the BGHS driven by canyon incision. Our study thus provides new insight into the functioning of this process. From our data, we also conceptualize two other models to describe how canyons could significantly change gas hydrate distribution and concentration. One scenario is related to deflection of fluid flow pathways from over-pressured regions at the BGHS toward the canyon, and the other is based on relationships between simultaneous seafloor uplift and canyon incision. The relationships and processes described are of global relevance because of considerations of gas hydrate as an energy resource and the influence of both submarine canyons and gas hydrate systems on seafloor biodiversity.

  14. Sub-marine groundwater for the supply of drinking water. A review of the hydro-geological potential and its technical and economical feasibility. (United States)

    Haakon Bakken, Tor; Mangset, Lars Erik


    Sub-marine groundwater is water stored in aquifers under the sea-bed and is expected to be present in large quantities on the continental shelf. The proposed utilization of sub-marine groundwater as a new source of drinking water supply is a radical and new idea that has never been fully explored or tested anywhere in the world. In regions where access to raw water of acceptable quality is very limited and desalination of sea water is the only realistic alternative to increase the supply of potable water, utilization of sub-marine groundwater might play a role. A technical concept deemed suitable to the hydrological and geological characteristics of sub-marine water is proposed based on well-proven technology from the off-shore oil & gas sector. A course economic assessment of this concept is conducted based on judgmental cost estimates from experts in the hydro-geological and oil & gas domain. The technical concept uses a jackup or a barge with a modular rig during drilling, while a steel jacket with a modular rig or a sub-sea installation is assumed to be feasible technical solutions during production. The selection of technology will vary from case to case depending on factors such as the local off-shore conditions (wave/wind exposure, drilling depth, distance from shore, etc.), required reliability of supply, access to/availability of technology and financial considerations. A standard reverse osmosis plant is proposed as treatment solution, given the assumed need to desalinate moderately saline water. The costs of each treatment step, as a function of raw water salinity are providing input to the subsequent economical estimates. The proposed treatment solution is assumed being a conservative choice of technology. The costs of producing drinking water from sub-marine groundwater are compared with desalination of sea water, given that this is the only realistic alternative. Based on a systematic risk assessment using the same comparative financial structure and

  15. Sun glitter imaging analysis of submarine sand waves in HJ-1A/B satellite CCD images (United States)

    Zhang, Huaguo; He, Xiekai; Yang, Kang; Fu, Bin; Guan, Weibing


    Submarine sand waves are a widespread bed-form in tidal environment. Submarine sand waves induce current convergence and divergence that affect sea surface roughness thus become visible in sun glitter images. These sun glitter images have been employed for mapping sand wave topography. However, there are lots of effect factors in sun glitter imaging of the submarine sand waves, such as the imaging geometry and dynamic environment condition. In this paper, several sun glitter images from HJ-1A/B in the Taiwan Banks are selected. These satellite sun glitter images are used to discuss sun glitter imaging characteristics in different sensor parameters and dynamic environment condition. To interpret the imaging characteristics, calculating the sun glitter radiance and analyzing its spatial characteristics of the sand wave in different images is the best way. In this study, a simulated model based on sun glitter radiation transmission is adopted to certify the imaging analysis in further. Some results are drawn based on the study. Firstly, the sun glitter radiation is mainly determined by sensor view angle. Second, the current is another key factor for the sun glitter. The opposite current direction will cause exchanging of bright stripes and dark stripes. Third, brightness reversal would happen at the critical angle. Therefore, when using sun glitter image to obtain depth inversion, one is advised to take advantage of image properties of sand waves and to pay attention to key dynamic environment condition and brightness reversal.

  16. Tectonic activity and the evolution of submarine canyons: The Cook Strait Canyon system, New Zealand (United States)

    Micallef, Aaron; Mountjoy, Joshu; Barnes, Philip; Canals, Miquel; Lastras, Galderic


    Submarine canyons are Earth's most dramatic erosional features, comprising steep-walled valleys that originate in the continental shelf and slope. They play a key role in the evolution of continental margins by transferring sediments into deep water settings and are considered important biodiversity hotspots, pathways for nutrients and pollutants, and analogues of hydrocarbon reservoirs. Although comprising only one third of continental margins worldwide, active margins host more than half of global submarine canyons. We still lack of thorough understanding of the coupling between active tectonics and submarine canyon processes, which is necessary to improve the modelling of canyon evolution in active margins and derive tectonic information from canyon morphology. The objectives of this study are to: (i) understand how tectonic activity influences submarine canyon morphology, processes, and evolution in an active margin, and (2) formulate a generalised model of canyon development in response to tectonic forcing based on morphometric parameters. We fulfil these objectives by analysing high resolution geophysical data and imagery from Cook Strait Canyon system, offshore New Zealand. Using these data, we demonstrate that tectonic activity, in the form of major faults and structurally-generated tectonic ridges, leaves a clear topographic signature on submarine canyon location and morphology, in particular their dendritic and sinuous planform shapes, steep and linear longitudinal profiles, and cross-sectional asymmetry and width. We also report breaks/changes in canyon longitudinal slope gradient, relief and slope-area regression models at the intersection with faults. Tectonic activity gives rise to two types of knickpoints in the Cook Strait Canyon. The first type consists of low slope gradient, rounded and diffusive knickpoints forming as a result of short wavelength folds or fault break outs and being restored to an equilibrium profile by upstream erosion and

  17. [Medical-physiological characteristics of combat training of nuclear-power submarine crews]. (United States)

    Dovgusha, V V; Myznikov, I L; Shalabodov, S A; Bumaĭ, O K


    The article presents an observe of general questions of peculiarities of military-professional activity of submarine staff These questions are defining value in ideology of medical supply of submarine troops of NAVY in now-days conditions. The article also presents the statistics of morbidity in long termed sails for last forty years, it's dynamics by different categories of sail staff, on different stages of combat training activity in dependence of perioditation of work cycle of submarine staff The authors have examined modern condition of medical supply of submarines; have presented statistics of quality indexes of health of submarine staff The authors have formed main problems of medical supply of submarines and have proposed ways of their solving on modern stage.

  18. Losses in armoured three-phase submarine cables

    DEFF Research Database (Denmark)

    Ebdrup, Thomas; Silva, Filipe Miguel Faria da; Bak, Claus Leth


    increases the losses in armoured cables compared to unarmoured cables. In this paper a thorough state of the art analysis is conducted on armour losses in three-phase armoured submarine power cables. The analysis shows that the IEC 60287-1-1 standard overestimates the armour losses which lead...... to the installation of cables with excessive phase conductor cross section. This paper also presents an example of the potential economic benefits of having a better knowledge of the losses introduced by the armour.......The number of offshore wind farms will keep increasing in the future as a part of the shift towards a CO2 free energy production. The energy harvested from the wind farm must be brought to shore, which is often done by using a three-phase armoured submarine power cable. The use of an armour...

  19. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.


    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, to obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular the dynamic pore pressure and the combined static and dynamic effective stresses are presented. 10 references, 11 figures.

  20. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.


    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, and obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular, the dynamic pore pressure and the combined static and dynamic effective stresses are presented.

  1. The Enemy is Still Below: The Global Diffusion of Submarines and Related Technology

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, K G


    The spread of submarines and related technology is an end product of globalization. Globalization is not a new story. By one estimate, our ancestors first crossed out of Africa roughly 80,000 years ago, and began the process that they now call globalization. With the dispersion of people around the world came the development of culture and civilization as well as the spread of ideas, goods, and technology. The process of globalization then is a long-standing one, not an innovation of the late 20th and early 21st centuries. Over the millennia, this process has been an uneven one. Globalization has often cuased great disruptions even to the societies that initiated various innovations in culture and civilization, including science and technology. Indeed, many cultures and civilizations have disappeared while some regions failed to advance as rapidly as others, so the process of globalization is not just one of continuing progress. Globalization in the current era seems to be penetrating the most remote corners of the world at a remarkable rate as a result of advances in science and technology, particularly information technology. The diffusion of science and technology is not necessarily a benign development. It could increase the potential for a global military industrial base that may have an adverse affect on world stability in the future. For example, the spread of key military capabilities, like submarines, could still have an impact, especially over the longer term, on the US capability to project power overseas.

  2. Neural Network Course Changing and Track Keeping Controller for a Submarine

    Directory of Open Access Journals (Sweden)

    Dur Muhammad Pathan


    Full Text Available This paper presents the performance of ANN (Artificial Neural Networks technique for the development of controller for heading motions of submarine. A MLP (Multi-Layer Preceptron FFNN (Feed-Forward Neural Network is used for development of controller. Supervised type of learning is used for training of network by using back-propagation Algorithm. The training is performed by providing a nonlinear sliding mode controller as a supervisor. The development of controller is based on nonlinear decoupled heading model of a submarine without consideration of external environmental disturbances. To demonstrate the robustness of controller the performance of controller is tested in different operating conditions: course changing, track keeping and under the influence of sea currents. Simulations results show that in all cases, the heading error comes to zero, which indicates that the actual heading converges to the desired heading in finite time. The maximum error is observed 0.5o for 45o command angle, in presence of sea currents. The result demonstrates that the performance neural network controller has been robust.

  3. Submarine geology of South Kona landslide complex: investigation using ROV Kaiko (United States)

    Yokose, H.; Yoshida, S.


    KR01-12 cruise of Japan Marine Science and Technology Center using ROV KAIKO and its mother ship R/V KAIREI were carried out around Hawaii islands in the early fall of 2001. During this cruise, two dives of ROV KAIKO were made on western submarine flank of the island of Hawaii: South Kona landslide complex (K210:proximal part of the south Kona landslide, K211: distal block of the landslide). One single channel seismic reflection line was collected from vicinity of the above dive sites. These areas have never been systematically studied using submersible due to the bad sea state and /or the depth of outcrops. Valuable information about the submarine geology and in situ rock samples from western franks of the island of Hawaii were obtained. K211 site is one of the distal landslide block and can be divided into 3 geological units from bottom to top: picritic sheet lava and hyaloclastite, volcaniclastic deposit with picritic breccia, muddy breccia with highly vesiculated ol basalt. On the other hand, rocks recovered from K210 are composed mainly of aa clinker and aa lava which are highly vesiculated and reddish in color. The rocks from K210 is similar to the upper part of K211 in their bulk rock chemistry. Based on the geological and bulk rock chemistry, rocks recovered from both sites should be erupted subaerially. It suggests that these landslide blocks were composed subaerial portion of the paleo-Mauna Loa volcano.

  4. Submarine Channel Association with Seamount Chain Alignment on the Ontong Java Plateau (United States)

    Meyers, H. G., IV; Sautter, L.


    The Ontong Java Plateau (OJP), north of the Solomon Islands, Indonesia, is a submerged seafloor platform, larger than Alaska and full of intricate systems of channels, atolls and seamounts. This area has remained relatively unstudied because of both the area's remote location and low number of ships carrying advanced sonar systems. The OJP is believed to have been formed by one of the largest volcanic eruptions in Earth's history. This study uses EM302 multibeam sonar data collected on the R/V Falkor in 2014 by the University of Tasmania's Institute for Marine and Antarctic Studies to better understand relationships between the seafloor geomorphology and tectonic processes that formed numerous unexplored seamounts. The area surveyed is situated along the OJP's central northeast margin, and includes a small chain of six seamounts that range from 300 to 700 m in vertical relief. These seamounts are situated within the axis of a major 14 km wide submarine channel that was likely formed by a sequence of turbidity currents. Using CARIS HIPS and SIPS 9.0 post-processing software, seamount and channel morphology were characterized with 2 dimensional profiles and 3 dimensional images. Backscatter intensity was used to identify relative substrate hardness of the seamounts and surrounding seafloor areas. Scour and depositional features from the turbidity flows are evident at the base of several seamounts, indicating that the submarine channel bifurcated when turbidity flows encountered the seamount chain.

  5. Submarine fresh groundwater discharge into Laizhou Bay comparable to the Yellow River flux (United States)

    Wang, Xuejing; Li, Hailong; Jiao, Jiu Jimmy; Barry, D. A.; Li, Ling; Luo, Xin; Wang, Chaoyue; Wan, Li; Wang, Xusheng; Jiang, Xiaowei; Ma, Qian; Qu, Wenjing


    Near- and off-shore fresh groundwater resources become increasingly important with the social and economic development in coastal areas. Although large scale (hundreds of km) submarine groundwater discharge (SGD) to the ocean has been shown to be of the same magnitude order as river discharge, submarine fresh groundwater discharge (SFGD) with magnitude comparable to large river discharge is never reported. Here, we proposed a method coupling mass-balance models of water, salt and radium isotopes based on field data of 223Ra, 226Ra and salinity to estimate the SFGD, SGD. By applying the method in Laizhou Bay (a water area of ~6000 km2), we showed that the SFGD and SGD are 0.57 ~ 0.88 times and 7.35 ~ 8.57 times the annual Yellow River flux in August 2012, respectively. The estimate of SFGD ranges from 4.12 × 107 m3/d to 6.36 × 107 m3/d, while SGD ranges from 5.32 × 108 m3/d to 6.20 × 108 m3/d. The proportion of the Yellow River input into Laizhou Bay was less than 14% of the total in August 2012. Our method can be used to estimate SFGD in various coastal waters. PMID:25742712


    Directory of Open Access Journals (Sweden)

    William Power


    Full Text Available Tsunami generated by submarine landslides are now recognised as an important hazard, following several historical events. Submarine landslides can occur in a variety of settings such as on continental slopes, volcanic slopes, and submerged canyons and fjords. While significant progress has been made in understanding tsunami generation processes on open slopes, the problem of tsunami generation by landslides within submarine canyons has received less attention. In this paper we examine the tsunami hazard posed by submarine landslides in the Cook Strait canyon system, near Wellington, New Zealand. Understanding of the hazard posed by this tsunami source has practical value because of its proximity to a populated coast. Our studies also provide general results highlighting the differences between tsunami generation on open coasts and tsunami generation within canyons. Geotechnical and geological studies of the Cook Strait region reveal evidence for many large landslide scars in the canyon walls, these are interpreted to be failures of consolidated material which descend the slopes on the sides of the canyon. Scouring of the base of the canyon slopes by strong tidal currents is believed to be an important process in bringing slopes to the point of failure, with most large failures expected to occur during earthquake shaking. We present the results of computer simulations of landslide failures using simplified canyon geometries represented in either 2D (vertical slice or 3D. These simulations were made using Gerris, an adaptive-grid fluid dynamics solver. A key finding is that the sudden deceleration of the landslide material after reaching the canyon floor, leads to larger amplitude waves in the back-propagation direction (i.e. in the opposite direction to the initial landslide motion.

  7. Improving Situational Awareness on Submarines Using Augmented Reality (United States)


    COSO ) are several pages of guidance for the evolution available to the watch officer for reference. There are also Operating Procedures that the watch...officer must follow to ensure the safe ascent to PD. The COSOs are specific to the each CO. The OPs are specific to a class of submarine. The...evolution in the framework described above can provide valuable insight to the capabilities of the proposed system. This of course is a hypothetical

  8. Analysis of SSN 688 Class Submarine Maintenance Delays (United States)


    errors an in-depth analysis into the job-level maintenance is required which is outside the scope of this analysis. 25 2. New Work Causes Late...attempting to determine the cause of this trend. Finally, this thesis proposes a solution to the systematic underestimation of availability durations by...illustrating the inherent error in the current equation and providing a notional equation to remove that error . 14. SUBJECT TERMS Submarine

  9. Submarine Pressure Hull Collapse Considering Corrosion and Penetrations (United States)


    corrosion. Des valeurs de la pression d’écrasement sont calculées pour les diverses dimensions de la zone de corrosion, et ce, dans les cas de présence ou...Research & Development Canada DRDIM Director Research and Development Knowledge and Information Management OOC Out-of-circularity R&D Research...Support SLA (Mr. John Porter) 1 Project Manager , Submarine Scientific Support SLA (LCdr Wade Temple) 9 TOTAL LIST PART I LIST PART II: External

  10. Europe’s Grand Canyon: Nazaré submarine canyon


    Tyler, P.; Amaro, T.; Arzola, R.; Cunha; Stigter, H. de; Gooday, A.; Huvenne, V.; Ingels, J; Kiriakoulakis, K; Lastras, G.; Masson, D.; Oliveira, A.; Pattenden, A.; Vanreusel, A.; van Weering, T.


    The Nazare submarine canyon extends similar to 210 km westward from the coast of Portugal, down to a water depth of > 4300 m. The considerable habitat heterogeneity found throughout the canyon is affected by strong currents and high turbidity, especially in the upper parts of the canyon. The canyon morphology comprises steep slopes, scarps, terraces, and overhangs, and a deeply incised thalweg is found in the lower part of the canyon. The seabed within the canyon is composed of varying propor...

  11. Submarine and Autonomous Vessel Proliferation: Implications for Future Strategic Stability at Sea (United States)


    replace the Ohio- class SSBN and Virginia -class SSN to replace the Los Angeles class attack submarine. Although more sophisticated than their...predecessors and with some modifications to demands of the post-Cold War era and (in the Virginia class) an emphasis on littoral conflict, these purchases...Congressional Research Service analyst Amy Woolf observes: “With few submarines in the fleet, the Navy would have to reduce the number of submarines on

  12. The future of the ballistic missile submarine force in the Russian nuclear triad


    Lesiw, Richard T.


    Approved for public release; distribution is unlimited This thesis analyzes the current status of the Russian Federation's ballistic missile submarine force. It reviews the history of the ballistic missile submarine force, its current status, and the implementation of plans currently in progress and as well as the advantages and disadvantages of maintaining a ballistic missile submarine force. This thesis also assesses the other two legs of the nuclear triad - the intercontinental balli...

  13. Gender Integration on U.S. Navy Submarines: Views of the First Wave (United States)


    submarines is to perform seek-and-destroy missions on enemy ships and submarines, conduct surveillance and reconnaissance, provide covert troop insertion...not only the missile payload they were designed to carry but also extended periods at sea without resupply. In terms of berthing and sanitary ...officer berthing and sanitary 28 facilities on board Ohio class submarines, however, no significant modifications would be necessary in order to

  14. Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress (United States)


    reactors or non- nuclear power sources such as diesel engines or fuel cells. All U.S. Navy submarines are nuclear - powered. A submarine’s use of...the Navy’s plan to design and procure a next - generation ballistic missile submarine called the Ohio Replacement Program or SSBN(X). 26...the next several years require these submarines to use up their nuclear fuel cores more quickly than the Navy now projects, then the amounts of time

  15. Introduction to the special issue on submarine geohazard records and potential seafloor instability

    Directory of Open Access Journals (Sweden)

    Song-Chuen Chen Jia-Jyun Dong


    Full Text Available Submarine landslides frequently occur in passive continental margins or active margins (Hampton et al. 1996; Wynn et al. 2000; Mienert et al. 2002; Korup et al. 2007; Twichell et al. 2009; Cukur et al. 2016. Submarine landslides have been studied extensively not only for scientific research but also for submarine geohazards. Submarine landslides could jeopardize marine infrastructures, such as offshore drilling platforms or submarine telecommunication cables, and could even trigger disastrous tsunamis (Bondevik et al. 2005; Harbitz et al. 2006; Hornbach et al. 2007, 2008; Hsu et al. 2008; Su et al. 2012; Tappin et al. 2014; Li et al. 2015. For instance, one disastrous tsunami hitting the coastal area of southwestern Taiwan in 1781 or 1782 was reported (Chen 1830; Hsu 1983; the tsunami event was probably generated by submarine landslides in the offshore area of southwestern Taiwan (Li et al. 2015. Moreover, several submarine landslides triggered by the 2006 Pingtung earthquake have induced turbidity currents off southwest Taiwan and destroyed about 14 submarine telecommunication cables off SW Taiwan (Hsu et al. 2008. The area of southwest Taiwan currently has a dense population (more than 3 million people in total, one deep-water Kaohsiung Port, several tanks of liquefied natural gas and a nuclear power plant on the coast (Fig. 1. Numerous submarine telecommunication cables exist off SW Taiwan. If a considerable tsunami event would hit again the costal area of SW Taiwan, the damage could very serious. Likewise, there are two nuclear power plants on the coast of northern Taiwan (Fig. 2, and the population in northern Taiwan has more than 10 million people. Submarine telecommunication cables also exist off northern Taiwan. In any case, it is important to understand the status of seafloor stability in the offshore areas of SW and NE Taiwan. For that, this special issue of submarine geohazard records and potential seafloor instability is aimed to

  16. Navy Virginia (SSN 774) Class Attack Submarine Procurement: Background and Issues for Congress (United States)


    powered attack submarines (SSNs). The SSNs are general -purpose submarines that can (when appropriately equipped and armed) perform a variety of...signs of tampering. The defective elbow pipe, used to funnel steam from the reactor to the sub’s propulsion turbines and generators , showed evidence of...Congressional Research Service Summary The Navy has been procuring Virginia (SSN-774) class nuclear- powered attack submarines since FY1998. The two Virginia

  17. Fuel-cell-propelled submarine-tanker-system study

    Energy Technology Data Exchange (ETDEWEB)

    Court, K E; Kumm, W H; O' Callaghan, J E


    This report provides a systems analysis of a commercial Arctic Ocean submarine tanker system to carry fossil energy to markets. The submarine is to be propelled by a modular Phosphoric Acid Fuel Cell system. The power level is 20 Megawatts. The DOE developed electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The twin screw submarine tanker design is sized at 165,000 deadweight tons and the study includes costs and an economic analysis of the transport system of 6 ships. The route will be under the polar icecap from a loading terminal located off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas-fed methanol cargo will be 450,000 barrels per day. The total delivered cost of the methanol including well head purchase price of natural gas, methanol production, and shipping would be $25/bbl from Alaska to the US East Coast. Of this, the shipping cost is $6.80/bbl. All costs in 1981 dollars.

  18. Pockmark morphology and turbulent buoyant plumes at a submarine spring (United States)

    Buongiorno Nardelli, B.; Budillon, F.; Watteaux, R.; Ciccone, F.; Conforti, A.; De Falco, G.; Di Martino, G.; Innangi, S.; Tonielli, R.; Iudicone, D.


    The input flow of groundwater from the seabed to the coastal ocean, known as Submarine Groundwater Discharge (SGD), has been only recently recognized as an important component of continental margin systems. It potentially impacts physical, chemical and biological marine dynamics. Independently of its specific nature (seepage, submarine springs, etc.) or fluid chemical composition, a SGD is generally characterized by low flow rates, hence making its detection and quantification very difficult, and explaining why it has been somewhat neglected by the scientific community for a long time. Along with the growing interest for SGDs emerged the need for in-situ observations in order to characterize in details how these SGDs behave. In this work, we describe the morphology of a pockmark field, detected in the Southern Tyrrhenian Sea (Mediterranean Sea), and provide observational evidences of the presence of active submarine springs over the coastal shelf area. We describe the effect of the fluid seeps on the water column stratification close to the main plumes and in the neighbouring areas, providing quantitative estimates of the intensity of the turbulent mixing and discussing their potential impact on the seabed morphology and pockmark formation in the context of turbulent buoyant plumes analytical modelling.

  19. Long-term eruptive activity at a submarine arc volcano. (United States)

    Embley, Robert W; Chadwick, William W; Baker, Edward T; Butterfield, David A; Resing, Joseph A; de Ronde, Cornel E J; Tunnicliffe, Verena; Lupton, John E; Juniper, S Kim; Rubin, Kenneth H; Stern, Robert J; Lebon, Geoffrey T; Nakamura, Ko-ichi; Merle, Susan G; Hein, James R; Wiens, Douglas A; Tamura, Yoshihiko


    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes.

  20. Scientific Ocean Drilling to Assess Submarine Geohazards along European Margins (United States)

    Ask, M. V.; Camerlenghi, A.; Kopf, A.; Morgan, J. K.; Ocean DrillingSeismic Hazard, P. E.


    Submarine geohazards are some of the most devastating natural events in terms of lives lost and economic impact. Earthquakes pose a big threat to society and infrastructure, but the understanding of their episodic generation is incomplete. Tsunamis are known for their potential of striking coastlines world-wide. Other geohazards originating below the sea surface are equally dangerous for undersea structures and the coastal population: submarine landslides and volcanic islands collapse with little warning and devastating consequences. The European scientific community has a strong focus on geohazards along European and nearby continental margins, especially given their high population densities, and long historic and prehistoric record of hazardous events. For example, the Mediterranean is surrounded by very densely-populated coastline and is the World's leading holiday destination, receiving up 30% of global tourism. In addition, its seafloor is criss-crossed by hydrocarbon pipelines and telecommunication cables. However, the governing processes and recurrence intervals of geohazards are still poorly understood. Examples include, but are not limited to, earthquakes and volcanic eruptions along the active tectonic margins of the Mediterranean and Sea of Marmara, landslides on both active and passive margins, and tsunamites and seismites in the sedimentary record that suggest a long history of similar events. The development of geophysical networks, drilling, sampling and long-term monitoring are crucial to the understanding of earthquake, landslide, and tsunami processes, and to mitigate the associated risks in densely populated and industrialized regions such as Europe. Scientific drilling, particularly in the submarine setting, offers a unique tool to obtain drill core samples, borehole measurements and long-term observations. Hence, it is a critical technology to investigate past, present, and possible future influences of hazardous processes in this area. The

  1. Tsunami Generated by a Two-Phase Submarine Debris Flow (United States)

    Pudasaini, S. P.


    The general two-phase debris flow model proposed by Pudasaini (2011) is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model includes several essential physical aspects, including Mohr-Coulomb plasticity for the solid stress, while the fluid stress is modelled as a solid volume fraction gradient enhanced non-Newtonian viscous stress. The generalized interfacial momentum transfer includes the viscous drag, buoyancy, and the virtual mass. The generalized drag covers both the solid-like and fluid-like contributions, and can be applied to linear to quadratic drags. Strong couplings exist between the solid and the fluid momentum transfer. The advantage of the real two-phase debris flow model over classical single-phase or quasi-two-phase models is that by considering the solid (and/or the fluid) volume fraction appropriately, the initial mass can be divided into several (even mutually disjoint) parts; a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This offers a unique and innovative opportunity within a single framework to simultaneously simulate (a) the sliding debris (or landslide), (b) the water lake or ocean, (c) the debris impact at the lake or ocean, (d) tsunami generation and propagation, (e) mixing and separation between the solid and the fluid phases, and (f) sediment transport and deposition process in the bathymetric surface. The new model is applied to two-phase subaerial and submarine debris flows. Benchmark numerical simulations reveal that the dynamics of the debris impact induced tsunamis are fundamentally different than the tsunami generated by pure rock avalanche and landslides. Special attention is paid to study the basic features of the debris impact to the mountain lakes or oceans. This includes the generation, amplification and propagation of the multiple

  2. The Impact of the General Board of the Navy on Interwar Submarine Design (United States)


    Navy had developed the Gato class submarine, which was successful independently operating in the vast Pacific Ocean in support of War Plan Orange. The...development of the Gato class submarine, which was successful independently operating in the vast Pacific Ocean in support of War Plan Orange. The...

  3. Procurements by the Non-Acoustic Anti-Submarine Warfare Program Through the Environmental Technologies Laboratory (United States)


    General, DoD, on contract offloading, including Report No. 93-068, " Procurement of Services for the Non-Acoustic Anti-Submarine Warfare Program...contract administration in response to Audit Report No. 93-042. Report No. 93-068, " Procurement of Services for the Non-Acoustic Anti- Submarine Warfare

  4. Study on the locational criteria for submarine rock repositories of low and medium level radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G. H.; Kang, W. J.; Kim, T. J. and others [Chungnam National Univ., Taejon (Korea, Republic of)


    Submarine repositories have significant advantages over their land counterparts locating close to the areas of daily human activities. Consequently, the construction of submarine repositories on the vast continental shelves around Korean seas is considered to be highly positive. In this context, the development of locational criteria primarily targeting the safety of submarine rock repositories is very important.The contents of the present study are: analyzing characteristics of marine environment: Search of potential hazards to, and environmental impact by, the submarine repositories; Investigation of the oceanographic, geochemical, ecological and sedimentological characteristics of estuaries and coastal seas. Locating potential hazards to submarine repositories by: Bibliographical search of accidents leading to the destruction of submarine structures by turbidity currents and other potentials; Review of turbidity currents. Consideration of environmental impact caused by submarine repositories: Logistics to minimize the environmental impacts in site selection; Removal and dispersion processes of radionuclides in sea water. Analyses of oceanographical characteristics of, and hazard potentials in, the Korean seas. Evaluation of the MOST 91-7 criteria for applicability to submarine repositories and the subsequent proposition of additional criteria.

  5. The risk of hydrogen explosion in a submarine p.I Catalytic combustion of hydrogen

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard


    Full Text Available The series of articles discuss issues related to conducting high risk projects on the example of modernisation of hydrogen incinerators on a submarine. The article depicts a technical problem situation connected with catalytic hydrogen combustion on a submarine.

  6. Isotopic evidence for the influence of typhoons and submarine canyons on the sourcing and transport behavior of biospheric organic carbon to the deep sea (United States)

    Zheng, Li-Wei; Ding, Xiaodong; Liu, James T.; Li, Dawei; Lee, Tsung-Yu; Zheng, Xufeng; Zheng, Zhenzhen; Xu, Min Nina; Dai, Minhan; Kao, Shuh-Ji


    Export of biospheric organic carbon from land masses to the ocean plays an important role in regulating the global carbon cycle. High-relief islands in the western Pacific are hotspots for such land-to-ocean carbon transport due to frequent floods and active tectonics. Submarine canyon systems serve as a major conduit to convey terrestrial organics into the deep sea, particularly during episodic floods, though the nature of ephemeral sediment transportation through such canyons remains unclear. In this study, we deployed a sediment trap in southwestern Taiwan's Gaoping submarine canyon during summer 2008, during which Typhoon Kalmaegi impacted the study area. We investigated sources of particulate organic carbon and quantified the content of fossil organic carbon (OCf) and biospheric non-fossil carbon (OCnf) during typhoon and non-typhoon periods, based on relations between total organic carbon (TOC), isotopic composition (δ13 C, 14C), and nitrogen to carbon ratios (N/C) of newly and previously reported source materials. During typhoons, flooding connected terrestrial rivers to the submarine canyon. Fresh plant debris was not found in the trap except in the hyperpycnal layer, suggesting that only hyperpycnal flow is capable of entraining plant debris, while segregation had occurred during non-hyperpycnal periods. The OCnf components in typhoon flood and trapped samples were likely sourced from aged organics buried in ancient landslides. During non-typhoon periods, the canyon is more connected to the shelf, where waves and tides cause reworking, thus allowing abiotic and biotic processes to generate isotopically uniform and similarly aged OCnf for transport into the canyon. Therefore, extreme events coupled with the submarine canyon system created an efficient method for deep-sea burial of freshly produced organic-rich material. Our results shed light on the ephemeral transport of organics within a submarine canyon system on an active tectonic margin.

  7. Maximizing the probability an aerial anti-submarine torpedo detects its target (United States)

    Wang, Zhi-Jie


    As a result of the high speed of anti-submarine patrol aircraft as well as their wide range, high efficiency and other characteristics, aerial torpedoes released by anti-submarine patrol aircraft have become the key anti submarine tool. In order to improve operational efficiency, a deep study was made of the target detection probabilities for aerial torpedoes released by anti-submarine patrol aircraft. The operational modes of aerial torpedoes were analyzed and mathematical-simulation models were then established. The detection probabilities of three attacking modes were then calculated. Measures were developed for improving low probabilities of detection when attacking a probable target position. This study provides an important frame of reference for the operation of aerial torpedo released by anti-submarine patrol aircraft.

  8. Main devices design of submarine oil-water separation system (United States)

    Cai, Wen-Bin; Liu, Bo-Hong


    In the process of offshore oil production, in order to thoroughly separate oil from produced fluid, solve the environment problem caused by oily sewage, and improve the economic benefit of offshore drilling, from the perspective of new oil-water separation, a set of submarine oil-water separation devices were designed through adsorption and desorption mechanism of the polymer materials for crude oil in this paper. The paper introduces the basic structure of gas-solid separation device, periodic separation device and adsorption device, and proves the rationality and feasibility of this device.

  9. Submarine glaciated landscapes of central and northern British Columbia, Canada (United States)

    Shaw, John; Lintern, Gwyn


    Recent systematic multibeam sonar mapping and ground-truthing surveys in the fjords and coastal waters of central and northern British Columbia, Canada, provide information on glacial processes associated with the Cordilleran Ice Sheet, and also on postglacial processes that have strongly modified the glacial terrain. During the last glacial maximum, ice covered the Coast Range, except for nunataks. Convergent streamlined glacial landforms in the Strait of Georgia testify to a strong flow of ice towards the southeast, between Vancouver Island and the mainland. During ice retreat, thick deposits of acoustically stratified glaciomarine mud were deposited in glacially over deepened basins. Retreat through the Douglas Channel fjord system was punctuated by still stands, resulting in a series of submarine moraines. Postglacial processes have created a suite of landforms that mask the primary glacial terrain: 1) Fjord floors host thick deposits of acoustically transparent postglacial mud with highly variable distribution: banks up to 80-m thick are commonly adjacent to erosional zones with glaciomarine mud exposed at the seafloor; 2) In this region of high precipitation and snowpack melt, numerous cone-shaped Holocene fan deltas developed on the fjord sidewalls transport coarse sediment to the fjord floors. Larger deltas are developed at fjord heads, notably at Kitimat and Kildala; 3) Submarine slope failures in this tectonically active area have resulted in a suite of mass transport deposits on sidewalls and fjord floors. The very large submarine slope failures at Camano Sound and KitKat Inlet occurred on the steep, rear facets of large transverse moraines, and involved the failure of glaciomarine sediment that moved into deeper basins, perhaps as a retrogressive failure. The ages of these events are unknown, although the presence of postglacial mud in the slide scar at Caamano suggests that the event at that location occurred in the late glacial or early Holocene. Also

  10. Micro-tunneling as an alternative to submarine cable

    Energy Technology Data Exchange (ETDEWEB)

    Russo, D.A. [Seattle City Light, WA (United States); Hansen, D. [CH2M Hill, Bellevue, WA (United States)


    The geography that gives Seattle its beauty can pose unique challenges for the engineers attempting to provide service to the customers who live near or upon these features. Steep, wooded hills and greenbelts create familiar problems of construction and right-of-way maintenance. The waterways and adjoining shoreline zones present a more difficult set of requirements. When Seattle City Light determined it was necessary to install 2-26 KV feeders across the Salmon Bay waterway, they discovered that submarine cables could not be used. Shallow angle directional drilling and micro-tunneling were examined and it was fond that a microtunneled duct bank was the best method to use.

  11. Sub-sea engineering course (offshore submarine systems); Subsea engineering course (systemes sous - marins offshore)

    Energy Technology Data Exchange (ETDEWEB)

    Preedy, J.; Chasserot, J.L. [Azur Offshore Ltd (United Kingdom)


    This document gathers 770 pages of information about offshore submarine systems and 16 pages of appendix (glossary). Content: course introduction, introduction to sub-sea engineering, review of diver-assisted sub-sea production systems, sub-sea completion and christmas trees, basis of offshore exploration and production, sub-sea manifolds and templates, new technology for sub-sea production, flow-lines and pipelines, design of risers (flexible, towers, steel catenary and rigid), reliability, risks and human factors, review of deep-water (diver-less) sub-sea production systems, sub-sea control systems and chemical injection, case study - Malampaya Field Tie Back (Philippines), sub-sea systems inspection, maintenance and repair, cost evaluations, field assessments and cost data base, sub-sea well operations and flow assurance.

  12. Relations Between Coastal Catchment Attributes and Submarine Groundwater Discharge at Different Scales (United States)

    Moosdorf, N.; Langlotz, S. T.


    Submarine groundwater discharge (SGD) has been recognized as a relevant field of coastal research in the last years. Its implications on local scale have been documented by an increasing number of studies researching individual locations with SGD. The local studies also often emphasize its large variability. On the other end, global scale studies try to estimate SGD related fluxes of e.g. carbon (Cole et al., 2007) and nitrogen (Beusen et al., 2013). These studies naturally use a coarse resolution, too coarse to represent the aforementioned local variability of SGD (Moosdorf et al., 2015). A way to transfer information of the local variability of SGD to large scale flux estimates is needed. Here we discuss the upscaling of local studies based on the definition and typology of coastal catchments. Coastal catchments are those stretches of coast that do not drain into major rivers but directly into the sea. Their attributes, e.g. climate, topography, land cover, or lithology can be used to extrapolate from the local scale to larger scales. We present first results of a typology, compare coastal catchment attributes to SGD estimates from field studies and discuss upscaling as well as the associated uncertainties. This study aims at bridging the gap between the scales and enabling an improved representation of local scale variability on continental to global scale. With this, it can contribute to a recent initiative to model large scale SGD fluxes (NExT SGD). References: Beusen, A.H.W., Slomp, C.P., Bouwman, A.F., 2013. Global land-ocean linkage: direct inputs of nitrogen to coastal waters via submarine groundwater discharge. Environmental Research Letters, 8(3): 6. Cole, J.J., Prairie, Y.T., Caraco, N.F., McDowell, W.H., Tranvik, L.J., Striegl, R.G., Duarte, C.M., Kortelainen, P., Downing, J.A., Middelburg, J.J., Melack, J., 2007. Plumbing the global carbon cycle: Integrating inland waters into the terrestrial carbon budget. Ecosystems, 10(1): 171-184. Moosdorf, N

  13. Assessing potential impacts of energized submarine power cables on crab harvests (United States)

    Love, Milton S.; Nishimoto, Mary M.; Clark, Scott; McCrea, Merit; Bull, Ann Scarborough


    Offshore renewable energy facilities transmit electricity to shore through submarine power cables. Electromagnetic field emissions (EMFs) are generated from the transmission of electricity through these cables, such as the AC inter-array (between unit) and AC export (to shore) cables often used in offshore energy production. The EMF has both an electric component and a magnetic component. While sheathing can block the direct electric field, the magnetic field is not blocked. A concern raised by fishermen on the Pacific Coast of North America is that commercially important Dungeness crab (Metacarcinus magister Dana, 1852)) might not cross over an energized submarine power cable to enter a baited crab trap, thus potentially reducing their catch. The presence of operating energized cables off southern California and in Puget Sound (cables that are comparable to those within the arrays of existing offshore wind energy devices) allowed us to conduct experiments on how energized power cables might affect the harvesting of both M. magister and another commercially important crab species, Cancer productus Randall, 1839. In this study we tested the questions: 1) Is the catchability of crabs reduced if these animals must traverse an energized power cable to enter a trap and 2) if crabs preferentially do not cross an energized cable, is it the cable structure or the EMF emitted from that cable that deters crabs from crossing? In field experiments off southern California and in Puget Sound, crabs were given a choice of walking over an energized power cable to a baited trap or walking directly away from that cable to a second baited trap. Based on our research we found no evidence that the EMF emitted by energized submarine power cables influenced the catchability of these two species of commercially important crabs. In addition, there was no difference in the crabs' responses to lightly buried versus unburied cables. We did observe that, regardless of the position of the cable

  14. Hydrodynamic modeling of magmatic-hydrothermal activity at submarine arc volcanoes, with implications for ore formation (United States)

    Gruen, Gillian; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; de Ronde, Cornel E. J.


    Subduction-related magmas have higher volatile contents than mid-ocean ridge basalts, which affects the dynamics of associated submarine hydrothermal systems. Interaction of saline magmatic fluids with convecting seawater may enhance ore metal deposition near the seafloor, making active submarine arcs a preferred modern analogue for understanding ancient massive sulfide deposits. We have constructed a quantitative hydrological model for sub-seafloor fluid flow based on observations at Brothers volcano, southern Kermadec arc, New Zealand. Numerical simulations of multi-phase hydrosaline fluid flow were performed on a two-dimensional cross-section cutting through the NW Caldera and the Upper Cone sites, two regions of active venting at the Brothers volcanic edifice, with the former hosting sulfide mineralization. Our aim is to explore the flow paths of saline magmatic fluids released from a crystallizing magma body at depth and their interaction with seawater circulating through the crust. The model includes a 3 × 2km2 sized magma chamber emplaced at ∼ 2.5 km beneath the seafloor connected to the permeable cone via a ∼ 200 m wide feeder dike. During the simulation, a magmatic fluid was temporarily injected from the top of the cooling magma chamber into the overlying convection system, assuming hydrostatic conditions and a static permeability distribution. The simulations predict a succession of hydrologic regimes in the subsurface of Brothers volcano, which can explain some of the present-day hydrothermal observations. We find that sub-seafloor phase separation, inferred from observed vent fluid salinities, and the temperatures of venting at Brothers volcano can only be achieved by input of a saline magmatic fluid at depth, consistent with chemical and isotopic data. In general, our simulations show that the transport of heat, water, and salt from magmatic and seawater sources is partly decoupled. Expulsion of magmatic heat and volatiles occurs within the first

  15. Seismicity and sedimentation rate effects on submarine slope stability (United States)

    Ten Brink, U. S.; Andrews, B. D.; Miller, N. C.


    Large submarine mass-transport scars are commonly observed on continental margins, but are noticeably less abundant on margins that experience frequent earthquakes than on those that seldom experience them. This is a surprising observation, given that horizontal acceleration from earthquakes and associated strength loss from cyclic loading and liquefaction are commonly thought to provide the primary triggers for inducing failures and subsequent mass movements. Mapping submarine failure scars in ten margins worldwide, we find decreasing scar abundance with both increasing frequency of earthquakes and decreasing sedimentation rate. The decrease in scar abundance is interpreted to represent increasing slope stability. The increase in stability is non linear (power law with btectonic activity (salt diapirs, seamount subduction, etc.) leads to relatively rapid oversteepening of the slope, implying that the morphology of most margins is in fact, stable over many earthquake cycles. Note that the above correlation averages scar area and sedimentation rate over entire margin areas. Variations in sedimentation rate with time, such as over glacial-interglacial cycles, and intra-margin variations in seismic attenuation, sedimentation rate, composition, and pore pressure, have likely affected the abundance of slope failures in time and space.

  16. A submarine fan in the Mesa Central, Mexico (United States)

    Silva-Romo, G.; Arellano-Gil, J.; Mendoza-Rosales, C.; Nieto-Obregón, J.


    The contact between the Guerrero and Sierra Madre tectonostratigraphic terranes has been proposed to lie in the Mesa Central, east of the city of Zacatecas. Marine Triassic units have been assigned to the Guerrero Terrane. It is here proposed that this contact occurs to the west of the city of Zacatecas and the Triassic marine sequence assigned to the Sierra Madre Terrane. We analyzed the stratigraphic record and structural features of pre-Late Jurassic sequences at four localities in the Mesa Central. They contain a marine turbiditic Triassic unit, which includes La Bellena, Taray, and Zacatecas Formations, and a continental unit of probable Middle Jurassic age. Triassic sandstones were derived from a cratonic area, without the influence of arc volcanism. The sequences were affected by two phases of deformation. The Triassic formations are unconformably overlain by a continental volcano-sedimentary sequence that contains fragments of sandstones derived from the underlying unit. Sedimentologic characteristics of the Triassic unit fit a submarine fan model. The submarine fan developed at the continental margin of Pangaea during Triassic times. Turbidite associations in the San Rafael Area indicate a middle fan depositional environment, while in the Real de Catorce Area, they correspond to the distal part (basin plain facies). At La Ballena and Zacatecas the turbidite associations occur in the middle part and perhaps the external part of the fan.

  17. Applying Set Based Methodology In Submarine Concept Design (United States)


    Fuel Cell PEM FC HT ...Phosphoric Acid PEM Alkaline FC SOFC MCFC Discrete Fuel Stowage (Diesel) Internal External Discrete Fuel Stowage ( Fuel Cell ...Internal External Discrete Fuel Cell Fuel Desulfurization None Onboard Shoreside Discrete Fuel Cell Fuel Reformation None

  18. Submarine geology of Hana Ridge and Haleakala Volcano's northeast flank, Maui (United States)

    Eakins, Barry W.; Robinson, Joel E.


    We present a morphostructural analysis of the submarine portions of Haleakala Volcano and environs, based upon a 4-year program of geophysical surveys and submersible explorations of the underwater flanks of Hawaiian volcanoes that was conducted by numerous academic and governmental research organizations in Japan and the U.S. and funded primarily by the Japan Agency for Marine–Earth Science and Technology. A resulting reconnaissance geologic map features the 135-km-long Hana Ridge, the 3000 km2 Hana slump on the volcano's northeast flank, and island-surrounding terraces that are the submerged parts of volcanic shields. Hana Ridge below 2000 m water depth exhibits the lobate morphology typical of the subaqueously erupted parts of Hawaiian rift zones, with some important distinctions: namely, subparallel crestlines, which we propose result from the down-rift migration of offsets in the dike intrusion zone, and an amphitheater at its distal toe, where a submarine landslide has embayed the ridge tip. Deformation of Haleakala's northeast flank is limited to that part identified as the Hana slump, which lies downslope from the volcano's submerged shield, indicating that flank mobility is also limited in plan, inconsistent with hypothesized volcanic spreading driven by rift-zone dilation. The leading edge of the slump has transverse basins and ridges that resemble the thrust ramps of accretionary prisms, and we present a model to describe the slump's development that emphasizes the role of coastally generated fragmental basalt on gravitational instability of Haleakala's northeast flank and that may be broadly applicable to other ocean-island slumps.

  19. Occupational stress in submariners: the impact of isolated and confined work on psychological well-being. (United States)

    Brasher, Kate S; Dew, Angela B C; Kilminster, Shaun G; Bridger, Robert S


    This study aimed to identify work-related and personal factors associated with occupational stress in submariners. Work and well-being questionnaires were distributed to 219 male submariners (mean age 34 years), as part of a larger cohort study involving a stratified sample of 4951 Royal Navy (RN) personnel. The stress rate in submariners was 40%; significantly higher than the stress rate in the general RN, although once demographic factors were controlled for in a matched control sample, this difference was no longer significant. A summary model accounted for 49% of the variance in submariner stress, with key differences emerging between the occupational factors associated with stress in submariners and in the general RN. The longitudinal nature of this study permits stress in submariners to be monitored over 5 years, which will provide valuable insights into the chronicity of stress in this specialised occupational group. STATEMENT OF RELEVANCE: This paper contributes to the current literature on the negative impact of working in isolated conditions. It is demonstrated that occupational stress in submarines can be partially explained using current theories of stress in the workplace. However, the constraints of a restricted environment introduce additional factors which can also be associated with occupational stress.

  20. Measuring currents in submarine canyons: technological and scientific progress in the past 30 years (United States)

    Xu, J. P.


    The development and application of acoustic and optical technologies and of accurate positioning systems in the past 30 years have opened new frontiers in the submarine canyon research communities. This paper reviews several key advancements in both technology and science in the field of currents in submarine canyons since the1979 publication of Currents in Submarine Canyons and Other Sea Valleys by Francis Shepard and colleagues. Precise placements of high-resolution, high-frequency instruments have not only allowed researchers to collect new data that are essential for advancing and generalizing theories governing the canyon currents, but have also revealed new natural phenomena that challenge the understandings of the theorists and experimenters in their predictions of submarine canyon flow fields. Baroclinic motions at tidal frequencies, found to be intensified both up canyon and toward the canyon floor, dominate the flow field and control the sediment transport processes in submarine canyons. Turbidity currents are found to frequently occur in active submarine canyons such as Monterey Canyon. These turbidity currents have maximum speeds of nearly 200 cm/s, much smaller than the speeds of turbidity currents in geological time, but still very destructive. In addition to traditional Eulerian measurements, Lagrangian flow data are essential in quantifying water and sediment transport in submarine canyons. A concerted experiment with multiple monitoring stations along the canyon axis and on nearby shelves is required to characterize the storm-trigger mechanism for turbidity currents.

  1. Prediction of nuclear submariner adaptability from autonomic indices and Rorschach Inkblot responses. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Weybrew, B.B.; Molish, H.B.


    To identify the most valid predictors of submariner adaptability, the authors derived 23 indices from the responses of 170 nuclear submariners to the Rorschach Inkblot Test, 11 measures of Autonomic Nervous System (ANS) reactivity to contrived stress, and five adjustment criteria. Factor analysis of this 39x39 correlation matrix yielded two Rorschach Factors, one of which correlated with three criterion dimensions. Two unique factors were also discovered, one, a structured ANS factor, and the other, a complex criterion scale. Selected Rorschach scores and, to a lesser extent, certain ANS indices emanating from this study, may be usefully-valid predictors of the adaptability of nuclear submariners during long patrols.

  2. Marine litter in submarine canyons of the Bay of Biscay (United States)

    van den Beld, Inge M. J.; Guillaumont, Brigitte; Menot, Lénaïck; Bayle, Christophe; Arnaud-Haond, Sophie; Bourillet, Jean-François


    Marine litter is a matter of increasing concern worldwide, from shallow seas to the open ocean and from beaches to the deep-seafloor. Indeed, the deep sea may be the ultimate repository of a large proportion of litter in the ocean. We used footage acquired with a Remotely Operated Vehicle (ROV) and a towed camera to investigate the distribution and composition of litter in the submarine canyons of the Bay of Biscay. This bay contains many submarine canyons housing Vulnerable Marine Ecosystems (VMEs) such as scleractinian coral habitats. VMEs are considered to be important for fish and they increase the local biodiversity. The objectives of the study were to investigate and discuss: (i) litter density, (ii) the principal sources of litter, (iii) the influence of environmental factors on the distribution of litter, and (iv) the impact of litter on benthic communities. Litter was found in all 15 canyons and at three sites on the edge of the continental shelf/canyon, in 25 of 29 dives. The Belle-île and Arcachon Canyons contained the largest amounts of litter, up to 12.6 and 9.5 items per 100 images respectively. Plastic items were the most abundant (42%), followed by fishing-related items (16%). The litter had both a maritime and a terrestrial origin. The main sources could be linked to fishing activities, major shipping lanes and river discharges. Litter appeared to accumulate at water depths of 801-1100 m and 1401-1700 m. In the deeper of these two depth ranges, litter accumulated on a geologically structured area, accounting for its high frequency at this depth. A larger number of images taken in areas of coral in the shallower of these two depth ranges may account for the high frequency of litter detection at this depth. A larger number of litter items, including plastic objects in particular, were observed on geological structures and in coral areas than on areas of bare substratum. The distribution of fishing-related items was similar for the various types of

  3. Hawaiian submarine manganese-iron oxide crusts - A dating tool? (United States)

    Moore, J.G.; Clague, D.A.


    Black manganese-iron oxide crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae

  4. Newly recognized submarine slide complexes in the southern California Bight (United States)

    Conrad, J. E.; Lee, H. J.; Edwards, B. D.; McGann, M.; Sliter, R. W.


    New high-resolution bathymetric and seismic-reflection surveys have imaged large (7) individual overlapping slides along the western margin of Santa Cruz Basin (SCB slide); 2) a series of slumps and slide scars on the slope south of San Pedro shelf (SPS slide); and 3) a slope failure along the shelf edge in northern San Diego County, termed the Del Mar slide. The SCB slide complex extends for 30 km along the western slope of Santa Cruz Basin, with debris lobes extending 5-8 km into the basin. Head scarps of some of these slides are 50-75 m high. The SPS slide complex also appears to consist of multiple slides, which roughly parallel the Palos Verdes Fault and the San Gabriel Canyon submarine channel on the shelf edge and slope south of San Pedro shelf. Slide deposits associated with this complex are only partially mapped due to limited high-resolution bathymetric coverage, but extend to the south in the area SW of Lasuen Knoll. Seismic-reflection profiles show that some of these deposits are up to 20 m thick. The Del Mar slide is located about 10 km north of La Jolla Canyon and extends about 6 km along the shelf edge. The head scarp lies along the trend of a branch of the Rose Canyon Fault Zone. Radiocarbon ages of sediment overlying this slide indicate the Del Mar slide is approximately 12-16 ka. These large slide complexes have several characteristics in common. Nearly all occur in areas of tectonic uplift. All of the complexes show evidence of recurrent slide activity, exhibiting multiple headwall scarps and debris lobes, and where available, high-resolution seismic-reflection profiles of these slide areas provide evidence of older, buried mass transport deposits. Assuming typical sedimentation rates, the recurrence interval of major slide events appears to be on the order of tens of thousands of years. Most of the slide complexes do not appear to be located in areas of high sediment input. The SCB and Del Mar slides are in areas receiving relatively small

  5. New types of submarine groundwater discharge from a saliferous clay formation - the case of the Dead Sea (United States)

    Siebert, Christian; Broder, Merkel; Thomas, Pohl; Yossi, Yechieli; Eldat, Hazan; Danny, Ionescu; Ulf, Mallast


    Along the coastline of the hyper-saline and dramatically dropping Dead Sea, fresh to highly saline groundwaters discharge abundantly from dry falling lakebed. During its history, the level and hence salinity of the lake strongly fluctuated, resulting in the deposition of an alternating sequence of clayey and chemical sediments (mainly halite, carbonates and sulfates), intercalated by thick beds of halite and of coarse clastics around wadi outlets, respectively. Due to the asymmetrical shape of the lake's basin, these strata are deposited unequally along the eastern and western flank, why only groundwaters coming from the west have to pass thick layers of these sediments on their way into the lake. On the base of trace elements (REE), element ratios, stable and radioisotopes and microbiological findings, the observed onshore and offshore springs revealed, freshwaters discharge from both Cretaceous limestone aquifers and efficiently dissolve the easily soluble halite and flush the interstitial brines from the saliferous clay formation, immediately after entering the sedimentary strata. Abundant microbial activity result in the widespread production of sulfuric acid, accelerating erosion of carbonates and sulfates. These processes result in a fast and striking karstification of the strata, enabling groundwaters to transcendent the fresh/saltwater interface trough open pipes. As results, submarine groundwater discharge (SGD) occurs randomly and in addition to terrestrial, submarine sinkholes develop very quickly too. Due to the variable maturity of the flow paths, salinity and chemical composition of SGD shows an extremely wide range, from potable water to TDS of >250 g/l. Submarine emerging groundwaters with salinities even higher then that of the Dead Sea and distinctly different chemical and isotopic composition form outlets, which are not known elsewhere and represent a novel and unique type of SGD, only observed in the Dead Sea yet.

  6. Multi-scale evaluations of submarine groundwater discharge

    Directory of Open Access Journals (Sweden)

    M. Taniguchi


    Full Text Available Multi-scale evaluations of submarine groundwater discharge (SGD have been made in Saijo, Ehime Prefecture, Shikoku Island, Japan, by using seepage meters for point scale, 222Rn tracer for point and coastal scales, and a numerical groundwater model (SEAWAT for coastal and basin scales. Daily basis temporal changes in SGD are evaluated by continuous seepage meter and 222Rn mooring measurements, and depend on sea level changes. Spatial evaluations of SGD were also made by 222Rn along the coast in July 2010 and November 2011. The area with larger 222Rn concentration during both seasons agreed well with the area with larger SGD calculated by 3D groundwater numerical simulations.

  7. Imaging deformation in submarine thrust belts using seismic attributes (United States)

    Iacopini, David; Butler, Robert W. H.


    Uncertainty exists as to the patterns of deformation that develop within submarine thrust belts. This case study uses a large-scale gravity-driven fold-thrust structure as an analogue for submarine fold thrust systems in general. Seismic attribute analysis and mapping provide ways of identifying complex fault patterns and associated deformation that are otherwise unresolved in conventional amplitude displays. These methods are developed and applied to a 3D dataset and used to investigate the geometry, internal architecture and the nature of the low signal/noise incoherency and discontinuities observed on the km-scale. Semblance (coherency), curvatures and spectral decomposition were all computed and used as attributes. Collectively these define volumes within the seismic data where the signal is greatly reduced — features termed here "disturbance geobodies". The study shows that thrust faults that, on conventional amplitude displays appear to be simple and continuous, are likely to consist of complex arrays of anastamosing fault strands. Adjacent to these composite fault zones are greater volumes of deformed rocks (disturbance geobodies) across which there are only minor stratal offsets. Similarly volumes of high stratal curvature coincide with disturbance geobodies, again interpreted as zones of weak, distributed deformation. These relationships between narrow thrust faults and broader zones of deformation are broadly comparable to those observed in outcrops within exhumed thrust systems. Application of the seismic imaging techniques developed here will improve the understanding of the localization of deformation in sedimentary successions with important implications for predicting fluid flow within other deep water structures such as subduction accretion complexes.

  8. Geo-hazard by sediment mass movements in submarine canyons (United States)

    Ghaith, Afif; Fakhri, Milad; Ivaldi, Roberta; Ciavola, Paolo


    Submarine mass movements and their consequences are of major concern for coastal communities and infrastructures but also for the exploitation and the development of seafloor resources. Elevated awareness of the need for better understanding of the underwater mass movement is coupled with great advances in underwater mapping technologies over the past two decades. The seafloor in the Nahr Ibrahim and Saida regions (Lebanon) is characterized by deep canyons, reaching one thousand meters depths in proximity of the coast. Signs of submarine mass movement instability related to these canyons create a connection between shallow and deep water. The presence of these canyons in a tectonically active area generates a particular drained mechanism to the sediment in form of mass movement and slumping. Identification of potential areas where slope movements could be triggered requires data with high spatial resolution. Since this area is poorly explored, in the framework of an international project between Lebanese Navy, Lebanese National Center for Marine Sciences, University of Ferrara and Italian Hydrographic Institute, we analyse the morpho-bathymetric and sedimentological characters of the coastal and shelf sectors. Multibeam echosounder and sub-bottom profiler acoustic systems calibrated with ground truths (sediment grab and core samples) allow us to characterize the nature of seafloor and sub-seafloor with particular detail to the geotechnical properties of sediments and high resolution seismic stratigraphy of the shallow layers. The detection of particular undersea features provides detail maps which are in support to littoral morpho-dynamics, coastal transport and sediment budget. Multilayer hydro-oceanographic map, referring to the seafloor dynamics in connection with deep water environment and drainage system, in accordance to the International Hydrographic Standards and nautical supports, are produced. This high resolution multibeam bathymetry dataset, integrated

  9. AUV Mapping and ROV Exploration of Los Frailes Submarine Canyon, Cabo Pulmo National Marine Park, Baja California Sur, Mexico (United States)

    Troni, G.; Caress, D. W.; Graves, D.; Thomas, H. J.; Thompson, D.; Barry, J. P.; Aburto-Oropeza, O.; Johnson, A. F.; Lundsten, L.


    Los Frailes submarine canyon is located at the south boundary of the Cabo Pulmo National Marine Park on the southeast tip of the Baja California Peninsula. During the Monterey Bay Aquarium Research Institute (MBARI) 2015 Gulf of California expedition we used an autonomous underwater vehicle (AUV) to map this canyon from 50 m to 450 m depths, and then explored the canyon with a small remotely operated vehicle (ROV). This three day R/V Rachel Carson cruise was a collaboration with the Center for Marine Biodiversity and Conservation at Scripps Institution of Oceanography and the Centro para la Biodiversidad Marina y la Conservación in La Paz. The MBARI AUV D. Allan B. collected high resolution bathymetry, sidescan, and subbottom profiles of Los Frailes submarine canyon and part of the north Cabo Pulmo deep reef. In order to safely generate a 1-m lateral resolution multibeam bathymetry map in the nearshore high relief terrain, the mapping operations consisted of an initial short survey following the 100-m isobath followed by a series of short, incremental AUV missions located on the deep edge of the new AUV bathymetry. The MBARI Mini-ROV was used to explore the submarine canyon within the detailed map created by the MBARI AUV. The Mini-ROV is a 1.2-m-long, 350 kg, 1,500-m-depth-rated ROV designed and constructed by MBARI. It is controlled by six 600-watt thrusters and is equipped with a high-definition video camera and navigation sensors. This small ROV carries less accurate, lower cost navigation sensors than larger vehicles. We implemented new algorithms to localize combining Doppler velocity log sensor data and low-cost MEMS-based inertial sensor data with sporadic ultra-short baseline position measurements to provide a high accuracy position estimation. The navigation performance allowed us to colocate the ROV video imagery with the 1-m resolution bathymetric map of the submarine canyon. Upper Los Frailes Canyon is rugged and, aside from small sand pockets along

  10. The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords

    NARCIS (Netherlands)

    Carroll, D.; Sutherland, D. A.; Hudson, B.; Moon, T.; Catania, G. A.; Shroyer, E. L.; Nash, J. D.; Bartholomaus, T. C.; Felikson, D.; Stearns, L. A.; Noël, B. P Y; van den Broeke, M. R.


    Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we

  11. An Analysis of the Effectiveness of a New Watchstanding Schedule for U.S. Submariners

    National Research Council Canada - National Science Library

    Osborn, Christopher


    A need exists within the U.S. submarine force to employ an operational schedule that provides more sleep and that is in better alignment with human circadian rhythms, thus improving cognitive effectiveness...

  12. Fuel cell systems for submarines: from the first idea to serial production (United States)

    Psoma, Angela; Sattler, Gunter

    The future submarines of Howaldtswerke-Deutsche Werft AG (HDW) will be equipped with fuel cell power plants for air independent propulsion. In the 1970s the decision for a fuel cell system on submarines was made. Tests in the 1980s confirmed the feasibility of fuel cells on submarines. Positive development results in the 1990s led to series production of fuel cell equipped submarines, which will be in operation from 2003 onwards. Strictly controlled development work was necessary to reach the goal of series production. The train of thought behind this process of development is described in this paper starting with the initial idea and ending with the description of the serial production of the fuel cell power plant. The future outlook gives an impression of current development work.

  13. Submarine Warfare in the 20th & 21st Centuries: A Bibliography

    National Research Council Canada - National Science Library

    Huygen, Michaele


    There are constant motions in the sea caused by atmospheric and seabed activities volcanic disruptions marine animals ships and submarines -- all of which create what is called the ambient noise level of the oceans...

  14. The risk of hydrogen explosion in a submarine p. IV The implementation of high risk projects

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard


    Full Text Available This series of articles on high risk projects looks at the example of the modernisation of hydrogen incinerators on a submarine. The article describes problems connected with the management of such a project.

  15. Volume transport data from a submarine cable in the Florida Strait in 2014 (NODC Accession 0125429) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily mean and raw voltage volume transport data of the Florida Current collected with a submarine cable spanning from South Florida to the Grand Bahama Island in...

  16. A Statistical Analysis of the Impact of Marital Status on Nuclear Submarine Officer Retention

    National Research Council Canada - National Science Library

    Phelps, Matthew


    This thesis develops multivariate logit models to estimate the impact of marital status and the independent effect of dependent children on nuclear submarine officer retention beyond the minimum service requirement (MSR...

  17. Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

    Directory of Open Access Journals (Sweden)

    P.W. Swarzenski


    New hydrological insights for the region: Estimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d mass balance model. Such estimates were complemented with a novel thoron (220Rn, t1/2 = 56 s groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

  18. Dance With the One That Brought You: Revitalizing Antisubmarine Warfare to Counter Chinese Diesel Submarines

    National Research Council Canada - National Science Library

    Farrell, Richard


    .... Navy needs to revitalize ASW, or risk losing the ability to gain sea control in strategic areas of the East Asian Littoral and South China Sea due to a rising Chinese diesel-electric submarine threat...

  19. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics, Version 1 (United States)

    National Aeronautics and Space Administration — This data set consists of upward looking sonar sea ice draft data collected by submarines in the Arctic Ocean. It includes data from both U.S. Navy and Royal Navy...

  20. Navy Trident Submarine Conversion (SSGN) Program: Background and Issues for Congress

    National Research Council Canada - National Science Library

    O'Rourke, Ronald


    ...) into cruisemissile- carrying and special operations forces (SOF) support submarines (SSGNs). The total estimated cost of the program, which has been increasing over time, is now $4,018 million...

  1. Submarine basaltic fountain eruptions in a back-arc basin during the opening of the Japan Sea (United States)

    Hosoi, Jun; Amano, Kazuo


    Basaltic rock generated during the middle Miocene opening of the Japan Sea, is widely distributed on the back-arc side of the Japanese archipelago. Few studies have investigated on submarine volcanism related to opening of the Japan Sea. The present study aimed to reconstruct details of the subaqueous volcanism that formed the back-arc basin basalts (BABB) during this event, and to discuss the relationship between volcanism and the tectonics of back-arc opening, using facies analyses based on field investigation. The study area of the southern Dewa Hills contains well-exposed basalt related to the opening of the Japan Sea. Five types of basaltic rock facies are recognized: (1) coherent basalt, (2) massive platy basalt, (3) jigsaw-fit monomictic basaltic breccia, (4) massive or stratified coarse monomictic basaltic breccia with fluidal clasts, and (5) massive or stratified fine monomictic basaltic breccia. The basaltic rocks are mainly hyaloclastite. Based on facies distributions, we infer that volcanism occurred along fissures developed mainly at the center of the study area. Given that the rocks contain many fluidal clasts, submarine lava fountaining is inferred to have been the dominant eruption style. The basaltic rocks are interpreted as the products of back-arc volcanism that occurred by tensional stress related to opening of the Japan Sea, which drove strong tectonic subsidence and active lava fountain volcanism.

  2. Multi-core Fibers in Submarine Networks for High-Capacity Undersea Transmission Systems

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Morioka, Toshio


    Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems......Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems...

  3. They Have Not Yet Begun to Fight: Women in the United States Navy Submarine Fleet (United States)


    Navy Nurse Corps in 1908. The Nurse Corps was highly educated for the time and maintained high professional standards.3 Regardless, the struggle to...nation’s navies who integrated women into their submarine fleets ahead of the U.S. Navy. Norway, Sweden , Australian, and Great Britain all...Nations such as Norway and Sweden have been incorporating females into their submarines since the mid-1980s. 39 Sweden has had female sailors

  4. The Close Aboard Bastion: a Soviet ballistic missile submarine deployment strategy


    Kreitler, Walter M


    Approved for public release; distribution is unlimited This thesis describes and analyzes a possible deployment posture for the Soviet ballistic missile submarine force. It examines the proposition that the Soviet Navy will establish a point defense, labeled "Close Aboard Bastions" (CABs), for its ballistic missile submarine fleet within the Soviet claimed 12 nautical mile territorial sea. This is a logical derivation of the currently widely held view that the Soviets will estab...

  5. Submarine channel evolution linked to rising salt domes, Gulf of Mexico, USA (United States)

    Carter, Rachel C.; Gani, M. Royhan; Roesler, Toby; Sarwar, Abu K. M.


    An examination of halokinetics and channel evolution together in a deepwater system provides an opportunity to investigate how submarine channel morphology is locally affected by rising salt domes. The study area is located in the northern Gulf of Mexico (GOM), directly off the Louisiana continental slope in a prominent salt dome region. The influence of salt growth on submarine channel evolution is relatively understudied, particularly in the GOM. Utilizing high-resolution 3D seismic and well data and seismic geomorphology techniques, a long-lived (~ 3 Myr) Plio-Pleistocene submarine channel system has been investigated to show a relationship between variable phases of salt motion and planform morphology of preserved submarine channels. Our data suggest that local salt motion acts as a driver for submarine channel evolution. During the late Pliocene, when salt moved upward at a relatively fast rate, channels show distinct entrenchment with narrow channel belts and overall less sinuosity. When salt motion slowed down at the beginning of the Pleistocene, channels aggraded rapidly with preserved levees, and moved toward an equilibrium state with the expansion of channel belt widths. As our results indicate, the rate of salt diapirism exerted a first-order control on channel location and morphology and distribution of reservoir-prone units. This study cautions against readily invoking allogenic factors (e.g., sea level and climate) in explaining changes in submarine channel behavior and associated fan sedimentation, particularly in regions with salt tectonics.

  6. Microbial communities in sunken wood are structured by wood-boring bivalves and location in a submarine canyon.

    Directory of Open Access Journals (Sweden)

    Sonja K Fagervold

    Full Text Available The cornerstones of sunken wood ecosystems are microorganisms involved in cellulose degradation. These can either be free-living microorganisms in the wood matrix or symbiotic bacteria associated with wood-boring bivalves such as emblematic species of Xylophaga, the most common deep-sea woodborer. Here we use experimentally submerged pine wood, placed in and outside the Mediterranean submarine Blanes Canyon, to compare the microbial communities on the wood, in fecal pellets of Xylophaga spp. and associated with the gills of these animals. Analyses based on tag pyrosequencing of the 16S rRNA bacterial gene showed that sunken wood contained three distinct microbial communities. Wood and pellet communities were different from each other suggesting that Xylophaga spp. create new microbial niches by excreting fecal pellets into their burrows. In turn, gills of Xylophaga spp. contain potential bacterial symbionts, as illustrated by the presence of sequences closely related to symbiotic bacteria found in other wood eating marine invertebrates. Finally, we found that sunken wood communities inside the canyon were different and more diverse than the ones outside the canyon. This finding extends to the microbial world the view that submarine canyons are sites of diverse marine life.

  7. A Comparison of American, Norwegian, and Russian Standards in Calculating the Wall Thickness of Submarine Gas Pipeline

    Directory of Open Access Journals (Sweden)

    Cindy Dianita


    Full Text Available One of the key issues in the pipeline design is wall thickness calculation. This paper highlights a comparison of wall thickness calculation methods of submarine gas pipeline based on Norwegian Standard (DNV-OS-F101, Indonesian Standard SNI 3474 which refers to American Standard(ASME B31.8, and Russian Standard (VN39-1.9-005-98. A calculation of wall thickness for a submarine gas pipeline in Indonesia (pressure 12 MPa, external diameter 668 mm gives the results of 18.2 mm (VN39-1.9-005-98, 16 mm (ASME B31.8, and 13.5 mm (DNV-OS-F101.The design formula of hoop stress due to internal pressure is interpreted in different ways for every standard. Only Norwegian Standard requires calculating hoop stresses in the inner surface, which leads to a decreased value of the wall thickness. Furthermore, the calculation of collapse factor dueto external pressure is only regulated in Americanand Norwegian Standards while Russian Standard uses that factor as an intermediate parameter in calculating local buckling. For propagation buckling, either Russian or American Standard explains empirical formula of critical hydrostatics pressure as the input in propagation buckling calculation. This formula is almost similar to the empirical formula of Norwegian Standard. From the comparison of these standards, DNV OS-F101 gives more stringent requirements than others

  8. Amplitude versus offset modeling of the bottom simulating reflection associated with submarine gas hydrates (United States)

    Andreassen, K.; Hart, P.E.; MacKay, M.


    A bottom simulating seismic reflection (BSR) that parallels the sea floor occurs worldwide on seismic profiles from outer continental margins. The BSR coincides with the base of the gas hydrate stability field and is commonly used as indicator of natural submarine gas hydrates. Despite the widespread assumption that the BSR marks the base of gas hydrate-bearing sediments, the occurrence and importance of low-velocity free gas in the sediments beneath the BSR has long been a subject of debate. This paper investigates the relative abundance of hydrate and free gas associated with the BSR by modeling the reflection coefficient or amplitude variation with offset (AVO) of the BSR at two separate sites, offshore Oregon and the Beaufort Sea. The models are based on multichannel seismic profiles, seismic velocity data from both sites and downhole log data from Oregon ODP Site 892. AVO studies of the BSR can determine whether free gas exists beneath the BSR if the saturation of gas hydrate above the BSR is less than approximately 30% of the pore volume. Gas hydrate saturation above the BSR can be roughly estimated from AVO studies, but the saturation of free gas beneath the BSR cannot be constrained from the seismic data alone. The AVO analyses at the two study locations indicate that the high amplitude BSR results primarily from free gas beneath the BSR. Hydrate concentrations above the BSR are calculated to be less than 10% of the pore volume for both locations studied.

  9. Experimental modeling of gravity underflow in submarine channels (United States)

    Islam, Mohammad Ashraful

    Active and relic meandering channels are common on the seafloor adjacent to continental margins. These channels and their associated submarine fan deposits are products of the density-driven gravity flows known as turbidity currents. Unlike natural rivers, few attempts have been made to explore the process of channel meandering in the submarine environment. This research focuses on resolving the flow field of submarine channels by conducting experiments in a large laboratory basin. Saline and particulate density flows were studied in a straight channel, a single bend sinuous channel with vertical sidewalls and a multiple-bend sinuous channel with sloping sidewalls. Instantaneous velocities in steady developed currents were measured using 3-component acoustic Doppler velocity probes. Excess fractional density was measured at selected locations by collecting water sample using a siphon rake. Turbulent kinetic energy and Reynolds stress components are derived from the instantaneous velocity data of the straight channel experiments. Structure functions for mean velocity, Reynolds stress and turbulent kinetic energy profiles are derived by fitting normalized data. The normalized Reynolds-averaged velocity shows excellent similarity collapse while the Reynolds-stress and the turbulent kinetic energy profiles display reasonable similarity. Vertical profiles of the turbulent kinetic energy display two peaks separated by a zone of low turbulence; the ratio of the maximum to the depth-averaged turbulent kinetic energy is approximately 1.5. Theoretical profile of turbulent kinetic energy is derived. Comparisons of experimentally and theoretically derived turbulent kinetic energy profiles show reasonable agreement except at the position of velocity maximum where the theoretical profile displays a very small value. Velocity profiles derived from the measurements with confined flow in the single bend channel reveal that channel curvature drives two helical flow cells, one

  10. Long-term flow monitoring of submarine gas emanations (United States)

    Spickenbom, K.; Faber, E.; Poggenburg, J.; Seeger, C.


    One of the Carbon Capture and Storage (CCS) strategies currently under study is the sequestration of CO2 in sub-seabed geological formations. Even after a thorough review of the geological setting, there is the possibility of leaks from the reservoirs. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. Technically, however, these systems are not limited to CO2 but can be used for monitoring of any free gas emission (bubbles) on the seafloor. The basic design of the gas flow sensor system was derived from former prototypes developed for monitoring CO2 and CH4 on mud volcanoes in Azerbaijan. This design was composed of a raft floating on the surface above the gas vent to collect the bubbles. Sensors for CO2 flux and concentration and electronics for data storage and transmission were mounted on the raft, together with battery-buffered solar panels for power supply. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, which is then guided above water level through a flexible tube. Besides some technical problems (condensed water in the tube, movement of the buoys due to waves leading to biased measurement of flow rates), this setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. To allow unattended long-term monitoring in a submarine environment, such a system has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system

  11. Using Google Earth for Submarine Operations at Pavilion Lake (United States)

    Deans, M. C.; Lees, D. S.; Fong, T.; Lim, D. S.


    During the July 2009 Pavilion Lake field test, we supported submarine "flight" operations using Google Earth. The Intelligent Robotics Group at NASA Ames has experience with ground data systems for NASA missions, earth analog field tests, disaster response, and the Gigapan camera system. Leveraging this expertise and existing software, we put together a set of tools to support sub tracking and mapping, called the "Surface Data System." This system supports flight planning, real time flight operations, and post-flight analysis. For planning, we make overlays of the regional bedrock geology, sonar bathymetry, and sonar backscatter maps that show geology, depth, and structure of the bottom. Placemarks show the mooring locations for start and end points. Flight plans are shown as polylines with icons for waypoints. Flight tracks and imagery from previous field seasons are embedded in the map for planning follow-on activities. These data provide context for flight planning. During flights, sub position is updated every 5 seconds from the nav computer on the chase boat. We periodically update tracking KML files and refresh them with network links. A sub icon shows current location of the sub. A compass rose shows bearings to indicate heading to the next waypoint. A "Science Stenographer" listens on the voice loop and transcribes significant observations in real time. Observations called up to the surface immediately appear on the map as icons with date, time, position, and what was said. After each flight, the science back room immediately has the flight track and georeferenced notes from the pilots. We add additional information in post-processing. The submarines record video continuously, with "event" timestamps marked by the pilot. We cross-correlate the event timestamps with position logs to geolocate events and put a preview image and compressed video clip into the map. Animated flight tracks are also generated, showing timestamped position and providing timelapse

  12. Modeled alongshore circulation and force balances onshore of a submarine canyon (United States)

    Hansen, Jeff E.; Raubenheimer, Britt; List, Jeffrey H.; Elgar, Steve


    Alongshore force balances, including the role of nonlinear advection, in the shoaling and surf zones onshore of a submarine canyon are investigated using a numerical modeling system (Delft3D/SWAN). The model is calibrated with waves and alongshore flows recorded over a period of 1.5 months at 26 sites along the 1.0, 2.5, and 5.0 m depth contours spanning about 2 km of coast. Field observation-based estimates of the alongshore pressure and radiation-stress gradients are reproduced well by the model. Model simulations suggest that the alongshore momentum balance is between the sum of the pressure and radiation-stress gradients and the sum of the nonlinear advective terms and bottom stress, with the remaining terms (e.g., wind stress and turbulent mixing) being negligible. The simulations also indicate that unexplained residuals in previous field-based estimates of the momentum balance may be owing to the neglect of the nonlinear advective terms, which are similar in magnitude to the sum of the forcing (pressure and radiations stress gradients) and to the bottom stress.

  13. Submarine pyroclastic deposits in Tertiary basins, NE Slovenia

    Directory of Open Access Journals (Sweden)

    Polona Kralj


    Full Text Available In Tertiary basins of NE Slovenia, Upper Oligocene volcanic activity occurred in a submarine environment that experienced contemporaneous clastic sedimentation. Pyroclastic deposits are essentially related to gas- and watersupported eruption-fed density currents. At Trobni Dol, the Lako Basin, an over 100 m thick deposit formed by a sigle sustained volcanic explosion that fed gas-supported pyroclastic flow. Diagnostic features are large matrixshard content, normal grading of pumice lapilli, collapsed pumice lapilli and the presence of charcoal. In the Smrekovec Volcanic Complex, several but only up to 5 m thick deposits related to eruption-fed gassupported pyroclastic flows occur. Deposits settled from water-supported eruption-fed density currents form fining- and thinning-upward sedimentary units which resemble the units of volcaniclastic turbidites. Pyroclastic deposits related to gas- and water-supported density currents occur in an up to 1000 m thick succession composed of coherent volcanics, autoclastic, pyroclastic, reworked volcaniclastic and mixed volcaniclastic-siliciclastic deposits that indicate a complex explosive and depositional history of the Smrekovec Volcanic Complex.

  14. Breathing modes of Kolumbo submarine volcano (Santorini, Greece). (United States)

    Bakalis, Evangelos; Mertzimekis, Theo J; Nomikou, Paraskevi; Zerbetto, Francesco


    Submarine volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo's hydrothermal vent system. The respective time series have been analyzed in terms of non-equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non-conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.

  15. High-efficiency airfoil rudders applied to submarines

    Directory of Open Access Journals (Sweden)

    ZHOU Yimei


    Full Text Available Modern submarine design puts forward higher and higher requirements for control surfaces, and this creates a requirement for designers to constantly innovate new types of rudder so as to improve the efficiency of control surfaces. Adopting the high-efficiency airfoil rudder is one of the most effective measures for improving the efficiency of control surfaces. In this paper, we put forward an optimization method for a high-efficiency airfoil rudder on the basis of a comparative analysis of the various strengths and weaknesses of the airfoil, and the numerical calculation method is adopted to analyze the influence rule of the hydrodynamic characteristics and wake field by using the high-efficiency airfoil rudder and the conventional NACA rudder comparatively; at the same time, a model load test in a towing tank was carried out, and the test results and simulation calculation obtained good consistency:the error between them was less than 10%. The experimental results show that the steerage of a high-efficiency airfoil rudder is increased by more than 40% when compared with the conventional rudder, but the total resistance is close:the error is no more than 4%. Adopting a high-efficiency airfoil rudder brings much greater lifting efficiency than the total resistance of the boat. The results show that high-efficiency airfoil rudder has obvious advantages for improving the efficiency of control, giving it good application prospects.

  16. Sea-level-induced seismicity and submarine landslide occurrence (United States)

    Brothers, Daniel S.; Luttrell, Karen M.; Chaytor, Jason D.


    The temporal coincidence between rapid late Pleistocene sea-level rise and large-scale slope failures is widely documented. Nevertheless, the physical mechanisms that link these phenomena are poorly understood, particularly along nonglaciated margins. Here we investigate the causal relationships between rapid sea-level rise, flexural stress loading, and increased seismicity rates along passive margins. We find that Coulomb failure stress across fault systems of passive continental margins may have increased more than 1 MPa during rapid late Pleistocene–early Holocene sea-level rise, an amount sufficient to trigger fault reactivation and rupture. These results suggest that sea-level–modulated seismicity may have contributed to a number of poorly understood but widely observed phenomena, including (1) increased frequency of large-scale submarine landslides during rapid, late Pleistocene sea-level rise; (2) emplacement of coarse-grained mass transport deposits on deep-sea fans during the early stages of marine transgression; and (3) the unroofing and release of methane gas sequestered in continental slope sediments.

  17. NESTOR - Neutrino Extended Submarine Telescope with Oceanographic Research

    CERN Document Server


    {\\bf NESTOR} is a deep-sea neutrino telescope that is being deployed in the Mediterranean off the south-west coast of the Peleponnese in Greece. Neutrinos, when they interact in the earth below or in the seawater around the detector, produce muons that can be observed by the Cherenkov radiation, which they emit. At an operating depth of 4000 metres, the detector is effectively shielded from muons produced in atmospheric interactions. {\\bf The site:} A major feature of the Ionian Sea floor is the Hellenic Trench, the deepest in the Mediterranean, which in places exceeds 5000 meters. It runs close to the western coast of the Peleponnese and is protected on its western side by the submarine Eastern Mediterranean Ridge. It is far from big city pollution or the effluent of major river systems flowing into the Mediterranean and is protected from deep-water perturbations.\\\\ The NESTOR site is located on a broad plateau some 8 $\\times$ 9 kilometres in area on the eastern side of the Hellenic Trench at a mean depth of...

  18. Ecostructuring of marine nematode communities by submarine groundwater discharge. (United States)

    Grzelak, Katarzyna; Tamborski, Joseph; Kotwicki, Lech; Bokuniewicz, Henry


    Inputs of submarine groundwater discharge (SGD) to the coastal ocean may alter local and regional-scale biology. Here, we report on nematode assemblages along the north shore of Long Island, NY. We test if nematode communities differed between sites impacted by mixed fresh-saline SGD and where SGD is exclusively saline. Diversity of nematodes was low at sites impacted by fresh SGD and communities were dominated by a few opportunistic genera. Moreover, a set of typical freshwater nematode genera restricted to impacted sites was observed. Their presence in the marine coastal zone is exceptional and underlines the structuring role that fresh SGD plays in the local ecosystem. Saline SGD structured nematode assemblages differently compared to sites impacted by fresh SGD. The number of nematode genera was markedly higher at saline SGD sites, with a different community structure. This study highlights the importance to which inputs of fresh SGD may have on local ecosystem diversity in marine coastal environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Breathing modes of Kolumbo submarine volcano (Santorini, Greece) (United States)

    Bakalis, Evangelos; Mertzimekis, Theo J.; Nomikou, Paraskevi; Zerbetto, Francesco


    Submarine volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo’s hydrothermal vent system. The respective time series have been analyzed in terms of non-equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non-conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.

  20. Can submarine groundwater discharge be a major source of mercury input to north Gulf of Mexico? (United States)

    Du, X.; Das, R.; Odom, L.


    Atmosphere deposition is generally regarded to be the primary source of mercury in the open ocean. Bone et al., 2007 measured an order of magnitude higher mercury concentration (0.47-1.9 nM of Hg m-2 day-1) in the submarine ground water discharge to the Waquoit Bay (Massachusetts), than the atmospheric deposition rate for the northeastern U.S and far greater than the dissolved Hg introduced through riverine input. This is a report initial findings of an investigation begun in April, 2009 to study what role submarine groundwater discharge along the northern Gulf of Mexico coast (Florida) might have in supplying dissolved mercury and methylmercury to gulf waters. Initial efforts have concentrated on part of a pristine and previously studied (Santos et al., 2008) subterranean estuary. The subterranean estuary is the zone in which encroaching seawater mixes with groundwater from land-based recharge. We collected water samples from five permanent PVC wells over small spatial scales (~ 10 m), sampling the subterranean estuary water at 4 m depth. Fresh groundwater and sea water were collected as well. Within the narrow subterranean estuary zone of the study area, both total dissolved mercury and methylmercury filtered samples reach concentrations nearly two orders of magnitude higher than that in either of the presumed end members (groundwater and seawater). Peak concentrations are approximately in the center of the zone (total mercury = 99.7 pM; methylmercury=16.9 pM). By comparison, Sunderland et al. (2009) found methylmercury concentration in North Pacific Ocean water to be 0.33pM. Isotopic measurements of mercury across the subterranean estuary zone reveal a mass-dependent fractionation pattern of heavy isotope enrichment increasing from δ202Hg = 0.1 (landward) to 1.1 (seaward). { δ202Hg = [(202Hg/200Hg)water/(202Hg/200Hg)NIST3133] -1x1000} Because of the low concentrations, isotopic measurements of seawater and groundwater are not presently available. While no

  1. Westward advance of the deformation front and evolution of submarine canyons offshore of southwestern Taiwan (United States)

    Han, Wei-Chung; Liu, Char-Shine; Chi, Wu-Cheng; Chen, Liwen; Lin, Che-Chuan; Chen, Song-Chuen


    This study analyzes both 2D and 3D seismic images around the Palm Ridge area offshore of southwestern Taiwan to understand how the deformation front shifted westward and how tectonic activities interact with submarine canyon paths in the transition area between the active and passive margins. Palm Ridge is a submarine ridge that developed on the passive China continental margin by down-dip erosion of several tributaries of Penghu Canyon; it extends eastward across the deformation front into the submarine Taiwan accretionary wedge. The presence of proto-thrusts that are located west of the frontal thrust implies that the compressional stress field has advanced westward due to the convergence of the Philippine Sea Plate and Eurasian Plate. Since the deformation front is defined as the location of the most frontal contractional structure, no significant contractional structure should appear west of it. We thus suggest moving the location of the previously mapped deformation front farther west to where the westernmost proto-thrust lies. High-resolution seismic and bathymetric data reveal that the directions of the paleo-submarine canyons run transverse to the present slope dip, while the present submarine canyons head down slope in the study area. We propose that this might be the result of the westward migration of the deformation front that changed the paleo-bathymetry and thus the canyon path directions. The interactions of down-slope processes and active tectonics control the canyon paths in our study area.

  2. Methane concentration inside a submarine mud volcano examined through seismic velocity profiles (United States)

    Kioka, Arata; Tsuji, Takeshi; Otsuka, Hironori; Ashi, Juichiro


    Mud volcanoes are considered to be among largest geological sources releasing hydrocarbon gases into the atmosphere. Numerous studies have revealed their origins and compositions from submarine mud volcanoes. A recent long-term observation at a submarine mud volcano sheds light on that larger volume of methane gas than expected is escaped from deep-water mud volcanoes, suggesting that the global methane flux from the seafloor is likely underestimated. Yet, estimates of the gas amount inside mud volcanoes have been still challenging, because of the difficulty of in-situ measurements. This study provides a new model to bridge methane amounts and seismic velocities in fluidized mud conduits of submarine mud volcanoes. This model is universally applicable and enables estimates of methane concentration in the mud conduits, using the seismic velocity profile derived from reflection/refraction seismic and/or downhole logging data. In this study, (1) we examine our modeled results through deep-drilling data obtained at mud volcanoes in the Olimpi mud field of the central Mediterranean Ridge accretionary margin, to evaluate the difference between in situ methane amounts and those calculated from our model, and (2) apply our model to the seismic velocity profile derived from seicmic data to estimate the methane amount inside the submarine mud volcano in the Nankai accretionary margin. Our scheme may provide an opportunity to re-estimate the total methane flux from submarine mud volcanoes.

  3. Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina) (United States)

    Porubsky, W.P.; Weston, N.B.; Moore, W.S.; Ruppel, C.; Joye, S.B.


    Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side

  4. DNV RP-F116 integrity management of submarine pipeline system

    Energy Technology Data Exchange (ETDEWEB)

    Leinum, B.H.; Etterdal, B. [Det Norske Veritas (DNV), Hoevik (Norway); Augustinovic, Z. [Dong Energy, Fredericia (Denmark); Paula, A. [Det Norske Veritas (DNV), Rio de Janeiro, RJ (Brazil)


    The need to keep pipelines operating safely and efficiently is paramount for any operator. Additionally, there is an increasing awareness at both regulatory and public level. Authorities around the world are adopting a more proactive approach as they seek to minimize the risk of human injuries or harm to the environment resulting from pipeline leaks. A joint industry project (JIP) led by DNV Energy is formulating guidelines for how to manage the integrity of submarine pipeline system. The resultant document of recommended practice, DNV RP-F116, will provide the oil and gas industry with a useful tool in an area where no such formal guidance currently exists. This paper gives an overview of the RP and demonstrates the use with a case study for the Siri field. The Siri field is operated by DONG Energy, Denmark and all infield pipelines were subjected to an integrity assessment using the Integrity Management process as outlined in the upcoming DNV RP-116. In parallel with establishing the RP, DNV has further developed the web-based software system, Orbit+, which is aligned with the RP. The software system is implemented and used by Dong Energy. (author)

  5. The Evaluation of Sanitary-Epidemiological Service Conditions On a Submarine

    Directory of Open Access Journals (Sweden)

    Żychliński Michał


    Full Text Available Service on a submarine is the most stressful and psychologically challenging form of military service. It is characterised by specific living and sanitaryepidemiological conditions which are far from typical. This work is based on the analyses of reports formulated from research conducted by a working environment laboratory, and on the control protocols of the sanitary supervision and control team (WOMP Gdynia, from the Kobben submersible vessels in the years 2014 and 2015. Military Centres of Preventive Medicine hold supervision over Military Units pursuant to generally applicable regulations in the civil environment and standardised NATO norms. Measurements concern the level of noise, mechanical vibrations, chemical agents, electromagnetic radiation, physiochemical and biological water and kitchenware tests. The objective of the research is to evaluate the service conditions on a submersible vessel with regard to sanitary-epidemiological aspects such as exposure to infectious and occupational diseases. In selected stations, the conducted measurements indicate an increased level of noise, electromagnetic radiation and excess quantities of bacteria colonies on kitchenware.

  6. The 1979 Submarine Landslide-Generated Tsunami in Mururoa, French Polynesia (United States)

    Poupardin, Adrien; Heinrich, Philippe; Frère, Antoine; Imbert, David; Hébert, Hélène; Flouzat, Mireille


    This paper aims at best describing the submarine landslide which induced partial submersion of the atolls of Mururoa and Fangataufa in 1979. More precisely, waves propagated along the south coast of Mururoa atoll and penetrated into its lagoon some minutes after the landslide triggering ( t = 0 s), whereas a train of eight water waves reached the runway located on the north-east coast of Fangataufa (40 km south of Mururoa) between t = 7 min 30 s and t = 20 min. A numerical model based on shallow water equations is used to simulate the landslide as well as the associated tsunami. Saint-Venant equations are used to propagate the tsunami in coastal areas, whereas the offshore propagation is simulated by solving weakly nonlinear Boussinesq equations. Low- and high-resolution nested grids are used to simulate the tsunami propagation in deep sea and in shallow waters, respectively. Several scenarios have been tested to reproduce the observed water and run-up heights in the near and far fields. The best scenarios correspond to a landslide with a volume in the range (75-90 Mm3) (for a basal friction angle of 35°) and with a basal friction angle in the range (30°-40°) (for a volume of 80 Mm3). These results have been completed by a parametric study on the slide parameters.

  7. Optimizing the balance between task automation and human manual control in simulated submarine track management. (United States)

    Chen, Stephanie I; Visser, Troy A W; Huf, Samuel; Loft, Shayne


    Automation can improve operator performance and reduce workload, but can also degrade operator situation awareness (SA) and the ability to regain manual control. In 3 experiments, we examined the extent to which automation could be designed to benefit performance while ensuring that individuals maintained SA and could regain manual control. Participants completed a simulated submarine track management task under varying task load. The automation was designed to facilitate information acquisition and analysis, but did not make task decisions. Relative to a condition with no automation, the continuous use of automation improved performance and reduced subjective workload, but degraded SA. Automation that was engaged and disengaged by participants as required (adaptable automation) moderately improved performance and reduced workload relative to no automation, but degraded SA. Automation engaged and disengaged based on task load (adaptive automation) provided no benefit to performance or workload, and degraded SA relative to no automation. Automation never led to significant return-to-manual deficits. However, all types of automation led to degraded performance on a nonautomated task that shared information processing requirements with automated tasks. Given these outcomes, further research is urgently required to establish how to design automation to maximize performance while keeping operators cognitively engaged. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  8. Calibration and use of continuous heat-type automated seepage meters for submarine groundwater discharge measurements (United States)

    Mwashote, B.M.; Burnett, W.C.; Chanton, J.; Santos, I.R.; Dimova, N.; Swarzenski, P.W.


    Submarine groundwater discharge (SGD) assessments were conducted both in the laboratory and at a field site in the northeastern Gulf of Mexico, using a continuous heat-type automated seepage meter (seepmeter). The functioning of the seepmeter is based on measurements of a temperature gradient in the water between downstream and upstream positions in its flow pipe. The device has the potential of providing long-term, high-resolution measurements of SGD. Using a simple inexpensive laboratory set-up, we have shown that connecting an extension cable to the seepmeter has a negligible effect on its measuring capability. Similarly, the observed influence of very low temperature (???3 ??C) on seepmeter measurements can be accounted for by conducting calibrations at such temperatures prior to field deployments. Compared to manual volumetric measurements, calibration experiments showed that at higher water flow rates (>28 cm day-1 or cm3 cm-2 day-1) an analog flowmeter overestimated flow rates by ???7%. This was apparently due to flow resistance, turbulence and formation of air bubbles in the seepmeter water flow tubes. Salinity had no significant effect on the performance of the seepmeter. Calibration results from fresh water and sea water showed close agreement at a 95% confidence level significance between the data sets from the two media (R2 = 0.98). Comparatively, the seepmeter SGD measurements provided data that are comparable to manually-operated seepage meters, the radon geochemical tracer approach, and an electromagnetic (EM) seepage meter. ?? 2009 Elsevier Ltd.

  9. Evidence for Submarine Groundwater Discharge into the Black Sea—Investigation of Two Dissimilar Geographical Settings

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    Michael Schubert


    Full Text Available The sustainable management of coastal marine environments requires a comprehensive understanding of the processes related to material transport from land to coastal sea. Besides surface water discharge (e.g., rivers and storm drains, submarine groundwater discharge (SGD plays a key role since it provides a major pathway for solute and particulate transport of contaminants and nutrients, both having considerable potential to cause deterioration of the overall ecological status of coastal environments. The aim of the presented study was the investigation of SGD in two exemplary and dissimilar areas at the Black Sea coast, one in the west (Romania and one in the east (Georgia. The approach included the assessment of the geological/geographical setting regarding the potential of SGD occurrence, the use of environmental tracer data (222Rn, δ18O, δ2H, salinity, and the evaluation of sea surface temperature patterns near the coastline using satellite data. Besides the individual site specific results, the study revealed that a combined evaluation of tracer data and satellite based information allows SGD localization with satisfying precision. A downscaling approach starting with large scale satellite data is generally recommended, continuing with medium scale tracer patterns and ending with local spot sampling.

  10. The Keelung Submarine Volcano in the near-shore area of northern Taiwan and its tectonic implication (United States)

    Tsai, Ching-Hui; Hsu, Shu-Kun; Lin, Shiao-Shan; Yang, Tsanyao F.; Wang, Shiou-Ya; Doo, Wen-Bin; Lee, Hsiao-Fen; Lan, Tefang; Huang, Jian-Cheng; Liang, Chin-Wei


    The Taiwan mountain belt has been created due to the collision between the Philippine Sea Plate and the Eurasian Plate. Northernmost Taiwan and its offshore area are now under post-collisional collapse. The post-collisional magmatism is distributed around northern Taiwan. Here we first report a submarine volcano, named Keelung Submarine Volcano, existing in the near-shore area of northern Taiwan. The high 3He/4He ratios in the collected seawater samples suggest that the magma of the Keelung Submarine Volcano is derived from a mantle source. Geometrically, both the Keelung Submarine Volcano and the Tatun Volcano Group are situated above the western border of the subducted Philippine Sea Plate and may have a same magma source. Both volcanic areas belong to the northern Taiwan volcanic zone, instead of the Ryukyu volcanic front. The Keelung Submarine Volcano has been rotated clockwise ∼48° after its formation, which implies that the Keelung Submarine Volcano has formed before the Luzon arc collided against northern Taiwan. Consequently, the post-collisional model to explain the formation of the northern Taiwan volcanic zone is questionable. As indicated by numerous shallow earthquakes and persistent emissions of the volcanic gases out of the seafloor around the volcanic cone, the Keelung Submarine Volcano is as active as the Tatun Volcano Group. For the sake of volcanic hazard assessment, it is essential to monitor the activity of the Keelung Submarine Volcano.

  11. CFD RANS Simulations on a Generic Conventional Scale Model Submarine: Comparison between Fluent and OpenFOAM (United States)


    1 – Hydrodynamics”, Defence Science and Technology Organisation Technical Report DSTO-TR-1622, 2004. UNCLASSIFIED DST-Group-TN-1449 UNCLASSIFIED...17 7. Joubert, P.N., “Some Aspects of Submarine Design Part 2– Shape of a Submarine 2026”, Defence Science and Technology Organisation Technical

  12. High accuracy station moving method for total station in submarine construction

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    MIN Shaosong


    Full Text Available [Objectives] When we measure submarine pressure hulls using a total station, it is essential to set several stations in order to complete the measurement of the whole cabin due to the complicated measuring environment. However, there are many restrictions related to the total station itself when moving stations, and it is also difficult to ensure measuring accuracy and satisfy the requirements of submarine measurement in complicated environments.[Methods] As such, a new station moving method is presented which can automatically establish standing relationships by measuring common points at every measuring position.[Results] This method can significantly improve accuracy and efficiency.[Conclusions] The experiment shows that the results of the new station moving method can meet sub-pixel precision and satisfy submarine measurement requirements with high accuracy.

  13. The Zambezi Channel: A new perspective on submarine channel evolution at low latitudes (United States)

    Wiles, E.; Green, A.; Watkeys, M.; Jokat, W.


    Submarine channels are not stand-alone systems. They are long-lived systems modified by imperceptibly slow processes and rapid gravity flows, in some part controlled by hinterland dynamics. The submarine Zambezi Channel, within the Mozambique Channel, receives sediment from the Zambezi River catchment which has a dynamic tectonic and morphological history. Using recently collected multibeam bathymetry and PARASOUND data we discuss the geomorphology of the Zambezi Channel. Results show this system to be distinct in geomorphologic character when compared to other low-latitude submarine channels, sharing similarities with high-latitude systems. We propose a new, source-to-sink, hypothesis for the evolution of the Zambezi Channel, taking in to consideration hinterland tectonics, palaeo-lake development, river capture and rapid gravity flows. This hypothesis accounts for the unique present-day anatomy of the Zambezi Channel within the dynamic framework of the systems regional setting.

  14. Chemical Fluxes from a Recently Erupted Submarine Volcano on the Mariana Arc (United States)

    Buck, N. J.; Resing, J. A.; Lupton, J. E.; Larson, B. I.; Walker, S. L.; Baker, E. T.


    While hydrothermal circulation is paramount to the geochemical budget for a wide array of elements, relatively few flux estimates exist in the literature. To date most studies have concentrated on constraining global and vent-field scale inputs originating from ocean spreading ridges. The goal of this study is to directly measure the chemical flux from an active submarine volcano injecting hydrothermal fluids into the surface ocean. Ahyi Seamount, a submarine intraoceanic arc volcano located in the Northern Mariana Islands, has a summit depth TSM and total and dissolved Fe and Mn. Laboratory analyses found enriched concentrations of H2, 3He, CO2 and Fe, consistent with a recent eruption. Preliminary flux calculations estimate a Fe input of 16 mmol s-1. This indicates shallow submarine arc volcanoes are capable of supplying appreciable quantities of Fe into the surface ocean. Further laboratory analyses and calculations to characterize and constrain the fluxes of other chemical constituents are underway.

  15. Air blast injuries killed the crew of the submarine H.L. Hunley.

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    Rachel M Lance

    Full Text Available The submarine H.L. Hunley was the first submarine to sink an enemy ship during combat; however, the cause of its sinking has been a mystery for over 150 years. The Hunley set off a 61.2 kg (135 lb black powder torpedo at a distance less than 5 m (16 ft off its bow. Scaled experiments were performed that measured black powder and shock tube explosions underwater and propagation of blasts through a model ship hull. This propagation data was used in combination with archival experimental data to evaluate the risk to the crew from their own torpedo. The blast produced likely caused flexion of the ship hull to transmit the blast wave; the secondary wave transmitted inside the crew compartment was of sufficient magnitude that the calculated chances of survival were less than 16% for each crew member. The submarine drifted to its resting place after the crew died of air blast trauma within the hull.

  16. The Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient (United States)

    Dowdeswell, Julian A.; Canals, Miquel; Jakobsson, Martin; Todd, Brian J.; Dowdeswell, Evelyn K.; Hogan, Kelly A.


    Twenty years ago, the international marine community brought together a first Atlas of Acoustic Images of the high-latitude geo-marine environment (Davies et al. 1997). The present Atlas is a new attempt to summarize the state of knowledge of high-latitude glacier-influenced systems, focusing on HR imagery derived from multibeam swath bathymetry and novel 2D and 3D seismic reflection tools. These new-generation techniques, aided by accurate global positioning, have revolutionized the imaging of the seafloor and subseafloor over the past two decades and have now been deployed widely in polar and subpolar waters, providing vast quantities of new data. It is, therefore, timely to provide a compilation of the variety of submarine glacial and related landforms, together with their stratigraphic setting where possible, for scientific, technological, environmental and economic reasons. The glacial imprint on the modern seabed and palaeo-shelf surfaces, buried in glacial-sedimentary depocentres, can now be imaged better than ever before using the above techniques, providing novel insights into present and past environmental conditions and sedimentary architecture. The understanding of polar regions and their changing ice cover is of enhanced significance as they are both a key driver of global change and important responders to it. Finally, industry is increasingly interested on the dimensions and architecture of glacial sedimentary depocentres on present and past continental shelves because of the hydrocarbon potential of some glacial-sedimentary systems. The Atlas consists of a comprehensive series of over 180 contributions that describe, illustrate and discuss the full variability of landforms found on the high-latitude, glacier-influenced systems, and is organised in terms of their positions on a continental margin into those from: (1) fjords, (2) continental shelves and plateaus, and (3) the deep margin and basins beyond. The Atlas has been published by the Geological

  17. Potential Impact of Submarine Power Cables on Crab Harvest (United States)

    Bull, A. S.; Nishimoto, M.


    Offshore renewable energy installations convert wave or wind energy to electricity and transfer the power to shore through transmission cables laid on or buried beneath the seafloor. West coast commercial fishermen, who harvest the highly prized Dungeness crab (Metacarcinus magister) and the rock crab (Cancer spp.), are concerned that the interface of crabs and electromagnetic fields (EMF) from these cables will present an electrified fence on the seafloor that their target resource will not cross. Combined with the assistance of professional fishermen, submarine transmission cables that electrify island communities and offshore oil platforms in the eastern Pacific provide an opportunity to test the harvest of crab species across power transmission cables. In situ field techniques give commercial crab species a choice to decide if they will cross fully energized, EMF emitting, power transmission cables, in response to baited traps. Each independent trial is either one of two possible responses: the crab crosses the cable to enter a trap (1) or the crab does not cross the cable to enter a trap (0). Conditions vary among sample units by the following categorical, fixed factors (i.e., covariates) of cable structure (buried or unburied); direction of cable from crab position (west or east, north or south); time and season. A generalized linear model is fit to the data to determine whether any of these factors affect the probability of crabs crossing an energized cable to enter baited traps. Additionally, the experimental design, aside from the number of runs (set of sample trials) and the dates of the runs, is the same in the Santa Barbara Channel for rock crab and Puget Sound for Dungeness crab, and allows us to compare the capture rates of the two species in the two areas. We present preliminary results from field testing in 2015.

  18. Anatomy of La Jolla submarine canyon system; offshore southern California (United States)

    Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.


    An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

  19. Evolution of submarine eruptive activity during the 2011-2012 El Hierro event as documented by hydroacoustic images and remotely operated vehicle observations (United States)

    Somoza, L.; González, F. J.; Barker, S. J.; Madureira, P.; Medialdea, T.; de Ignacio, C.; Lourenço, N.; León, R.; Vázquez, J. T.; Palomino, D.


    Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.Plain Language SummaryToday and through most of geological history, the greatest number and volume of volcanic eruptions on Earth have occurred underwater. However, in comparison to subaerial eruption, little is known about submarine eruptive processes as they are dangerous to cruise it over

  20. Scattering effect of submarine hull on propeller non-cavitation noise (United States)

    Wei, Yingsan; Shen, Yang; Jin, Shuanbao; Hu, Pengfei; Lan, Rensheng; Zhuang, Shuangjiang; Liu, Dezhi


    This paper investigates the non-cavitation noise caused by propeller running in the wake of submarine with the consideration of scattering effect caused by submarine's hull. The computation fluid dynamics (CFD) and acoustic analogy method are adopted to predict fluctuating pressure of propeller's blade and its underwater noise radiation in time domain, respectively. An effective iteration method which is derived in the time domain from the Helmholtz integral equation is used to solve multi-frequency waves scattering due to obstacles. Moreover, to minimize time interpolation caused numerical errors, the pressure and its derivative at the sound emission time is obtained by summation of Fourier series. It is noted that the time averaging algorithm is used to achieve a convergent result if the solution oscillated in the iteration process. Meanwhile, the developed iteration method is verified and applied to predict propeller noise scattered from submarine's hull. In accordance with analysis results, it is summarized that (1) the scattering effect of hull on pressure distribution pattern especially at the frequency higher than blade passing frequency (BPF) is proved according to the contour maps of sound pressure distribution of submarine's hull and typical detecting planes. (2) The scattering effect of the hull on the total pressure is observable in noise frequency spectrum of field points, where the maximum increment is up to 3 dB at BPF, 12.5 dB at 2BPF and 20.2 dB at 3BPF. (3) The pressure scattered from hull is negligible in near-field of propeller, since the scattering effect surrounding analyzed location of propeller on submarine's stern is significantly different from the surface ship. This work shows the importance of submarine's scattering effect in evaluating the propeller non-cavitation noise.

  1. Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands (United States)

    Watson, S. J.; Coffin, M. F.; Whittaker, J. M.; Lucieer, V.; Fox, J. M.; Carey, R.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Martin, T.; Cooke, F.


    Heard and McDonald Islands (HIMI) are World Heritage listed sub-Antarctic active volcanic islands in the Southern Indian Ocean. Built atop the Kerguelen Plateau by Neogene-Quaternary volcanism, HIMI represent subaerial exposures of the second largest submarine Large Igneous Province globally. Onshore, processes influencing island evolution include glaciers, weathering, volcanism, vertical tectonics and mass-wasting (Duncan et al. 2016). Waters surrounding HIMI are largely uncharted, due to their remote location. Hence, the extent to which these same processes shape the submarine environment around HIMI has not been investigated. In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice). Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.

  2. Impact of Submarine Groundwater Discharge on Marine Water Quality and Reef Biota of Maui.

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    Daniel W Amato

    Full Text Available Generally unseen and infrequently measured, submarine groundwater discharge (SGD can transport potentially large loads of nutrients and other land-based contaminants to coastal ecosystems. To examine this linkage we employed algal bioassays, benthic community analysis, and geochemical methods to examine water quality and community parameters of nearshore reefs adjacent to a variety of potential, land-based nutrient sources on Maui. Three common reef algae, Acanthophora spicifera, Hypnea musciformis, and Ulva spp. were collected and/or deployed at six locations with SGD. Algal tissue nitrogen (N parameters (δ15N, N %, and C:N were compared with nutrient and δ15N-nitrate values of coastal groundwater and nearshore surface water at all locations. Benthic community composition was estimated for ten 10-m transects per location. Reefs adjacent to sugarcane farms had the greatest abundance of macroalgae, low species diversity, and the highest concentrations of N in algal tissues, coastal groundwater, and marine surface waters compared to locations with low anthropogenic impact. Based on δ15N values of algal tissues, we estimate ca. 0.31 km2 of Kahului Bay is impacted by effluent injected underground at the Kahului Wastewater Reclamation Facility (WRF; this region is barren of corals and almost entirely dominated by colonial zoanthids. Significant correlations among parameters of algal tissue N with adjacent surface and coastal groundwater N indicate that these bioassays provided a useful measure of nutrient source and loading. A conceptual model that uses Ulva spp. tissue δ15N and N % to identify potential N source(s and relative N loading is proposed for Hawai'i. These results indicate that SGD can be a significant transport pathway for land-based nutrients with important biogeochemical and ecological implications in tropical, oceanic islands.

  3. Impact of Submarine Groundwater Discharge on Marine Water Quality and Reef Biota of Maui. (United States)

    Amato, Daniel W; Bishop, James M; Glenn, Craig R; Dulai, Henrietta; Smith, Celia M


    Generally unseen and infrequently measured, submarine groundwater discharge (SGD) can transport potentially large loads of nutrients and other land-based contaminants to coastal ecosystems. To examine this linkage we employed algal bioassays, benthic community analysis, and geochemical methods to examine water quality and community parameters of nearshore reefs adjacent to a variety of potential, land-based nutrient sources on Maui. Three common reef algae, Acanthophora spicifera, Hypnea musciformis, and Ulva spp. were collected and/or deployed at six locations with SGD. Algal tissue nitrogen (N) parameters (δ15N, N %, and C:N) were compared with nutrient and δ15N-nitrate values of coastal groundwater and nearshore surface water at all locations. Benthic community composition was estimated for ten 10-m transects per location. Reefs adjacent to sugarcane farms had the greatest abundance of macroalgae, low species diversity, and the highest concentrations of N in algal tissues, coastal groundwater, and marine surface waters compared to locations with low anthropogenic impact. Based on δ15N values of algal tissues, we estimate ca. 0.31 km2 of Kahului Bay is impacted by effluent injected underground at the Kahului Wastewater Reclamation Facility (WRF); this region is barren of corals and almost entirely dominated by colonial zoanthids. Significant correlations among parameters of algal tissue N with adjacent surface and coastal groundwater N indicate that these bioassays provided a useful measure of nutrient source and loading. A conceptual model that uses Ulva spp. tissue δ15N and N % to identify potential N source(s) and relative N loading is proposed for Hawai'i. These results indicate that SGD can be a significant transport pathway for land-based nutrients with important biogeochemical and ecological implications in tropical, oceanic islands.

  4. Development and experimental verification of a robust active noise control system for a diesel engine in submarines (United States)

    Sachau, D.; Jukkert, S.; Hövelmann, N.


    This paper presents the development and experimental validation of an ANC (active noise control)-system designed for a particular application in the exhaust line of a submarine. Thereby, tonal components of the exhaust noise in the frequency band from 75 Hz to 120 Hz are reduced by more than 30 dB. The ANC-system is based on the feedforward leaky FxLMS-algorithm. The observability of the sound pressure in standing wave field is ensured by using two error microphones. The noninvasive online plant identification method is used to increase the robustness of the controller. Online plant identification is extended by a time-varying convergence gain to improve the performance in the presence of slight error in the frequency of the reference signal.

  5. A novel positioning method for dual Mach-Zehnder interferometric vibration sensor in submarine cable security application (United States)

    Xie, Shangran; Zhang, Min; Li, Yanhe; Liao, Yanbiao


    Dual Mach-Zehnder interferometric vibration sensor is an appropriate solution for submarine cable security application. While in this application the detected vibration signal is always narrow-bandwidth and short-duration subject to environmental constraints, which makes correlation based vibration positioning algorithm a poor robustness to noise. A preprocessing method focusing on expanding signal 3dB bandwidth before correlation is proposed in purpose of reducing ultimate positioning mean square error. A high pass filter is imposed to enhance the weight of high frequency components by attenuating low frequency main lobe. Field test results indicate a significant positioning error reduction when using this novel method as long as the cutoff frequency of high pass filter is selected in a valid region where positive effect of bandwidth extension is larger than effect of SNR reduction, and MSE reduction value in valid region agrees well with theoretical prediction.

  6. Impact of Submarine Geohazards on Organic Carbon Burial Offshore Southwestern Taiwan (United States)

    Su, C. C.; Tsai, P. H.; Liu, J. T.; Hsu, S. K.; Chiu, S. D.


    The tectonically active setting and climatic conditions give Taiwan a high exposure to severe natural hazards. After the Pingtung Earthquake and Morakot Typhoon which occurred in 2006 and 2009, the turbidity currents caused a series of submarine cable breaks along the Gaoping and Fangliao Submarine Canyons off SW Taiwan. Large amounts of terrestrial sediments were fast transported bypass the narrow continental shelf and rapidly moved southward through submarine canyons to the deep sea. Two piston cores which were taken from the Tsangyao Ridge and its adjacent area (OR5-1302-2-MT7 and MT6) might shed light on understanding the export of terrestrial organic carbon to the abyss by submarine geo-hazards. The 210Pb profile of MT7 in conjunction with the grain size data indicates the existence of the Pingtung Earthquake and Morakot Typhoon related deposits. The sedimentation rate of these two cores which derived from 210Pb is approximately 0.05 cm/yr. The cores collected from the Gaoping Submarine Canyon, Gaoping Slope and Fangliao Submarine Canyon are used for analyzing TOC, organic C/N and δ13C ratios. The concentrations of total organic carbon are ~0.5%, and C/N rations almost remain between 4 and 8. The high TOC (~1%) and C/N ratio (>10) are observed in the samples with plant debris. The fluctuation of TOC and C/N ratios in near-shore samples is higher than deep sea. In terms of δ13C-values, it progressively decreases with distances from coastal zone to the deep sea. Due to the larger proportions of land-derived organic carbon, the δ13C-values in the surface sediment of upper Gaoping Submarine Canyon, Gaoping Slope, and the turbidite layers at the head of Fangliao Submarine Canyon are lighter. Furthermore, we use the TOC concentrations and δ13C-values to estimate the fractional contributions of terrestrial organic carbon by a simple two component mixing model, and integrate with the 210Pb-derived sediment accumulation rates to evaluate the organic carbon burial

  7. Nuclear-powered submarine accidents; Les accidents de sous-marins nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Tournyol du Clos, A.


    Most of nuclear-powered ships are military ships and submarines represent 95% of the total. Most of the propulsion reactors used are of PWR type. This paper gives the principal technical characteristics of PWR ship propulsion reactors and the differences with their civil homologues. The principal accidents that occurred on US and Russian nuclear-powered submarines are also listed and the possible effects of a shipwreck on the reactor behaviour are evaluated with their environmental impact. (J.S.). 1 tab., 1 photo.

  8. Modeling and Synthesis Methods for Retrofit Design of Submarine Actuation Systems. Energy Storage for Electric Actuators (United States)


    sternplane v - sway w - heave u - surge X Y Z y z x Figure 2: Coordinate frame definitions of submarine vehicular dynamics. 2.1 Six Degree of Freedom...where Mν̇ is the total inertial matrix, C(ν) is the Coriolis/centripetal matrix, D(ν) is the total damping matrix, g(η) are the buoyancy and weight...Natick, MA. Retrofit Design of Submarine Actuation Systems Page 7 q - pitch w - heave u - surge δs Msp Figure 3: Hydrodynamic moment unit definition

  9. The impact of the Type 094 ballistic missile submarine on China's nuclear policy


    Bell, Samuel D.


    Approved for public release, distribution unlimited This thesis examines the implication of China’s near completion of a viable nuclear triad. The objective is to determine first, how this submarine will fit into China’s no-first-use policy with regards to their nuclear weapons. And second, determine how advanced this weapon platform will be. With the introduction of multiple Type 094 “Jin” class ballistic missile submarines, has Beijing set the stage for a possible return to Cold War leve...

  10. Worst case meteorological scenario for Norway in case of hypothetical accident related to recovery of the Russian submarine K-27

    Energy Technology Data Exchange (ETDEWEB)

    Bartnicki, J.; Klein, H. [Norwegian Meteorological Institute, Oslo (Norway); Centre for Environmental Radioactivity, Aas (Norway); Amundsen, I.; Hosseini, A. [Norwegian Radiation Protection Authority, Oesteraas (Norway); Centre for Environmental Radioactivity, Aas (Norway); Haakenstad, H. [Norwegian Meteorological Institute, Oslo (Norway); Lind, O.C.; Salbu, B. [Norwegian University of Life Sciences, Aas (Norway); Centre for Environmental Radioactivity, Aas (Norway)


    This study is a part of a comprehensive Norwegian project led by Norwegian Radiation Protection Authority assessing risks related to a potential salvaging and decommissioning of the Russian nuclear submarine, K-27. In September 1981, the K-27 submarine was scuttled at shallow waters in the outer part of Stepovogo Bay, situated at the north-eastern coast of Novaya Zemlya. One of the scenarios that are included in the assessment is the lifting of the submarine to the surface and the subsequent transport to the Murmansk area for decommissioning. Thus, the risk of a criticality accident as a consequence of lifting and transport event cannot be ignored. A hypothetical accident might pose a serious threat to Norwegian territories and has to be considered from different perspectives. Here, we focus on the worst case meteorological scenario for Norway, but the same approach can be applied for other Scandinavian countries and Russia. As a first step, a large database with meteorological data has been prepared for the period of thirty years (1980-2010). These meteorological data are available in the 1000 km x 1000 km domain which includes both the entire Norwegian territory and the region of Novaya Zemlya. The spatial resolution of the meteorological data is 11 km and temporal 3 hours. The vertical structure includes 40 layers. The most important meteorological elements are the 3-D velocity field, the surface precipitation field and the 3-D temperature field. The second step is the development of the source terms for potential accidents which can be used by the dispersion model SNAP (Severe Nuclear Accident Program). Three locations for potential accidents with subsequent releases of radioactivity to the environment are assumed: 1) at the present location of K-27, 2) transport on the route to Murmansk and 3) in the Murmansk region. In the third step, the SNAP model will be run with meteorological data starting every 6. hour of each day during the 30 years period. As a result

  11. Geological Implications on the Different Products of Submarine Volcanism in Sangihe Waters : View from the Rov (Remotely Operated Vehicles) (United States)

    Priyadi, B.; Basuki, N.; Abidin, H.; Permana, H.; Handayani, L.; Wirasantosa, S.; Nganro, N.; Djamaluddin, R.; Ch. Kusuma, L.; Ratna Setyawidati, N.; Makarim, S.; Solihudin, T.


    Index Satal 2010, a joint marine research of Indonesia - USA, was realized in June-August 2010 to explore the deep sea of the Sangihe - Talaud Waters of Indonesia. This research was conducted by RV Baruna Jaya-4 and RV Okeanos Explorer of NOAA. Beside conducting multi beam imagery, RV Okeanos Explorer produced photos and video of the selected sites through high definition cameras mounted on an ROV operated from onboard RV Okeanos Explorer. The following discussion were based on ROV observation concerning the occurrence of volcanic products in the dive sites. Two submarine volcanoes (Naung and Kawio Barat), indicate various textures of submarine volcanic products from which magmatic composition and eruption types can be inferred. Lava is mostly observed around Kawio Barat and reflecting slightly coarse grained, thick and less structured, and in some spots flow textures could be observed especially in rough morphology. The overlying lavas show finer grain size with relatively shinny surface and darker color and supposedly having less contents of silica as it forms pillow and sheeting joint structures. The rock composition is presumably basaltic and is related with the subduction systems of the Sangihe arc. The coarser lavas might be more andesitic in composition, hence they are originated from the more differentiated magma chamber. This phenomenon indicates a change of magmatic composition from more differentiated magma to the less differentiated one. Geologically, this observation may indicate new formation of magma that may be related with the increasing intensity of subduction activity. Volcanic products around Naung are observed as pyroclastic covers on basaltic lavas. Pyroclastics present as lapilli deposit in light to dark brown colors forming stratification of 2 cm to 30 cm thick and unconsolidated clastic materials. The occurrence of pebble-size fragments of igneous rocks associated with pyroclastics indicate a phreatic to phreato-magmatic explosions of the

  12. Submarine landslide triggered by eruption recorded by in-situ hydrophone at NW Rota-1 submarine volcano, Mariana Arc (Invited) (United States)

    Chadwick, B.; Dziak, R. P.; Embley, R. W.; Tunnicliffe, V.; Sherrin, J.; Cashman, K. V.; Deardorff, N.


    An expedition to NW Rota-1, Mariana Arc, in March 2010 with R/V Kilo Moana and ROV Jason found that the submarine volcano (summit depth 520 m) was still erupting more or less continuously as has been observed since 2004, In addition, the expedition also discovered that a major landslide had occurred since the last visit in April 2009, demonstrating the dynamic processes of eruption, collapse, and regrowth in the submarine arc environment. The dive observations reveal the responses of the volcano’s magmatic and hydrothermal systems to such a collapse, as well as how the resident chemosynthetic biological community has responded to the event. The morphologic changes from the landslide can be quantified by comparing multibeam bathymetric surveys between 2009 and 2010. The headwall of the slide is now ~100 m north of the former summit ridge where depth changes up to -90 m occurred between surveys. The slide excavated material from the upper southern slope of the volcano to a distance of 3.5 km downslope, and deposited material between 2-8 km from the summit down to at least 2800 m on the volcano flank. The area and volume of slide deposits (positive depth changes) are 7.1 x 106 m2 and 5.3 x 107 m3, respectively, and the maximum thickness is +42 m. The area and volume of material removed by the slide (negative depth changes) are 2.2 x 106 m2 and -4.1 x 107 m3, respectively. We have found no evidence for a local tsunami generated by this event. The changes in morphology near the summit show that the landslide primarily removed loose volcaniclastic deposits that had accumulated near the active eruptive vent, exposing an underlying stock-like core of resistant intrusive rocks and massive lavas at the summit. During March 2010, there were at least 5 active eruptive vents, located along a line 200-m long, that changed between active and inactive day-to-day and even hour-to-hour, suggesting that the near-surface magmatic plumbing system was still reorganizing after the

  13. Swath sonar mapping of Earth's submarine plate boundaries (United States)

    Carbotte, S. M.; Ferrini, V. L.; Celnick, M.; Nitsche, F. O.; Ryan, W. B. F.


    The recent loss of Malaysia Airlines flight MH370 in an area of the Indian Ocean where less than 5% of the seafloor is mapped with depth sounding data (Smith and Marks, EOS 2014) highlights the striking lack of detailed knowledge of the topography of the seabed for much of the worlds' oceans. Advances in swath sonar mapping technology over the past 30 years have led to dramatic improvements in our capability to map the seabed. However, the oceans are vast and only an estimated 10% of the seafloor has been mapped with these systems. Furthermore, the available coverage is highly heterogeneous and focused within areas of national strategic priority and community scientific interest. The major plate boundaries that encircle the globe, most of which are located in the submarine environment, have been a significant focus of marine geoscience research since the advent of swath sonar mapping. While the location of these plate boundaries are well defined from satellite-derived bathymetry, significant regions remain unmapped at the high-resolutions provided by swath sonars and that are needed to study active volcanic and tectonic plate boundary processes. Within the plate interiors, some fossil plate boundary zones, major hotspot volcanoes, and other volcanic provinces have been the focus of dedicated research programs. Away from these major tectonic structures, swath mapping coverage is limited to sparse ocean transit lines which often reveal previously unknown deep-sea channels and other little studied sedimentary structures not resolvable in existing low-resolution global compilations, highlighting the value of these data even in the tectonically quiet plate interiors. Here, we give an overview of multibeam swath sonar mapping of the major plate boundaries of the globe as extracted from public archives. Significant quantities of swath sonar data acquired from deep-sea regions are in restricted-access international archives. Open access to more of these data sets would

  14. Submarine Groundwater Discharge in Stony Brook Harbor, NY (United States)

    Durand, J. M.; Young, C.; Wong, T.; Hanson, G. N.


    As nutrients can significantly impact coastal ecosystems, understanding their path to embayments and oceans is crucial. In Stony Brook Harbor (Long Island, NY), submarine groundwater discharge (SGD) is the only significant contribution of freshwater and thus constitutes the main pathway for nutrients, which may eventually reach Long Island Sound. Subterranean estuaries have been shown to be highly reactive zones where nitrogen attenuation can occur. Understanding the fate of nitrogen in Stony Brook Harbor requires knowing the volume of groundwater entering the bay as well as the amount of denitrification, in the context of the hydrogeological framework. This is achieved by combining electrical resistivity survey, water sampling in piezometers, point conductivity and seepage measurements. A Trident probe inserted 60 cm deep into the sediments allows measuring the conductivity and temperature of the sediments and the overlying seawater. In spring 2011, five Trident transects spreading across the head of the harbor were used as a preliminary study to reveal potential locations for SGD. Locations with significant difference between sediment and seawater temperature and/or conductivities were further investigated using an AGI SuperSting 8-channel receiver resistivity meter. Two ultrasonic seepage meters were deployed in May and July 2011 about 20 m below the low tide mark. Five piezometers were aligned parallel to one resistivity survey. Our resistivity data indicate superficial mixing in the intertidal zone. The freshwater extends quite far under the seafloor, above 67 meters after the low tide mark for one location. The freshwater/saltwater interface seems to be almost horizontal. The piezometer data agree relatively well with the resistivity data. The preliminary average seepage rates observed vary from 3 to 60 cm/d. The resistivity sections reveal the presence of a thin layer of high conductivity above the low tide mark. This matches the observation of a superficial

  15. Geophysical evidence and inferred triggering factors of submarine landslides on the western continental margin of the Ulleung Basin, East Sea (United States)

    Cukur, Deniz; Kim, Seong-Pil; Kong, Gee-Soo; Bahk, Jang-Jun; Horozal, Senay; Um, In-Kwon; Lee, Gwang-Soo; Chang, Tae-Soo; Ha, Hun-Jun; Völker, David; Kim, Jung-Ki


    Submarine landslides form very complex depositional and erosional features on the seafloor, and their dynamics and triggering processes are yet to be understood completely. Numerous studies are being undertaken both because of the scientific significance but also for their potential harm to seafloor infrastructure and coastal areas. This study investigates the styles and causes of landsliding along the western margin of the Ulleung Basin in the East Sea, based on multiple sparker, subbottom profiler, multibeam echosounder and sediment core datasets collected in 2015. The bathymetric analyses indicate that the southern slope of the Ulleung Basin has experienced at least seven submarine failures. These failures left clear arcuate-shaped scarps that initiated at water depths of 600 m. The observed headwall scarps have heights that exceed 60 m and appear to be the result of retrogressive-type failures. Seismic reflection data clearly image the basal sliding surface that is characterized by a prominent high-amplitude reflector. Chaotic-to-transparent seismic facies occur immediately downslope of the headwall scarps; these represent 20 m thick landslide deposits. Gravity cores taken from areas adjacent to the scars suggest that these slides are older than ca. 97 ka. Interpretation of the present data shows that faults appear to cut recent sediments upslope of scarps, and that the slope may still be in an active phase of failure. Seismic data also image various overpressurized gases and/or gas fluids, as evidenced by the occurrence of pockmarks and seismic chimneys in upslope or adjacent areas of the scarps. Hence, earthquakes associated with tectonic activity and development of fluid overpressure may have acted as the main conditioning factor for destabilizing the slope sediments. Geotechnical stability analyses indicate that the sampled slope sediments are exceptionally stable under present-day conditions, even under seismic loading. This finding points to additional

  16. Experimental research on the double-peak characteristic of underwater radiated noise in the near field on top of a submarine (United States)

    Liu, Ning; Wang, Sande; Guo, Tao; Li, Xiyou; Yu, Ziyang


    The double-peak characteristic of underwater radiated noise in the near field on top of the target submarine was analyzed in depth on the basis of submarine test data on the sea. The contribution of three major noise sources to the radiated noise of a submarine were compared and analyzed, and emphasis was put on the original source, production mechanism, and their correlative characteristics. On the basis of analysis on underwater tracking and pass through characteristics of the target submarine, the double-peak phenomenon was reasonably interpreted. Furthermore, the correctness of the theoretical interpretation was verified adequately in real submarine tests. The double-peak phenomenon indicates that the space distributing character on submarine radiated noise are both asymmetrical with time and space, whereas that is provided with directivity. Studying the double-peak phenomenon in depth has important reference value and meaning in engineering practice for understanding the underwater radiated noise field of submarines.

  17. The Italian Submarine Force in the Battle of the Atlantic: Left in the Dark (United States)


    design during the Interwar period. Part of this discussion will focus on German U-boat design and capabilities prior to the Versailles Treaty in...patrols can be attributed to the restrictions imposed by the Treaty of Versailles and the amount of time required to re-build a German submarine force...

  18. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system. (United States)

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai


    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.

  19. Environmental monitoring of El Hierro Island submarine volcano, by combining low and high resolution satellite imagery (United States)

    Eugenio, F.; Martin, J.; Marcello, J.; Fraile-Nuez, E.


    El Hierro Island, located at the Canary Islands Archipelago in the Atlantic coast of North Africa, has been rocked by thousands of tremors and earthquakes since July 2011. Finally, an underwater volcanic eruption started 300 m below sea level on October 10, 2011. Since then, regular multidisciplinary monitoring has been carried out in order to quantify the environmental impacts caused by the submarine eruption. Thanks to this natural tracer release, multisensorial satellite imagery obtained from MODIS and MERIS sensors have been processed to monitor the volcano activity and to provide information on the concentration of biological, chemical and physical marine parameters. Specifically, low resolution satellite estimations of optimal diffuse attenuation coefficient (Kd) and chlorophyll-a (Chl-a) concentration under these abnormal conditions have been assessed. These remote sensing data have played a fundamental role during field campaigns guiding the oceanographic vessel to the appropriate sampling areas. In addition, to analyze El Hierro submarine volcano area, WorldView-2 high resolution satellite spectral bands were atmospherically and deglinted processed prior to obtain a high-resolution optimal diffuse attenuation coefficient model. This novel algorithm was developed using a matchup data set with MERIS and MODIS data, in situ transmittances measurements and a seawater radiative transfer model. Multisensor and multitemporal imagery processed from satellite remote sensing sensors have demonstrated to be a powerful tool for monitoring the submarine volcanic activities, such as discolored seawater, floating material and volcanic plume, having shown the capabilities to improve the understanding of submarine volcanic processes.

  20. The fate of the submarine ikaite tufa columns in southwest Greenland under changing climate conditions

    DEFF Research Database (Denmark)

    Hansen, Marc O.; Buchardt, Bjørn; Kühl, Michael


    carbonate tufa columns. Here, ikaite is formed as a result of submarine spring water mixing with cold seawater. As ikaite disintegrates at temperatures above 6–7uC, it has been speculated that global warming could endanger this unique habitat as well as other sites. In Ikka Fjord in situ water chemistry...

  1. Frontal and Lateral Submarine Lobe Fringes: Comparing Sedimentary Facies, Architecture and Flow Processes

    NARCIS (Netherlands)

    Spychala, Yvonne T.; Hodgson, David M.; Prélat, Amandine; Kane, Ian A.; Flint, Stephen S.; Mountney, Nigel P.


    Submarine lobe-fringe deposits form heterolithic successions that may include a high proportion of hybrid beds. The identification of lobe-fringe successions aids interpretation of paleogeographic setting and the degree of basin confinement. Here, for the first time, the sedimentological and

  2. Contributions for the modelling of submarine cables – current density and simplified modelling of wired layers

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Bak, Claus Leth; Ebdrup, Thomas


    This article researches two topics relevant for the development of accurate formulae able to estimate the ampacity of HVAC submarine cables. Simplified formulae for estimating the current density distribution, which can be used for theoretical analyses, are developed and compared with the exact...

  3. The Future of the Ballistic Missile Submarine Force in the Russian Nuclear Triad (United States)


    financial setbacks, missile technology failures, and the Kursk sinking in 2000, the SSBN force has slipped back to a lesser prominence.9 B. MAJOR...range category. In the battle for survival, the SLBMs and ALCMs are the most likely potential losers. When the two platforms – submarines and

  4. Scientific Ocean Drilling Behind the Assessment of Geo-Hazards from Submarine Slides

    Directory of Open Access Journals (Sweden)

    Gemma Ercilla


    Full Text Available The workshop ‘Scientific Ocean Drilling Behind the Assessment of Geo-hazards from Submarine Slides’ was held on 25–27 October 2006 in Barcelona (Spain. Fifty mainly European scientists and industry representatives attended from a wide spectrum of disciplines such as geophysics, stratigraphy, sedimentology, paleoceanography, marinegeotechnology, geotechnical engineering, and tsunami modeling.

  5. Estimation of submarine mass failure probability from a sequence of deposits with age dates (United States)

    Geist, Eric L.; Chaytor, Jason D.; Parsons, Thomas E.; ten Brink, Uri S.


    The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from renewal process theory and Monte Carlo methods. The estimated mean return time from these methods, unlike estimates from a simple arithmetic mean of the center age dates and standard likelihood methods, includes the effects of age-dating uncertainty and of open time intervals before the first and after the last event. The likelihood techniques are evaluated using Akaike’s Information Criterion (AIC) and Akaike’s Bayesian Information Criterion (ABIC) to select the optimal model. The techniques are applied to mass transport deposits recorded in two Integrated Ocean Drilling Program (IODP) drill sites located in the Ursa Basin, northern Gulf of Mexico. Dates of the deposits were constrained by regional bio- and magnetostratigraphy from a previous study. Results of the analysis indicate that submarine mass failures in this location occur primarily according to a Poisson process in which failures are independent and return times follow an exponential distribution. However, some of the model results suggest that submarine mass failures may occur quasiperiodically at one of the sites (U1324). The suite of techniques described in this study provides quantitative probability estimates of submarine mass failure occurrence, for any number of deposits and age uncertainty distributions.

  6. CLAM - CoLlAborative eMbedded networks for submarine surveillance: An overview

    NARCIS (Netherlands)

    Meratnia, Nirvana; Havinga, Paul J.M.; Casari, Paolo; Petrioli, Chiara; Grythe, Knut; Husoy, Thor; Zorzi, Michele


    This paper provides an overview of the CLAM project, which aims at developing a collaborative embedded monitoring and control platform for submarine surveillance by combining cutting edge acoustic vector sensor technology and 1D, 2D, 3D sensor arrays, underwater wireless sensor networks protocol

  7. Terrestrial-style slow-moving earthflow kinematics in a submarine landslide complex (United States)

    Joshu J. Mountjoy; Jim McKean; Philip M. Barnes; Jarg R. Pettinga


    Morphometric analysis of Simrad EM300 multibeam bathymetric DEMs reveals details of deformation patterns in a ~145 km2 submarine landslide complex that are commonly associated with slow-moving earthflows in terrestrial settings. This mode of failure, where existing landslide debris is remobilised repeatedly along discrete shear boundaries and is...

  8. Exchange Flow of Oil and Sea-Water in a Ruptured Submarine Pipeline

    NARCIS (Netherlands)

    Kranenburg, C.


    The rupture of a submarine oil pipeline starts var10US mechanisms leading to an oil spill. Among these mechanisms the leakage of oil driven by the difference in specific gravities of oil and seawater is difficult to quantify. A simple mathematical model has been developed and laboratory experiments

  9. Buoyancy-driven leakage of oil from a ruptured submarine pipeline

    NARCIS (Netherlands)

    Kranenburg, C.


    The rupture of a submarine oil pipeline starts various mechanisms leading to an oil spill. Among these mechanisms the leakage of oil driven by the difference in specific gravities of oil and sea-water is difficult to estimate. A simple mathematical model has been developed and laboratory experiments

  10. Geochemical stratigraphy of submarine lavas (3-5 Ma) from the Flamengos Valley, Santiago, Cape Verde

    DEFF Research Database (Denmark)

    Barker, Abigail K; Holm, Paul Martin; Peate, David W.


    New high-precision Pb-Sr-Nd isotope, major and trace element and mineral chemistry data are presented for the submarine stage of ocean island volcanism on Santiago, one of the southern islands of the Cape Verde archipelago. Pillow basalts and hyaloclastites in the Flamengos Valley are divided...

  11. Common Submarine Radio Room: A Case Study of a System of Systems Approach (United States)


    11. Land Attack/Strike Mission Scenario (from PMW770 2011b, 52) .................30 Figure 12. CSG/ ESG Mission Scenario (from PMW770 2011b, 67...request EHF extremely high frequency ESG expeditionary strike group ETR Submarine communications electronics technician FRD Fleet readiness...expeditionary strike group operations mission (CSG/ ESG ) 4. Special operations forces mission (SOF) 5. Mine warfare operations mission (MIW) 6

  12. Mapping submarine sand waves with multiband imaging radar - 2. Experimental results and model comparison

    NARCIS (Netherlands)

    Vogelzang, J.; Wensink, G.J.; Calkoen, C.J.; Kooij, M.W.A. van der


    On August 16, 1989, and on July 12, 1991, experiments were performed to study the mapping of submarine sand waves with the airborne imaging radar, a polarimetric (and, in 1991, interferometric) airborne P, L, and C band synthetic aperture radar system. The experiments took place in an area 30 km off

  13. Adaptation of a submarine transient detector to the detection of whale sounds

    NARCIS (Netherlands)

    Hotho, G.H.


    As part of an international effort to investigate a potential link between acoustic trials (SWAC 4) of SACLANTCEN with a stranding of Cuvier's beaked whales on the Greek coast in May 1996. TNO-FEL's Transient Detection Demonstrator (TDD). a tool to automatically search for submarine transients in

  14. The Risk of Hydrogen Explosion an a Submarine Part 3 Production of Hydrogen Mixes

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard


    Full Text Available This series of articles presents the problems associated with the conduction of a high-risk project aimed at modernising the hydrogen combustion engines on a submarine. The article describes technical issues connected with obtaining hydrogen-air mixes.

  15. Global land-ocean linkage: direct inputs of nitrogen to coastal waters via submarine groundwater discharge

    NARCIS (Netherlands)

    Beusen, A.H.W.; Slomp, C.P.; Bouwman, A.F.


    The role of submarine groundwater discharge (SGD), the leakage of groundwater from aquifers into coastal waters, in coastal eutrophication has been demonstrated mostly for the North American and European coastlines, but poorly quantified in other regions. Here, we present the first spatially

  16. Possible climate preconditioning on submarine landslides along a convergent margin, Nankai Trough (NE Pacific) (United States)

    Kremer, Katrina; Usman, Muhammed O.; Satoguchi, Yasufumi; Nagahashi, Yoshitaka; Vadakkepuliyambatta, Sunil; Panieri, Giuliana; Strasser, Michael


    Submarine landslides are major agents of sediment mass transfer from the shallow to deep sea. Due to their rapid emplacement and tsunamigenic potential, such landslides are significant geohazards for society and off- and on-shore infrastructure. The relationship between climate change and the occurrence of submarine landslides is widely debated. However, there is a lack of continuous long-term submarine landslide records with which to comprehensively understand the relationship between climate-driven forces and submarine landslide occurrence. Here, using oxygen isotope stratigraphy in combination with tephrochronology, we date a 1 Myr continuous record of six landslide deposits (at 13.0-14.2, 323-339, 372-384, 394-413, 508-521, and 857-867 ka) recorded in a slope basin of the Nankai Trough subduction zone, off-shore Japan, which represents the major outcome of this study. The ages of the six landslides coincide mostly with interglacial periods. Thus, we propose that climate forcing might act as a preconditioning factor for slope instability in this active tectonic region.[Figure not available: see fulltext.

  17. Near-bottom particulate matter dynamics in the Nazare submarine canyon under calm and stormy conditions

    NARCIS (Netherlands)

    Martín, J.; Palanques, A.; Vitorino, J.; Oliveira, A.; de Stigter, H.C.


    Two mooring lines equipped with near-bottom sediment traps were deployed in the axis of the Nazare submarine canyon at similar to 1600 and similar to 3300 m depth, respectively. We studied time-series of particle flux, composition (biogenic silica, carbonates, organic matter and lithogenic

  18. Autonomous long-term gamma-spectrometric monitoring of submarine groundwater discharge trends in Hawaii

    Czech Academy of Sciences Publication Activity Database

    Dulai, H.; Kameník, Jan; Waters, C. A.; Kennedy, J.; Babinec, J.; Jolly, J.; Williamson, M.


    Roč. 307, č. 3 (2016), s. 1865-1870 ISSN 0236-5731. [10th International Conference on Methods and Applications of Radioanalytical Chemistry (MARC). Kailua Kona, 12.04.2015-17.04.2015] Institutional support: RVO:61389005 Keywords : submarine groundwater discharge * long-term SGD monitoring * underwater gammaspectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.282, year: 2016

  19. Probabilistic Hazard of Tsunamis Generated by Submarine Landslides in the Cook Strait Canyon (New Zealand) (United States)

    Lane, Emily M.; Mountjoy, Joshu J.; Power, William L.; Mueller, Christof


    Cook Strait Canyon is a submarine canyon that lies within ten kilometres of Wellington, the capital city of New Zealand. The canyon walls are covered with scars from previous landslides which could have caused local tsunamis. Palaeotsunami evidence also points to past tsunamis in the Wellington region. Furthermore, the canyon's location in Cook Strait means that there is inhabited land in the path of both forward- and backward-propagating waves. Tsunamis induced by these submarine landslides pose hazard to coastal communities and infrastructure but major events are very uncommon and the historical record is not extensive enough to quantify this hazard. The combination of infrequent but potentially very consequential events makes realistic assessment of the hazard challenging. However, information on both magnitude and frequency is very important for land use planning and civil defence purposes. We use a multidisciplinary approach bringing together geological information with modelling to construct a Probabilistic Tsunami Hazard Assessment of submarine landslide-generated tsunami. Although there are many simplifying assumptions used in this assessment, it suggests that the Cook Strait open coast is exposed to considerable hazard due to submarine landslide-generated tsunamis. We emphasise the uncertainties involved and present opportunities for future research.

  20. Beam propagation of tidal internal waves over a submarine slope of the Mascarene Ridge (United States)

    Morozov, E. G.; Nechvolodov, L. V.; Sabinin, K. D.


    The generation of internal tides over the Mascarene Ridge is studied on the basis of moored measurements and numerical modeling. The beam structure of the internal wave propagation over a submarine ridge is analyzed. The dependence of the beam propagation of the perturbations on the steepness of the slope, the depth of the ridge crest, and the stratification is studied.

  1. Noble gas systematics of submarine alkalic lavas near the Hawaiian hotspot

    NARCIS (Netherlands)

    Hanyu, T.; Clague, D.A.; Kaneoka, I.; Dunai, T.J.; Davies, G.R.


    Noble gas isotopic ratios were determined for submarine alkalic volcanic rocks distributed around the Hawaiian islands to constrain the origin of such alkalic volcanism and hence understand the details of mantle upwelling beneath Hawaii. Samples were collected by dredging or using submersibles from

  2. Submarine groundwater discharge within a landslide scar at the French Mediterranean coast (United States)

    Oehler, Till; Mogollón, José M.; Moosdorf, Nils; Winkler, Andreas; Kopf, Achim; Pichler, Thomas


    Submarine groundwater discharge (SGD), the flow of fresh and saline groundwater from the seabed into the coastal ocean, has been intensively investigated in the recent years. This research has usually been restricted to shallow water and intertidal areas, whereas knowledge about groundwater seepage in deeper water is mainly limited to point sources from karstic aquifers. In this study we observed submarine groundwater seepage and a subterranean estuary in sediments at water depths of 20-44 m located within the Ligurian Margin, western Mediterranean Sea. Here, a catastrophic submarine landslide occurred near the Nice airport (French Ligurian coast) in the fall of 1979 after a period of heavy rainfall. During two research cruises, gravity cores were recovered in and around the area of the landslide scar. Pore water samples collected from sediment cores indicated sediments containing freshwater within the landslide scar. Pore water profiles of selected ions, such as chloride, ammonium, manganese, sulfate and barium were used to assess transport and reaction processes within the sediment. A 1-dimensional transport model indicates in most cores upward pore water velocities of 2.3-8.8 cm yr-1. This study shows that submarine groundwater seepage along the French Mediterranean coastline can occur at water depths reaching 44 m.

  3. Internal Structure of the West Submarine Flanks of Mauna Loa and Hualalai, Hawaii Island: investigation of ROV KAIKO and Manned Submersible SHINKAI (United States)

    Yokose, H.


    Submersible-based exploration of basaltic rocks west flank of the Hawaii Island, mostly at 2000 to 5000 m depths, was a focus of Japan USA joint research during two cruises by the JAMSTEC in 2001-02. The observations from submersibles and samples recovered are summarized, based on the twelve recent submersible dives and numerous newly obtained samples from deep submarine flanks of Hualalai and Mauna Loa Topographic nature of the studied area are categorized using high-resolution bathymetric data obtained during the cruses and are very effective for deciphering the sequence of landslides. Because the west of Hawaii Island is lee side having a little rain, topographic characteristics of landslide deposits are preserved without buried by material of the later subaerial erosion process. Submarine geological map of the west flank of Hawaii Island has been revised on the basis of these investigations. Major difference between maps proposed previously and this work is twofold. The first is the submarine flank of this area consists mainly of pillow lavas. This is contrastive to the Nuuanu landslide and Hilina slump regions in which hyaloclastite and fragmental debris are dominated. The debris avalanche deposits are prevailing only in the lower submarine slope. The second is the sequence of landslide events. Base on the topographic and geologic investigations major landslide events can be redefined in the sequence from early to late: South Kona Slide 1(South Kona slump and Ka Lae west debris-avalanche), South Kona Slide 2 (South Kona slide), North Kona Slump (North Kona slide + Alika 1 debris-avalanche), Ka Lae slump (newly defined), Ka Lae debris-avalanche (Ka Lae East debris-avalanche), Alika debris-avalanche (Alika 2 debris-avalanche). It is concluded that these slope failures were probably result in the rift propagation rather than instability of the slope itself which made of unstable fragmental lavas. Therefore, the pillow lava model is more suitable for present case

  4. US Navy Submarine Sea Trial of the NASA Air Quality Monitor (United States)

    Limero, Thomas; Wallace, William T.; Manney, Joshua A.; Mudgett, Paul D.


    For the past four years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. Most importantly, the AQM operates at atmospheric pressure and uses air as the GC carrier gas, which translates into a small reliable instrument. Onboard ISS there are two AQMs, with different GC columns that detect and quantify 22 compounds. The AQM data contributes valuable information to the assessment of air quality aboard ISS for each crew increment. The U.S. Navy is looking to update its submarine air monitoring suite of instruments, and the success of the AQM on ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which was successfully flown on ISS as a technology demonstration to measure major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial results. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only one AQM will be deployed during the sea trial, but it is sufficient to detect the compounds of interest to the Navy for the purposes of this trial. A significant benefit of the AQM is that runs can be scripted for pre-determined intervals and no crew intervention is required. The data from the sea trial will be compared to archival samples collected prior to and during the trial period. This paper will give a brief overview of the AQM technology and protocols for the submarine trial. After a quick review of the AQM preparation, the main focus of the paper will be on the results of the submarine trial. Of particular interest will be the comparison of the contaminants found in the ISS and submarine atmospheres, as both represent

  5. Rapid Submarine Melting Driven by Subglacial Discharge, LeConte Glacier, Alaska (United States)

    Motyka, R. J.; Dryer, W. P.; Amundson, J. M.; Truffer, M.; Fahnestock, M. A.


    Submarine melting impacts the stability of tidewater glaciers worldwide, but the connections between the ocean, a warming climate, and retreat of outlet glaciers are poorly known. Clearly warm seawater plays an important role, but the tremendous heat potential resident in oceans and fjords must first be brought into contact with outlet glacier termini in order to affect them. We show here that for many glaciers, the principal process driving high rates of submarine melting is subglacial discharge of freshwater. This buoyant discharge draws in warm seawater, entraining it in a turbulent upwelling convective flow along the submarine face that melts glacier ice. To capture the effect of changing subglacial discharge on submarine melting, we conducted four days of hydrographic transects during late summer 2012 at LeConte Glacier, Alaska. A major rainstorm allowed us to directly measure the influence of large changes in subglacial discharge. We found strong submarine melt rates that increased from 9.0×1.0 to 16.8×1.3 m/d (ice face equivalent frontal ablation) as subglacial discharge increased from 130 to 440 m^3/s over a four day period. This subglacial discharge drove influx of warm seawater (thermal forcing ~ 8° C) to the terminus with fluxes increasing from 1800 to 4000 m3/s. Our ice equivalent frontal ablation rates due to submarine melting are two to three times values found for Greenland glaciers, where thermal forcing is substantially lower (~ 1 - 4 °C) and termini are wider. Together, these studies confirm the importance of submarine melting at grounded glaciers. At LeConte, the total frontal ablation rate (calving flux plus submarine melting) is ~ 3.0 x10^6 m^3/d w.e., which far surpasses surface ablation. One-half to two-thirds of the frontal ablation during September 2012 can be attributed to submarine melting. A two-layer model driven by a buoyant plume of subglacial discharge has been previously invoked to describe the proglacial fjord circulation

  6. Earthquake and submarine landslide tsunamis: how can we tell the difference? (Invited) (United States)

    Tappin, D. R.; Grilli, S. T.; Harris, J.; Geller, R. J.; Masterlark, T.; Kirby, J. T.; Ma, G.; Shi, F.


    Several major recent events have shown the tsunami hazard from submarine mass failures (SMF), i.e., submarine landslides. In 1992 a small earthquake triggered landslide generated a tsunami over 25 meters high on Flores Island. In 1998 another small, earthquake-triggered, sediment slump-generated tsunami up to 15 meters high devastated the local coast of Papua New Guinea killing 2,200 people. It was this event that led to the recognition of the importance of marine geophysical data in mapping the architecture of seabed sediment failures that could be then used in modeling and validating the tsunami generating mechanism. Seabed mapping of the 2004 Indian Ocean earthquake rupture zone demonstrated, however, that large, if not great, earthquakes do not necessarily cause major seabed failures, but that along some convergent margins frequent earthquakes result in smaller sediment failures that are not tsunamigenic. Older events, such as Messina, 1908, Makran, 1945, Alaska, 1946, and Java, 2006, all have the characteristics of SMF tsunamis, but for these a SMF source has not been proven. When the 2011 tsunami struck Japan, it was generally assumed that it was directly generated by the earthquake. The earthquake has some unusual characteristics, such as a shallow rupture that is somewhat slow, but is not a 'tsunami earthquake.' A number of simulations of the tsunami based on an earthquake source have been published, but in general the best results are obtained by adjusting fault rupture models with tsunami wave gauge or other data so, to the extent that they can model the recorded tsunami data, this demonstrates self-consistency rather than validation. Here we consider some of the existing source models of the 2011 Japan event and present new tsunami simulations based on a combination of an earthquake source and an SMF mapped from offshore data. We show that the multi-source tsunami agrees well with available tide gauge data and field observations and the wave data from

  7. A submarine landslide source for the devastating 1964 Chenega tsunami, southern Alaska (United States)

    Brothers, Daniel; Haeussler, Peter J.; Lee Liberty,; David Finlayson,; Geist, Eric L.; Labay, Keith A.; Michael Byerly,


    During the 1964 Great Alaska earthquake (Mw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost – the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120–360 m. Analysis of bathymetric change between 1957 and 2014 indicates the upper 20–50 m (∼0.7 km3) of glacimarine sediment was destabilized and evacuated from the steep face of a submerged moraine and an adjacent ∼21 km2 perched sedimentary basin. Once mobilized, landslide debris poured over the steep, 130 m-high face of a deeper moraine and then blanketed the terminal basin (∼465 m water depth) in 11 ± 5 m of sediment. These results, combined with inverse tsunami travel-time modeling, suggest that earthquake- triggered submarine landslides generated the tsunami that struck the village of Chenega roughly 4 min after shaking began. Unlike other tsunamigenic landslides observed in and around Prince William Sound in 1964, the failures in Dangerous Passage are not linked to an active submarine delta. The requisite environmental conditions needed to generate large submarine landslides in glacimarine fjords around the world may be more common than previously thought. 

  8. Boulder emplacement and remobilisation by cyclone and submarine landslide tsunami waves near Suva City, Fiji (United States)

    Lau, A. Y. Annie; Terry, James P.; Ziegler, Alan; Pratap, Arti; Harris, Daniel


    The characteristics of a reef-top boulder field created by a local submarine landslide tsunami are presented for the first time. Our examination of large reef-derived boulders deposited by the 1953 tsunami near Suva City, Fiji, revealed that shorter-than-normal-period tsunami waves generated by submarine landslides can create a boulder field resembling a storm boulder field due to relatively short boulder transport distances. The boulder-inferred 1953 tsunami flow velocity is estimated at over 9 m s- 1 at the reef edge. Subsequent events, for example Cyclone Kina (1993), appear to have remobilised some large boulders. While prior research has demonstrated headward retreat of Suva Canyon in response to the repeated occurrence of earthquakes over the past few millennia, our results highlight the lingering vulnerability of the Fijian coastlines to high-energy waves generated both in the presence (tsunami) and absence (storm) of submarine failures and/or earthquakes. To explain the age discrepancies of U-Th dated coral comprising the deposited boulders, we introduce a conceptual model showing the role of repeated episodes of tsunamigenic submarine landslides in removing reef front sections through collapse. Subsequent high-energy wave events transport boulders from exposed older sections of the reef front onto the reef where they are deposited as 'new' boulders, alongside freshly detached sections of the living reef. In similar situations where anachronistic deposits complicate the deposition signal, age-dating of the coral boulders should not be used as a proxy for determining the timing of the submarine landslides or the tsunamis that generated them.

  9. Methanoculleus sediminis sp. nov., a methanogen from sediments near a submarine mud volcano. (United States)

    Chen, Sheng-Chung; Chen, Mei-Fei; Lai, Mei-Chin; Weng, Chieh-Yin; Wu, Sue-Yao; Lin, Saulwood; Yang, Tsanyao F; Chen, Po-Chun


    A mesophilic, hydrogenotrophic methanogen, strain S3Fa(T), was isolated from sediments collected by Ocean Researcher I cruise ORI-934 in 2010 near the submarine mud volcano MV4 located at the upper slope of south-west Taiwan. The methanogenic substrates utilized by strain S3Fa(T) were formate and H2/CO2 but not acetate, secondary alcohols, methylamines, methanol or ethanol. Cells of strain S3Fa(T) were non-motile, irregular cocci, 0.5-1.0 μm in diameter. The surface-layer protein showed an Mr of 128,000.The optimum growth conditions were 37 °C, pH 7.1 and 0.17 M NaCl. The DNA G+C content of the genome of strain S3Fa(T) was 62.3 mol%. Phylogenetic analysis revealed that strain S3Fa(T) was most closely related to Methanoculleus marisnigri JR1(T) (99.3% 16S rRNA gene sequence similarity). Genome relatedness between strain S3Fa(T) and Methanoculleus marisnigri JR1(T) was computed using both genome-to-genome distance analysis (GGDA) and average nucleotide identity (ANI) with values of 46.3-55.5% and 93.08%, respectively. Based on morphological, phenotypic, phylogenetic and genomic relatedness data, it is evident that strain S3Fa(T) represents a novel species of the genus Methanoculleus, for which the name Methanoculleus sediminis sp. nov. is proposed. The type strain is S3Fa(T) ( = BCRC AR10044(T) = DSM 29354(T)).

  10. Composition, Distribution and Abundance of Anthropogenic Marine Debris in Northwest Atlantic Submarine Canyons (United States)

    Heyl, T. P.; Nizinski, M. S.; Kinlan, B. P.; Shank, T. M.


    Submarine canyons are important productive habitats in the deep-sea, as well as downslope conduits for transporting sediment and organic material that enhances local and regional species diversity, including species and ecosystems vulnerable to anthropogenic activities. In 2012 and 2013, we documented and characterized deep-sea coral and sponge ecosystems in virtually unexplored northeast and mid-Atlantic canyons using WHOI's TowCam towed imaging system on the FSV Bigelow. Specifically, thirty-eight digital image TowCam surveys were completed in 10 canyons, with more than 91,000 images documenting not only deep-sea coral and sponge ecosystems and habitat features, but also anthropogenic debris. Canyons surveyed cover most of the latitudinal range of the northeast US region and include Toms Canyon complex, Ryan, Veatch, Gilbert, Powell, and Munson canyons. Each of these canyon hosted debris across depths of 550 to 2100m, consisting mostly of fisheries equipment, including fishing lines, traps, and nets. Potentially-land-based debris (e.g., plastic bags and magazines) was also present in all canyons surveyed. These substrates likely enhance colonization and often served as habitat for specific sessile and mobile species. Comparisons of debris in these canyons revealed depth-related differences, likely due to offshore extent of fishing activities, and will be compared to density and abundances of other deep-sea environments. The occurrence of anthropogenic debris on Northeast US canyon floors suggests major sources via transport ship and fishing-related activities and perhaps the rapid transport of debris through near-shore zones and entrainment in bottom currents.

  11. Nutrient inputs through submarine groundwater discharge in an embayment: A radon investigation in Daya Bay, China (United States)

    Wang, Xuejing; Li, Hailong; Yang, Jinzhong; Zheng, Chunmiao; Zhang, Yan; An, An; Zhang, Meng; Xiao, Kai


    Daya Bay, a semi-closed bay of the South China Sea, is famous for its aquaculture, agriculture and tourism. Although routine environmental investigations in the bay have been conducted since the early 1980s, evaluations of submarine groundwater discharge (SGD), an important process in exchange between groundwater and coastal seawater, and its environmental impacts have never been reported. In this study, naturally occurring radon isotope (222Rn) was measured continuously at two sites (north-west and middle-east sites) and used as a tracer to estimate SGD and associated nutrient inputs into the bay. The SGD rates estimated based on the 222Rn mass balance model were, on average, 28.2 cm/d at north-west site and 30.9 cm/d at middle-east site. The large SGD rate at middle-east site may be due to the large tidal amplitude and the sandy component with high permeability in sediments. The SGD-driven nutrient fluxes, which were calculated as the product of SGD flux and the difference of nutrient concentrations between coastal groundwater and seawater, were 3.28 × 105 mol/d for dissolved nitrates (NO3-N), 5.84 × 103 mol/d for dissolved inorganic phosphorous (DIP), and 8.97 × 105 mol/d for reactive silicate (Si). These nutrient inputs are comparable to or even higher than those supplied by local rivers. In addition, these SGD-driven nutrients have a nitrogen-phosphorous ratio as high as ∼43, which may significantly affect the ecology of coastal waters and lead to frequent occurrence of harmful algal blooms.

  12. Around the world with professor Vening Meinesz onboard the submarine K-XVIII (United States)

    Root, Bart; Hanssen, Ramon; Vermeersen, Bert; Munnik, Michiel; Vlijm, Rozemarijn


    In November 1934, Den Helder, The Netherlands, the start of a remarkable voyage commenced. The Hr. Ms. K-XVIII, a Dutch submarine, was about to set sail to Soerabaya, Indonesia. Onboard was a Dutch professor, Felix Andries Vening Meinesz. He was able to measure the Earth's gravity field with similar precision as on land for the first time in history using his innovative pendulum apparatus. His ground breaking data and systematic way of working changed the way of performing scientific expeditions. With the Library of the TUDelft and "Stichting Academisch Erfgoed" (Academic Heritage Foundation), we revisit this particular expedition and use it as a stepping stone to web-based geodetic and geophysical education for students and the public. The K-XVIII sailed over spreading ridges, transform faults, hotspot volcanos, subduction zones and many more interesting geological structures, which are discussed in this application. The importance of geodetic research is heavily present along the complete voyage in the form of global geoid determination. Moreover, the precision of the observations onboard the K-XVIII are compared with current satellite gravimetry and prove to be remarkable accurate. The goal of the project is to make the several datasets of Vening Meinesz, his measurements, articles, media, old foto's and other objects of the K-XVIII voyage, accessible for the public. The user can follow the famous voyage from Den Helder to Soerabaya in an interactive web application, stopping at interesting geophysical or historical places in space and time. The user can learn about plate tectonics and its historical findings, study the equipment that Vening Meinesz used to observe the gravity field with extreme precision, and learn about the important collaboration between science and the Navy. Dive into the adventure of the geo-scientific research of professor Vening Meinesz.

  13. Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean

    Directory of Open Access Journals (Sweden)

    J. M. Schwab


    Full Text Available 2-D seismic data from the top and the western slope of Mergui Ridge in water depths between 300 and 2200 m off the Thai west coast have been investigated in order to identify mass transport deposits (MTDs and evaluate the tsunamigenic potential of submarine landslides in this outer shelf area. Based on our newly collected data, 17 mass transport deposits have been identified. Minimum volumes of individual MTDs range between 0.3 km3 and 14 km3. Landslide deposits have been identified in three different settings: (i stacked MTDs within disturbed and faulted basin sediments at the transition of the East Andaman Basin to the Mergui Ridge; (ii MTDs within a pile of drift sediments at the basin-ridge transition; and (iii MTDs near the edge of/on top of Mergui Ridge in relatively shallow water depths (< 1000 m. Our data indicate that the Mergui Ridge slope area seems to have been generally unstable with repeated occurrence of slide events. We find that the most likely causes for slope instabilities may be the presence of unstable drift sediments, excess pore pressure, and active tectonics. Most MTDs are located in large water depths (> 1000 m and/or comprise small volumes suggesting a small tsunami potential. Moreover, the recurrence rates of failure events seem to be low. Some MTDs with tsunami potential, however, have been identified on top of Mergui Ridge. Mass-wasting events that may occur in the future at similar locations may trigger tsunamis if they comprise sufficient volumes. Landslide tsunamis, emerging from slope failures in the working area and affecting western Thailand coastal areas therefore cannot be excluded, though the probability is very small compared to the probability of earthquake-triggered tsunamis, arising from the Sunda Trench.

  14. Submarine Groundwater Discharge and Coastal Water Quality on the Kona Coast: The Land Use Connection (United States)

    Knee, K. L.; Street, J. H.; Grossman, E. G.; Boehm, A. B.; Paytan, A.


    For several decades, the Kona, or western, coast of the island of Hawai'i (Hawai'i, USA) has been recognized as a region of exceptionally high submarine groundwater discharge (SGD). Maintaining good water quality on the Kona coast is important for the local coral reef ecosystems and tourism-based economy. However, rapid development in the recent past and planned development in the near future may pose a threat to coastal waters. In this study, we quantified SGD-related fluxes of freshwater, nutrients and trace metals into the coastal ocean at 12 sites on the Kona coast. Radium-224 activity, silica concentration, and salinity were used as groundwater tracers, and a mass-balance approach was used to estimate fluxes. The relation between fresh groundwater quality and land use was also investigated. Fresh SGD was pervasive along the Kona coast, occurring to a measurable extent at 11 of 12 study sites. However, the volume percent of fresh groundwater at coastal ocean sites varied considerably, from 0-47%, indicating that SGD affects some sites much more than others. Inverse, linear relationships between salinity and concentrations of nitrate+nitrite, phosphate, and silica in the coastal ocean indicated conservative behavior and suggested that nutrients are diluted or advected away from shore faster than they can be used biologically. Neither the population density nor the percentage of urbanized, agricultural, forested or bare land in the vicinity of the study sites influenced groundwater nutrient concentrations; however, sites closest to golf courses had significantly higher concentrations of nitrate+nitrite. Relations between land use and trace metal concentrations in groundwater were also investigated.

  15. Tectonic controls on nearshore sediment accumulation and submarine canyon morphology offshore La Jolla, Southern California (United States)

    Le Dantec, Nicolas; Hogarth, Leah J.; Driscoll, Neal W.; Babcock, Jeffrey M.; Barnhardt, Walter A.; Schwab, William C.


    CHIRP seismic and swath bathymetry data acquired offshore La Jolla, California provide an unprecedented three-dimensional view of the La Jolla and Scripps submarine canyons. Shore-parallel patterns of tectonic deformation appear to control nearshore sediment thickness and distribution around the canyons. These shore-parallel patterns allow the impact of local tectonic deformation to be separated from the influence of eustatic sea-level fluctuations. Based on stratal geometry and acoustic character, we identify a prominent angular unconformity inferred to be the transgressive surface and three sedimentary sequences: an acoustically laminated estuarine unit deposited during early transgression, an infilling or “healing-phase” unit formed during the transgression, and an upper transparent unit. Beneath the transgressive surface, steeply dipping reflectors with several dip reversals record faulting and folding along the La Jolla margin. Scripps Canyon is located at the crest of an antiform, where the rocks are fractured and more susceptible to erosion. La Jolla Canyon is located along the northern strand of the Rose Canyon Fault Zone, which separates Cretaceous lithified rocks to the south from poorly cemented Eocene sands and gravels to the north. Isopach and structure contour maps of the three sedimentary units reveal how their thicknesses and spatial distributions relate to regional tectonic deformation. For example, the estuarine unit is predominantly deposited along the edges of the canyons in paleotopographic lows that may have been inlets along barrier beaches during the Holocene sea-level rise. The distribution of the infilling unit is controlled by pre-existing relief that records tectonic deformation and erosional processes. The thickness and distribution of the upper transparent unit are controlled by long-wavelength, tectonically induced relief on the transgressive surface and hydrodynamics.

  16. Mercury speciation and transport via submarine groundwater discharge at a southern California coastal lagoon system (United States)

    Ganguli, P.M.; Conaway, C.H.; Swarzenski, P.W.; Izbicki, J.A.; Flegal, A.R.


    We measured total mercury (Hg T) and monomethylmercury (MMHg) concentrations in coastal groundwater and seawater over a range of tidal conditions near Malibu Lagoon, California, and used 222Rn-derived estimates of submarine groundwater discharge (SGD) to assess the flux of mercury species to nearshore seawater. We infer a groundwater-seawater mixing scenario based on salinity and temperature trends and suggest that increased groundwater discharge to the ocean during low tide transported mercury offshore. Unfiltered Hg T (U-Hg T) concentrations in groundwater (2.2-5.9 pM) and seawater (3.3-5.2 pM) decreased during a falling tide, with groundwater U-Hg T concentrations typically lower than seawater concentrations. Despite the low Hg T in groundwater, bioaccumulative MMHg was produced in onshore sediment as evidenced by elevated MMHg concentrations in groundwater (0.2-1 pM) relative to seawater (???0.1 pM) throughout most of the tidal cycle. During low tide, groundwater appeared to transport MMHg to the coast, resulting in a 5-fold increase in seawater MMHg (from 0.1 to 0.5 pM). Similarly, filtered Hg T (F-Hg T) concentrations in seawater increased approximately 7-fold during low tide (from 0.5 to 3.6 pM). These elevated seawater F-Hg T concentrations exceeded those in filtered and unfiltered groundwater during low tide, but were similar to seawater U-Hg T concentrations, suggesting that enhanced SGD altered mercury partitioning and/or solubilization dynamics in coastal waters. Finally, we estimate that the SGD Hg T and MMHg fluxes to seawater were 0.41 and 0.15 nmol m -2 d -1, respectively - comparable in magnitude to atmospheric and benthic fluxes in similar environments. ?? 2012 American Chemical Society.

  17. Apparent resistivity and spectral induced polarization in the submarine environment

    Directory of Open Access Journals (Sweden)



    Full Text Available Relatively few investigations have employed electrical methods in the submarine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea surface, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2N hertz, N = -2, -1, 0, 1, 2,.....10. The measurement allowed the analysis of the electric field as a function of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fit with previous drilling data. Analysis of the spectrum of the complex apparent resistivity and the comparison with equivalent circuits, provided information about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of the present research show the feasibility of measuring the variation of seawater resistivity in situ, as well as the resistivity of sea bottom sediments.Relativamente poucas investigações têm empregado métodos elétricos no ambiente submarino, o qual pode ser promissor para depósitos minerais ou ameaçado por problemas ambientais. Nós medimos o campo elétrico usando eletrodos em forma de disco e de barra na água do mar, em três níveis distintos: superfície, sete metros de profundidade, e fundo do mar a dez metros de profundidade, empregando um dispositivo dipolo-dipolo com 2m de afastamento, 7 níveis de investigação e 13 valores de freqüência a intervalos de (2N hertz, N = -2, -1, 0, 1, 2, ... 10. A medida permitiu a análise do campo elétrico como uma função de freqüência e afastamento, e da polarização induzida espectral. A modelagem e a interpretação da resistividade aparente se ajustaram bem

  18. Hydrothermal processes related to some Triassic and Jurassic submarine basaltic complexes in northeastern Hungary, the Dinarides and Hellenides

    National Research Council Canada - National Science Library

    Gabriella B Kiss; Ferenc Molnár; Ladislav A Palinkas


      Comparative studies on hydrothermal alteration of submarine peperitic basalt occurrences related to the Triassic early rifting of the Neotethys were carried out in various parts of the Dinarides and Hellenides...

  19. Volume transport data from a submarine cable in the Florida Strait from 1982 to 1998 (NODC Accession 0087879) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily mean volume transport data of the Florida Current collected with a submarine cable spanning from South Florida to the Grand Bahama Island in the Florida Strait...

  20. Submarine flow discharge changes as a way to explain incission-overspilling and other cycles in submarine channel sequences (United States)

    Milana, J. P.; Kneller, B.; Dykstra, M.


    -stratification. The second bedform recognized is related to described macrodunes, and is comparable to large-scale antidunes, and produce tabular bodies with very subtle undulating structure. The third and perhaps more important is described as "gravel sheets" although they could be also low-relief gravel dunes developed during low-flow events, on top of the large-scale bedforms or directly over a flat gravelly bed. It is well known that bedforms produce the effect of delay averaged sediment velocity with respect to flow velocity, and thus we propose that this delay has an important geological effect as it creates a lag time between the onset of discharge increase and the time the channel bed reaches an equilibrium with the dominant flows. The effect of changes in the transport efficiency of submarine slope systems in the resulting depositional architecture is already known. However, we introduce here the concept of lagging the coarsest-grained fractions, delayed by the fact they involve in bedform building which move at lower velocities of the flows and hence allow the system to pass along a stage in which flows are big and fast, but the bed is not in equilibrium with them and as a result, canyoning may occur. These changes in external conditions (flow discharge) is likely to occur as a result of changes of turbid water near the slope by fluvial action and hence it would be t result of the interplay of river discharge and eustacy.

  1. ESR dating of submarine hydrothermal activities using barite in sulfide deposition (United States)

    Toyoda, S.; Fujiwara, T.; Ishibashi, J.; Isono, Y.; Uchida, A.; Takamasa, A.; Nakai, S.


    The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). Determining the ages of the hydrothermal deposit will provide essential information on such studies. Dating methods using disequilibrium between radioisotopes such as U-Th method (e.g. You and Bickle, 1998), 226}Ra-{210Pb and 228}Ra-{228Th method (e.g. Noguchi et al., 2011) have been applied to date submarine hydrothermal deposits. ESR (electron spin resonance) dating method is commonly applied to fossil teeth, shells, and quartz of Quaternay period where the natural accumulated dose is obtained from the intensities of the ESR signals which are created by natural radiation. The natural dose is divided by the dose rate to the mineral/sample to deduce the age. Okumura et al., (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite (BaSO4) to obtain preliminary ages, where Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Knowing that ESR dating of barite is promising, in this paper, we will present how we have investigated each factor that contributes ESR dating of barite in submarine hydrothermal sulfide deposition. (1) The best ESR condition for measuring the SO3- signal in barite is with the microwave power of 1mW and modulation amplitude of 0.1mT. (2) As results of heating experiments, the signal was found to be stable for the dating age range of several thousands. (3) 226Ra replacing Ba in barite is the source of the radiation. The amount of radioactive elements in sulfide mineral surrounding barite is negligible. (4) The external radiation from the sea water is negligible even in the submarine hydrothermal area where the radiation level is much

  2. Changes to United States Navy Submarine Design and Construction during World War I, as Determined by the General Board. (United States)


    and influence of operational doctrine that led to significant innovation during the interwar period. 15. SUBJECT TERMS Anti-Submarine Warfare (ASW...naval technology and influence of operational doctrine that led to significant innovation during the interwar period. v ACKNOWLEDGMENTS Many...Russian government Anti Access and Area Denial programs, it can be seen how submarine design and construction remains as important today as when Germany

  3. Modeling of geochemical processes in the submarine discharge zone of hydrothermal solutions

    Directory of Open Access Journals (Sweden)

    С. М. Судариков


    Full Text Available The paper reviews the main methods and analyzes modeling results for geochemical processes in the submarine discharge zone of hydrothermal solutions of mid-ocean ridges. Initial data for modeling have been obtained during several marine expeditions, including Russian-French expedition SERPENTINE on the research vessel «Pourquoi Рas?» (2007. Results of field observations, laboratory experiments and theoretical developments are supported by the analysis of regression model of mixing between hydrothermal solutions and sea water. Verification of the model has been carried out and the quality of chemical analysis has been assessed; degree and character of participation of solution components in the hydrothermal process have been defined; the content of end members has been calculated basing on reverse forecasting of element concentration, depending on regression character; data for thermodynamic modeling have been prepared. Regression model of acid-base properties and chloridity of mineralizing thermal springs confirms adequacy of the model of double-diffusive convection for forming the composition of hydrothermal solutions.  Differentiation of solutions according to concentrations of chloride-ion, depending on temperature and pH indicator within this model, is associated with phase conversions and mixing of fluids from two convection cells, one of which is a zone of brine circulation. In order to carry out computer thermodynamic modeling, hydro-geochemical and physicochemical models of hydrothermal discharge zone have been created. Verification of the model has been carried out basing on changes of Mn concentration in the hydrothermal plume. Prevailing forms of Mn migration in the plume are Mn2+, MnCl+, MnCl2. Two zones have been identified in the geochemical structure of the plume: 1 high-temperature zone (350-100 °С with prevalence of chloride complexes – ascending plume; 2 low-temperature zone (100-2 °С, where predominant form of

  4. Representing distributed cognition in complex systems: how a submarine returns to periscope depth. (United States)

    Stanton, Neville A


    This paper presents the Event Analysis of Systemic Teamwork (EAST) method as a means of modelling distributed cognition in systems. The method comprises three network models (i.e. task, social and information) and their combination. This method was applied to the interactions between the sound room and control room in a submarine, following the activities of returning the submarine to periscope depth. This paper demonstrates three main developments in EAST. First, building the network models directly, without reference to the intervening methods. Second, the application of analysis metrics to all three networks. Third, the combination of the aforementioned networks in different ways to gain a broader understanding of the distributed cognition. Analyses have shown that EAST can be used to gain both qualitative and quantitative insights into distributed cognition. Future research should focus on the analyses of network resilience and modelling alternative versions of a system.

  5. Physical activity aboard nuclear submarines as measured by pedometry. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Bondi, K.R.; Dougherty, J.H.


    Activity levels of 44 submarines were monitored before and during a fleet ballistic missile submarine patrol. These levels were determined by use of a pedometer worn on the hip. Readings were obtained daily and recorded in a log as miles walked. Through extensive preliminary testing it was determined that the miles unit was useless, due to variability in the sensitivity of the pedometer pendulum movements and the inability to determine a meaningful stride length . Results for any combination of pedometer/user were, however, repeatable. For lack of a better term, results are reported in miles per day and are as follows: Control = 2.11 + or - 0.32 and Underway = 1.01 + or - 0.27 (P<.05 Student T). This reduction of more than 50% in activity level may in part be responsible for the physical deconditioning observed during the course of a 40-70 day submergence period.

  6. Submarine groundwater discharge into the near-shore zone of the Great Barrier Reef, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Stieglitz, Thomas [Marine Geophysical Laboratory, School of Mathematical and Physical Sciences, James Cook University, Townsville QLD 4811 (Australia) and Australian Institute of Marine Science, Townsville QLD 4810 (Australia)]. E-mail:


    Along the tropical coastline of the Great Barrier Reef (GBR) region, little is known to date about submarine groundwater discharge (SGD) into the near-shore ocean. In an oceanographic sense, SGD consists of freshwater flow from land as well as seawater circulated through sediments. Recent radiochemical and geophysical studies, using the tracer {sup 222}Rn and apparent ground conductivity respectively, provide evidence for SGD to occur in a variety of hydrogeological settings. In this paper, a non-quantitative overview of different settings of SGD in the region is presented: (1) recirculation of seawater through animal burrows in mangrove forests, (2) freshwater SGD from unconfined aquifers as a narrow coastal fringe of freshwater along Wet Tropics beaches, (3) SGD from coastal dune systems in form of localised freshwater springs in the intertidal zone, (4) inner-shelf SGD from confined submarine aquifer systems comprised of riverine paleochannels incised into the shelf.

  7. Research on Fairing design and CFD Analysis of Submarine Pipeline Inspection ARV

    Directory of Open Access Journals (Sweden)

    Jin Xiaojian


    Full Text Available Along with the fast development of the ocean exploitation, the cost-effective requirement of autonomous & remotely operated vehicle (ARV, which can perform more complicated missions such as the oil exploitation and the inspection of the submarine pipeline is more urgent. The submarine pipeline inspection ARV can help us better understand, protect and efficiently utilize them for human welfare. Fairing design of a new detection ARV are introduced in this paper. In order to select an appropriate thruster that will achieve the required speed of the ARV, the ANSYS-CFX tools are used to predicted the drag force. The CFD results reveal the distribution of velocity and pressure values of the ARV. In order to verify the CFD modeling process, a towed body was developed and analyzed, compared against the corresponding physical test data.

  8. Fiscal 1997 project on the R and D of industrial scientific technology under consignment from NEDO (book on the handling / gas lift system). Report on the results of the R and D of the overall base technology of ocean resources (R and D of submarine oil drilling technology, etc.); 1997 nendo sangyo kagaku gijutsu kenkyu kaihatsu jigyo Shine Energy Sangyo Gijutsu Sogo Kaihatsu Kiko itaku. Kaiyo shigen sogo kiban gijutsu no kenkyu kaihatsu (kaitei sekiyu kussaku gijutsu nado kenkyu kaihatsu) seika hokokusho (handling / gas lift system hen)

    Energy Technology Data Exchange (ETDEWEB)



    The paper conducted a R and D on the handling of drilling equipment in drilling/collecting of submarine oil and the gas lift of artificial oil extraction technology. As to each equipment of a barge style handling system, conducted were assembly/adjustment/trial run on land and pipe handling experiments on sea. In the experiment, confirmed were pipe transfer function, lifting function, fitting function, grasping function, etc. In the ocean experiment, studied were pipe bending stress, Karman vortex control effects, etc. Relating to the gas lift system, experiments were made on confirmation of fabrication/performance of air compressor. Moreover, a technique of air transportation to the blowing inlet of the gas lift pipe was established by developing an air blowing system and fabricating a long-distance flexible pipe. Concerning the gas/liquid/solid three-phase separator, a cyclone separator was developed, and improvement in lifting efficiency was confirmed. Helped by these, the problems of the gas lift system were almost solved, and a possibility of the commercial-base production system was obtained. 2 refs., 182 figs., 47 tabs.

  9. Spatial and temporal variations of diffuse CO2 degassing at El Hierro volcanic system: Relation to the 2011-2012 submarine eruption (United States)

    Melián, Gladys; Hernández, Pedro A.; Padrón, Eleazar; Pérez, Nemesio M.; Barrancos, José; Padilla, Germán.; Dionis, Samara; Rodríguez, Fátima; Calvo, David; Nolasco, Dacil


    We report herein the results of extensive diffuse CO2 emission surveys performed on El Hierro Island in the period 1998-2012. More than 17,000 measurements of the diffuse CO2 efflux were carried out, most of them during the volcanic unrest period that started in July 2011. Two significant precursory signals based on geochemical and geodetical studies suggest that a magma intrusion processes might have started before 2011 in El Hierro Island. During the preeruptive and eruptive periods, the time series of the diffuse CO2 emission released by the whole island experienced two significant increases. The first started almost 2 weeks before the onset of the submarine eruption, reflecting a clear geochemical anomaly in CO2 emission, most likely due to increasing release of deep-seated magmatic gases to the surface. The second one, between 24 October and 27 November 2011, started before the most energetic seismic events of the volcanic-seismic unrest. The data presented here demonstrate that combined continuous monitoring studies and discrete surveys of diffuse CO2 emission provide important information to optimize the early warning system in volcano monitoring programs and to monitor the evolution of an ongoing volcanic eruption, even though it is a submarine eruption.

  10. The acoustic response of submarine volcanoes in the Tofua Arc and northern Lau Basin following two great earthquakes in Samoa and Chile (United States)

    Bohnenstiehl, D. R.; Dziak, R. P.; Matsumoto, H.; Conder, J. A.


    Using a correlation-based detector operating on data from a short-baseline hydrophone array, persistent volcano-acoustic sources are identified within the ambient noise field of the Lau Basin during the period between January 2009 and April 2010. The submarine volcano West Mata and adjacent volcanic terrains, including the northern Matas and Volcano O, are the most active acoustic sources during the 15-month period of observation. Other areas of long-term activity include the Niua hydrothermal field, the volcanic islands of Hunga-Ha'apai, Founalei, Niuatoputapu and Niuafo'ou, two unnamed seamounts located along the southern Tofua Arc, and at least three unknown sites within the northern Lau Basin. Following the great Samoan earthquake on 29 September of 2009, seven of the volcano-acoustic sources identified exhibit increases in the rate of acoustic detection. These changes persist over time scales of days-to-months and are observed up to 900 km from the earthquake hypocenter. At least one of the volcano-acoustic sources that did not respond to the 2009 Samoan earthquake exhibits an increase in detection rate following the great Mw 8.8 Chile earthquake that occurred at a distance of ~9,500 km on 27 February 2010. These observations suggest that great earthquakes may have undocumented impacts on Earth's vast submarine volcanic systems, potentially increasing the short-term flux of magma and volcanic gas into the overlying ocean.

  11. Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon


    Hunter, W. R.; Jamieson, A; Huvenne, V. A. I.; Witte, U


    The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM) transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days) responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii) and ni...

  12. Submarine groundwater discharge and associated nutrient fluxes to Discovery Bay, Jamaica (United States)

    Gordon-Smith, D.


    Recent studies have suggested that submarine groundwater discharge can be a significant source of terrestrially-derived nutrients to coastal waters as groundwater fluxes may be comparable to surface fluxes, especially where river flow is small or non-existent, and more attention is now being paid to the contribution of groundwater discharge to biogeochemical processes within the coastal zone. Due to the high temporal and spatial variability of groundwater discharge, quantification may be difficult and various methods have been used to estimate fluxes. The submarine groundwater discharge and associated nutrient fluxes to Discovery Bay, a small tropical embayment on the island of Jamaica, were investigated. Fluxes via submarine springs and seepage through bottom sediments were determined from direct flow measurements and chemical analysis of groundwater and coastal waters. The total groundwater discharge into the bay ranged from 13 to 67 x 103 m3 d-1. Discharge from submarine springs accounted for 70% of the total discharge during dry periods and was not affected by seasonal (rainfall-related) changes. After periods of heavy rainfall, seepage rates increased ten-fold and accounted for about 80% of the total discharge. Subterranean mixing of freshwater and marine water resulted in brackish (salinity ≥ 11) spring and seepage water. The nitrogen and phosphorus originating in the groundwater diluted conservatively within the bay and the average groundwater nutrient concentrations, predicted from dilution curves, were 97(±39) μM N and 0.76(±0.55) μM P. The highest nutrient fluxes to the bay (1200 mol N d-1 and 29 mol P d-1) occurred following heavy rainfall in the watershed. An extension of the study utilizing the naturally-occurring tracers Rn and Ra, to verify the groundwater discharge estimates, and the results of preliminary 222Rn surveys within the bay are also discussed.

  13. Undersea Communications Between Submarines and Unmanned Undersea Vehicles in a Command and Control Denied Environment (United States)


    models in the Map Aware Non- Unifonn Automata (MANA) modeling environment. This analysis explores the value of several different UUV characteristics as...configurations for UUV and submarine interaction in a C2DE area using a series of models in the Map Aware Non- Uniform Automata (MANA) modeling environment...Non-Uniform Automata MANA-V Map Aware Non-Uniform Automata -Vector Mbps Mega-bits Per Second MOE Measure of Effectiveness MSE Mean Square Error

  14. Zone Defense -- Anti-Submarine Warfare Strategy in the age of Littoral Warfare (United States)


    systems malfunctioned at critical times and there is one documented case where the torpedoes they fired failed to detonate .9 However, they were still...Argentine submarine.25 While many ships in the U.S. Navy serve as multi-mission platforms, capable of simultaneously executing numerous tasks, with the implosion of the Russian economy. Recently, the Russian economy has shown a resurgence and it has coincided with a resurgence in

  15. Insulation coordination for lightning overvoltages on a long HVDC submarine cable

    Energy Technology Data Exchange (ETDEWEB)

    Mader, D.J.


    This paper demonstrates by detailed modelling and simulation a statistical approach to determining the lightning-induced overvoltage stresses on the insulation of a 220 km HVDC submarine cable due to lightning strikes to the overhead line, and explores methods of controlling these overvoltages to levels that will allow lightning impulse withstand levels as low as 2.0 per unit of working voltage with an adequate safety margin.

  16. Coastal Karst Aquifers in Mediterranean Regions. 2. A Methodology for Exploring, Exploiting and monitoring Submarine Springs


    Bakalowicz, Michel; Fleury, P.; Jouvencel, Bruno; Promé, Jean-Jacques; Becker, P.; Carlin, Thierry; Dörfliger, Nathalie; Seidel, Jean-Luc; Sergent, Philippe


    International audience; In coastal regions, the study of karst aquifers and the ground water resource exploitation require a specific methodology and exploration and monitoring techniques. Two directions are investigated, leading to new technological and methodological developments. The first investigation axis deals with the exploration of fresh water plumes from submarine karst springs. An Autonomous Underwater Vehicle (AUV) is being developed and tested in order to collect all data (salini...

  17. Learning from Experience, Volume 3: Lessons from the United Kingdom’s Astute Submarine Program (United States)


    Nuclear Installations Inspectorate NSRP nuclear steam-raising plant PNO Principal Naval Overseer RCNC Royal Corps of Naval Constructors SEPP Submarine...experience. The Royal Corps of Naval Constructors (RCNC)8 and the engineering officers of the Royal Navy supplemented the technical resources at the MOD...shipyard’s Dockside Test Organisation composed of members from the shipyard, the ship crew, and the MOD. They pre- pared the test agenda and acceptance

  18. Onset of submarine debris flow deposition far from original giant landslide. (United States)

    Talling, P J; Wynn, R B; Masson, D G; Frenz, M; Cronin, B T; Schiebel, R; Akhmetzhanov, A M; Dallmeier-Tiessen, S; Benetti, S; Weaver, P P E; Georgiopoulou, A; Zühlsdorff, C; Amy, L A


    Submarine landslides can generate sediment-laden flows whose scale is impressive. Individual flow deposits have been mapped that extend for 1,500 km offshore from northwest Africa. These are the longest run-out sediment density flow deposits yet documented on Earth. This contribution analyses one of these deposits, which contains ten times the mass of sediment transported annually by all of the world's rivers. Understanding how this type of submarine flow evolves is a significant problem, because they are extremely difficult to monitor directly. Previous work has shown how progressive disintegration of landslide blocks can generate debris flow, the deposit of which extends downslope from the original landslide. We provide evidence that submarine flows can produce giant debris flow deposits that start several hundred kilometres from the original landslide, encased within deposits of a more dilute flow type called turbidity current. Very little sediment was deposited across the intervening large expanse of sea floor, where the flow was locally very erosive. Sediment deposition was finally triggered by a remarkably small but abrupt decrease in sea-floor gradient from 0.05 degrees to 0.01 degrees. This debris flow was probably generated by flow transformation from the decelerating turbidity current. The alternative is that non-channelized debris flow left almost no trace of its passage across one hundred kilometres of flat (0.2 degrees to 0.05 degrees) sea floor. Our work shows that initially well-mixed and highly erosive submarine flows can produce extensive debris flow deposits beyond subtle slope breaks located far out in the deep ocean.

  19. The Dragonian Subsurface Abyss and Submarine Force’s Ability to Counter the Rising Threat (United States)


    36Desmond Ball , Trends in Military Acquisitions in the Asia-Pacific Region : Implications for Security and Prospects for Constraints and Controls...accessed January 24, 2013). 53IHS Jane’s, "Enter the Dragon : Inside China’s New Model Navy," Jane’s Navy International, April 20, 2011. https...99s-overhyped-submarine-threat/ (accessed November 7, 2011). Ball , Desmond. Trends in Military Acquisitions in the Asia-Pacific Region : Implications

  20. Navigation and history of science: autopsy to submarine Kursk. Survival previsions were not sufficient

    Directory of Open Access Journals (Sweden)

    Ignacio Jáuregui-Lobera


    Full Text Available On August 12, 2000, Saturday, a Russian submarine of the Oscar II class, the K-141 Kursk, sank in the Barents Sea, while sailing as part of the "Summer-X Exercise" manoeuvres. The Kursk was a giant double-hulled submarine, with nine sealed compartments, considered impossible to be sunk. During the manoeuvres, at 08:51 local time, the Kursk requested permission to prepare a torpedo and it received the response "Dobro" (good in English. At 11:29:34 (07:29:50 UTC the Norwegian seismic monitoring network (NORSAR registered an earthquake of intensity 1.5 on the Richter scale at northeast of Murmansk, approximately 250 Km from Norway, and 80 Km from the Kola Peninsula. At 11:31:48, two minutes and fourteen seconds later, a second movement, 4.2 on the Richter scale and 250 times longer than the first, was recorded by different seismographs, even being detected in Alaska. It was equivalent to an explosion of 2-3 Tm of TNT. After a great confusion and propaganda, there was no choice other than to accept the facts: the Kursk had suffered two explosions, had sunk and the whole crew had perished. But what happened in that submarine? It seems clear that survival previsions were not sufficient.

  1. Aerobic performance of Special Operations Forces personnel after a prolonged submarine deployment. (United States)

    Fothergill, D M; Sims, J R


    The US Navy's Sea, Air and Land Special Operations Forces personnel (SEALs) perform a physically demanding job that requires them to maintain fitness levels equivalent to elite athletes. As some missions require SEALs to be deployed aboard submarines for extended periods of time, the prolonged confinement could lead to deconditioning and impaired mission-related performance. The objective of this field study was to quantify changes in aerobic performance of SEAL personnel following a 33-day submarine deployment. Two age-matched groups of SEALs, a non-deployed SEAL team (NDST, n = 9) and a deployed SEAL team (DST, n = 10), performed two 12-min runs for distance (Cooper tests) 5 days apart pre-deployment and one Cooper test post-deployment. Subjects wore a Polar Vantage NVTM heart rate (HR) monitor during the tests to record exercise and recovery HR. Variables calculated from the HR profiles included mean exercise heart rate (HRmean), maximum exercise heart rate (HRmax), the initial slope of the HR recovery curve (HRrecslope) and HR recovery time (HRrectime). The second pre-deployment test (which was used in the comparison with the post-deployment test) showed a 2% mean increase in the distance achieved compared with the first (n = 18, p submarine compromises the aerobic performance of SEAL personnel. The resulting deconditioning could influence mission success.

  2. River and Submarine Groundwater Discharge Effects on Diatom Phytoplankton Abundance in the Gulf of Alaska

    Directory of Open Access Journals (Sweden)

    Alanna L. Lecher


    Full Text Available The Gulf of Alaska is a highly productive ecosystem that supports fisheries and subsistence harvesting of marine resources. The highly productive summer season begins with a bloom that is dominated by diatoms. Both river and submarine groundwater discharge have been recognized as substantial terrestrial nutrient (nitrate and silicate sources to the Gulf’s coastal waters. Here, the response of in-situ phytoplankton to groundwater and river water additions was evaluated via a bioassay incubation experiment. Special attention was given to diatom genera, as previous studies have shown that submarine groundwater discharge preferentially induces growth of diatoms. The abundance of Pseudo-nitzschia spp., Chaetoceros spp., and Leptocylindrus spp. increased significantly in groundwater and river water containing treatments. Although groundwater and river water are both rich in nitrate and silicate, groundwater treatments with a higher salinity favored a higher relative abundance of Pseudo-nitzschia spp. Conversely, in the highest river water concentration treatments with lower salinity, relative abundances of Pseudo-nitzschia spp. decreased, while Chaetoceros spp. and Leptocylindrus spp. increased. Total abundances of all three genera increased in the lower salinity treatments. These findings could portend changes in the phytoplankton community composition in the Gulf of Alaska as the climate warms and river discharge increases in the coming decades. Furthermore, the findings support previous assertions that submarine groundwater discharge, with higher salinity than river water, is a preferable source of nutrients to the genus Pseudo-nitzschia.

  3. Anthropogenic impacts on deep submarine canyons of the western Mediterranean Sea (United States)

    Sanchez-Vidal, A.; Tubau, X.; Llorca, M.; Woodall, L.; Canals, M.; Farré, M.; Barceló, D.; Thompson, R.


    Submarine canyons are seafloor geomorphic features connecting the shallow coastal ocean to the deep continental margin and basin. Often considered biodiversity hotspots, submarine canyons have been identified as preferential pathways for water, sediment, pollutant and litter transfers from the coastal to the deep ocean. Here we provide insights on the presence of some of the most insidious man-made debris and substances in submarine canyons of the western Mediterranean Sea, which are relevant to achieve a "Good Environmental Status" by 2020 as outlined in the European Union's ambitious Marine Strategy Framework Directive. Ranked by size on a decreasing basis, we review the origin, distribution and transport mechanisms of i) marine litter, including plastic, lost fishing gear and metallic objects; ii) microplastics in the form of fibers of rayon, polyester, polyamide and acetates; and iii) persistent organic pollutants including the toxic and persistent perfluoroalkyl substances. This integrated analysis allows us to understand the pivotal role of atmospheric driven oceanographic processes occurring in Mediterranean deep canyons (dense shelf water cascading, coastal storms) in spreading any type of man-made compound to the deep sea, where they sink and accumulate before getting buried.

  4. Turbidity Currents, Submarine Landslides and the 2006 Pingtung Earthquake off SW Taiwan

    Directory of Open Access Journals (Sweden)

    Shu-Kun Hsu


    Full Text Available Submarine landslides or slumps may generate turbidity currents consisting of mixture of sediment and water. Large and fast-moving turbidity currents can incise and erode continental margins and cause damage to artificial structures such as telecommunication cables on the seafloor. In this study, we report that eleven submarine cables across the Kaoping canyon and Manila trench were broken in sequence from 1500 to 4000 m deep, as a consequence of submarine landslides and turbidity currents associated with the 2006 Pingtung earthquakes offshore SW Taiwan. We have established a full-scale scenario and calculation of the turbidity currents along the Kaoping canyon channel from the middle continental slope to the adjacent deep ocean. Our results show that turbidity current velocities vary downstream ranging from 20 to 3.7 and 5.7 m/s, which demonstrates a positive relationship between turbidity current velocity and bathymetric slope. The violent cable failures happened in this case evidenced the destructive power of the turbidity current to seafloor or underwater facilities that should not be underestimated.

  5. Frontally confined versus frontally emergent submarine landslides: A 3D seismic characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Frey-Martinez, Jose; Cartwright, Joe; James, David [3DLab. School of Earth, Ocean and Planetary Sciences, Cardiff University, P.O. Box 914, Cardiff CF10 3YE (United Kingdom)


    Three-dimensional (3D) seismic data from the continental margin offshore Israel (Eastern Mediterranean) have been used to analyse the compressional structures within the toe regions of two major buried submarine landslides: the ISC and the T20. Both landslides are developed within a Plio-Pleistocene slope succession composed predominately of claystones, limestones and siltstones. The high spatial resolution provided by the seismic data has allowed a detailed analysis of the geometries and deformational structures within the toe regions of the two landslides, and this has been used to develop a mechanical model for their development. Importantly, it has been recognised that submarine landslides may be divided into two main types according to their form of frontal emplacement: frontally confined and frontally emergent. In the former, the landslide undergoes a restricted downslope translation and does not overrun the undeformed downslope strata. In the latter, much larger downslope translation occurs because the landslide is able to ramp up from its original basal shear surface and translate in an unconfined manner over the seafloor. We propose that these two types of submarine landslides are end members of a continuum of gravity-driven slope failure processes, which extends from landslides where the headscarp is completely evacuated, to landslides where the material remains entirely within the headscarp. The differentiation of these two end members is of critical importance as their respective mechanisms of formation, downslope propagation and emplacement are significantly different, and hence need to be taken into consideration when analysing their respective kinematics. (author)

  6. Using multiple geochemical tracers to characterize the hydrogeology of the submarine spring off Crescent Beach, Florida (United States)

    Swarzenski, P.W.; Reich, C.D.; Spechler, R.M.; Kindinger, J.L.; Moore, W.S.


    A spectacular submarine spring is located about 4 km east of Crescent Beach, FL, in the Atlantic Ocean. The single vent feature of Crescent Beach Spring provides a unique opportunity to examine onshore-offshore hydrogeologic processes, as well as point source submarine ground water discharge. The Floridan aquifer system in northeastern Florida consists of Tertiary interspersed limestone and dolomite strata. Impermeable beds confine the water-bearing zones under artesian pressure. Miocene and younger confining strata have been eroded away at the vent feature, enabling direct hydrologic communication of Eocene ground water with coastal bottom waters. The spring water had a salinity of 6.02, which was immediately diluted by ambient seawater during advection/mixing. The concentration of major solutes in spring water and onshore well waters confirm a generalized easterly flow direction of artesian ground water. Nutrient concentrations were generally low in the reducing vent samples, and the majority of the total nitrogen species existed as NH3. The submarine ground water tracers, Rn-222 (1174 dpm I-1, dpm), methane (232 nM) and barium (294.5 nM) were all highly enriched in the spring water relative to ambient seawater. The concentrations of the reverse redox elements U, V and Mo were expectedly low in the submarine waters. The strontium isotope ratio of the vent water (87Sr/86Sr = 0.70798) suggests that the spring water contain an integrated signature indicative of Floridan aquifer system ground water. Additional Sr isotopic ratios from a series of surficial and Lower Floridan well samples suggest dynamic ground water mixing, and do not provide clear evidence for a single hydrogeologic water source at the spring vent. In this karst-dominated aquifer, such energetic mixing at the vent feature is expected, and would be facilitated by conduit and fractured flow. Radium isotope activities were utilized to estimate flow-path trajectories and to provide information on

  7. Potential Impact of Atmospheric Releases at Russian Far East Nuclear Submarine Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Parker, F.; Mahura, A.; Compton, K.; Brown, K.; Takano, M.; Novikov, V.; Soerensen, J. H.; Baklanov, A.


    An ''Assessment of the Impact of Russian Nuclear Fleet Operations on Far Eastern Coastal Regions'' is being performed as part of the Radiation Safety of the Biosphere Project (RAD) of the International Institute for Applied Systems Analysis (IIASA) of Laxenburg, Austria. To the best of our knowledge, this is the first comprehensive unclassified analysis of the potential impact of accidents at the Russian Far East nuclear submarine sites near Vladivostok and Petropavlovsk. We have defined the situation there based upon available information and studies commissioned by RAD in collaboration with Russian research institutes including Russian Research Center-''Kurchatov Institute'', Institute of Northern Environmental Problems and Lazurit Central Design Bureau. Further, in our original work, some in collaboration with the staff of the Danish Meteorological Institute (DMI) and members of the Japan Atomic Energy Research Institute, we have calculated the nuclide trajectories from these sites in the atmospheric boundary layer, less than 1.5 kilometers high, and determined their probability of crossing any of the nearby countries as well as Asiatic Russia. We have further determined the concentrations in each of these crossings as well as the total, dry and wet depositions of nuclides on these areas. Finally, we have calculated the doses to the Japanese Island population from typical winter airflow patterns (those most likely to cross the Islands in the minimum times), strong north winds, weak north winds and cyclonic winds for conditions similar to the Chazhma Bay criticality accident (fresh fuel) and for a criticality accident for the same type of reactor with fuel being withdrawn (spent fuel). The maximum individual committed dosages were less than 2 x 10-7 and 2 x 10-3 mSv, respectively. The long-term external doses by radionuclides deposited on the ground and the internal doses by consumption of foods were not evaluated as it is

  8. The history of retreat dynamics of Petermann Glacier inferred from submarine glacial landforms (United States)

    Jakobsson, M.; Hogan, K.; Mayer, L. A.; Mix, A. C.; Jerram, K.; Mohammad, R.; Stranne, C.; Eriksson, B.


    Preserved submarine glacial landforms produced at the base and margin of ice sheets and outlet glaciers comprise records of past ice dynamics complementary to modern glaciological process studies. The Petermann 2015 Expedition on the Swedish icebreaker Oden systematically mapped approximately 3100 km2 of the seafloor in Petermann Fjord and the adjacent Hall Basin of Nares Strait, northwest Greenland, with an EM122 (12 kHz) multibeam and SBP120 (2-7 kHz) chirp sub-bottom profiler. Complete, overlapping mapping coverage permitted compilation of a high-quality (15x15m) digital terrain model (DTM). In addition, the seafloor at the margin of one of the smaller outlet glaciers draining into the Petermann Fjord and selected shallow areas along the coast were mapped using a small survey boat (RV Skidbladner), equipped with an EM2040 (200-300 kHz) multibeam. High-resolution (2 x 2 m) DTMs were compiled from the RV Skidbladner surveys. The seafloor morphology of Petermann Fjord and adjacent Hall Basin is dominated by a stunning glacial landform record comprising the imprints of Petermann Glacier's retreat dynamics since the Last Glacial Maximum (LGM). The entrance to Petermann Fjord consists of a prominent bathymetric sill formed by a large well-develop grounding zone wedge that undoubtedly represents a stability point during the glacier's retreat history. The deepest entrance to the fjord is 443 m and located on the southern side of this grounding zone wedge. Outside of this grounding zone wedge in Hall Basin, less well developed grounding zones appears to be present. The landform assemblage in between the grounding zones, in particular the lack of retreat ridges, may signify a leap-frog behavior of the glacier's retreat; rapid break-up and disintegration of the outlet glacier causing retreat back to the next stability point dictated by the local bedrock geology. While numerous classical glacial landforms characteristic for fast flowing ice streams are identified, the

  9. Implementation of the environmental management plan for the dismantling of nuclear powered submarines at Zvezdochka shipyard, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Washer, M. [Dept. of Foreign Affairs and International Trade, Ontario (Canada); Cull, M.; Crocker, C. [Teledyne Brown Engineering Limited, Arlington, Virginia (United States); Ivanov, V.; Shepurev, A. [FSUE Zvezdochka, Arkhangelsk region, Severodvinsk (Russian Federation); Khan, B.U.Z.; Lee, M.; Gerchikov, M. [Nuclear Safety Solutions Limited, Toronto, Ontario (Canada)


    Department of Foreign Affairs and International Trade Canada is funding the dismantling of twelve nuclear powered submarines (NPS) from the Russian Federation's Northern Fleet as part of the Global Partnership Initiative against weapons and materials of mass destruction. In this paper, work performed by Nuclear Safety Solutions Ltd. and its collaborators in support of these activities is described. First, an environmental impact assessment of towing and dismantling NPS in the Kola Peninsula, and the Barents and White Seas was performed. The assessed activities included: towing of NPS from Naval Bases in Murmansk Region to the Zvezdochka shipyard (Severodvinsk); defuelling of onboard reactors; dismantling of NPS at Zvezdochka; and waste management. The assessment helped identify mitigation measures that could prevent the occurrence of adverse effects. Next, the project team defined and implemented an environmental management plan (EMP) based on the shipyard's existing environmental policy and the mitigating measures identified during the environmental assessment. Specific targets were defined to track the progress of the EMP implementation, and are described in this paper. During the study period, three Victor Class NPS were dismantled at Zvezdochka. The major benefits realized include: removal of spent nuclear fuel assemblies; treatment/ decontamination of liquid and solid radioactive waste; and the cultivation of collaboration between Russian and Western expertise. (author)

  10. Implementation of the environmental management plan for the dismantling of nuclear powered submarines at Zvezdochka Shipyard, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Washer, M. [Dept. of Foreign Affairs and International Trade, Ottawa, Ontario (Canada); Cull, M.; Crocker, C. [Teledyne Brown Engineering Limited, Arlington, Virginia (United States); Ivanov, V.; Shepurev, A. [FSUE Zvezdochka, Arkhangelsk region, Severodvinsk (Russian Federation); Khan, B.U.Z.; Lee, M.; Gerchikov, M. [Nuclear Safety Solutions Limited, Toronto, Ontario (Canada)


    Department of Foreign Affairs and International Trade Canada is funding the dismantling of twelve nuclear powered submarines (NPS) from the Russian Federation's Northern Fleet as part of the Global Partnership Initiative against weapons and materials of mass destruction. In this paper, work performed by Nuclear Safety Solutions Ltd. and its collaborators in support of these activities is described. First, an environmental impact assessment of towing and dismantling NPS in the Kola Peninsula, and the Barents and White Seas was performed. The assessed activities included: towing of NPS from Naval Bases in Murmansk Region to the Zvezdochka shipyard (Severodvinsk); defuelling of onboard reactors; dismantling of NPS at Zvezdochka; and waste management. The assessment helped identify mitigation measures that could prevent the occurrence of adverse effects. Next, the project team defined and implemented an environmental management plan (EMP) based on the shipyard's existing environmental policy and the mitigating measures identified during the environmental assessment. Specific targets were defined to track the progress of the EMP implementation, and are described in this paper. During the study period, three Victor Class NPS were dismantled at Zvezdochka. The major benefits realized include: removal and spent nuclear fuel assemblies; treatment/decontamination of liquid and solid radioactive waste; and the cultivation of collaboration between Russian and Western expertise. (author)

  11. Late Cretaceous Sub-Marine Fan System in Batain Mélange Zone, the Fayah Formation in Northeastern Oman

    Directory of Open Access Journals (Sweden)

    Iftikhar Ahmed Abbasi


    , possibly as olistostrome formed due to submarine slumping and sliding. The turbidite lithofacies association is comprised of monotonous grayish-green to brown coloured clays tens of meters thick interbedded with thin, clean, well-sorted sandstone. The Interbedded sandstone and shale lithofacies association is comprised of a half to one meter thick cross-bedded, burrowed arkosic sandstone and plane laminated shale. The sandstone constitutes about 25% of the association with ripple lamination in the upper part of the unit indicating a fining-upward trend. Dewatering structures are common. This association constitutes the upper 100m of the formation. These sediments were deposited in shallow water conditions by channelized flows. Based on the lithofacies associations described above, especially the dominance of debris-flow units and turbidites, the greater part of the Fayah Formation are interpreted as having been deposited under a sub-marine fan setting. Only the upper part of the formation was deposited in a shallow water setting before the onset of overlying carbonate deposits. The sub-marine fan system was active during the last stages of the Tethys Ocean closure at the time of onset of the Batain nappe.

  12. Examples of Models Fit to Magnetic Anomalies Observed Over Subaerial, Submarine, and Subglacial Volcanoes in the West Antarctic Rift System (United States)

    Behrendt, J. C.; Finn, C. A.; Blankenship, D. D.


    Aeromagnetic and marine magnetic surveys over the volcanically active West Antarctic rift system, constrained by seismic reflection profiles over the Ross Sea continual shelf, and radar ice sounding surveys over the West Antarctic Ice Sheet (WAIS) allowed calculation of models fit to very high-amplitude anomalies. We present several examples: exposed 2700-m high, subaerial erupted volcano Mt Melbourne; the 750-m high source of anomaly D (Hamilton submarine volcano) in the Ross sea; and the 600-m high edifice of Mt. CASERTZ beneath the WAIS. The character of these anomalies and their sources varies greatly, and is inferred to be the result of subaerial, submarine and subglacial emplacement respectively. Mt. Melbourne erupted through the WAIS at a time when it was grounded over the Ross Sea continental shelf. Highly magnetic volcanic flows inferred to have high remanent (normal) magnetization in the present field direction produce the 600-nT positive anomaly. The flows protected the edifice above the ice from erosion. Negligible amounts of probably subglacially erupted, apparently non-magnetic hyaloclastite exist in association with Mt. Melbourne. Mt. CASERTZ is nonmagnetic and the edifice is interpreted as consisting of a transient mound of unconsolidated hyaloclastite injected into the WAIS. However Mt. CASERTZ, about 8-km diameter, overlies a 200-m high, 40-km wide highly magnetic residual edifice modeled as the top of the source (an active subglacial volcano) of a 400-nT high positive anomaly. Any former edifices comprising hyaloclastite, pillow breccia or other volcanic debris injected into the moving WAIS apparently have been removed. About 400 other high- amplitude anomalies associated with low relief (80 percent less than 200 m) edifices at the base of the ice (the tops of the sources of these steep gradient anomalies) beneath the WAIS defined by radar ice sounding have been interpreted as having former hyaloclastite edifices, which were removed by the moving

  13. Numerical simulation of the submarine landslides and tsunami occurred at Port Valdez, AK during 1964 Alaska Earthquake with Landslide-HySEA model (United States)

    González-Vida, Jose M.; Ortega, Sergio; Macías, Jorge; Castro, Manuel J.; Escalante, Cipriano


    This is a benchmark problem recently proposed in the framework of the Landslide Tsunami Model Benchmarking Workshop organized by the NTHMP (National tsunami Hazard mitigation program -USA-) at Galveston (USA). The benchmark is based on the historical event which occurred at Port Valdez, AK during the Alaska Earthquake of March 27, 1964. The great disaster during the Mw9.2 Alaska Earthquake happened in the dock and harbour area of Port Valdez, where a massive submarine landslide generated a tsunami, inundating the waterfront up to two blocks inland. Then, a second wave crossed the waterfront 10-15 minutes after the first wave, carrying a large amount of the debris. It has been described as a violent surging wave only slightly smaller than the first. It is believed that the second wave which flooded the waterfront was originated at the other side of the Port Valdez near the Shoup Bay moraine. The benchmark consists in simulating with the (GPU based) Landslide-HySEA model the extent of inundation for two slide events, based on before and after bathymetry data, eye-witness observations of the event, and observed runup distribution. First, both landslides have been simulated separately, studying time series of the water waves at determined locations, runups at different areas and the extent of inundation around the first two blocks inland of Port Valdez. Then, the two landslides are triggered at the same time and the joint effect is studied. Obtained results are satisfactory and they agree with the existing observations. References Castro, M. J., Fernández-Nieto, E. D., González-Vida, J. M., Parés, C. (2011). Numerical Treatment of the Loss of Hyperbolicity of the Two-Layer Shallow-Water System. Journal of Scientific Computing, 48(1):16-40. Fernández, E.H., Bouchut, F., Bresh, D., Castro, M.J. and, Mangeney, A. (2008). A new Savage-Hutter type model for submarine avalanches and generated tsunami. J. Comp. Phys., 227: 7720-7754. Fernández-Nieto, E.D., Castro, M

  14. Evidence from acoustic imaging for submarine volcanic activity in 2012 off the west coast of El Hierro (Canary Islands, Spain) (United States)

    Pérez, Nemesio M.; Somoza, Luis; Hernández, Pedro A.; de Vallejo, Luis González; León, Ricardo; Sagiya, Takeshi; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Barrancos, José; Ibáñez, Jesús; Sumino, Hirochika; Nogami, Kenji; Romero, Carmen


    We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS network (Nagoya University-ITER-GRAFCAN) with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) observed positive peak in the air-corrected value of 3He/4He ratio monitored in ground waters (8.5 atmospheric 3He/4He ratio ( R A)) at the northwestern El Hierro on June 16, 2012. Combining these submarine and subaerial information, we suggest these plumes are the consequence of submarine vents exhaling volcanic gas mixed with fine ash as consequence of an event of rapid rise of volatile-rich magma beneath the NW submarine ridge

  15. Investigation of weldments in Victoria-class submarine pressure-hull using magnetic flux leakage and Barkhausen noise (United States)

    Samimi, A. A.; Babbar, V.; Krause, T. W.; Clapham, L.


    Evaluation of the stress state within submarine hulls can contribute to risk assessments, which provide assurance that in-service induced stresses will not adversely affect the service life of the naval structure. The purpose of this study was to evaluate the feasibility of using magnetic NDE techniques for identification of stresses associated with weldments in two original pressure hulls of Canada's Victoria class submarines. Magnetic Flux Leakage (MFL) and flux-controlled Barkhausen Noise measurements were investigated for identification of patch boundaries and welds in two sections of Victoria-class submarine-hull steel. While MFL showed clear demarcation of weld boundaries, Barkhausen measurements did not provide sufficiently clear response to identify these features in submarine hull samples. For a better understanding of Barkhausen response, uniaxial tensile stress was investigated on separate samples of submarine steel. A nonlinear dependence of Barkhausen response was observed, with a weaker sensitivity to tensile stresses below 200 MPa. This behavior, combined with the presence of substantial surface compressive stresses, was used to explain the observed insensitivity of Barkhausen measurements to the presence of welds.

  16. The study of the impact of ice conditions on the possibility of the submarine vessels surfacing in the ice cover (United States)

    Zemlyak, V. L.; Kozin, V. M.; Baurin, N. O.; Ipatov, K. I.; Kandelya, M. V.


    Traditionally submarine vessels emerging from under ice cover performing by static loading of ice from bellow through the creation of positive buoyancy by main ballast tanks. However thickness of ice (approximately 1 meter) from under which modern submarine vessel can emerge essentially limits the use of traditional method, particularly during submarine vessels motion in the severe ice conditions of Arctic region. For breaking the ice cover of greater thickness can be used flexural gravity waves caused by the submarine vessel motion with certain critical speed near the bottom ice. It is also known that in the coastal areas water depth is often less than 100 meters, and the presence of projections on the bottom surface may effect on the wave propagation pattern. This paper presents experimental study of influence of bottom contour on the deflection and the length of the flexural gravity waves from the movement of submarine. Ice cover failure pattern determined. Assessment of ice-breaking capacity of flexural-gravity waves with using the criterion of ice failure is performed.

  17. Comparison of Subaerial and Submarine Mixing and Sediment Transport in Sinuous Channel Bends Using Turbulence-Resolving Numerical Models (United States)

    Schmeeckle, M. W.


    Large eddy simulations (LES) of turbulence and sediment suspension are conducted in both subaerial and submarine meandering channels. The Boussinesq approximation of buoyancy is applied to the spatially-filtered, Navier-Stokes equations through the simultaneous solution of the suspended sediment continuity equation with the Smith-McLean boundary condition. Production of turbulence and, consequently, turbulent kinetic energy is stronger at channel bends than in straight sections. This pattern is more pronounced in subaerial channels. Depth integrated, two-dimensional models of turbidity currents critically rely upon parameterization of the entrainment of water at the top of the flow and sediment exchange with the bed. Secondary flow and turbulence structure due to channel sinuosity significantly alter these parameterizations and the assumed vertical profiles of velocity and sediment concentration. Large turbulent structures episodically inject relatively clear water from the top to the base of the flow at the outside of channel bends, and, simultaneously, sediment laden fluid is ejected from the bed at the inside of channel bends. As a result, sediment deposition in sinuous channels is reduced compared to application of two-dimensional models. The LES turbidity current model is extended to channel morphodynamics by grid adjustment at each fluid and sedment time step. The LES morphodynamic model has been tested, thus far, in strongly depositional sinuous channel turbidity currents. Relatively uniform channel deposition and rapidly developing sharp-crested levees are built in these conditions. Further simulations involving partially erosional conditions and bedload transport will be presented.

  18. Seawater-groundwater exchange and nutrients carried by submarine groundwater discharge in different types of wetlands at Jiaozhou Bay, China (United States)

    Qu, Wenjing; Li, Hailong; Huang, Hao; Zheng, Chunmiao; Wang, Chaoyue; Wang, Xuejing; Zhang, Yan


    In Jiaozhou Bay, there are four wetland types, including sandy beaches, mud flats, tidal marshes, and estuarine intertidal zones. Four typical transects representing each of the wetland types were selected to investigate the flow dynamics, seawater-groundwater exchange and nutrients carried by submarine groundwater discharge (SGD). Based on field measurements of groundwater heads and salinity along each transect, the SGD averaged over the observation period was estimated using generalized Darcy's law. The SGD along the four transects ranges from 3.6 × 10-3 to 7.6 cm/d with the maximum occurring at the sandy beach. The SGD rate has a good correlation with the hydraulic conductivities of the wetland sediments. There is a positive correlation between the ratio of NO3-N/DIN and SGD rates. The SGD-associated nutrient output rate ranges from 3.3 × 10-2 to 9.5 mmol/m2/d for DIN (dissolved inorganic nitrogen), and from 6.2 × 10-5 to 1.8 × 10-2 mmol/m2/d for DIP (dissolved inorganic phosphorus). Compared to the nutrients delivered by the river, nutrients carried by SGD provide a more important source for the phosphate-limited environment to plankton in Jiaozhou Bay.

  19. An investigation of submarine groundwater-borne nutrient fluxes to the west Florida shelf and recurrent harmful algal blooms (United States)

    Smith, Christopher G.; Swarzenski, Peter W.


    A cross-shelf, water-column mass balance of radon-222 (222Rn) provided estimates of submarine groundwater discharge (SGD), which were then used to quantify benthic nutrient fluxes. Surface water and groundwater were collected along a shore-normal transect that extended from Tampa Bay, Florida, across the Pinellas County peninsula, to the 10-m isobath in the Gulf of Mexico. Samples were analyzed for 222Rn and radium-223,224,226 (223,224,226Ra) activities as well as inorganic and organic nutrients. Cross-shore gradients of 222Rn and 223,224,226Ra activities indicate a nearshore source for these isotopes, which mixes with water characterized by low activities offshore. Radon-based SGD rates vary between 2.5 and 15 cm d-1 proximal to the shoreline and decrease offshore. The source of SGD is largely shallow exchange between surface and pore waters, although deeper groundwater cycling may also be important. Enrichment of total dissolved nitrogen and soluble reactive phosphorus in pore water combined with SGD rates results in specific nutrient fluxes comparable to or greater than estuarine fluxes from Tampa Bay. The significance of these fluxes to nearshore blooms of Karenia brevis is highlighted by comparison with prescribed nutrient demands for bloom maintenance and growth. Whereas our flux estimates do not indicate SGD and benthic fluxes as the dominant nutrient source to the harmful algal blooms, SGD-derived loads do narrow the deficit between documented nutrient supplies and bloom demands.

  20. Petrological and geochemical Highlights in the floating fragments of the October 2011 submarine eruption offshore El Hierro (Canary Islands): Relevance of submarine hydrothermal processes (United States)

    Rodriguez-Losada, Jose A.; Eff-Darwich, Antonio; Hernandez, Luis E.; Viñas, Ronaldo; Pérez, Nemesio; Hernandez, Pedro; Melián, Gladys; Martinez-Frías, Jesús; Romero-Ruiz, M. Carmen; Coello-Bravo, Juan Jesús


    This paper describes the main physical, petrological and geochemical features of the floating fragments that were emitted in the initial stages of the 2011-2012 submarine eruption off the coast of the Canarian island of El Hierro, located 380 km from the Northwest African Coast. It attempts to assess the potential of radiometric analyses to discern the intriguing origin of the floating fragments and the differences between their constituent parts. In this regard, the material that conforms the core of the fragments contains the largest concentration of uranium (U) ever found in volcanic rocks of the Canary Islands. This enrichment in U is not found in the content of thorium (Th), hence the floating fragments have an unusual U/Th ratio, namely equal to or larger than 3. Although the origin of this material is under discussion, it is proposed that the enrichment in U is the result of hydrothermal processes.

  1. EAARL Submarine Topography-Florida Keys National Marine Sanctuary (United States)

    U.S. Geological Survey, Department of the Interior — Lidar is a remote sensing technique that uses laser light to detect, range, or identify remote objects based on light reflected by the object or emitted through its...

  2. EAARL Submarine Topography-Northern Florida Keys Reef Tract (United States)

    U.S. Geological Survey, Department of the Interior — Lidar is a remote sensing technique that uses laser light to detect, range, or identify remote objects based on light reflected by the object or emitted through its...

  3. Digital elevation models in the marine domain: investigating the offshore tsunami hazard from submarine landslides (United States)

    Tappin, David R.


    Over the past 30 years multibeam bathymetry has replaced single-beam echo soundings as the main tool used to map the sea floor. Developed as a military tool its expansion into the scientific domain has revolutionized our ability not only to visualise seabed morphology, but also to interpret the active processes taking place at and beneath the seabed. DEMs derived from multibeam are now comparable to those on land. One aspect of the improved seabed visualization is in mapping marine geohazards, in this instance, submarine landslides. One of the first multibeam surveys actually programmed to investigate an actual event was in 1999 after the tsunami on the north coast of Papua New Guinea killed 2,200 people. It was a wake-up call, as the relatively small magnitude earthquake - 7.1 - could not generate tsunami waves up to 15m high at the coast. The submarine slump was clearly visible on the multibeam and associated seabed sampling confirmed that it was a recent event. Subsequent research proved that the landslide generated the tsunami as, again for the first time the multibeam was used as the basis for the tsunami simulations. Since 1999 many submarine landslides have been mapped, but not all have an associated identified tsunami. Some landslides are associated with earthquakes and this causes confusion if there is an anomalously large tsunami for example Alaska, 1946 and Java, 2006. Others are suspected of causing a tsunami, but their evidence on the seabed is hard to identify as with Messina, 1908. The most confusing recent tsunami event has been 2011 Japan tsunami, where a submarine landslide to the north of the main rupture is almost certainly responsible for the 40m high coastal waves that struck northern Honshu. The seabed has now been mapped on a broadscale by satellite gravity, but maps from this method cannot identify any but the largest seabed morphologies; most submarine landslides cannot therefore be recognised. Large seabed areas still remain unmapped to

  4. Energy dissipation by submarine obstacles during landslide impact on reservoir - potentially avoiding catastrophic dam collapse (United States)

    Kafle, Jeevan; Kattel, Parameshwari; Mergili, Martin; Fischer, Jan-Thomas; Tuladhar, Bhadra Man; Pudasaini, Shiva P.


    Dense geophysical mass flows such as landslides, debris flows and debris avalanches may generate super tsunami waves as they impact water bodies such as the sea, hydraulic reservoirs or mountain lakes. Here, we apply a comprehensive and general two-phase, physical-mathematical mass flow model (Pudasaini, 2012) that consists of non-linear and hyperbolic-parabolic partial differential equations for mass and momentum balances, and present novel, high-resolution simulation results for two-phase flows, as a mixture of solid grains and viscous fluid, impacting fluid reservoirs with obstacles. The simulations demonstrate that due to the presence of different obstacles in the water body, the intense flow-obstacle-interaction dramatically reduces the flow momentum resulting in the rapid energy dissipation around the obstacles. With the increase of obstacle height overtopping decreases but, the deflection and capturing (holding) of solid mass increases. In addition, the submarine solid mass is captured by the multiple obstacles and the moving mass decreases both in amount and speed as each obstacle causes the flow to deflect into two streams and also captures a portion of it. This results in distinct tsunami and submarine flow dynamics with multiple surface water and submarine debris waves. This novel approach can be implemented in open source GIS modelling framework r.avaflow, and be applied in hazard mitigation, prevention and relevant engineering or environmental tasks. This might be in particular for process chains, such as debris impacts in lakes and subsequent overtopping. So, as the complex flow-obstacle-interactions strongly and simultaneously dissipate huge energy at impact such installations potentially avoid great threat against the integrity of the dam. References: Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117, F03010, doi: 10.1029/ 2011JF002186.

  5. Preparation of the NASA Air Quality Monitor for a U.S. Navy Submarine Sea Trial (United States)

    Limero, Thomas; Wallace, William T.; Manney, Joshua A.; Smith, Matthew J.; O'Connor, Sara Jane; Mudgett, Paul D.


    For the past 4 years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. Onboard the ISS are two AQMs with different GC columns that detect and quantify 22 compounds. The AQM data contributes valuable information to the assessment of air quality aboard ISS for each crew increment. The US Navy is looking to update its submarine air monitoring suite of instruments and the success of the AQM on ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which measures major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial preparation and the analysis of most recent ISS data. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only one AQM will be deployed during the sea trial, but this is sufficient for NASA purposes and to detect the compounds of interest to the US Navy for this trial. The data from the sea trial will be compared to data from archival samples collected before, during, and after the trial period. This paper will start with a brief history of past collaborations between NASA and the U.S. and U.K. navies for trials of air monitoring equipment. An overview of the AQM technology and protocols for the submarine trial will be presented. The majority of the presentation will focus on the AQM preparation and a summary of available data from the trial.

  6. Growth History of Kaena Volcano, the Isolated, Dominantly Submarine, Precursor Volcano to Oahu, Hawaii (United States)

    Sinton, J. M.; Eason, D. E.


    The construction of O'ahu began with the recently recognized, ~3.5-4.9 Ma Ka'ena Volcano, as an isolated edifice in the Kaua'i Channel. Ka'ena remained submarine until, near the end of its lifetime as magma supply waned and the volcano transitioned to a late-shield stage of activity, it emerged to reach a maximum elevation of ~1000 m above sea level. We estimate that Ka'ena was emergent only for the last 15-25% of its lifespan, and that subaerial lavas make up < 5% of the total volume (20-27 x 103 km3). O'ahu's other volcanoes, Wai'anae (~3.9-2.85 Ma) and Ko'olau (~3.0-1.9 Ma), were built at least partly on the flanks of earlier edifices and both were active subaerial volcanoes for at least 1 Ma. The constructional history of Ka'ena contrasts with that of Wai'anae, Ko'olau, and many other Hawaiian volcanoes, which likely emerge within a few hundred kyr after inception, and with subaerial lavas comprising up to 35 volume % of the volcano. These relations suggest that volcano growth history and morphology are critically dependent on whether volcanic initiation and growth occur in the deep ocean floor (isolated), or on the flanks of pre-existing edifices. Two other volcanoes that likely formed in isolation are West Moloka'i and Kohala, both of which have long submarine rift zones, and neither attained great heights above sea level despite having substantial volume. The partitioning of volcanism between submarine and subaerial volcanism depends on the distance between volcanic centers, whether new volcanoes initiate on the flanks of earlier ones, and the time over which neighboring volcanoes are concurrently active. Ka'ena might represent an end-member in this spectrum, having initiated far from its next oldest neighbor and completed much of its evolution in isolation.

  7. Echo structures and Target Strength modelling for a synthetic submarine

    NARCIS (Netherlands)

    Schippers, P.; Beerens, S.P.


    Since the early nineties, performance modelling of active sonars has been developed at TNO in the ALMOST model, including propagation and sonar processing, based on point targets of given Target Strength. Recently, the modelling was extended with a computation module for target echo structure,

  8. Submarine hydrothermal environments as sites for the origin and evolution of life (United States)

    Hoffman, S.; Baross, J.


    That life formed and evolved in hydrothermal environments is proposed. This hypothesis is plausible in terms of the tectonic, paleontological, and degassing history of the Earth. Submarine hydrothermal vents are the only contemporary geological environment which may truly be called primeval and which today continue to be a major source of gases and dissolved elements to the ocean. The microbial assemblages in present day hydrothermal systems therefore could be living analogues of the earliest microbial communities to develop on Earth. The evidence for the hypothesis is reviewed.

  9. Near-Real-Time Sismo-acoustic Submarine Station for offshore monitoring (United States)

    D'Anna, Giuseppe; D'Alessandro, Antonino; Fertitta, Gioacchino; Fraticelli, Nicola; Calore, Daniele


    From the early 1980's, Italian seismicity is monitored by the National Seismic Network (NSN). The network has been considerably enhanced by INGV since 2005 by 24-bit digital stations equipped with broad-band sensors. The NSN is nowadays constituted by about 300 on-land seismic station able to detect and locate also small magnitude earthquake in the whole Italian peninsula. However, the lack of offshore seismic stations does not allow the accurate estimation of hypocentral and focal parameters of small magnitude earthquakes occurring in offshore areas. As in the Mediterranean area there is an intense offshore seismic activity, an extension of the seismic monitoring to the sea would be beneficial. There are two types of stations that could be used to extend the network towards the sea: the first type is connected to the coast though a cable, the second type is isolated (or stand alone) and works autonomously. Both solutions have serious limitations: the first one, for several technical and economic problems, linked to the indispensable transmission/alimentation cable, cannot be installed far from the coast; the second one, allows access to the recorded data, only after they are recovered from the seabed. It is clear that these technical solutions are not suitable for the real time monitoring of the offshore seismicity or for the realization of a tsunami warning system. For this reason, in early 2010, the OBSLab of Gibilmanna begins the design of a submarine station able to overcome the limitations of the two systems above. The station isbuilt under the project EMSO-MedIT. The two stations built have already been tested in dock and ready for installation. One of this station will be installed, in few time, in the southern Tyrrhenian Sea, near the epicentre of the Palermo 2002 main shock. The sea bottom station will be equipped with 2 very broadband 3C seismometers, a broad band hydrophone, a differential and an absolute pressure gauge. The station includes a submarine

  10. Focused sound from three-dimensional sound propagation effects over a submarine canyon. (United States)

    Chiu, Linus Y S; Lin, Ying-Tsong; Chen, Chi-Fang; Duda, Timothy F; Calder, Brian


    Ship noise data reveal an intensification of the near-surface sound field over a submarine canyon. Numerical modeling of sound propagation is used to study the effect. The noise data were collected during an ocean acoustic and physical oceanography experiment northeast of Taiwan in 2009. In situ measurements of water sound-speed profiles and a database of high-resolution bathymetry are used in the modeling study. The model results suggest that the intensification is caused by three-dimensional sound focusing by the concave canyon seafloor. Uncertainties in the model results from unsampled aspects of the environment are discussed. © 2011 Acoustical Society of America

  11. [Effect of noise in submarine compartment on signal discrimination and arithmetic performance]. (United States)

    Hu, Z; Liang, Z; Shi, X; Tang, Z


    To study the effects of noise level in submarine compartment on signal discrimination and arithmetic performance, experiments were carried out on 13 subjects. The results showed that as noise level raised from moderate (73 dBA) to higher levels (85-92 dBA), work efficiency showed a progressive decrease, but when noise level reached 96 dBA the decrease in efficiency reached a steady state. The results indicated that impairment of efficiency apparently occurred at a level of 85 dBA and that the interference effect of noise was more pronounced on task performance with mental strain.

  12. Effects of symmetrical foundation on sound radiation from a submarine hull structure. (United States)

    Li, Chenyang; Su, Jinpeng; Wang, Jian; Hua, Hongxing


    The effects of a passive noise control method for suppressing sound radiation from a submarine hull structure are investigated. The control method is realized by symmetrizing the foundation about the horizontal plane. The coupled finite element method and boundary element method are adopted to compute the acoustic characteristics of the submerged hull. From the numerical results, the symmetrical foundation has advantages in sound radiation reduction when the hull is subjected to the axial load, but has little influences in the vertical and transverse load cases. Using the modal decomposition technique, the contributions of each individual mode to the sound radiation are analyzed to reveal the mechanism of the control method.

  13. Characteristics and features of the submarine landslides in passive and active margin southwestern offshore Taiwan (United States)

    Yeh, Y. C.


    In the past decade, numerous multi-channel seismic surveys as well as near seafloor high resolution geophysical investigations were conducted in order to explore and estimate the reserves of gas hydrate southwestern offshore Taiwan. The previous object was focused on searching substitute energy (i.e. gas hydrate) rather than geo-hazards. However, it is suggested that most of the gas hydrate is generally distributed at slope area southwestern offshore Taiwan, which indicates the slope may be failed when steady state was disturbed by some factors, such as sea level or climate change. In addition, once gas hydrate was dissociated, this may induce submarine landslide that further cause devastated tsunami. Thus, it is of great urgency to investigate potential landslide area, particularly, the hydrate-rich continental slope (active and passive margins) in adjacent to populous city like Kaohsiung. In this study, we collected several high resolution multi-channel seismic data with ten seconds shooting rate and 3.125 meters group interval streamer by using R/V ORI and R/V ORV. The seismic data were processed in conventional data processing strategy: bad trace clean, geometry settings, band-pass filter, de-convolution, surface-related multiple rejection, radon filter, stacking,kirchhoff migration and time to depth conversion. Combine the results obtained from the MCS data and subbottom profiles, two major results could be raised in the active margin as followed: (1) Most of the surface creeping and landslide was occurred shallower than 500 meters in water depth, which should be related to the inter-bedded fluid activities. (2) The landslide distribution is lagly affected by the presence of diaper, suggesting the subsequent mud diapirism may destruct slope stability; (3) The submarine landslide deeper than 800 meters in water depth distributes in the thrust fold area, that is probably referred to active thrusting. In the passive margin, large volume mass transportation

  14. A model to calculate effectiveness of a submarine-launched nuclear ASW weapon

    Energy Technology Data Exchange (ETDEWEB)

    Magnoli, D.E.


    LLNL's Navy Tactical Applications Group (NTAG) has produced a computer model to calculate the probability of kill of a submarine-launched nuclear ASW standoff-weapon. Because of the uncertainties associated with target position and motion and with weapon delivery, this is a problem appropriately treated statistically. The code is a Monte Carlo's simulation which follows the engagement from localization through optional evasive maneuvers of the target to attack and damage assessment. For a given scenario (weapon characteristics, target characteristics, firing platform depth and hardness, etc.) the code produces a table and ultimately a plot of Pk as a function of range. 2 figs., 1 tab.

  15. OPERATION HARDTACK. Project 3.5. Loading and Response of Submarine Hulls from Underwater Bursts (United States)


    Hulls from Underwater Bursts, Extracted Version 12. PERSONAL AUTHOR(S) Rich, H.L., Project Officer; Weinberger, F.; Habib, E.T.; Bort , R.L.; Sette, W.J...SLO A D IN G oa n d R E S P O N S E o f S U B M A R IN E tULLS from UNDERWATER BURSTS H. L. Rich, Project Officer F. Weinberger E.T. Habib R.L. Bort W...OBJECTIVES The objectives established for Project 3.5 were to: (1) determine the range ior lethal hull dam - age to a submarine-like (Squaw) target

  16. Logistics of nuclear fuel production for nuclear submarines; Logistica de producao de combustiveis para submarinos nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Leonam dos Santos [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil). E-mail:


    The future acquisition of nuclear attack submarines by Brazilian Navy along next century will imply new requirements on Naval Logistic Support System. These needs will impact all the six logistic functions. Among them, fuel supply could be considered as the one which requires the most important capacitating effort, including not only technological development of processes but also the development of a national industrial basis for effective production of nuclear fuel. This paper presents the technical aspects of the processes involved and an annual production dimensioning for an squadron composed by four units. (author)

  17. Discerning Primary and Secondary Processes in the Volatile Geochemistry of Submarine Basalts (United States)

    Hauri, E. H.


    Defining the primary volatile composition of submarine basalts from mid-ocean ridges, back-arc basins and arc-front volcanoes is key to understanding volatile cycling and the influence of volatiles on melting in the upper mantle. The volatile and halogen geochemistry of submarine volcanic glasses and melt inclusions has been the subject of an increasing number of studies that have made progress in distinguishing between secondary seawater contamination of magmas, and true melting and mantle-source variations, thus enabling observed magma compositions to be used to study the time-integrated cycling of volatiles through the upper mantle. But fewer studies have examined in detail the local-and segment-scale variations of volatiles together with trace elements and radiogenic isotopes, so that it can be understood how and where in the oceanic crust submarine magmas are contaminated by seawater-derived components. Mid-ocean ridge basalts (MORB) are significantly affected by secondary seawater assimilation processes due to their low volatile contents. From combined CO2-H2O-Cl systematics, it is apparent that addition of seawater-derived components is enhanced in magmas that ascend more slowly through the crust, and/or erupt away from the ridge axis. Highly depleted magmas that erupt in extensional zones within transform faults (e.g. Siqueiros) show little evidence for seawater addition, due to the near absence of thick crust and hydrothermal systems in such environments. At the same time, there also exists a second tier of more subtle seawater addition that is evident as a function of the extent of differentiation in MORB, pointing to combined assimilation and fractional crystallization as an important process operating in MORB petrogeneis. In detail the geochemistry of the assimilants can vary substantially from simple seawater compositions. Discerning seawater contamination in arc and back-arc magmas is more difficult, not only because of higher volatile concentrations

  18. Raman amplification in an optically high-powered data link dedicated to a 10 km long extension for submarine cabled observatories (United States)

    Audo, F.; Perhirin, S.; Quintard, V.; Guegan, M.; Perennou, A.; Auffret, Y.


    We describe a quasi-all-optical extension dedicated to simplifying the deployment of submarine cabled observatories. Based on power-over-fiber technologies, high power supply and data are both transmitted in one optical fiber of a few kilometers in length. We study the Raman amplification on the down- and up-stream data in the static regime with the high optical power varying from 100 mW to 4 W over a 10 km long single-mode optical fiber. We focus on the data optical budget and signal to noise ratio dependence with respect to the high optical power value and the data optical wavelength. We also present the transmission quality in the dynamic regime of this quasi-all-optical extension.

  19. Sustaining U.S. Nuclear Submarine Design Capabilities (United States)


    Lafayette 9 1963–1964 Ballistic missile James Madison 10 1964 Ballistic missile Benjamin Franklin 12 1965–1967 Ballistic missile Sturgeon 37 1966– 1 The survey instrument sent to vendors is reproduced in Appendix C . 2 See Mark V. Arena, Hans Pung, Cynthia R. Cook, Jefferson P. Marquis ...Hans Pung, Cynthia R. Cook, Jefferson P. Marquis , Jessie Riposo, and Gordon T. Lee, The United Kingdom’s Shipbuilding Industrial Base: The Next

  20. Calving on tidewater glaciers amplified by submarine frontal melting

    CERN Document Server

    O'Leary, Martin


    While it has been shown repeatedly that ocean conditions exhibit an important control on the behaviour of grounded tidewater glaciers, modelling studies have focused largely on the effects of basal and surface melting. Here, a finite-element model of stresses near the front of a tidewater glacier is used to investigate the effects of frontal melting on calving, independently of the calving criterion used. Applications of the stress model to idealized scenarios reveal that undercutting of the ice front due to frontal melting can drive calving at up to ten times the mean melt rate. Factors which cause increased frontal melt-driven calving include a strong thermal gradient in the ice, and a concentration of frontal melt at the base of the glacier. These properties are typical of both Arctic and Antarctic tidewater glaciers. The finding that frontal melt near the base is a strong driver of calving leads to the conclusion that water temperatures near the bed of the glacier are critically important to the glacier f...

  1. Modeling and Experimental Validation for Tsunamis Generated by Submarine Mass Failure (United States)

    Enet, F.; Grilli, S. T.; Watts, P.; Kirby, J. T.


    Numerical models of tsunamis generation by Submarine Mass Failure (SMF) were developed in earlier work by the authors. More recently, this included a three-dimensional (3D) SMF tsunami source model, based on Fully Nonlinear Potential Flow equations (FNPF) (Grilli et al., 2002), and the integration of this model into a Boussinesq wave propagation and runup model (Watts et al., 2003a). The combined model for SMF tsunami generation, propagation, and runup, referred to as GEOWAVE, was successfully applied to a number of case studies, including PNG 1998, Skagway 1994, and Unimak 1946 (e.g., Watts et al., 2003ab). In the present work, we first describe recent improvements made to the model components of GEOWAVE, and their application to historical case studies. One recent addition to the Boussinesq propagation model, in particular, is its implementation in spherical coordinates, which allows using it over larger scale tsunami propagation areas. This is useful to study both transoceanic SMF tsunami near- and far-field propagation within the same dispersive long wave model. Second, we report results of recent large scale three-dimensional experiments performed at the University of Rhode Island, to investigate tsunami generation by underwater landslides. Each experiment consists of a solid landslide of idealized smooth shape sliding over a plane slope. Surface elevations are measured using capacitance gages placed at strategic locations. Gage calibration is performed using a newly developed automated system. Runup at the shoreline is measured using a remotely operated digital camera. Landslide acceleration is measured with a micro-accelerometer embedded at the landslide center of mass and an optical system also measures landslide displacement, as a way of cross-validation. The repeatability of experiments is first investigated, and then by varying the initial depth of the landslide, different conditions of wave non-linearity and dispersion are generated and compared. Third

  2. Prodigious submarine landslides during the inception and early growth of volcanic islands. (United States)

    Hunt, James E; Jarvis, Ian


    Volcanic island inception applies large stresses as the ocean crust domes in response to magma ascension and is loaded by eruption of lavas. There is currently limited information on when volcanic islands are initiated on the seafloor, and no information regarding the seafloor instabilities island inception may cause. The deep sea Madeira Abyssal Plain contains a 43 million year history of turbidites among which many originate from mass movements in the Canary Islands. Here, we investigate the composition and timing of a distinctive group of turbidites that we suggest represent a new unique record of large-volume submarine landslides triggered during the inception, submarine shield growth, and final subaerial emergence of the Canary Islands. These slides are predominantly multi-stage and yet represent among the largest mass movements on the Earth's surface up to three or more-times larger than subaerial Canary Islands flank collapses. Thus whilst these deposits provide invaluable information on ocean island geodynamics they also represent a significant, and as yet unaccounted, marine geohazard.

  3. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island. (United States)

    Santana-Casiano, J M; Fraile-Nuez, E; González-Dávila, M; Baker, E T; Resing, J A; Walker, S L


    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 10(5) ± 1.1 10(5 )kg d(-1) which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.

  4. Cyclic thermal behavior associated to the degassing process at El Hierro submarine volcano, Canary Islands. (United States)

    Fraile-Nuez, E.; Santana-Casiano, J. M.; González-Dávila, M.


    One year after the ceasing of magmatic activity in the shallow submarine volcano of the island of El Hierro, significant physical-chemical anomalies produced by the degassing process as: (i) thermal anomalies increase of +0.44 °C, (ii) pH decrease of -0.034 units, (iii) total dissolved inorganic carbon, CT increase by +43.5 µmol kg-1 and (iv) total alkalinity, AT by +12.81 µmol kg-1 were still present in the area. These evidences highlight the potential role of the shallow degassing processes as a natural ecosystem-scale experiments for the study of significant effects of global change stressors on marine environments. Additionally, thermal time series obtained from a temporal yo-yo CTD study, in isopycnal components, over one of the most active points of the submarine volcano have been analyzed in order to investigate the behavior of the system. Signal processing of the thermal time series highlights a strong cyclic temperature period of 125-150 min at 99.9% confidence, due to characteristic time-scales revealed in the periodogram. These long cycles might reflect dynamics occurring within the shallow magma supply system below the island of El Hierro.

  5. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island (United States)

    Santana-Casiano, J. M.; Fraile-Nuez, E.; González-Dávila, M.; Baker, E. T.; Resing, J. A.; Walker, S. L.


    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d-1 which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.

  6. Tsunamis caused by submarine slope failures along western Great Bahama Bank. (United States)

    Schnyder, Jara S D; Eberli, Gregor P; Kirby, James T; Shi, Fengyan; Tehranirad, Babak; Mulder, Thierry; Ducassou, Emmanuelle; Hebbeln, Dierk; Wintersteller, Paul


    Submarine slope failures are a likely cause for tsunami generation along the East Coast of the United States. Among potential source areas for such tsunamis are submarine landslides and margin collapses of Bahamian platforms. Numerical models of past events, which have been identified using high-resolution multibeam bathymetric data, reveal possible tsunami impact on Bimini, the Florida Keys, and northern Cuba. Tsunamis caused by slope failures with terminal landslide velocity of 20 ms-1 will either dissipate while traveling through the Straits of Florida, or generate a maximum wave of 1.5 m at the Florida coast. Modeling a worst-case scenario with a calculated terminal landslide velocity generates a wave of 4.5 m height. The modeled margin collapse in southwestern Great Bahama Bank potentially has a high impact on northern Cuba, with wave heights between 3.3 to 9.5 m depending on the collapse velocity. The short distance and travel time from the source areas to densely populated coastal areas would make the Florida Keys and Miami vulnerable to such low-probability but high-impact events.

  7. High Speed Submarine Optical Fiber Communication System:Pressure and Temperature Effects

    Directory of Open Access Journals (Sweden)

    A. A. Mohammed


    Full Text Available In the present paper, the performance of high speed submarine optical fiber cable systems is investigated, taking into account both the pressure and the temperature effects. Both the pressure and the temperature are depth-dependent variables, while both the spectral losses and the dispersion effects are temperature as well as wavelength dependent variables. Two important cases with real fibers are processed: a case with dispersion cancellation and a case without dispersion cancellation. It is found that the ocean pressure (due to the depth shifts the dispersion-free wavelength towards the third communication window. In general, as the depth increases the maximum transmitted bit rate increases in the range of interest. The system capacity as well as the spectral losses, and the dispersion effects are parametrically investigated over wide-range ranges of the set of affecting parameters {wavelength, ocean depth (and consequently the ocean pressure and temperature, and the chemical structure}. Key Words: Submarine Optical Fiber, Undersea Optical Communication, Pressure and Temperature Effects, Transoceanic Optical Communications

  8. Validation and verification of a virtual environment for training naval submarine officers (United States)

    Zeltzer, David L.; Pioch, Nicholas J.


    A prototype virtual environment (VE) has been developed for training a submarine officer of the desk (OOD) to perform in-harbor navigation on a surfaced submarine. The OOD, stationed on the conning tower of the vessel, is responsible for monitoring the progress of the boat as it negotiates a marked channel, as well as verifying the navigational suggestions of the below- deck piloting team. The VE system allows an OOD trainee to view a particular harbor and associated waterway through a head-mounted display, receive spoken reports from a simulated piloting team, give spoken commands to the helmsman, and receive verbal confirmation of command execution from the helm. The task analysis of in-harbor navigation, and the derivation of application requirements are briefly described. This is followed by a discussion of the implementation of the prototype. This implementation underwent a series of validation and verification assessment activities, including operational validation, data validation, and software verification of individual software modules as well as the integrated system. Validation and verification procedures are discussed with respect to the OOD application in particular, and with respect to VE applications in general.

  9. Relation of submarine landslide to hydrate occurrences in Baiyun Depression, South China Sea (United States)

    Sun, Yunbao; Zhang, Xiaohua; Wu, Shiguo; Wang, Lei; Yang, Shengxiong


    Submarine landslides have been observed in the Baiyun Depression of the South China Sea. The occurrence of hydrates below these landslides indicates that these slope instabilities may be closely related to the massive release of methane. In this study, we used a simple Monte-Carlo model to determine the first-order deformation pattern of a gravitationally destabilizing slope. The results show that a stress concentration occurs due to hydrate dissociation on the nearby glide surface and on top of a gas chimney structure. Upon the dissolution of the gas hydrate, slope failure occurs due to the excess pore pressure generated by the dissociation of the gas hydrates. When gas hydrates dissociate at shallow depths, the excess pore pressure generated can be greater than the total stress acting at those points, along with the forces that resist sliding. Initially, the failure occurs at the toe of the slope, then extends to the interior. Although our investigation focused only on the contribution of hydrate decomposition to submarine landslide, this process is also affected by both the slope material properties and topography.

  10. Deep macrobenthic communities from Nazaré Submarine Canyon (NW Portugal

    Directory of Open Access Journals (Sweden)

    J. Cúrdia


    Full Text Available Macrofauna community structure within Nazaré Submarine Canyon is analysed and used to assess the potential effects of natural enrichment in this area subjected to accumulation of coastal sediments. A transect including three stations (2894, 3514 and 4141 m was carried out in the Nazaré Submarine Canyon (NW Portugal during a cruise of OMEX II programme (Ocean Margin Exchange, in the winter season of 1999. Although data was not collected in order to calculate sedimentation rates, sampling station at 2894 m is located in an area characterised by high levels of sedimentation, thus a high amount of organic matter is expected to be available for the local communities. Faunistic data are discussed in the context of the different features of the stations sampled. Multivariate analysis clearly separates the shallowest station from the other ones, which otherwise appear to be very similar. It also revealed a perceptible gradient along sediment depth at all stations, from shallow to deeper layers. Exceptionally depressed species richness and low evenness values were observed at the 2894 m station. The high number of individuals of a single species, Cossura sp. A, and the atypical diversity, dominance and evenness values obtained for this station support the hypothesis of community disturbance due to organic enrichment.

  11. 'Green' Submarine Cable Systems for Ocean/Climate Monitoring and Disaster Warning (United States)

    Barnes, C. R.; Butler, R.; Howe, B. M.; Bueti, M. C.


    A recent joint initiative between three UN agencies is proposing to develop trans-ocean mini-observatories to measure changing seafloor ocean observables. A Joint Task Force (JTF), established in 2012 by the International Telecommunication Union (ITU), the World Meteorological Organization (WMO) and the Intergovernmental Oceanographic Commission (IOC) of UNESCO, is examining novel uses for submarine telecommunication cables. With ITU secretariat support, the JTF is developing a strategy and roadmap that could lead to enabling the availability of modified 'green' submarine cable systems equipped with scientific sensors (such as temperature, pressure and acceleration) for climate monitoring and disaster risk reduction (particularly tsunamis). If successful and needing support from industry and regulatory bodies, a wide network of mini-observatories could be established at many places across the world's ocean floors to measure these important parameters accurately over several decades. The initiative addresses two main issues: a) the need for sustained climate-quality data from the sparsely observed deep oceans and continental slopes but extending into coastal waters; and b) the desire to increase the reliability and integrity of the global tsunami warning networks. Presently, plans are being developed to launch a pilot project with the active involvement of cable industry players and existing ocean observatory researchers.

  12. Submarine Groundwater Discharge of Trace Elements and Isotopes from Karst Systems (Invited) (United States)

    Charette, M. A.; Henderson, P. B.; Gonneea, M. E.; Breier, C.; Murray, J.; Jenson, J. W.; Morales, S.; Herrera-Silveira, J.


    Coastal hydrogeology is a major driver of the flux of trace elements and isotopes associated with submarine groundwater discharge (SGD). Karst geomorphology, which makes up 25% of the world’s coastline, is often characterized by highly permeable soils result that result in fast infiltration of rainfall such that overland runoff is minimal. As a result, the major vector for land-ocean freshwater transport is submarine groundwater discharge. This talk will focus on process studies at two karst settings: the Yucatan Peninsula, Mexico and Guam in the western Pacific Mariana Island chain. A feature common to both locations was minimal non-conservative behavior of trace metals and isotopes within subsurface mixing zones at the coast and substantial fluxes of trace metals associated with dissolution of carbonate minerals within the aquifer. The levels of trace metal enrichment appear correlated with subsurface path length, with groundwater endmember concentrations at the Yucatan site being ~2-5 times higher than at Guam. We surmise that SGD fluxes from karst systems were less significant during glacial periods when carbonate platforms are fully exposed and therefore subject to less intense weathering processes. These results have implications for interpretation of trace element and isotope distributions in the geologic record.

  13. Experimental study on hydrodynamic coefficients for high-incidence-angle maneuver of a submarine

    Directory of Open Access Journals (Sweden)

    Jong-Yong Park


    Full Text Available Snap rolling during hard turning and instability during emergency rising are important features of submarine operation. Hydrodynamics modeling using a high incidence flow angle is required to predict these phenomena. In the present study, a quasi-steady dynamics model of a submarine suitable for high-incidence-angle maneuvering applications is developed. To determine the hydrodynamic coefficients of the model, static tests, dynamic tests, and control surface tests were conducted in a towing tank and wind tunnel. The towing tank test is conducted utilizing a Reynolds number of 3.12 × 106, and the wind tunnel test is performed utilizing a Reynolds number of 5.11 × 106. In addition, least squares, golden section search, and surface fitting using polynomial models were used to analyze the experimental results. The obtained coefficients are presented in tabular form and can be used for various purposes such as hard turning simulation, emergency rising simulation, and controller design.

  14. Partitioning of Submarine Melt and Calving across the front of Store Glacier, Greenland (United States)

    Hubbard, A., II; Chauche, N.


    Processes unique to the marine-termini of fast-flowing tidewater outlet glaciers can potentially drive extreme rates of mass wastage thereby providing a rapid link between the terrestrial ice reservoir and the oceanic sink. Here we attempt to directly quantify the pattern and magnitude of calving and melt at the front of Store Glacier, a major outlet draining the western sector of the Greenland ice sheet. Integration of range-survey technologies on a robust, heavy displacement marine platform coupled with high-resolution photogrammetry allowed the production of accurate, ~m resolution 3d digital terrain models (DTMs) of the glacier front. A swath-interferometric sonar system calibrated via an inertial motion unit stabilized with RTK GPS and vector-compass data-streams was combined with photogrammetric processing of repeat UAV surveys. The results of three repeat surveys across the front of Store Glaciers in 2012 is presented during which significant ice flow, melt and calving events were imaged, complimented with AWS, on-ice GPS stations and time-lapse/video camera sequences. The residual of successive DTMs yield the 3d pattern of frontal change allowing the processes calving and melt to be quantified and constrained in unprecedented detail. The pattern of submarine melt is further validated against indirect estimates of submarine melt derived from oceanographic circulation measurements within the fjord.

  15. Elemental mercury at submarine hydrothermal vents in the Bay of Plenty, Taupo volcanic zone, New Zealand (United States)

    Stoffers, P.; Hannington, M.; Wright, I.; Herzig, P.; de Ronde, C.; Scientific Party, Shipboard


    Hot springs in active geothermal areas such as Yellowstone National Park, the Geysers geothermal field in California, and the Taupo volcanic zone in New Zealand are notably enriched in the trace metals Au, Ag, As, Sb, and Hg. Such near-surface hot springs have formed many of the world's important deposits of gold and silver and some of the largest deposits of mercury. The majority of these are associated with continental geothermal systems in subaerial environments. Here we report the discovery of active mercury-depositing hot springs in a submarine setting, at nearly 200 m water depth, within the offshore extension of the Taupo volcanic zone of New Zealand. These vents contain the first documented occurrence of elemental mercury on the sea floor and provide an important link between offshore hydrothermal activity and mercury-depositing geothermal systems on land. The discovery has implications for mercury transport in sea-floor hydrothermal systems and underscores the importance of submarine volcanic and geothermal activity as a source of mercury in the oceans.

  16. Submarine Slope Failure Primed and Triggered by Bottom Water Warming in Oceanic Hydrate-Bearing Deposits

    Directory of Open Access Journals (Sweden)

    Tae-Hyuk Kwon


    Full Text Available Many submarine slope failures in hydrate-bearing sedimentary deposits might be directly triggered, or at least primed, by gas hydrate dissociation. It has been reported that during the past 55 years (1955–2010 the 0–2000 m layer of oceans worldwide has been warmed by 0.09 °C because of global warming. This raises the following scientific concern: if warming of the bottom water of deep oceans continues, it would dissociate natural gas hydrates and could eventually trigger massive slope failures. The present study explored the submarine slope instability of oceanic gas hydrate-bearing deposits subjected to bottom water warming. One-dimensional coupled thermal-hydraulic-mechanical (T-H-M finite difference analyses were performed to capture the underlying physical processes initiated by bottom water warming, which includes thermal conduction through sediments, thermal dissociation of gas hydrates, excess pore pressure generation, pressure diffusion, and hydrate dissociation against depressurization. The temperature rise at the seafloor due to bottom water warming is found to create an excess pore pressure that is sufficiently large to reduce the stability of a slope in some cases. Parametric study results suggest that a slope becomes more susceptible to failure with increases in thermal diffusivity and hydrate saturation and decreases in pressure diffusivity, gas saturation, and water depth. Bottom water warming can be further explored to gain a better understanding of the past methane hydrate destabilization events on Earth, assuming that more reliable geological data is available.

  17. The Revolutionary Armed Forces of Colombia (FARC and the Development of Narco-Submarines

    Directory of Open Access Journals (Sweden)

    Michelle Jacome Jaramillo


    Full Text Available The Revolutionary Armed Forces of Colombia (FARC have been one of the world's most consistently formidable violent non-state actors over the last forty years. Unsurprisingly, the group has provided one of the most compelling and concerning examples of the level of technical sophistication attainable by sub-state organizations. Over the last two decades the group has carried out an iterative and innovative process that, in reaction to improved detection capabilities, has brought them from depending on disposable go-fast boats to transport drugs to possessing fully submersible and reusable covert vessels for transportation. The following case study will discuss the development of narco-submarines and the underlying motivations behind the pursuit of this complex engineering task. The case study will outline the different phases of the narco-submarine development and highlight FARC’s determination to overcome the challenges present in each design. This discussion will show how FARC’s systematized acquiring of information and expertise has resulted in the accomplishment of fully submersible vessels, capable of transporting more than 10 tons of illicit product.

  18. Submarine seepage of natural gas in Norton Sound, Alaska (United States)

    Cline, J.D.; Holmes, M.L.


    Unusual concentrations of dissolved two- to four-carbon alkanes were observed in the waters in Norton Sound in a localized area approximately 40 kilometers south of Nome, Alaska, in 1976. The hydrocarbons were identified in the near-bottom waters downcurrent for more than 100 kilometers from a sea-floor point source. Preliminary dynamic modeling estimates of the initial gas phase composition predict methane/ethane and ethane/propane ratios of 24 and 1.7, respectively, assuming the hydrocarbons were introduced by bubbles. The low ethane/propane ratio is indicative of gas from a liquid petroleum source rather than from nonassociated or biogenic natural gas. Preliminary data on the structural geology of Norton Basin lend support to the interpretation based on the hydrocarbon plume. Unconformably truncated strata dip basinward from the seep locus; acoustic anomalies and numerous steeply dipping faults in the immediate vicinity of the seep are corroborating evidence that shallow gas- or petroleum-charged sediments and strata coincide with avenues for migration of mobile hydrocarbons to the sea floor. These factors, taken in concert with the sedimentological regime, the recent revision (increase) of basin depth estimates, and the highly localized hydrocarbon source, strongly suggest a thermogenic rather than a recent biogenic origin for these gaseous compounds.

  19. Submarine landslides in the Santa Barbara Channel as potential tsunami sources

    Directory of Open Access Journals (Sweden)

    H. G. Greene


    Full Text Available Recent investigations using the Monterey Bay Aquarium Research Institutes (MBARI Remotely Operated Vehicles (ROVs 'Ventana' and 'Tiburon' and interpretation of MBARI's EM 300 30 kHz multibeam bathymetric data show that the northern flank of the Santa Barbara Basin has experienced massive slope failures. Of particular concern is the large (130 km2 Goleta landslide complex located off Coal Oil Point near the town of Goleta, that measures 14.6-km long extending from a depth of 90 m to nearly 574 m deep and is 10.5 km wide. We estimate that approximately 1.75 km3 has been displaced by this slide during the Holocene. This feature is a complex compound submarine landslide that contains both surfical slump blocks and mud flows in three distinct segments. Each segment is composed of a distinct head scarp, down-dropped head block and a slide debris lobe. The debris lobes exhibit hummocky topography in the central areas that appear to result from compression during down slope movement. The toes of the western and eastern lobes are well defined in the multibeam image, whereas the toe of the central lobe is less distinct. Continuous seismic reflection profiles show that many buried slide debris lobes exist and comparison of the deformed reflectors with ODP Drill Site 149, Hole 893 suggest that at least 200 000 years of failure have occurred in the area (Fisher et al., 2005a. Based on our interpretation of the multibeam bathymetry and seismic reflection profiles we modeled the potential tsunami that may have been produced from one of the three surfical lobes of the Goleta slide. This model shows that a 10 m high wave could have run ashore along the cliffs of the Goleta shoreline. Several other smaller (2 km2 and 4 km2 slides are located on the northern flank of the Santa Barbara Basin, both to the west and east of Goleta slide and on the Conception fan along the western flank of the basin. One slide, named the Gaviota slide, is 3.8 km2, 2.6 km long and 1

  20. Delineation of submarine groundwater discharge (SGD) in a large-scaled reclaimed land (United States)

    Lee, B.; Park, S.; Hwang, J.; Song, S.; Choi, J.; Nam, K.


    The Saemangeum reclaimed land in Korea is currently under construction for an eco-friendly multifunctional complex including agriculture, eco-tourism, business, and renewable energy industry. Regarding water supply for the reclaimed land, groundwater is the sustainable water resource and submarine groundwater discharge (SGD), subsurface fluids flowing from land to the sea, is considered as an alternative one. This study was conducted to identify SGD below a southeastern part of the reclaimed land and to delineate its pathway by investigating groundwater chemistry and electrical resistivity distribution of subsurface. Thirty four groundwater samples were collected from shallow agricultural wells placed along the past coast line (~5 km length) of the southeastern part in May and October, 2009. Field parameters including pH, EC, temperature, and ORP were measured using a portable multi-sensor and alkalinity by titration. They were analyzed for stable isotopes (δ18O and δ2H), cations (Na, K, Ca, Mg, Si, and NH4), anions (Cl, NO3, SO4, and PO4), and metals (Fe and Mn). Mean EC value was 1,163 µS/cm, corresponding to the appropriate crop growth because the criteria of crop yield is less 2,000 µS/cm. Stable isotopes results were plotted on the local meteoric water line, indicating lighter than those from sea water. It implied that the groundwater originated from inland precipitation and occurred as SGD along the coast line. From the groundwater compositions showing various water types including Na-HCO3, Ca-Cl, and Na-Cl, it could be concluded that small-scale SGD and seawater intrusion have great influences on the groundwater quality. From correlation analysis of EC-pH, Cl-HCO3, NO3-SO4, NO3-Cl, and (Fe, Mn)-NH4, spatial distributions of SGD were identified. A small catchment (0.2 km2) in the reclaimed land was selected to delineate a SGD flow path by two-dimensional electrical resistivity survey. The longitudinal and transverse lines were 760 and 275 m, respectively

  1. Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea

    Directory of Open Access Journals (Sweden)

    A. N. Charkin


    Full Text Available It has been suggested that increasing terrestrial water discharge to the Arctic Ocean may partly occur as submarine groundwater discharge (SGD, yet there are no direct observations of this phenomenon in the Arctic shelf seas. This study tests the hypothesis that SGD does exist in the Siberian Arctic Shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The field-observational approach in the southeastern Laptev Sea used a combination of hydrological (temperature, salinity, geological (bottom sediment drilling, geoelectric surveys, and geochemical (224Ra, 223Ra, 228Ra, and 226Ra techniques. Active SGD was documented in the vicinity of the Lena River delta with two different operational modes. In the first system, groundwater discharges through tectonogenic permafrost talik zones was registered in both winter and summer. The second SGD mechanism was cryogenic squeezing out of brine and water-soluble salts detected on the periphery of ice hummocks in the winter. The proposed mechanisms of groundwater transport and discharge in the Arctic land-shelf system is elaborated. Through salinity vs. 224Ra and 224Ra / 223Ra diagrams, the three main SGD-influenced water masses were identified and their end-member composition was constrained. Based on simple mass-balance box models, discharge rates at sites in the submarine permafrost talik zone were 1. 7 × 106 m3 d−1 or 19.9 m3 s−1, which is much higher than the April discharge of the Yana River. Further studies should apply these techniques on a broader scale with the objective of elucidating the relative importance of the SGD transport vector relative to surface freshwater discharge for both water balance and aquatic components such as dissolved organic carbon, carbon dioxide, methane, and nutrients.

  2. An Initial AUV Investigation of the Morainal Bank and Ice-Proximal Submarine Processes of the Advancing Hubbard Glacier, Southeast Alaska (United States)

    Lawson, D. E.; Gulick, S. P. S.; Goff, J. A.; O'Halloran, W.


    The movement of an advancing tidewater glacier occurs in concert with the morainal bank that underlies its terminus. The mechanics of motion and sedimentological processes responsible for this advance of the morainal bank with the calving terminus are not well-defined and based largely on inferences from geophysical analyses of remnant morainal banks on fjord floors. There is a general absence of in situ or direct observation of the submarine margin because it is nearly impossible to access the immediate area of the ice face by boat safely. In order to obtain such data, in June 2014 we tested the ability of a Bluefin 9M AUV (autonomous underwater vehicle) to acquire high resolution swath bathymetry and sidescan backscatter across a ~2 km long section of the ice face of Hubbard Glacier (see also Goff et al., this meeting). Additionally onboard oceanographic measurements were taken that can be compared with surface cast CTD profiles obtained during AUV deployment, including locations with subglacial discharges. The AUV test provides details on the geometry of the morainal bank and nature of the fjord wall surfaces. The decimeter-scale imagery of the seabed reveals numerous erosional and depositional bedforms and gravitational features on the morainal bank's proximal slope. Closer to the ice face, the morainal bank surface appears much coarser, with textural patterns of unknown origin, and gravel lags including boulder fields. Comparing the water depth from the AUV survey with that of NOAA bathymetric data from 2004/2006 shows the morainal bank continued to advance in pace with ice advance into fjord waters over 200m deep, water depths shoaling up to 100m near the present ice margin. The glimpse of the morainal bank afforded by the AUV test clearly demonstrated the value of this technology to ice marginal submarine investigations.

  3. NeMO-Net: A System for Near Real-Time Remote Sensing of Hydrothermal and Biological Activity in the Caldera of an Active Submarine Volcano (United States)

    Hammond, S. R.; Butterfield, D.; Embley, R. W.; Meinig, C.; Stalin, S.


    In July of 2000, a camera and three temperature sensors were placed on the seafloor near a hydrothermal vent located in the caldera of an active submarine volcano. The volcano's summit lies at a depth of about 1500 m and is located at 46° N, 130° W, approximately 250 nautical miles off the Oregon coast. The volcano is the site of a long-term interdisciplinary study focused in part on discovering relationships between submarine volcanic and hydrothermal activity and a microbial biosphere which exists beneath the sea floor within the volcano's summit caldera. NeMO-Net utilizes an acoustic modem to communicate with a surface mooring anchored nearby. The mooring, in turn, is linked from the ocean surface to the Pacific Marine Environmental Laboratory by means of satellite systems. A unique feature of NeMO-Net is that it enables shore-based investigators to interrogate and command the system to perform specific tasks, the results of which are then reported back typically within several minutes . In the initial year-long deployment, photographic images, along with hourly readings from the three temperature probes, were available on a website which was updated every 24 hours. During the year, the camera documented a dynamic vent biological community as well as water temperature variations due to the influence of tides, and possibly with changing vent fluid temperatures The NeMO-Net system is under continuing development with particular emphasis on linking it to multiple sea floor instruments including near-real-time chemical and water samplers. Near-future plans also call for NeMO Net to be linked to a resident sea floor AUV.

  4. Submarine seismic monitoring of El Hierro volcanic eruption with a 3C-geophone string: applying new acquisition and data processing techniques to volcano monitoring (United States)

    Jurado, Maria Jose; Ripepe, Maurizio; Lopez, Carmen; Blanco, Maria Jose; Crespo, Jose


    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2011 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. Right after the eruption onset, in October 2011 a geophone string was deployed by the CSIC-IGN to monitor seismic activity. Monitoring with the seismic array continued till May 2012. The array was installed less than 2 km away from the new vol¬cano, next to La Restinga village shore in the harbor from 6 to 12m deep into the water. Our purpose was to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. Each geophone consists on a 3-component module based on 3 orthogonal independent sensors that measures ground velocity. Some of the geophones were placed directly on the seabed, some were buried. Due to different factors, as the irregular characteristics of the seafloor. The data was recorded on the surface with a seismometer and stored on a laptop computer. We show how acoustic data collected underwater show a great correlation with the seismic data recorded on land. Finally we compare our data analysis results with the observed sea surface activity (ash and lava emission and degassing). This evidence is disclosing new and innovative tecniques on monitoring submarine volcanic activity. Reference Instituto Geográfico Nacional (IGN), "Serie El Hierro." Internet: /volcanologia/HIERRO.html [May, 17. 2013

  5. Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea (United States)

    Charkin, Alexander N.; Rutgers van der Loeff, Michiel; Shakhova, Natalia E.; Gustafsson, Örjan; Dudarev, Oleg V.; Cherepnev, Maxim S.; Salyuk, Anatoly N.; Koshurnikov, Andrey V.; Spivak, Eduard A.; Gunar, Alexey Y.; Ruban, Alexey S.; Semiletov, Igor P.


    It has been suggested that increasing terrestrial water discharge to the Arctic Ocean may partly occur as submarine groundwater discharge (SGD), yet there are no direct observations of this phenomenon in the Arctic shelf seas. This study tests the hypothesis that SGD does exist in the Siberian Arctic Shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The field-observational approach in the southeastern Laptev Sea used a combination of hydrological (temperature, salinity), geological (bottom sediment drilling, geoelectric surveys), and geochemical (224Ra, 223Ra, 228Ra, and 226Ra) techniques. Active SGD was documented in the vicinity of the Lena River delta with two different operational modes. In the first system, groundwater discharges through tectonogenic permafrost talik zones was registered in both winter and summer. The second SGD mechanism was cryogenic squeezing out of brine and water-soluble salts detected on the periphery of ice hummocks in the winter. The proposed mechanisms of groundwater transport and discharge in the Arctic land-shelf system is elaborated. Through salinity vs. 224Ra and 224Ra / 223Ra diagrams, the three main SGD-influenced water masses were identified and their end-member composition was constrained. Based on simple mass-balance box models, discharge rates at sites in the submarine permafrost talik zone were 1. 7 × 106 m3 d-1 or 19.9 m3 s-1, which is much higher than the April discharge of the Yana River. Further studies should apply these techniques on a broader scale with the objective of elucidating the relative importance of the SGD transport vector relative to surface freshwater discharge for both water balance and aquatic components such as dissolved organic carbon, carbon dioxide, methane, and nutrients.

  6. Continuous flow fluorescence based immunosensor for the detection of explosives and environmental pollutants (United States)

    Charles, Paul T.; Bart, John C.; Judd, Linda L.; Gauger, Paul R.; Ligler, Frances S.; Kusterbeck, Anne W.


    A continuous flow fluorescence based immunosensor has been developed at the Naval Research Laboratory as an inexpensive, field portable device to detect environmental pollutants. Detection of environmental pollutants such as explosives [e.g. trinitrotoluene (TNT) and hexahydro-1,3,5 trinitro- 1,3,5-triazine (RDX)[ and polychlorinated biphenyls (PCBs) have been achieved at low level concentrations. The continuous flow immunosensor (CFI) employs antibodies as recognition elements for specific antigens. Antibodies specific for the environmental pollutants of interest are covalently immobilized on a solid support matrix. Subsequent saturation of the antibody-support complex with a fluorescence analog (i.e. cyanine dye) of the pollutant completes the sensor matrix. The derivatized matrix is prepacked into a micro column with a continuous flow stream of buffer that removes nonspecifically bound fluorescent analog. After a stable baseline is obtained sample injections of the desired pollutant (PCBs, TNT, RDX, etc.) into the flow stream displaces the fluorescence analog from the immobilized antibody on the solid support. A signal response over background from the displaced fluorescence analog is measured and integrated by an in-line fluorometer. Dose response curves reveal the lowest limit of detection for TNT and RDX is 20 ppb (parts-per-billion). Detection limits for PCBs is slightly higher at 1.0 ppm (part-per-million). Results from field trials conducted at two military bases, Umatilla Army Depot (Hermiston, Ore.) and Site F and A at Naval SUBASE Bangor (Bangor, Wash.) demonstrated the capabilities of the immunosensor in performing on-site field analysis in groundwater and soil leachate matrices.

  7. Factors Related to Drug Abuse in the Submarine Service. IV. Correlates of Permissiveness of Attitudes Toward Drug Abuse (United States)


    originating from the Submarine Service and from the civilian sector. Thus, borrowing from the language of psychoanalysis , D.A. cases may be classified...A. flashback 97 o 0 3 B. C. D. E, habituation psychosis revelation, I don’t know 17. LSD has been stated (with some scientific

  8. The timing of sediment transport down Monterey Submarine Canyon, offshore California (United States)

    Stevens, Thomas; Paull, Charles K.; Ussler, William III; McGann, Mary; Buylaert, Jan-Pieter; Lundsten, Eve M.


    While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages measured on benthic foraminifera to examine the timing of sediment transport through the axial channel of Monterey Submarine Canyon and Fan, offshore California. The OSL ages date the timing of sediment entry into the canyon head while the 14C ages of benthic foraminifera record the deposition of hemipelagic sediments that bound the sand horizons. We use both single-grain and small (∼2 mm area) single-aliquot regeneration approaches on vibracore samples from fining-upward sequences at various water depths to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand (from 14C ages of benthic foraminifera in bracketing hemipelagic sediments) are interpreted as indicating that the sand does not pass through the entire canyon instantly in large individual events, but rather moves multiple times before emerging onto the fan. The increased spread in single-grain OSL dates with water depth provides evidence of mixing and temporary storage of sediment as it moves through the canyon system. The ages also indicate that the frequency of sediment transport events decreases with distance down the canyon channel system. The amalgamated sands near the canyon head yield OSL ages that are consistent with a sub-decadal recurrence frequency while the fining-upward sand sequences on the fan indicate that the channel is still experiencing events with a 150

  9. Simulating hydroplaning of submarine landslides by quasi 3D depth averaged finite element method (United States)

    De Blasio, Fabio; Battista Crosta, Giovanni


    G.B. Crosta, H. J. Chen, and F.V. De Blasio Dept. Of Earth and Environmental Sciences, Università degli Studi di Milano Bicocca, Milano, Italy Klohn Crippen Berger, Calgary, Canada Subaqueous debris flows/submarine landslides, both in the open ocean as well as in fresh waters, exhibit extremely high mobility, quantified by a ratio between vertical to horizontal displacement of the order 0.01 or even much less. It is possible to simulate subaqueous debris flows with small-scale experiments along a flume or a pool using a cohesive mixture of clay and sand. The results have shown a strong enhancement of runout and velocity compared to the case in which the same debris flow travels without water, and have indicated hydroplaning as a possible explanation (Mohrig et al. 1998). Hydroplaning is started when the snout of the debris flow travels sufficiently fast. This generates lift forces on the front of the debris flow exceeding the self-weight of the sediment, which so begins to travel detached from the bed, literally hovering instead of flowing. Clearly, the resistance to flow plummets because drag stress against water is much smaller than the shear strength of the material. The consequence is a dramatic increase of the debris flow speed and runout. Does the process occur also for subaqueous landslides and debris flows in the ocean, something twelve orders of magnitude larger than the experimental ones? Obviously, no experiment will ever be capable to replicate this size, one needs to rely on numerical simulations. Results extending a depth-integrated numerical model for debris flows (Imran et al., 2001) indicate that hydroplaning is possible (De Blasio et al., 2004), but more should be done especially with alternative numerical methodologies. In this work, finite element methods are used to simulate hydroplaning using the code MADflow (Chen, 2014) adopting a depth averaged solution. We ran some simulations on the small scale of the laboratory experiments, and secondly

  10. Updated size distribution of submarine landslides along the U.S. Atlantic margin (United States)

    Ten Brink, U. S.; Chaytor, J. D.; Andrews, B. D.; Brothers, D. S.; Geist, E. L.


    The volume of failed material in submarine landslides is one of the primary factors controlling tsunami amplitude, hence the cumulative volume distribution of submarine landslides on the U.S. Atlantic continental slope and rise provides information important for the evaluation of tsunami hazard potential for U.S. the East Coast. Landslide size distributions also help constrain the initiation mechanisms of submarine landslides in siliciclastic and carbonate environments [1,2], and thus improve our understanding of the pre-conditioning and propagation of landslides. Previous compilations of landslide distributions along the Atlantic continental margin used regional side-scan sonar data, seismic reflection profiles and multibeam bathymetry data that lacked coverage of large portions of the upper continental slope [3, 4]. We updated this regional database by compiling and merging multibeam echosounder data from 36 surveys conducted by various federal agencies and academia between Georges Banks and Cape Hatteras from 1990-2012. The result is a continuous 594,000 km2 digital bathymetric surface with a spatial resolution of 100 m spanning water depths between 55-6150 m. The new grid allows better identification and delineation of the areas and heights of the headwall scarps, and more precise volume estimates of the evacuated slide regions. Acoustic backscatter derived from the multibeam data and an updated compilation of sub-bottom seismic profiles and core logs improve the identification of the extent of mass transport deposits. The updated analysis includes uncertainties in the determination of the landslide areas. The cumulative area and volume distributions of the landslides excavations, their area/volume ratio, the water depth of the head wall, and the fraction of slope and rise areas covered by headwall scarps and landslide deposits, are quantified and discussed. Combining landslide size distribution with the overall rate of occurrence of landslides derived from age

  11. Space-for-time substitution and the evolution of submarine canyons in a passive, progradational margin. (United States)

    Micallef, Aaron; Ribó, Marta; Canals, Miquel; Puig, Pere; Lastras, Galderic; Tubau, Xavier


    40% of submarine canyons worldwide are located in passive margins, where they constitute preferential conduits of sediment and biodiversity hotspots. Recent studies have presented evidence that submarine canyons incising passive, progradational margins can co-evolve with the adjacent continental slope during long-term margin construction. The stages of submarine canyon initiation and their development into a mature canyon-channel system are still poorly constrained, however, which is problematic when attempting to reconstruct the development of passive continental margins. In this study we analyse multibeam echosounder and seismic reflection data from the southern Ebro margin (western Mediterranean Sea) to document the stages through which a first-order gully develops into a mature, shelf-breaching canyon and, finally, into a canyon-channel system. This morphological evolution allows the application of a space-for-time substitution approach. Initial gully growth on the continental slope takes place via incision and downslope elongation, with limited upslope head retreat. Gravity flows are the main driver of canyon evolution, whereas slope failures are the main agent of erosion; they control the extent of valley widening, promote tributary development, and their influence becomes more significant with time. Breaching of the continental shelf by a canyon results in higher water/sediment loads that enhance canyon development, particularly in the upper reaches. Connection of the canyon head with a paleo-river changes evolution dynamics significantly, promoting development of a channel and formation of depositional landforms. Morphometric analyses demonstrate that canyons develop into geometrically self-similar systems that approach steady-state and higher drainage efficiency. Canyon activity in the southern Ebro margin is pulsating and enhanced during sea level lowstands. Rapid sedimentation by extension of the palaeo-Millars River into the outermost shelf and upper

  12. Internal tides affect benthic community structure in an energetic submarine canyon off SW Taiwan (United States)

    Liao, Jian-Xiang; Chen, Guan-Ming; Chiou, Ming-Da; Jan, Sen; Wei, Chih-Lin


    Submarine canyons are major conduits of terrestrial and shelf organic matter, potentially benefiting the seafloor communities in the food-deprived deep sea; however, strong bottom currents driven by internal tides and the potentially frequent turbidity currents triggered by storm surges, river flooding, and earthquakes may negatively impact the benthos. In this study, we investigated the upper Gaoping Submarine Canyon (GPSC), a high-sediment-yield canyon connected to a small mountain river (SMR) off southwest (SW) Taiwan. By contrasting the benthic meiofaunal and macrofaunal communities within and outside the GPSC, we examined how food supplies and disturbance influenced the benthic community assemblages. The benthic communities in the upper GPSC were mainly a nested subset of the adjacent slope assemblages. Several meiofaunal (e.g. ostracods) and macrofaunal taxa (e.g. peracarid crustaceans and mollusks) that typically occurred on the slope were lost from the canyon. The polychaete families switched from diverse feeding guilds on the slope to motile subsurface deposit feeders dominant in the canyon. The diminishing of epibenthic peracarids and proliferation of deep burrowing polychaetes in the GPSC resulted in macrofauna occurring largely within deeper sediment horizons in the canyon than on the slope. The densities and numbers of taxa were depressed with distinct and more variable composition in the canyon than on the adjacent slope. Both the densities and numbers of taxa were negatively influenced by internal tide flushing and positively influenced by food availability; however, the internal tides also negatively influenced the food supplies. While the meiofauna and macrofauna densities were both depressed by the extreme physical conditions in the GPSC, only the macrofaunal densities increased with depth in the canyon, presumably related to increased frequency and intensity of disturbance toward the canyon head. The population densities of meiofauna, on the

  13. Seismic evidence of a second submarine eruption in the north of El Hierro Island (United States)

    Ortiz, R.; Berrocoso, M.; de la Cruz-Reyna, S.; Marrero, J. M.; Garcia, A.


    From the July 19, 2011 an increase of seismicity, accompanied by a remarkable process of deformation, was detected on the island of El Hierro. This reactivation process, instrumental and scientifically monitored, culminates in the occurrence of a submarine eruption, with the emergence of a strong tremor signal, in the south of the island on October 10, 2011. Both processes (unrest and eruption) have different phases and behaviors clearly evidenced by the deformation and seismicity. This work is the result of an exhaustive analysis of seismic signals from three stations deployed on the island of El Hierro(CTAB and CTIG (IGN) and REST (CSIC)), in order to explain the behavior of the volcanic system responsible for the submarine eruption of Las Calmas sea and its evolution, as well as evidence of a second submarine eruption in the north of the island (ElGolfo). The spectral content of signals from the seismic stations in the north of the island (CTIG and CTAB) and the area around the eruption (REST) has the dominant peak at different frequencies. The amplitude modulations of the seismic noise evolved differently in CTAB and CTIG than REST being particularly significant changes in amplitude and frequency after the occurrence of events of magnitude greater than 4. The evolution of the volcano-tectonic cumulative seismic energy shows the occurrence of two similar eruptive episodes, in which two phases can be distinguished. The first phase of both cycles has a constant rate with seismic events of magnitude less than 3 to reach the energy of 10 ^ 11 Joule. From that moment the magnitude grows rapidly exceeding magnitude 4. In the second phase the seismic events are mainly located in the south of the island, before the onset of visual evidences of the eruption (October 11, 2011) and later (November 2011) the seismic events are mainly located in the north of the island, where no visible signs have been detected. In both cases the appearance or changes in the tremor signal

  14. Structural vibration and acoustic radiation of coupled propeller-shafting and submarine hull system due to propeller forces (United States)

    Qu, Yegao; Su, Jinpeng; Hua, Hongxing; Meng, Guang


    This paper investigates the structural and acoustic responses of a coupled propeller-shafting and submarine pressure hull system under different propeller force excitations. The entire system, which consists of a rigid propeller, a main shaft, two bearings and an orthogonally stiffened pressure hull, is submerged in a heavy fluid. The shaft is elastically connected to the pressure hull by a radial bearing and a thrust bearing. The theoretical model of the structural system is formulated based on a modified variational method, in which the propeller, the main shaft and the bearings are treated as a lumped mass, an elastic beam and spatially distributed spring-damper systems, respectively. The rings and stringers in the pressure hull are modeled as discrete structural elements. The acoustic field generated by the hull is calculated using a spectral Kirchhoff-Helmholtz integral formulation. A strongly coupled structure-acoustic interaction analysis is employed to achieve reasonable solutions for the coupled system. The displacement of the pressure hull and the sound pressure of the fluid are expanded in the form of a double mixed series using Fourier series and Chebyshev orthogonal polynomials, providing a flexible way for the present method to account for the individual contributions of circumferential wave modes to the vibration and acoustic responses of the pressure hull in an analytical manner. The contributions of different circumferential wave modes of the pressure hull to the structural and acoustic responses of the coupled system under axial, transversal and vertical propeller forces are investigated. Computed results are compared with those solutions obtained from the coupled finite element/boundary element method. Effects of the ring and the bearing stiffness on the acoustic responses of the coupled system are discussed.

  15. Methodology for prediction and estimation of consequences of possible atmospheric releases of hazardous matter: 'Kursk' submarine study

    Directory of Open Access Journals (Sweden)

    A. Baklanov


    Full Text Available There are objects with some periods of higher than normal levels of risk of accidental atmospheric releases (nuclear, chemical, biological, etc.. Such accidents or events may occur due to natural hazards, human errors, terror acts, and during transportation of waste or various operations at high risk. A methodology for risk assessment is suggested and it includes two approaches: 1 probabilistic analysis of possible atmospheric transport patterns using long-term trajectory and dispersion modelling, and 2 forecast and evaluation of possible contamination and consequences for the environment and population using operational dispersion modelling. The first approach could be applied during the preparation stage, and the second - during the operation stage. The suggested methodology is applied on an example of the most important phases (lifting, transportation, and decommissioning of the ``Kursk" nuclear submarine operation. It is found that the temporal variability of several probabilistic indicators (fast transport probability fields, maximum reaching distance, maximum possible impact zone, and average integral concentration of 137Cs showed that the fall of 2001 was the most appropriate time for the beginning of the operation. These indicators allowed to identify the hypothetically impacted geographical regions and territories. In cases of atmospheric transport toward the most populated areas, the forecasts of possible consequences during phases of the high and medium potential risk levels based on a unit hypothetical release (e.g. 1 Bq are performed. The analysis showed that the possible deposition fractions of 10-11 (Bq/m2 over the Kola Peninsula, and 10-12 - 10-13 (Bq/m2 for the remote areas of the Scandinavia and Northwest Russia could be observed. The suggested methodology may be used successfully for any potentially dangerous object involving risk of atmospheric release of hazardous materials of nuclear, chemical or biological nature.

  16. Diffuse degassing He/CO2 ratio before and during the 2011-12 El Hierro submarine eruption, Canary Islands (United States)

    Padrón, Eleazar; Hernández, Pedro A.; Melián, Gladys V.; Barrancos, José; Padilla, Germán; Pérez, Nemesio M.; Dionis, Samara; Rodríguez, Fátima; Asensio-Ramos, María; Calvo, David


    El Hierro Island (278 km2) is the youngest and the SW-most of the Canary Islands. On July 16, 2011, a seismic-volcanic crisis started with the occurrence of more than 11,900 seismic events and significant deformation along the island, culminating with the eruption onset in October 12. Since at El Hierro Islands there are not any surface geothermal manifestation (fumaroles, etc), we have focused our studies on soil degassing surveys. Between July 2011 to March 2012, seventeen diffuse CO2 and He emissions soil gas surveys were undertaken at El Hierro volcanic system (600 observation sites) with the aim to investigate the relationship between their temporal variations and the volcanic activity (Padrón et al., 2013; Melián et al., 2014). Based on the diffuse He/CO2 emission ratio, a sharp increase before the eruption onset was observed, reaching the maximum value on September 26 (6.8×10-5), sixteen days before the occurrence of the eruption. This increase coincided with an increase in seismic energy release during the volcanic unrest and occurred together with an increase on the 3He/4He isotopic ratio in groundwaters from a well in El Hierro Island (Padrón et al., 2013; from 2-3 RA to 7.2 RA where RA = 3He/4He ratio in air), one month prior to the eruption onset. Early degassing of new gas-rich magma batch at depth could explain the observed increase on the He/CO2 ratio, causing a preferential partitioning of CO2 in the gas phase with respect to the He, due to the lower solubility of CO2 than that of He in basaltic magmas. During the eruptive period (October 2011-March 2012) the prevalence of a magmatic CO2-dominated component is evident, as indicated by the generally lower He/CO2 ratios and high 3He/4He values (Padrón et al., 2013). The onset of the submarine eruption might have produced a sudden release of volcanic gases, and consequently, a decrease in the volcanic gas pressure of the magma bodies moving beneath the island, reflected by a drastic decrease in

  17. Potential tsunamigenic hazard associated to submarine mass movement along the Ionian continental margin (Mediterranean Sea). (United States)

    Ceramicola, S.; Tinti, S.; Praeg, D.; Zaniboni, F.; Planinsek, P.


    Submarine mass movements are natural geomorphic processes that transport marine sediment down continental slopes into deep-marine environments. Type of mass wasting include creep, slides, slump, debris flows, each with its own features and taking place over timescale from seconds to years. Submarine landslides can be triggered by a number of different causes, either internal (such as changes in physical chemical sediment properties) or external (e.g. earthquakes, volcanic activity, salt movements, sea level changes etc.). Landslides may mobilize sediments in such a way as to form an impulsive vertical displacement of a body of water, originating a wave or series of waves with long wavelengths and long periods called tsunamis ('harbor waves'). Over 600 km of continental margin has been investigated by OGS in the Ionian sea using geophysical data - morpho-bathymetry (Reson 8111, 8150) and sub-bottom profiles (7-10 KHz) - collected aboard the research vessel OGS Explora in the framework of the MAGIC Project (Marine Geohazard along the Italian Coasts), funded by the Italian Civil Protection. The objective of this project is the definition of elements that may constitute geological risk for coastal areas. Geophysical data allowed the recognition of four main types of mass wasting phenomena along the slopes of the ICM: 1) mass transport complexes (MTCs) within intra-slope basins. Seabed imagery show the slopes of all the seabed ridges to be marked by headwall scarps recording widespread failure, multiple debris flows in several basins indicate one or more past episodes of failure that may be linked to activity on the faults bounding the structural highs. 2) submarine landslide - a multiple failure event have been identified (Assi landslide) at about 6 km away from the coastline nearby Riace Marina. Headwall scars up to 50 m high across water depths of 700 to 1400 m, while sub-bottom profiles indicate stacked slide deposits at and near seabed. 4) canyon headwalls - in the

  18. A proposal of multi-objective function for submarine rigid pipelines route optimization via evolutionary algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, D.H.; Medeiros, A.R. [Subsea7, Niteroi, RJ (Brazil); Jacob, B.P.; Lima, B.S.L.P.; Albrecht, C.H. [Universidade Federaldo Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Coordenacao de Programas de Pos-graduacao em Engenharia


    This work presents studies regarding the determination of optimal pipeline routes for offshore applications. The assembly of an objective function is presented; this function can be later associated with Evolutionary Algorithm to implement a computational tool for the automatic determination of the most advantageous pipeline route for a given scenario. This tool may reduce computational overheads, avoid mistakes with route interpretation, and minimize costs with respect to submarine pipeline design and installation. The following aspects can be considered in the assembly of the objective function: Geophysical and geotechnical data obtained from the bathymetry and sonography; the influence of the installation method, total pipeline length and number of free spans to be mitigated along the routes as well as vessel time for both cases. Case studies are presented to illustrate the use of the proposed objective function, including a sensitivity analysis intended to identify the relative influence of selected parameters in the evaluation of different routes. (author)

  19. Numerical and experimental investigations of submarine groundwater discharge to a coastal lagoon

    DEFF Research Database (Denmark)

    Haider, Kinza

    of the groundwater discharge occurred near the shoreline of the lagoon, but also off-shore discharge from deep confined aquifers system occurred at places where confining clay layers are eroded by buried valleys. The simulated fresh groundwater discharge was a non-negligible component, 59 % of recharge on the lagoon......The main goal of this study is to understand and estimate the amount of submarine groundwater discharge into Ringkøbing Fjord from shallow and deep aquifer systems at the Eastern shoreline from Ringkøbing catchment in Western Denmark. In order to accomplish this objective, the study was initiated...... using an existing large-scale airborne geophysical survey and hydrogeological data from the boreholes in the study area. This data helped in locating zones of groundwater discharge as well estimating complex salinity distribution under the sediment bed along with information about geology under lagoon...

  20. United Space Alliance waits to test its one-man submarine for SRB retrieval (United States)


    The one-man submarine dubbed DeepWorker 2000 sits on the deck of Liberty Star, one of two KSC solid rocket booster recovery ships. Inside the sub is the pilot, Anker Rasmussen. The sub is being tested on its ability to duplicate the sometimes hazardous job United Space Alliance (USA) divers perform to recover the expended boosters in the ocean after a launch. The boosters splash down in an impact area about 140 miles east of Jacksonville and after recovery are towed back to KSC for refurbishment by the specially rigged recovery ships. DeepWorker 2000 was built by Nuytco Research Ltd., North Vancouver, British Columbia. It is 8.25 feet long, 5.75 feet high, and weighs 3,800 pounds. USA is a prime contractor to NASA for the Space Shuttle program.

  1. Effect of an offshore sinkhole perforation in a coastal confined aquifer on submarine groundwater discharge (United States)

    Fratesi, S.E.; Leonard, V.; Sanford, W.E.


    In order to explore submarine groundwater discharge in the vicinity of karst features that penetrate the confining layer of an offshore, partially confined aquifer, we constructed a three-dimensional groundwater model using the SUTRA (Saturated-Unsaturated TRAnsport) variable-density groundwater flow model. We ran a parameter sensitivity analysis, testing the effects of recharge rates, permeabilities of the aquifer and confining layer, and thickness of the confining layer. In all simulations, less than 20% of the freshwater recharge for the entire model exits through the sinkhole. Recirculated seawater usually accounts for 10-30% of the total outflow from the model. Often, the sinkhole lies seaward of the transition zone and acts as a recharge feature for recirculating seawater. The permeability ratio between aquifer and confining layer influences the configuration of the freshwater wedge the most; as confining layer permeability decreases, the wedge lengthens and the fraction of total discharge exiting through the sinkhole increases. Copyright ?? 2007 IAHS Press.

  2. Analytical Expression of Equivalent Transverse Magnetic Permeability for Three-core Wire Armoured Submarine Cables

    DEFF Research Database (Denmark)

    Viafora, Nicola; Baù, Matteo; Dall, Laurits Bergholdt


    As three-core wire-armoured submarine cables become progressively more relevant, the need for refined modelling techniques grows likewise. IEC Standard 60287 indications though are still widely recognized to be insufficiently accurate, since several effects due to the presence of the collective...... of a simplified yet effective formulation. Such analytical approach is tested in a 2D FEM environment in terms of power losses distribution and compared both to the IEC indications and to an existing formula in the literature. It is found that the values of permeability proposed by the IEC Standard underestimate...... the induced sheath power losses due to the presence of the armour, whereas the proposed approach improves the accuracy, as the magnetic flux density enhancement within the cable is accounted for....

  3. Remarks about the apparent increasing of the drag coefficient on flexible submarine cables

    Energy Technology Data Exchange (ETDEWEB)

    Marichal, D. [Ecole Centrale de Nantes, 44 (France)


    A lot of elongated flexible underwater structures (towing and mooring cables, trawl lines, oil risers...) are used in exploitation of sea resources. All theoretical calculations require to know the hydrodynamic forces acting on these structures (especially the drag coefficient). It was usually assumed that the drag coefficient of a cylindrical element is a constant and takes the value of 1.2 as a rigid cylinder at the typical Reynolds numbers. But, if the cylindrical structure has transverse vibrations - as it is usual for submarine cables -, an important increase of the drag coefficient seems to appear Our purpose is to show that the first explanation of the drag coefficient increase comes partly from the problem formulation. It is usual to think that the towing speed is very important compared with the transverse motion velocity. But, in fact, the drag results in the combination of the normal component of the flow and this transverse motion velocity. (author)

  4. Response of the Black Sea methane budget to massive short-term submarine inputs of methane

    DEFF Research Database (Denmark)

    Schmale, O.; Haeckel, M.; McGinnis, D. F.


    A steady state box model was developed to estimate the methane input into the Black Sea water column at various water depths. Our model results reveal a total input of methane of 4.7 Tg yr(-1). The model predicts that the input of methane is largest at water depths between 600 and 700 m (7......% of the total input), suggesting that the dissociation of methane gas hydrates at water depths equivalent to their upper stability limit may represent an important source of methane into the water column. In addition we discuss the effects of massive short-term methane inputs (e. g. through eruptions of deep......-water mud volcanoes or submarine landslides at intermediate water depths) on the water column methane distribution and the resulting methane emission to the atmosphere. Our non-steady state simulations predict that these inputs will be effectively buffered by intense microbial methane consumption...

  5. Mapping the sound field of an erupting submarine volcano using an acoustic glider. (United States)

    Matsumoto, Haru; Haxel, Joseph H; Dziak, Robert P; Bohnenstiehl, Delwayne R; Embley, Robert W


    An underwater glider with an acoustic data logger flew toward a recently discovered erupting submarine volcano in the northern Lau basin. With the volcano providing a wide-band sound source, recordings from the two-day survey produced a two-dimensional sound level map spanning 1 km (depth) × 40 km(distance). The observed sound field shows depth- and range-dependence, with the first-order spatial pattern being consistent with the predictions of a range-dependent propagation model. The results allow constraining the acoustic source level of the volcanic activity and suggest that the glider provides an effective platform for monitoring natural and anthropogenic ocean sounds. © 2011 Acoustical Society of America

  6. Initiation of breakout of half-buried submarine pipe from sea bed due to wave action

    Energy Technology Data Exchange (ETDEWEB)

    Law, A.W.K. [Nanyang Technological Univ. (Singapore). School of Civil and Structural Engineering; Foda, M.A. [California Univ., Berkeley, CA (United States). Dept. of Civil Engineering


    A formulation is presented for the analysis of the breakout of a half-buried submarine pipe due to wave action. The formulation accounts for the contact between the pipe and the soil due to the oscillating horizontal hydrodynamic force. Results demonstrate the existence of an initial gap in the breakout experiments. With this initial gap the gap flux dominated the influx of water into the gap throughout the breakout process. The linear pipe rise persisted although the second-order expansion of the gap should have grown to the same order of magnitude as the initial gap with the poro-rigid soil assumption. It is postulated that the persistence of the linear rise was due to the localized passive failure around the ends of the soil trench which inhibited the growth of the opening due to the pipe`s rise. (Author)

  7. Significance of the actual nonlinear slope geometry for catastrophic failure in submarine landslides. (United States)

    Puzrin, Alexander M; Gray, Thomas E; Hill, Andrew J


    A simple approach to slope stability analysis of naturally occurring, mild nonlinear slopes is proposed through extension of shear band propagation (SBP) theory. An initial weak zone appears in the steepest part of the slope where the combined action of gravity and seismic loads overcomes the degraded peak shear resistance of the soil. If the length of this steepest part is larger than the critical length, the shear band will propagate into the quasi-stable parts of the slope, where the gravitational and seismically induced shear stresses are smaller than the peak but larger than the residual shear strength of the soil. Growth of a shear band is strongly dependent on the shape of the slope, seismic parameters and the strength of soil and less dependent on the slope inclination and the sensitivity of clay. For the slope surface with faster changing inclination, the criterion is more sensitive to the changes of the parameters. Accounting for the actual nonlinear slope geometry eliminates the main challenge of the SBP approach-determination of the length of the initial weak zone, because the slope geometry can be readily obtained from submarine site investigations. It also helps to identify conditions for the early arrest of the shear band, before failure in the sliding layer or a change in loading or excess pore water pressures occurs. The difference in the size of a landslide predicted by limiting equilibrium and SBP approaches can reach orders of magnitude, potentially providing an explanation for the immense dimensions of many observed submarine landslides that may be caused by local factors acting over a limited portion of the slope.

  8. The Chronic Detrimental Impact of Interruptions in a Simulated Submarine Track Management Task. (United States)

    Loft, Shayne; Sadler, Andreas; Braithwaite, Janelle; Huf, Samuel


    The objective of this article is to examine the extent to which interruptions negatively impact situation awareness and long-term performance in a submarine track management task where pre- and postinterruption display scenes remained essentially identical. Interruptions in command and control task environments can degrade performance well beyond the first postinterruption action typically measured for sequential static tasks, because individuals need to recover their situation awareness for multiple unfolding display events. Participants in the current study returned to an unchanged display scene following interruption and therefore could be more immune to such long-term performance deficits. The task required participants to monitor a display to detect contact heading changes and to make enemy engagement decisions. Situation awareness (Situation Present Assessment Method) and subjective workload (NASA-Task Load Index) were measured. The interruption replaced the display for 20 s with a blank screen, during which participants completed a classification task. Situation awareness after returning from interruption was degraded. Participants were slower to make correct engagement decisions and slower and less accurate in detecting heading changes, despite these task decisions being made at least 40 s following the interruption. Interruptions negatively impacted situation awareness and long-term performance because participants needed to redetermine the location and spatial relationship between the displayed contacts when returning from interruption, either because their situation awareness for the preinterruption scene decayed or because they did not encode the preinterruption scene. Interruption in work contexts such as submarines is unavoidable, and further understanding of how operators are affected is required to improve work design and training. © 2015, Human Factors and Ergonomics Society.

  9. Looking for Larvae Above an Erupting Submarine Volcano, NW Rota-1, Mariana Arc (United States)

    Beaulieu, S.; Hanson, M.; Tunnicliffe, V.; Chadwick, W. W., Jr.; Breuer, E. R.


    In 2009 the first marine protected areas for deep-sea hydrothermal vents in U.S. waters were established as part of the Volcanic Unit of the Marianas Trench Marine National Monument. In this region, hydrothermal vents are located along the Mariana Arc and back-arc spreading center. In particular hydrothermal vents are located near the summit of NW Rota-1, an active submarine volcano on the Mariana Arc which was erupting between 2003 and 2010 and ceased as of 2014. NW Rota-1 experienced a massive landslide in late 2009, decimating the habitat on the southern side of the volcano. This project looked at zooplankton tow samples taken from the water column above NW Rota-1 in 2010, searching for larvae which have the potential to recolonize the sea floor after such a major disturbance. Samples were sorted in entirety into coarse taxa, and then larvae were removed for DNA barcoding. Overall zooplankton composition was dominated by copepods, ostracods, and chaetognaths, the majority of which are pelagic organisms. Comparatively few larvae of benthic invertebrates were found, but shrimp, gastropod, barnacle, and polychaete larvae did appear in low numbers in the samples. Species-level identification obtained via genetic barcoding will allow for these larvae to be matched to species known to inhabit the benthic communities at NW Rota-1. Identified larvae will give insight into the organisms which can re-colonize the seafloor vent communities after a disturbance such as the 2009 landslide. Communities at hydrothermal vents at other submarine volcanoes in the Monument may act as sources for these larvae, but connectivity in this region of complex topography is unknown. As the microinvertebrate biodiversity in the Monument has yet to be fully characterized, our project also provides an opportunity to better describe both the zooplankton and benthic community composition in this area of the Monument.

  10. Paleoseismicity on the Dense Network of Holocene Submarine Faults in Beppu Bay, Southwest Japan (United States)

    Shimazaki, K.; Matsuoka, H.; Okamura, M.; Chida, N.


    Beppu Bay, approximately 30 km by 15 km in size, contains a complex network of Holocene submarine faults whose total length amounts to 230km. They are normal dip-slip fault with left-lateral strike-slip component. The maximum vertical offset accumulated in the past 7,300 years exceeds 20 m. A detailed study on paleoseismicity on one of the faults shows a feature of the time-predictable recurrence, i.e., the larger the vertical offset, the longer the following inter-event time. Branching features can be often recognized near the end of fault and the consistency in branching direction of neighboring faults suggest repeated rupture propagation in the same direction. A detailed examination of high-resolution seismic profiling of branch indicates a repeat of branching and a slow transition of rupture from an old branch to a new one. The central Beppu-Bay fault running WNW to ESE in the center of the bay forms the northern boundary of the major graben structure of the bay. The Asamigawa fault in the west of the bay, running parallel to the central Beppu-Bay fault, has been considered as the southern boundary, but its eastern continuation was not clear. Recent seismic profiling carried out by Chida et al. (2003) showed an existence of Holocene normal fault beneath the city of Oita whose population is 440,000 and interpreted it as a part of the southern boundary. Our high-resolution shallow-water profiling survey revealed the submarine portion of the southern boundary fault, filling a gap between two subaerial faults. We continuously sample marine sediments down to a subbottom depth of 20m by piston coring and correlate specific features of sediment, 20 volcanic ash layers, a few features of magnetic susceptibility and coarse fraction together with C-14 ages of echinoids, pelecypods, and plant remains on the both sides of a targe fault to estimate the date and vertical offset of paleoearthquakes.

  11. Submarine Groundwater Discharge at a Single Spot Location: Evaluation of Different Detection Approaches

    Directory of Open Access Journals (Sweden)

    Michael Schubert


    Full Text Available Submarine groundwater discharge (SGD into the ocean is of general interest because it acts as vehicle for the transport of dissolved contaminants and/or nutrients into the coastal sea and because it may be accompanied by the loss of significant volumes of freshwater. Due to the large-scale and long-term nature of the related hydrological processes, environmental tracers are required for SGD investigation. The water parameters of electrical conductivity and temperature, the naturally occurring radionuclides of radon and radium as well as the stable water isotopes 18O and 2H have proven in previous studies their general suitability for the detection and quantification of SGD. However, individual hydrogeological settings require a site-specific application of this “tool box”. This study evaluates and compares the applicability of the abovementioned tracers for investigating SGD from a distinct submarine source in a karst environment at Cabbé, southern France. The specific advantages and disadvantages of each individual parameter under the given hydrogeological conditions are discussed. Radon appeared to be the most suitable environmental tracer in the site specific context. The water temperature was less reliable due to the little temperature difference between seawater and groundwater and since the diurnal variation of the air temperature masks potential SGD signals. Radium isotopes are less applicable in the studied region due to the lack of a well-developed subterranean estuary. The stable water isotopes showed results consistent with the salinity and radon data; however, the significantly higher effort required for stable isotope analyses is disadvantageous. A multi-temporal thermal remote sensing approach proved to be a powerful tool for initial SGD surveying.

  12. Partly standing internal tides in a dendritic submarine canyon observed by an ocean glider (United States)

    Hall, Rob A.; Aslam, Tahmeena; Huvenne, Veerle A. I.


    An autonomous ocean glider is used to make the first direct measurements of internal tides within Whittard Canyon, a large, dendritic submarine canyon system that incises the Celtic Sea continental slope and a site of high benthic biodiversity. This is the first time a glider has been used for targeted observations of internal tides in a submarine canyon. Vertical isopycnal displacement observations at different stations fit a one-dimensional model of partly standing semidiurnal internal tides - comprised of a major, incident wave propagating up the canyon limbs and a minor wave reflected back down-canyon by steep, supercritical bathymetry near the canyon heads. The up-canyon internal tide energy flux in the primary study limb decreases from 9.2 to 2.0 kW m-1 over 28 km (a dissipation rate of 1 - 2.5 ×10-7 Wkg-1), comparable to elevated energy fluxes and internal tide driven mixing measured in other canyon systems. Within Whittard Canyon, enhanced mixing is inferred from collapsed temperature-salinity curves and weakened dissolved oxygen concentration gradients near the canyon heads. It has previously been hypothesised that internal tides impact benthic fauna through elevated near-bottom current velocities and particle resuspension. In support of this, we infer order 20 cm s-1 near-bottom current velocities in the canyon and observe high concentrations of suspended particulate matter. The glider observations are also used to estimate a 1 °C temperature range and 12 μmol kg-1 dissolved oxygen concentration range, experienced twice a day by organisms on the canyon walls, due to the presence of internal tides. This study highlights how a well-designed glider mission, incorporating a series of tide-resolving stations at key locations, can be used to understand internal tide dynamics in a region of complex topography, a sampling strategy that is applicable to continental shelves and slopes worldwide.

  13. Low forced expiratory flow rates and forceful exhalation as a cause for arterial gas embolism during submarine escape training: a case report. (United States)

    Hartge, Francis J; Bennett, Thomas L


    A 26-year-old male U.S. Navy submariner suffered an arterial gas embolism during pressurized submarine escape training. Routine pretraining medical screening revealed no history of asthma, pneumothorax or recent respiratory infection. Pulmonary function testing and posterioranterior/lateral chest X-ray were normal. He forcefully exhaled at the start of his ascent and developed neurological abnormalities including lightheadedness with lower extremity weakness and paresthesias after surfacing. He fully recovered after a U.S. Navy Treatment Table 6. This case represents the first report of an arterial gas embolism since the U.S. Navy resumed pressurized submarine escape training utilizing the Submarine Escape and Immersion Equipment suit. We discuss possible contributing factors and propose that his AGE was caused by pulmonary barotrauma due to a combination of low forced expiratory flow rates and an overly forceful exhalation during his ascent.

  14. Successive, large mass-transport deposits in the south Kermadec fore-arc basin, New Zealand: The Matakaoa Submarine Instability Complex

    National Research Council Canada - National Science Library

    Geoffroy Lamarche; Cathy Joanne; Jean-Yves Collot


    Four >100 km3 mass-transport deposits (MTDs) identified from their morphology and seismic facies across the Matakaoa Margin and Raukumara fore-arc basin, NE New Zealand, constitute the Matakaoa Submarine Instability Complex (MSIC...

  15. CRED 10m Gridded bathymetry of the submarine volcanos between Olosega and Ta'u Islands of the Manu'a Island group, American Samoa (Arc ASCII Format) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry of the submarine volcanos between Olosega and Ta'u Islands of the Manu'a Island group, American Samoa This survey provides almost complete...

  16. Submarine groundwater discharge at Kahana Bay, Oahu, 1997-2001: in situ CTD and water chemistry tracer data (NODC Accession 0011399) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Submarine groundwater discharge (SGD) is neither well understood nor commonly investigated in Hawaii, but it is recognized as a potential pollution source to coastal...

  17. Proceedings of Tripartite Conference on Submarine Medicine and IEP B-52 - France, United Kingdom, United States (6th) Held in Groton, Connecticut on 1-4 June 1987 (United States)


    such as electrolysers -, scrubbers, and burners, etc, give a good general technical description of the hardware and provide details of the physical...control is achieved. Oxygen Generation - In nuclear submarines oxygen is pruvidedby use of electrolysers . Currently the majority of submarines are fitted...with High Pressure Electrolysers .. A new Low Pressure Electrolyser using solid polymer electrolyte developed by General Electric has now been

  18. Development and validation of a modified Hybrid-III six-year-old dummy model for simulating submarining in motor-vehicle crashes. (United States)

    Hu, Jingwen; Klinich, Kathleen D; Reed, Matthew P; Kokkolaras, Michael; Rupp, Jonathan D


    In motor-vehicle crashes, young school-aged children restrained by vehicle seat belt systems often suffer from abdominal injuries due to submarining. However, the current anthropomorphic test device, so-called "crash dummy", is not adequate for proper simulation of submarining. In this study, a modified Hybrid-III six-year-old dummy model capable of simulating and predicting submarining was developed using MADYMO (TNO Automotive Safety Solutions). The model incorporated improved pelvis and abdomen geometry and properties previously tested in a modified physical dummy. The model was calibrated and validated against four sled tests under two test conditions with and without submarining using a multi-objective optimization method. A sensitivity analysis using this validated child dummy model showed that dummy knee excursion, torso rotation angle, and the difference between head and knee excursions were good predictors for submarining status. It was also shown that restraint system design variables, such as lap belt angle, D-ring height, and seat coefficient of friction (COF), may have opposite effects on head and abdomen injury risks; therefore child dummies and dummy models capable of simulating submarining are crucial for future restraint system design optimization for young school-aged children. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  19. Development of an underwater ROV system for submarine cable maintenance. Kaitei cable maintenance yo suichu robot no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iyama, T.; Takahashi, Y.; Kaya, F.; Shigemitsu, T. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))


    For the purpose of repairing, burying, and inspecting submarine telecommunication cables more speedily and at greater depth than conventional processes, an underwater remotely operated robot system for submarine cable maintenance has been developed. The system is composed of an underwater remotely operated vehicle (ROV), tether cables, a tether management system, umbilical cables, a launch and recovery system, control units, and electric power units. The ROV is loaded with thrusters for propulsion, a television camera, a cable location system, manipulators, a cable gripper/cutter unit, a cable burier/digger unit, a variable ballast unit, various sensors, et al. Since its entrance into service in October, 1989, the system has been successfully operated in various sea areas around Japan with a crew of three or four for operation and maintenance. This paper describes the outline of the system configuration and their specifications. 12 figs., 1 tab.

  20. Development of a Web-Based Periscope Simulator for Submarine Officer Training (United States)


    valuable advice, even during your vacations. Thank you, Chris, for presenting me with otherwise hard subjects of modeling and simulation in such a didactic ...environment, or intrinsic, when the motivation is built by the learning environment. 6. Teacher Role: Ranging from a didactic (direct participation) books ?hl=en&lr=&id=JhV6Ry6UMDQC&oi=fnd&pg=PP2&dq=Simulation+Mo deling+Handbook:+A+Practical+Approach&ots=JiTEnN_- Jg&sig

  1. Anti-Submarine Warfare (ASW) Capability Transformation: Strategy of Response to Effects Based Warfare (United States)


    Operations. Edward A. Smith, CCRP, July 2006 10 Strategic Surveillance Operational Localization Tactical Engagement Strategic Wide Area... Thorndike , Operations Evaluation Group Office of the Chief of Naval Operations Navy Department, Washington, D.C., 1946THIS volume embodies the

  2. Towards a Game-Based Periscope Simulator for Submarine Officers Tactical Training (United States)


    45 Table 5. Paired-Samples t- Test Results for Participants’ Adjusted Scores. ............55 Table 6. Paired-Samples t- Test Results for...Paired-Samples t- Test Results for Participants’ Adjusted Scores in the RTF Group...surface vessel. At this depth, there is sufficient separation from the keel of the surface ship and the top of the submarine’s sail (NATO, 2002). This

  3. Main results of the 2012 joint Norwegian-Russian expedition to the dumping sites of the nuclear submarine K-27 and solid radioactive waste in Stepovogo Fjord, Novaya Zemlya. (United States)

    Gwynn, Justin P; Nikitin, Aleksander; Shershakov, Viacheslav; Heldal, Hilde Elise; Lind, Bjørn; Teien, Hans-Christian; Lind, Ole Christian; Sidhu, Rajdeep Singh; Bakke, Gunnar; Kazennov, Alexey; Grishin, Denis; Fedorova, Anastasia; Blinova, Oxana; Sværen, Ingrid; Lee Liebig, Penny; Salbu, Brit; Wendell, Cato Christian; Strålberg, Elisabeth; Valetova, Nailja; Petrenko, Galina; Katrich, Ivan; Logoyda, Igor; Osvath, Iolanda; Levy, Isabelle; Bartocci, Jean; Pham, Mai Khanh; Sam, Adam; Nies, Hartmut; Rudjord, Anne Liv


    This paper reports the main results of the 2012 joint Norwegian-Russian expedition to investigate the radioecological situation of the Stepovogo Fjord on the eastern coast of Novaya Zemlya, where the nuclear submarine K-27 and solid radioactive waste was dumped. Based on in situ gamma measurements and the analysis of seawater and sediment samples taken around the submarine, there was no indication of any leakage from the reactor units of K-27. With regard to the radioecological status of Stepovogo Fjord, activity concentrations of all radionuclides in seawater, sediment and biota in 2012 were in general lower than reported from the previous investigations in the 1990s. However in 2012, the activity concentrations of (137)Cs and, to a lesser extent, those of (90)Sr remained elevated in bottom water from the inner part of Stepovogo Fjord compared with surface water and the outer part of Stepovogo Fjord. Deviations from expected (238)Pu/(239,240)Pu activity ratios and (240)Pu/(239)Pu atom ratios in some sediment samples from the inner part of Stepovogo Fjord observed in this study and earlier studies may indicate the possibility of leakages from dumped waste from different nuclear sources. Although the current environmental levels of radionuclides in Stepovogo Fjord are not of immediate cause for concern, further monitoring of the situation is warranted. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Learning from Experience, Volume 2: Lessons from the U.S. Navy’s Ohio, Seawolf, and Virginia Submarine Programs (United States)


    man/docs/bur/index.html Barney, LT James R., and RADM John J. Zerr, USN, “NSSN - New Attack Submarine: US Navy’s ‘ Paperless Submarine’ Undergoes...Trident: Setting the Requirements, Kennedy School of Government, C15-88-802.0, 1987. ———, Trident Contracting (B): Evaluating the Bids, Cambridge...Mass.: Harvard Kennedy School of Government, 1988a. ———, Trident Contracting (C): Negotiating the Contract, Cambridge, Mass.: Harvard Kennedy School

  5. Satellite-derived submarine melt rates and mass balance (2011–2015 for Greenland's largest remaining ice tongues

    Directory of Open Access Journals (Sweden)

    N. Wilson


    Full Text Available Ice-shelf-like floating extensions at the termini of Greenland glaciers are undergoing rapid changes with potential implications for the stability of upstream glaciers and the ice sheet as a whole. While submarine melting is recognized as a major contributor to mass loss, the spatial distribution of submarine melting and its contribution to the total mass balance of these floating extensions is incompletely known and understood. Here, we use high-resolution WorldView satellite imagery collected between 2011 and 2015 to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues – Nioghalvfjerdsbræ (79 North Glacier, 79N, Ryder Glacier (RG, and Petermann Glacier (PG. Submarine melt rates under the ice tongues vary considerably, exceeding 50 m a−1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. We compare the total melt rates to the influx of ice to the ice tongue to assess their contribution to the current mass balance. At Petermann Glacier and Ryder Glacier, we find that the combined submarine and aerial melt approximately balances the ice flux from the grounded ice sheet. At Nioghalvfjerdsbræ the total melt flux (14.2 ± 0.96 km3 a−1 w.e., water equivalent exceeds the inflow of ice (10.2 ± 0.59 km3 a−1 w.e., indicating present thinning of the ice tongue.

  6. Submarine explosive activity and ocean noise generation at Monowai Volcano, Kermadec Arc: constraints from hydroacoustic T-waves


    Grevemeyer, Ingo; Metz, Dirk; Watts, Anthony


    Submarine volcanic activity is difficult to detect, because eruptions at depth are strongly attenuated by seawater. With increasing depth the ambient water pressure increases and limits the expansion of gas and steam such that volcanic eruptions tend to be less violent and less explosive with depth. Furthermore, the thermal conductivity and heat capacity of water causes rapid cooling of ejected products and hence erupted magma cools much more quickly than during subaerial eruptions. Therefore...

  7. Combining airborne thermal infrared images and radium isotopes to study submarine groundwater discharge along the French Mediterranean coastline


    Simon Bejannin; Pieter van Beek; Thomas Stieglitz; Marc Souhaut; Joseph Tamborski


    Study region: The French Mediterranean coastline, which includes karstic springs discharging into coastal seas and coastal lagoons. Study focus: We investigated submarine groundwater discharge (SGD), an important vector for many chemical elements that may impact the quality of the coastal environment. First, we acquired airborne thermal infrared (TIR) images to detect terrestrial groundwater inputs. Then we report in situ data (salinity; temperature; radium isotopes). We use these data i) ...

  8. Marine electrical resistivity imaging of submarine groundwater discharge: Sensitivity analysis and application in Waquoit Bay, Massachusetts, USA (United States)

    Henderson, Rory; Day-Lewis, Frederick D.; Abarca, Elena; Harvey, Charles F.; Karam, Hanan N.; Liu, Lanbo; Lane, John W.


    Electrical resistivity imaging has been used in coastal settings to characterize fresh submarine groundwater discharge and the position of the freshwater/salt-water interface because of the relation of bulk electrical conductivity to pore-fluid conductivity, which in turn is a function of salinity. Interpretation of tomograms for hydrologic processes is complicated by inversion artifacts, uncertainty associated with survey geometry limitations, measurement errors, and choice of regularization method. Variation of seawater over tidal cycles poses unique challenges for inversion. The capabilities and limitations of resistivity imaging are presented for characterizing the distribution of freshwater and saltwater beneath a beach. The experimental results provide new insight into fresh submarine groundwater discharge at Waquoit Bay National Estuarine Research Reserve, East Falmouth, Massachusetts (USA). Tomograms from the experimental data indicate that fresh submarine groundwater discharge may shut down at high tide, whereas temperature data indicate that the discharge continues throughout the tidal cycle. Sensitivity analysis and synthetic modeling provide insight into resolving power in the presence of a time-varying saline water layer. In general, vertical electrodes and cross-hole measurements improve the inversion results regardless of the tidal level, whereas the resolution of surface arrays is more sensitive to time-varying saline water layer.

  9. Dive and Explore: An Interactive Web Visualization that Simulates Making an ROV Dive to an Active Submarine Volcano (United States)

    Weiland, C.; Chadwick, W. W.


    Several years ago we created an exciting and engaging multimedia exhibit for the Hatfield Marine Science Center that lets visitors simulate making a dive to the seafloor with the remotely operated vehicle (ROV) named ROPOS. The exhibit immerses the user in an interactive experience that is naturally fun but also educational. The public display is located at the Hatfield Marine Science Visitor Center in Newport, Oregon. We are now completing a revision to the project that will make this engaging virtual exploration accessible to a much larger audience. With minor modifications we will be able to put the exhibit onto the world wide web so that any person with internet access can view and learn about exciting volcanic and hydrothermal activity at Axial Seamount on the Juan de Fuca Ridge. The modifications address some cosmetic and logistic ISSUES confronted in the museum environment, but will mainly involve compressing video clips so they can be delivered more efficiently over the internet. The web version, like the museum version, will allow users to choose from 1 of 3 different dives sites in the caldera of Axial Volcano. The dives are based on real seafloor settings at Axial seamount, an active submarine volcano on the Juan de Fuca Ridge (NE Pacific) that is also the location of a seafloor observatory called NeMO. Once a dive is chosen, then the user watches ROPOS being deployed and then arrives into a 3-D computer-generated seafloor environment that is based on the real world but is easier to visualize and navigate. Once on the bottom, the user is placed within a 360 degree panorama and can look in all directions by manipulating the computer mouse. By clicking on markers embedded in the scene, the user can then either move to other panorama locations via movies that travel through the 3-D virtual environment, or they can play video clips from actual ROPOS dives specifically related to that scene. Audio accompanying the video clips informs the user where they are

  10. Applications of radon and radium isotopes to determine submarine groundwater discharge and flushing times in Todos os Santos Bay, Brazil. (United States)

    Hatje, Vanessa; Attisano, Karina Kammer; de Souza, Marcelo Friederichs Landim; Mazzilli, Barbara; de Oliveira, Joselene; de Araújo Mora, Tamires; Burnett, William C


    Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD. A time-series mooring over a tidal cycle at Marina do Bonfim showed a systematic enrichment of the short-lived radium isotopes (223)Ra and (224)Ra during the falling tide. Assuming that the elevated radium isotopes were related to SGD and using measured radium activities from a shallow well at the site, we estimated groundwater seepage at about 70 m(3)/day per unit width of shoreline. Extrapolating to an estimated total shoreline length provided a first approximation of total (fresh + saline) SGD into BTS of 300 m(3)/s, about 3 times the average river discharge into the bay. Just applying the shoreline lengths from areas identified with high radon and reduced salinity results in a lower SGD estimate of 20 m(3)/s. Flushing times of the Paraguaçu Estuary were estimated at about 3-4 days based on changing radium isotope ratios from low to high salinities. The flushing time for the entire BTS was also attempted using the same approach and resulted in a surprisingly low value of only 6-8 days. Although physical oceanographic models have proposed flushing times on the order of months, a simple tidal prism calculation provided results in the range of 4-7 days, consistent with the radium approach. Based on these initial results, we recommend a strategy for refining both SGD and flushing time estimates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Evaluation of tsunami hazard associated to the Assi submarine landslide along the Ionian Calabrian margin, Italy (United States)

    Zaniboni, F.; Tinti, S.; Pagnoni, G.; Ceramicola, S.; Planinsek, P.; Marson, I.


    Continental margins are frequently prone to submarine sliding, which constitutes a severe hazard when the slides occur close to the coast and move in shallow water, since they might generate destructive waves. In the Mediterranean Sea, especially, the potential sources of landslide-induced tsunamis are often located critically close to coastal communities, and the knowledge of how the event may evolve together with awareness of the associated risk are key factors for civil protection issues. A series of recent geophysical surveys carried out by OGS in the framework of The MAGIC (Marine Geohazards along the Italian Coasts) project, brought relevant contribution to the imaging and functioning of submarine landslides. Along the tectonically active Ionian Calabrian Margin (ICM) a multiple failure event has been identified (Assi landslide) at about 6 km away from the coastline nearby Riace Marina: headwall scars, mobilized sediments along the scour, stacked deposits at and near the seabed, at the foot of the slope have been identified. The data allowed to estimate the volume of mobilized material and to reconstruct the failure dynamics. One of the most susceptible areas along the ICM is located in the southern part, around the coastal village of Riace Marina in the province of Reggio Calabria. The coastal area adjacent to Riace Marina is not a very urbanized settlement, however becomes intensely crowded in the tourist season. The evidence of the occurrence of such an extensive failure event so close to the coast, motivated us to assess the potential tsunamigenic hazard associated to the Assi submarine landslide event in this area. A number of scenarios were considered starting from a more conservative scenario (i.e. a sequence of successive failures) to the most critical case (i.e. a unique big event mobilizing all the sediments at once). In this work we present the results concerning the worst-case scenario, that is we assume that a single big landslide event occurred

  12. New Mapping of Mariana Submarine Volcanoes with Sidescan and Multibeam Sonars (United States)

    Embley, R. W.; Chadwick, W. W.; Baker, E. T.; Johnson, P. D.; Merle, S. G.; Ristau, S.


    An expedition in February/March 2003 on the R/V Thomas G. Thompson mapped more than 18,000 km2 with the towed MR1 sidescan sonar and almost 28,000 km2 with an EM300 hull-mounted multibeam system along the Mariana volcanic arc. The expedition was funded by NOAA's Office of Ocean Exploration (more on the expedition can be found at: The MR1 sidescan surveys began at the northern end of a 2001 R/V Melville MR1 survey at 16§ N and extended to Nikko Volcano at 23\\deg 05'N. A portion of the southern back-arc spreading center and the arc volcanoes south of 16\\deg N were mapped using the EM300 system. Of 43 submarine arc volcanoes surveyed that have basal diameters of 10 km or greater, 17 have summit calderas or craters. Of these, however, only 5 have diameters more than 2 km. In an accompanying survey of hydrothermal activity along the arc, CTD casts and/or tows were conducted over more than 50 individual volcanoes. The 11 volcanoes with active hydrothermal systems found in the course of these surveys appear to be about equally divided between those with and without summit calderas or craters (for additional information, see Baker et al., Resing et al., and Lupton et al., this session). The flanks of the submarine volcanoes and islands of the central and northern Mariana Arc consist largely of volcaniclastic flows. Most of the larger edifices have high-backscatter spoke-like patterns that probably represent coarser and/or younger flows from the summits. Higher relief high-backscatter areas, also commonly exhibiting a radial pattern, are found on many of the volcanoes' flanks. These are probably lava flows erupted along radial fissures. The Mariana Arc volcanoes are shedding large volumes of volcaniclastic material westward into the back-arc basin through a series of deep-sea channels oriented transverse to the arc that are in many places fed by flows from several volcanoes. On many of the volcaniclastic

  13. Submarine landslides in contourite drifts along the Pianosa Ridge (Northern Tyrrhenian Sea): A geotechnical approach. (United States)

    Miramontes Garcia, Elda; Sultan, Nabil; Garziglia, Sebastien; Jouet, Gwenael; Cauquil, Eric; Cattaneo, Antonio


    The Pianosa Ridge is a tectonic structure in the Northern Tyrrhenian Sea that forms the eastern flank of the Corsica trough (between Corsica and the Tuscan shelf). It is characterised by the presence of submarine landslides within the Pianosa Contourite Depositional System. Multibeam bathymetry, High-Resolution-72 channel (50-250 Hz) and CHIRP (3200-5200 Hz) seismic reflection profiles, collected during cruises PRISME2 and PRISME3 in 2013, revealed that bottom currents created a heterogeneous sedimentation pattern, resulting in zones of preferential deposition (drifts) and zones of erosion and/or non-deposition (moat and abraded surfaces). The sector where the largest submarine landslides took place is characterised by the presence of a plastered drift, a sediment body with a maximum thickness in the mid-low continental slope and a moat at the toe of the slope. Calypso piston cores and piezocone CPTu data acquired during the PRISME3 cruise in 2013 also provide valuable information about the lithology, geomechanical properties and stress history of contourite drifts and of the shallowest submarine landslide, named Pianosa Slump. Contourites in this area are mostly muddy, with coarser layers deposited during sea level falls. During sea level low-stands sedimentation rates (up to 115 cm•kyr-1 in the plastered drift) are higher than during sea level high-stands (20 cm•kyr-1 in the plastered drift). The plastered drift is underconsolidated with Overconsolidation Ratios (OCR) that range between 0.5 and 0.8. The Pianosa Slump formed in the plastered drift at 43-50 kyr BP has a volume of 2.62 km3, and it is covered by 17-20 m of sediment. The basal shear surface of the Pianosa Slump, at 30-56 m below the present-day seafloor, is correlated with a sediment layer characterised by the presence of zeolite minerals (up to 4% of sediment volume), high water content, low density, high compressibility, high permeability, high undrained shear strength and a post-peak strain


    Directory of Open Access Journals (Sweden)

    Haryadi Permana


    Full Text Available The new bathymetry and seismic data were acquired during the PreTI-Gap marine survey (February 15 to March 6, 2008. The survey was carried out along the NE margin of Mentawai Island using multi-beam swath bathymetry equipment, and 28-channels seismic streamer and four-airgun source. The first target was the Mega Island region near the epicenter of the 2007 great earthquake. The shallow bathymetry is characterized as a flat coral platform suggesting that 200 km elongated plateau is slowly subsiding without any active faults. Further north, from South Pagai to North of Siberut Islands, the seafloor morphology changes significantly. The deep and wide canyons or valleys produce very rough seafloor morphology between 50 and 1100 m water. In general, the submarine topography shows two break slopes at different depths. Between slope breaks, the undulating, hilly and circular features dominate, possibly caused by landslides. A push-up ridge is observed that dams the sediments eroded within a steep slope northeastward side. The seismic reflection data acquired along 14 dip seismic lines at the NE flank of Mentawai Islands, from Siberut to the South of Pagai Islands. We observed a set of southwestward dipping back thrust bounding the NE margin of the Mentawai Island. Keywords: submarine landslide, tsunami, Mentawai basin, Sumatra. Data batimetri dan seismik baru telah dihasilkan selama survey kelautan PreTi-Gap (15 Februari hingga 6 Maret 2008. Survei dilaksanakan sepanjang tepian timurlaut P. Mentawai menggunakan peralatan multibeam, seismic saluran ganda 28 kanal dengan sumber energi airgun. Sasaran pertama adalah memetakan kawasan pulau dekat pusat gempa tahun 2007. Kenampakan batimetri dangkal dicirikan dengan adanya dataran terumbu karang yang secara perlahan mengalami penurunan tanpa aktifitas sesar. Lebih jauh ke Utar, dari Pagai Selatan ke utara P. Siberut, morfologi dasar laut memperlihatkan perubahan secara signifikan, dimana lembah dasar laut

  15. First Use of an Autonomous Glider for Exploring Submarine Volcanism in the SW Pacific (United States)

    Matsumoto, H.; Embley, R. W.; Haxel, J. H.; Dziak, R. P.; Bohnenstiehl, D. R.; Stalin, S.; Meinig, C.


    A 1000-m Slocum glider® (Teledyne Webb Research Corporation) with CTD, turbidity, and hydrophone sensors was operated for two days in the Northeast Lau Basin. The survey was conducted near West Mata Volcano, where in November of 2008 the NOAA PMEL Vents program observed an active eruption at its 1207 m summit—the deepest submarine activity ever before witnessed. Our goal was to use the glider as a forensic tool to search for other nearby eruption sites with onboard sensors that detect the chemical and hydroacoustic signatures associated with the volcanic and hydrothermal plumes. The glider was launched approximately 40 km to the west of West Mata. It flew toward West Mata and was recovered near the summit of the volcano after repeating 13 yos during a 41-hour mission. Although the recordings were affected by mechanical noise from the glider’s rudder, the data demonstrate that the system can detect the wide-band noises (>1 kHz) associated with submarine volcanic and intense hydrothermal activity. The glider recorded complex acoustic amplitudes due to the multiple raypaths from West Mata as well as temporal variations in the volcano’s rate of activity, and demonstrated that these geologic processes contribute to the region’s high ambient noise levels. With the exception of the deployment and recovery, the mission was managed entirely by the shore teams in PMEL (Seattle, WA) and OSU labs (Newport, OR), ~5000 miles away without an engineer onboard. The dive cycle of the 950-m dives was ~3.5 hours and the average speed was ~0.27 cm/s. The CTD data were downloaded at every surface cycle and appeared to be of high quality. However we found that the sensitivity of the Wetlabs ECO flntu turbidity sensor was not adequate for the detection of volcanic plumes. The mission demonstrated PMEL’s ability to use autonomous gliders to monitor a variety of environmental parameters including ambient sound levels, temperature, salinity and turbidity for the purpose of finding

  16. Cyclic eruptions and sector collapses at Monowai submarine volcano, Kermadec arc: 1998-2007 (United States)

    Chadwick, W. W.; Wright, I. C.; Schwarz-Schampera, U.; Hyvernaud, O.; Reymond, D.; de Ronde, C. E. J.


    Repeated multibeam bathymetric surveys at Monowai Cone, a shallow submarine basaltic volcano and part of the Monowai Volcanic Center in the northern Kermadec arc, were conducted in 1998, 2004, and 2007. These surveys document dramatic depth changes at the volcano including negative changes up to -176 m from two sector collapses and positive changes up to +138 m from volcanic reconstruction near the summit and debris avalanche deposits downslope of the slide scars. One sector collapse occurred on the SE slope between 1998 and 2004 with a volume of ˜0.09 km3, and another occurred on the SW slope between 2004 and 2007 with a volume of ˜0.04 km3. The volume of positive depth change due to addition of volcanic material by eruption is of the same order: ˜0.05 km3 between 1998 and 2004 and ˜0.06 km3 between 2004 and 2007. During these time intervals, monitoring by the Polynesian Seismic Network detected frequent T wave swarms at Monowai, indicative of explosive eruptive activity every few months. An unusual T wave swarm on 24 May 2002 was previously interpreted as the collapse event between the 1998 and 2004 surveys, but no similarly anomalous T waves were detected between 2004 and 2007, probably because the Polynesian Seismic Network stations were acoustically shadowed from the second slide event. We interpret that the sector collapses on Monowai are caused by the unstable loading of fragmental erupted material on the summit and steep upper slopes of the volcano (>20°). Moreover, there appears to be a cyclic pattern in which recurrent eruptions oversteepen the cone and periodically lead to collapse events that transport volcaniclastic material downslope to the lower apron of the volcano. Volumetric rate calculations suggest that these two processes may be more or less in equilibrium. The repeated collapses at Monowai are relatively modest in volume (involving only 0.1-0.5% of the edifice volume), have occurred much more frequently than is estimated for larger debris

  17. Unsteady hydrodynamics of blade forces and acoustic responses of a model scaled submarine excited by propeller's thrust and side-forces (United States)

    Wei, Yingsan; Wang, Yongsheng


    This study presents the unsteady hydrodynamics of the excitations from a 5-bladed propeller at two rotating speeds running in the wake of a small-scaled submarine and the behavior of the submarine's structure and acoustic responses under the propeller excitations. Firstly, the propeller flow and submarine flows are independently validated. The propulsion of the hull-propeller is simulated using computational fluid dynamics (CFD), so as to obtain the transient responses of the propeller excitations. Finally, the structure and acoustic responses of the submarine under propeller excitations are predicted using a finite element/boundary element model in the frequency domain. Results show that (1) the propeller excitations are tonal at the propeller harmonics, and the propeller transversal force is bigger than vertical force. (2) The structure and acoustic responses of the submarine hull is tonal mainly at the propeller harmonics and the resonant mode frequencies of the hull, and the breathing mode in axial direction as well as the bending modes in vertical and transversal directions of the hull can generate strong structure vibration and underwater noise. (3) The maximum sound pressure of the field points increases with the increasing propeller rotating speed at structure resonances and propeller harmonics, and the rudders resonant mode also contributes a lot to the sound radiation. Lastly, the critical rotating speeds of the submarine propeller are determined, which should be carefully taken into consideration when match the propeller with prime mover in the propulsion system. This work shows the importance of the propeller's tonal excitation and the breathing mode plus the bending modes in evaluating submarine's noise radiation.

  18. Response of key stress-related genes of the seagrass Posidonia oceanica in the vicinity of submarine volcanic vents (United States)

    Lauritano, C.; Ruocco, M.; Dattolo, E.; Buia, M. C.; Silva, J.; Santos, R.; Olivé, I.; Costa, M. M.; Procaccini, G.


    Submarine volcanic vents are being used as natural laboratories to assess the effects of increased ocean acidity and carbon dioxide (CO2) concentration on marine organisms and communities. However, in the vicinity of volcanic vents other factors in addition to CO2, which is the main gaseous component of the emissions, may directly or indirectly confound the biota responses to high CO2. Here we used for the first time the expression of antioxidant and stress-related genes of the seagrass Posidonia oceanica to assess the stress levels of the species. Our hypothesis is that unknown factors are causing metabolic stress that may confound the putative effects attributed to CO2 enrichment only. We analyzed the expression of 35 antioxidant and stress-related genes of P. oceanica in the vicinity of submerged volcanic vents located in the islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to characterize gene expression patterns. Fifty-one percent of genes analyzed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls at both Ischia and Panarea, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The up-regulation of genes involved in the free radical detoxification response (e.g., CAPX, SODCP and GR) indicates that, in contrast with Ischia, P. oceanica at the Panarea site faces stressors that result in the production of reactive oxygen species, triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. These proteins are activated to adjust stress-accumulated misfolded proteins and prevent their aggregation as a response to some stressors, not necessarily high temperature. This is the first

  19. Oblique strike-slip faulting of the Cascadia submarine forearc: The Daisy Bank fault zone off central Oregon (United States)

    Goldfinger, Chris; Kulm, LaVerne D.; Yeats, Robert S.; Hummon, Cheryl; Huftile, Gary J.; Niem, Alan R.; McNeill, Lisa C.

    The Cascadia submarine forearc off Oregon and Washington is deformed by numerous active WNW-trending, left-lateral strike-slip faults. The kinematics of this set of sub-parallel left-lateral faults suggests clockwise block rotation of the forearc driven by oblique subduction. One major left-lateral strike-slip fault, the 94 km-long Daisy Bank fault, located off central Oregon, was studied in detail using high-resolution AMS 150 kHz and SeaMARC-lA sidescan sonar, swath bathymetry, multichannel seismic reflection profiles and a submersible. The Daisy Bank fault zone cuts the sediments and basaltic basement of the subducting Juan de Fuca plate, and the overriding North American plate, extending from the abyssal plain to the upper slope-outer shelf region. The Daisy Bank fault, a near-vertical left-lateral fault striking 292°, is a wide structural zone with multiple scarps observed in high-resolution sidescan images. From a submersible, we observe that these scarps offset late Pleistocene gray clay and overlying olive green Holocene mud, dating fault activity as post-12 ka on the upper slope. Vertical separation along individual fault scarps ranges from a few centimeters to 130 meters. Using a retrodeformation technique with multichannel reflection records, we calculate a net slip of 2.2±0.5 km. Fault movement commenced at about 380±50 ka near the western fault tip, based upon an analysis of growth strata and correlation with deep-sea drill hole biostratigraphy. We calculate a slip rate of 5.7±2.0 mm/yr. for the Daisy Bank fault at its western end on the Juan de Fuca plate. The motion of the set of oblique faults, including the Daisy Bank fault, may accommodate a significant portion of the oblique component of plate motion along the central Cascadia margin. We propose a block rotation model by which the seawardmost part of the forearc rotates clockwise and translates northward.

  20. An experimental investigation of the dynamics of submarine leveed channel initiation as sediment-laden density currents experience sudden unconfinement

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    Rowland, Joel C [Los Alamos National Laboratory; Hilley, George E [STANFORD UNIV; Fildani, Andrea [CHEVRON ETC


    Leveed submarine channels play a critical role in the transfer of sediment from the upper continental slopes to interslope basins and ultimately deepwater settings. Despite a reasonable understanding of how these channels grow once established, how such channels initiate on previously unchannelized portions of the seafloor remains poorly understood. We conducted a series of experiments that elucidate the influence of excess density relative to flow velocity on the dynamics of, and depositional morphologies arising from, density currents undergoing sudden unconfinement across a sloped bed. Experimental currents transported only suspended sediment across a non-erodible substrate. Under flow conditions ranging from supercritical to subcritical (bulk Richardson numbers of 0.02 to 1.2) our experiments failed to produce deposits resembling or exhibiting the potential to evolve into self-formed leveed channels. In the absence of excess density, a submerged sediment-laden flow produced sharp crested lateral deposits bounding the margins of the flow for approximately a distance of two outlet widths down basin. These lateral deposits terminated in a centerline deposit that greatly exceeded marginal deposits in thickness. As excess density increased relative to the outlet velocity, the rate of lateral spreading of the flow increased relative to the downstream propagation of the density current, transitioning from a narrow flow aligned with the channel outlet to a broad radially expanding flow. Coincident with these changes in flow dynamics, the bounding lateral deposits extended for shorter distances, had lower, more poorly defined crests that were increasingly wider in separation than the initial outlet, and progressively became more oblong rather than linear. Based on our results, we conclude that leveed channels cannot initiate from sediment-laden density currents under strictly depositional conditions. Partial confinement of these currents appears to be necessary to

  1. Gravitational, erosional and depositional processes on volcanic ocean islands: Insights from the submarine morphology of Madeira Archipelago (United States)

    Quartau, Rui; Ramalho, Ricardo S.; Madeira, José; Santos, Rúben; Rodrigues, Aurora; Roque, Cristina; Carrara, Gabriela; Brum da Silveira, António


    The submarine flanks of volcanic ocean islands are shaped by a variety of physical processes. Whilst volcanic constructional processes are relatively well understood, the gravitational, erosional and depositional processes that lead to the establishment of large submarine tributary systems are still poorly comprehended. Until recently, few studies have offered a comprehensive source-to-sink approach, linking subaerial morphology with near-shore shelf, slope and far-field abyssal features. In particular, few studies have addressed how different aspects of the subaerial part of the system (island height, climate, volcanic activity, wave regime, etc.) may influence submarine flank morphologies. We use multibeam bathymetric and backscatter mosaics of an entire archipelago - Madeira - to investigate the development of their submarine flanks. Crucially, this dataset extends from the nearshore to the deep sea, allowing a solid correlation between submarine morphologies with the physical and geological setting of the islands. In this study we also established a comparison with other island settings, which allowed us to further explore the wider implications of the observations. The submarine flanks of the Madeira Archipelago are deeply dissected by large landslides, most of which also affected the subaerial edifices. Below the shelf break, landslide chutes extend downslope forming poorly defined depositional lobes. Around the islands, a large tributary system composed of gullies and channels has formed where no significant rocky/ridge outcrops are present. In Madeira Island these were likely generated by turbidity currents that originated as hyperpycnal flows, whilst on Porto Santo and Desertas their origin is attributed to storm-induced offshore sediment transport. At the lower part of the flanks (-3000 to -4300 m), where seafloor gradients decrease to 0.5°-3°, several scour and sediment wave fields are present, with the former normally occurring upslope of the latter

  2. Magmatic sill intrusions beneath El Hierro Island following the 2011-2012 submarine eruption (United States)

    Benito-Saz, María Á.; Sigmundsson, Freysteinn; Parks, Michelle M.; García-Cañada, Laura; Domínguez Cerdeña, Itahiza


    El Hierro, the most southwestern island of Canary Islands, Spain, is a volcano rising from around 3600 m above the ocean floor and up to of 1500 m above sea level. A submarine eruption occurred off the coast of El Hierro in 2011-2012, which was the only confirmed eruption in the last ~ 600 years. Activity continued after the end of the eruption with six magmatic intrusions occurring between 2012-2014. Each of these intrusions was characterized by hundreds of earthquakes and 3-19 centimeters of observed ground deformation. Ground displacements at ten continuous GPS sites were initially inverted to determine the optimal source parameters (location, geometry, volume/pressure change) that best define these intrusions from a geodetic point of view. Each intrusive period appears to be associated with the formation of a separate sill, with inferred volumes between 0.02 - 0.3 km3. SAR images from the Canadian RADARSAT-2 satellite and the Italian Space Agency COSMO-SkyMed constellation have been used to produce high-resolution detailed maps of line-of-sight displacements for each of these intrusions. These data have been combined with the continuous GPS observations and a joint inversion undertaken to gain further constraints on the optimal source parameters for each of these separate intrusive events. The recorded activity helps to understand how an oceanic intraplate volcanic island grows through repeated sill intrusions; well documented by seismic, GPS and InSAR observations in the case of the El Hierro activity.

  3. Response of the Black Sea methane budget to massive short-term submarine inputs of methane

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    O. Schmale


    Full Text Available A steady state box model was developed to estimate the methane input into the Black Sea water column at various water depths. Our model results reveal a total input of methane of 4.7 Tg yr−1. The model predicts that the input of methane is largest at water depths between 600 and 700 m (7% of the total input, suggesting that the dissociation of methane gas hydrates at water depths equivalent to their upper stability limit may represent an important source of methane into the water column. In addition we discuss the effects of massive short-term methane inputs (e.g. through eruptions of deep-water mud volcanoes or submarine landslides at intermediate water depths on the water column methane distribution and the resulting methane emission to the atmosphere. Our non-steady state simulations predict that these inputs will be effectively buffered by intense microbial methane consumption and that the upward flux of methane is strongly hampered by the pronounced density stratification of the Black Sea water column. For instance, an assumed input of methane of 179 Tg CH4 d−1 (equivalent to the amount of methane released by 1000 mud volcano eruptions at a water depth of 700 m will only marginally influence the sea/air methane flux increasing it by only 3%.

  4. CO2 leakage alters biogeochemical and ecological functions of submarine sands (United States)

    Molari, Massimiliano; Guilini, Katja; Lott, Christian; Weber, Miriam; de Beer, Dirk; Meyer, Stefanie; Ramette, Alban; Wegener, Gunter; Wenzhöfer, Frank; Martin, Daniel; Cibic, Tamara; De Vittor, Cinzia; Vanreusel, Ann; Boetius, Antje


    Subseabed CO2 storage is considered a future climate change mitigation technology. We investigated the ecological consequences of CO2 leakage for a marine benthic ecosystem. For the first time with a multidisciplinary integrated study, we tested hypotheses derived from a meta-analysis of previous experimental and in situ high-CO2 impact studies. For this, we compared ecological functions of naturally CO2-vented seafloor off the Mediterranean island Panarea (Tyrrhenian Sea, Italy) to those of nonvented sands, with a focus on biogeochemical processes and microbial and faunal community composition. High CO2 fluxes (up to 4 to 7 mol CO2 m−2 hour−1) dissolved all sedimentary carbonate, and comigration of silicate and iron led to local increases of microphytobenthos productivity (+450%) and standing stocks (+300%). Despite the higher food availability, faunal biomass (−80%) and trophic diversity were substantially lower compared to those at the reference site. Bacterial communities were also structurally and functionally affected, most notably in the composition of heterotrophs and microbial sulfate reduction rates (−90%). The observed ecological effects of CO2 leakage on submarine sands were reproduced with medium-term transplant experiments. This study assesses indicators of environmental impact by CO2 leakage and finds that community compositions and important ecological functions are permanently altered under high CO2. PMID:29441359

  5. Radionuclides as tracer for submarine groundwater discharge (SGD) research at Dapeng Bay in Southern Taiwan (United States)

    Huang, Jun-Chen; Su, Chih-Chieh


    Conventionally, river is the most important source for delivering nutrients, such as nitrogen, phosphorus and silicon, and trace elements into the ocean. The issues of land-sea interaction by rivers have been long-tern concerned and studied, on contrary, the pathway and impact through submarine groundwater discharge (SGD) is still unclear and the relevant researches need to be strengthened. The research site, Dapeng Bay, is located at Pingtung County in Southern Taiwan. Dapeng Bay is an bag-shape lagoon with a sand spit serving as the single outlet of the bay. The longshore currents transport sediments which delivered by Donggang and Linbian Rivers deposited at the nearshore and eventually form the semi-enclosed shallow bay. In the Dapeng Bay, there is no river poured into the lagoon and the main sources of freshwater are rainwater, domestic wastewater and fish ponds etc. The tidal driven water exchange between lagoon and ocean is through the sand spit outlet. The purpose of this study is to evaluate the weighting and seasonal change between SGD and riverine input in the Dapeng Bay. The radium isotopes, 223Ra (11.4d), 224Ra (3.7d), 226Ra (1600y), 228Ra (5.7y), were used as tracers for assessing SGD and riverine inputs. Samples were collected by using MnO2-coated fibers for radium isotopes adsorption.

  6. Temperature as a tracer of hydrological dynamics in an anchialine cave system with a submarine spring (United States)

    Domínguez-Villar, David; Cukrov, Neven; Krklec, Kristina


    Although temperature is a nonconservative tracer, it often provides useful information to understand hydrological processes. This study explores the potential of temperature to characterize the hydrological dynamics of a submarine spring and its coastal karst aquifer in Krka Estuary (Croatia). The estuary is well stratified and its water column has a clear thermocline. A network of loggers was designed to monitor the temperature along vertical profiles in the estuary and the coastal aquifer, taking advantage of an anchialine cave that enabled access to the subterranean estuary. The location of the thermocline in the groundwater, which defines the upper boundary of the saline intrusion, depends on (1) the recharge of the aquifer via infiltration of precipitation, (2) the evolution of the thermocline in the estuary, and (3) the tidal oscillations. The sources of water flowing though the anchialine cave were identified: brackish water from the estuary above the thermocline, saline water from the estuary below the thermocline, and freshwater from infiltrated precipitation. A conceptual model is described that characterizes the hydrological dynamics of this coastal aquifer and its interactions with the estuary. Thus, at least for some hydrological settings, temperature is a valid tracer to characterize the main hydrological processes. The measurement of temperature is inexpensive compared to other (conservative) tracers. Therefore, for those hydrological settings that have water masses with distinct temperatures, the use of temperature as a tracer to establish conceptual models of the hydrological dynamics is encouraged.

  7. Green tide development associated with submarine groundwater discharge in a coastal harbor, Jeju, Korea. (United States)

    Kwon, Hyeong Kyu; Kang, Hyekyung; Oh, Yong Hwa; Park, Sang Rul; Kim, Guebuem


    We measured the magnitude of submarine fresh groundwater discharge (SFGD) and associated nutrient inputs to Jocheon harbor, on Jeju Island, Korea, during four sampling periods, in order to determine the link between SFGD and Ulva sp. green tide development. Good correlations among salinity, 222Rn, and dissolved inorganic nitrogen (DIN) in harbor seawater suggest that SFGD is the major source of DIN and fresh water since there are no surface runoffs. Using a 222Rn mass balance model, SFGD to the harbor was estimated to be 5.8 ± 2.3 × 104 m3 d-1. The DIN inputs through SFGD enhanced DIN concentrations in harbor seawater approximately 10-fold of those in the open-ocean (outer harbor) seawater. Results from mesocosm experiments showed that the growth rate of U. pertusa increased by 160% on average due to the enhanced DIN concentrations (from 1 to 24 µM) through SFGD in this harbor. Thus, we conclude that DIN inputs through SFGD cause the green tide development in Jocheon harbor and perhaps in other green tide regions where river inputs are absent.

  8. Mixing and phytoplankton dynamics in a submarine canyon in the West Antarctic Peninsula (United States)

    Carvalho, Filipa; Kohut, Josh; Oliver, Matthew J.; Sherrell, Robert M.; Schofield, Oscar


    Bathymetric depressions (canyons) exist along the West Antarctic Peninsula shelf and have been linked with increased phytoplankton biomass and sustained penguin colonies. However, the physical mechanisms driving this enhanced biomass are not well understood. Using a Slocum glider data set with over 25,000 water column profiles, we evaluate the relationship between mixed layer depth (MLD, estimated using the depth of maximum buoyancy frequency) and phytoplankton vertical distribution. We use the glider deployments in the Palmer Deep region to examine seasonal and across canyon variability. Throughout the season, the ML becomes warmer and saltier, as a result of vertical mixing and advection. Shallow ML and increased stratification due to sea ice melt are linked to higher chlorophyll concentrations. Deeper mixed layers, resulting from increased wind forcing, show decreased chlorophyll, suggesting the importance of light in regulating phytoplankton productivity. Spatial variations were found in the canyon head region where local physical water column properties were associated with different biological responses, reinforcing the importance of local canyon circulation in regulating phytoplankton distribution in the region. While the mechanism initially hypothesized to produce the observed increases in phytoplankton over the canyons was the intrusion of warm, nutrient enriched modified Upper Circumpolar Deep Water (mUCDW), our analysis suggests that ML dynamics are key to increased primary production over submarine canyons in the WAP.

  9. Quantifying submarine groundwater discharge in the coastal zone via multiple methods. (United States)

    Burnett, W C; Aggarwal, P K; Aureli, A; Bokuniewicz, H; Cable, J E; Charette, M A; Kontar, E; Krupa, S; Kulkarni, K M; Loveless, A; Moore, W S; Oberdorfer, J A; Oliveira, J; Ozyurt, N; Povinec, P; Privitera, A M G; Rajar, R; Ramessur, R T; Scholten, J; Stieglitz, T; Taniguchi, M; Turner, J V


    Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. As such, this flow may contribute to the biogeochemical and other marine budgets of near-shore waters. These discharges typically display significant spatial and temporal variability making assessments difficult. Groundwater seepage is patchy, diffuse, temporally variable, and may involve multiple aquifers. Thus, the measurement of its magnitude and associated chemical fluxes is a challenging enterprise. A joint project of UNESCO and the International Atomic Energy Agency (IAEA) has examined several methods of SGD assessment and carried out a series of five intercomparison experiments in different hydrogeologic environments (coastal plain, karst, glacial till, fractured crystalline rock, and volcanic terrains). This report reviews the scientific and management significance of SGD, measurement approaches, and the results of the intercomparison experiments. We conclude that while the process is essentially ubiquitous in coastal areas, the assessment of its magnitude at any one location is subject to enough variability that measurements should be made by a variety of techniques and over large enough spatial and temporal scales to capture the majority of these changing conditions. We feel that all the measurement techniques described here are valid although they each have their own advantages and disadvantages. It is recommended that multiple approaches be applied whenever possible. In addition, a continuing effort is required in order to capture long-period tidal fluctuations, storm effects, and seasonal variations.

  10. Searching for structural medium changes during the 2011 El Hierro (Spain) submarine eruption (United States)

    Sánchez-Pastor, Pilar S.; Schimmel, Martin; López, Carmen


    Submarine volcanic eruptions are often difficult to study due to their restricted access that usually inhibits direct observations. That happened with the 2011 El Hierro eruption, which is the first eruption that has been tracked in real time in Canary Islands. For instance, despite the real-time tracking it was not possible to determine the exact end of the eruption. Besides, volcanic eruptions involve many dynamic (physical and chemical) processes, which cause structural changes in the surrounding medium that we expect to observe and monitor through passive seismic approaches. The purpose of this study is to detect and analyse these changes as well as to search for precursory signals to the eruption itself using ambient noise auto and cross-correlations. We employ different correlation strategies (classical and phase cross-correlation) and apply them to field data recorded by the IGN network during 2011 and 2012. The different preprocessing and processing steps are tested and compared to better understand the data, to find the robust signatures, and to define a routine work procedure. One of the problems we face is the presence of volcanic tremors, which cause a varying seismic response that we can not attribute to structural changes. So far, structural changes could not be detected unambiguously and we present our ongoing research in this field.

  11. Newly recognized turbidity current structure can explain prolonged flushing of submarine canyons. (United States)

    Azpiroz-Zabala, Maria; Cartigny, Matthieu J B; Talling, Peter J; Parsons, Daniel R; Sumner, Esther J; Clare, Michael A; Simmons, Stephen M; Cooper, Cortis; Pope, Ed L


    Seabed-hugging flows called turbidity currents are the volumetrically most important process transporting sediment across our planet and form its largest sediment accumulations. We seek to understand the internal structure and behavior of turbidity currents by reanalyzing the most detailed direct measurements yet of velocities and densities within oceanic turbidity currents, obtained from weeklong flows in the Congo Canyon. We provide a new model for turbidity current structure that can explain why these are far more prolonged than all previously monitored oceanic turbidity currents, which lasted for only hours or minutes at other locations. The observed Congo Canyon flows consist of a short-lived zone of fast and dense fluid at their front, which outruns the slower moving body of the flow. We propose that the sustained duration of these turbidity currents results from flow stretching and that this stretching is characteristic of mud-rich turbidity current systems. The lack of stretching in previously monitored flows is attributed to coarser sediment that settles out from the body more rapidly. These prolonged seafloor flows rival the discharge of the Congo River and carry ~2% of the terrestrial organic carbon buried globally in the oceans each year through a single submarine canyon. Thus, this new structure explains sustained flushing of globally important amounts of sediment, organic carbon, nutrients, and fresh water into the deep ocean.

  12. Submarine canyons as coral and sponge habitat on the eastern Bering Sea slope

    Directory of Open Access Journals (Sweden)

    Robert J. Miller


    Full Text Available Submarine canyons have been shown to positively influence pelagic and benthic biodiversity and ecosystem function. In the eastern Bering Sea, several immense canyons lie under the highly productive “green belt” along the continental slope. Two of these, Pribilof and Zhemchug canyons, are the focus of current conservation interest. We used a maximum entropy modeling approach to evaluate the importance of these two canyons, as well as canyons in general, as habitat for gorgonian (alcyonacean corals, pennatulacean corals, and sponges, in an area comprising most of the eastern Bering Sea slope and outer shelf. These invertebrates create physical structure that is a preferred habitat for many mobile species, including commercially important fish and invertebrates. We show that Pribilof canyon is a hotspot of structure-forming invertebrate habitat, containing over 50% of estimated high-quality gorgonian habitat and 45% of sponge habitat, despite making up only 1.7% of the total study area. The amount of quality habitat for gorgonians and sponges varied in other canyons, but canyons overall contained more high-quality habitat for structure-forming invertebrates compared to other slope areas. Bottom trawling effort was not well correlated with habitat quality for structure-forming invertebrates, and bottom-contact fishing effort in general, including longlining and trawling, was not particularly concentrated in the canyons examined. These results suggest that if conserving gorgonian coral habitat is a management goal, canyons, particularly Pribilof Canyon, may be a prime location to do this without excessive impact on fisheries.

  13. Epibiotic relationships on Zygochlamys patagonica (Mollusca, Bivalvia, Pectinidae) increase biodiversity in a submarine canyon in Argentina (United States)

    Schejter, Laura; López Gappa, Juan; Bremec, Claudia Silvia


    The continental slope of the southern SW Atlantic Ocean has many distinguishable deep submarine canyons, varying in depth and extension. The benthic fauna within one of them, detected in April 2005 by means of a multibeam SIMRAD EM1002 sonar, and located at 43°35‧S to 59°33‧W, 325 m depth, was studied to discuss faunal affinities with the neighbouring Patagonian scallop fishing grounds located at upper slope depths. In order to add faunal information to the previous general study, we studied the epibiotic species settled on Patagonian scallops (the dominant species in the area) collected in the reference sampling site using a 2.5-m mouth-opening dredge, 10 mm mesh size. We sampled 103 scallops with shell heights between 22 and 69 mm; epibionts were recorded on both valves. We found 53 epibiotic taxa, which were most conspicuous on the upper valve. Bryozoa was the most diverse group (34 species) while Polychaeta was the most abundant group, recorded on 94% of the scallops. Stylasteridae (2 species) and Clavulariidae (Cnidaria) conform newly recorded epibionts on Z. patagonica and the sponge Tedania (Tedaniopsis) infundibuliformis also represents a new record for the SW Atlantic Ocean.

  14. Radium tracing nutrient inputs through submarine groundwater discharge in the global ocean. (United States)

    Cho, Hyung-Mi; Kim, Guebuem; Kwon, Eun Young; Moosdorf, Nils; Garcia-Orellana, Jordi; Santos, Isaac R


    Riverine and atmospheric inputs are often considered as the main terrestrial sources of dissolved inorganic nitrogen (DIN), phosphorus (DIP), and silicon (DSi) in the ocean. However, the fluxes of nutrients via submarine groundwater discharge (SGD) often exceed riverine inputs in different local and regional scale settings. In this study, we provide a first approximation of global nutrient fluxes to the ocean via total SGD, including pore water fluxes, by combining a global compilation of nutrient concentrations in groundwater and the SGD-derived 228 Ra fluxes. In order to avoid overestimations in calculating SGD-derived nutrient fluxes, the endmember value of nutrients in global groundwater was chosen from saline groundwater samples (salinity >10) which showed relatively lower values over all regions. The results show that the total SGD-derived fluxes of DIN, DIP, and DSi could be approximately 1.4-, 1.6-, and 0.7-fold of the river fluxes to the global ocean (Indo-Pacific and Atlantic Oceans), respectively. Although significant portions of these SGD-derived nutrient fluxes are thought to be recycled within sediment-aquifer systems over various timescales, SGD-derived nutrient fluxes should be included in the global ocean budget in order to better understand dynamic interactions at the land-ocean interface.

  15. Submarine landslides of San Pedro Escarpment, southwest of Long Beach, California (United States)

    Bohannon, R.G.; Gardner, J.V.


    The coastal infrastructure of the southern greater Los Angeles metropolitan area would be profoundly affected by a large tsunami. Submarine slope failures and active faults, either of which could have generated a tsunami, are known on the shelf and slope near Long Beach. Large slope failures are present on the San Pedro Escarpment and on the basin slope adjacent to the San Pedro shelf. The southeastern part of the escarpment has had a long history of slope failure. The most recent failure, the Palos Verdes slide, is over 4.5 km long, has been dated as 7500 years old, and involved over 0.34 km 3 of material, which now litters the adjacent basin floor. Other, smaller, deposits from nearby failures are also present, as are buried wedges of debris that indicate slope failures have occurred locally throughout the Holocene and much of the late Pleistocene. Slope failures have occurred in response to continual Quaternary uplift of the Palos Verdes anticlinorium. The Palos Verdes slide could potentially have generated a failure-related tsunami with an amplitude in the range of 8-12 m because it apparently failed catastrophically, started in shallow water, evolved on low-drag bedding planes, had a long slide path, and involved high-strength lithified material. ?? 2003 Elsevier B.V. All rights reserved.

  16. The summer assemblage of large pelagic Crustacea in the Gully submarine canyon: Major patterns (United States)

    MacIsaac, K. G.; Kenchington, T. J.; Kenchington, E. L. R.; Best, M.


    We describe the trawl-vulnerable crustacean micronekton and macrozooplankton of the Gully, a large, shelf-incising submarine canyon off Nova Scotia, Canada, and a Marine Protected Area. Over 68 species of pelagic crustacea were collected with an International Young Gadoid Pelagic Trawl during three annual summer surveys at one fixed station in the canyon. Depths sampled ranged from the surface to the upper bathypelagic zone, concentrated in the upper 1250 m, with a maximum depth of 1500 m. The crustacean fauna was dominated by cold temperate species typical of mid- to higher-latitudes in the North Atlantic. Meganyctiphanes norvegica and Eusergestes arcticus were particularly dominant in terms of both observed biomass and abundance above 750 m depth. At least 17 species were new records for Canadian waters. The species assemblage of the station varied primarily with depth and diel cycle, the only dominant members of the assemblage showing pronounced inter-annual variations in catch being M. norvegica and Themisto gaudichaudii, both relatively shallow living species.

  17. On the geotechnical characterisation of the polluted submarine sediments from Taranto. (United States)

    Vitone, Claudia; Federico, Antonio; Puzrin, Alexander M; Ploetze, Michael; Carrassi, Elettra; Todaro, Francesco


    This paper reports the results of the first geomechanical laboratory experiments carried out on the polluted submarine clayey sediments of the Mar Piccolo in Taranto (South of Italy). The study had to face with extreme difficulties for the very soft consistency of the sediments and the contaminants. The mineralogy, composition and physical properties of the sediments were analysed, along with their compression and shearing behaviour. The investigation involved sediments up to about 20 m below the seafloor, along three vertical profiles in the most polluted area of the Mar Piccolo, facing the Italian Navy Arsenal. The experimental results were used to derive a preliminary geotechnical model of the site, necessary for the selection and design of the most sustainable in situ mitigation solutions. Moreover, the experimental data reveal that the clayey sediments of the most polluted top layer do not follow the classical geotechnical correlations for normally consolidated deposits. This seems to open interesting perspectives about the effects of pollutants on the geotechnical behaviour of the investigated sediments.

  18. Effective transport of event sediments from shelf to deep-sea through submarine canyon: Examples from the Japan and Ryukyu trench forearc (United States)

    Ikehara, K.; Kanamatsu, T.; Usami, K.


    Large earthquakes and their related tsunamis resuspend and remobilize unconsolidated shallow marine sediments. Some of the resuspended grains form the dense water masses, and move downslope-ward gravitationally. Confined bathymetry of submarine canyon may play an important role on maintaining their density, and protecting dispersion and dilution of their bodies, and further leading the long-distance transport of the sediment grains from shelf to deep-sea. The 2011 Tohoku-oki earthquake and tsunami made erosion and resuspension of shelf sediments at the wide areas along the Tohoku coast. Although generation of tsunami-induced turbidity currents was reported, there are only a few examples of the shelf sediment transport to deep-sea. Weak development of submarine canyons at the upper slope may explain this phenomena. On the other hand, many turbidites were observed in the sediment cores collected from a submarine fan at a forearc basin along the southern Ryukyu Trench. A lot of bioclastic (carbonate) coarse grains of shallow marine origin composed the turbidites. Deep incision of submarine canyons along the upper forearc slope may contribute the effective transport of coarse bioclasts from shelf to deep-sea in this area. No or few submarine canyon connecting the shelf with the trench floor makes the different source of the trench fill deposits at both trenchs.

  19. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia over a 6-year period.

    Directory of Open Access Journals (Sweden)

    Anne ePostec


    Full Text Available Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phyotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field. Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta- and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.

  20. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia) over a 6-year period. (United States)

    Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël


    Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.

  1. Source characterization and tsunami modeling of submarine landslides along the Yucatán Shelf/Campeche Escarpment, southern Gulf of Mexico (United States)

    Chaytor, Jason D.; Geist, Eric L.; Paull, Charles K.; Caress, David W; Gwiazda, Roberto; Urrutia Fucugauchi, Jaime; Rebolledo Vieyra, Mario


    Submarine landslides occurring along the margins of the Gulf of Mexico (GOM) represent a low-likelihood, but potentially damaging source of tsunamis. New multibeam bathymetry coverage reveals that mass wasting is pervasive along the Yucatán Shelf edge with several large composite landslides possibly removing as much as 70 km3 of the Cenozoic sedimentary section in a single event. Using GIS-based analysis, the dimensions of six landslides from the central and northern sections of the Yucatán Shelf/Campeche Escarpment were determined and used as input for preliminary tsunami generation and propagation models. Tsunami modeling is performed to compare the propagation characteristics and distribution of maximum amplitudes throughout the GOM among the different landslide scenarios. Various factors such as landslide geometry, location along the Yucatán Shelf/Campeche Escarpment, and refraction during propagation result in significant variations in the affected part of the Mexican and US Gulf Coasts. In all cases, however, tsunami amplitudes are greatest along the northern Yucatán Peninsula.

  2. Submarine slope earthquake-induced instability and associated tsunami generation potential along the Hyblean-Malta Escarpment (offshore eastern Sicily, Italy) (United States)

    Ausilia Paparo, Maria; Pagnoni, Gianluca; Zaniboni, Filippo; Tinti, Stefano


    The stability analysis of offshore margins is an important step for the assessment of natural hazard: the main challenge is to evaluate the potential slope failures and the consequent occurrence of submarine tsunamigenic landslides to mitigate the potential coastal damage to inhabitants and infrastructures. But the limited geotechnical knowledge of the underwater soil and the controversial scientific interpretation of the tectonic units make it often difficult to carry out this type of analysis reliably. We select the Hyblean-Malta Escarpment (HME), the main active geological structure offshore eastern Sicily, because the amount of data from historical chronicles, the records about strong earthquakes and tsunami, and the numerous geological offshore surveys carried out in recent years make the region an excellent scenario to evaluate slope failures, mass movements triggered by earthquakes and the consequent tsunamis. We choose several profiles along the HME and analyse their equilibrium conditions using the Minimun Lithostatic Deviation (MLD) method (Tinti and Manucci, 2006, 2008; Paparo et al. 2013), that is based on the limit-equilibrium theory. Considering the morphological and geotechnical features of the offshore slopes, we prove that large-earthquake shaking may lead some zones of the HME to instability, we evaluate the expected volumes involved in sliding and compute the associated landslide-tsunami through numerical tsunami simulations. This work was carried out in the frame of the EU Project called ASTARTE - Assessment, STrategy And Risk Reduction for Tsunamis in Europe (Grant 603839, 7th FP, ENV.2013.6.4-3).

  3. Submarine groundwater discharge estimation in an urbanized embayment in Hong Kong via short-lived radium isotopes and its implication of nutrient loadings and primary production. (United States)

    Luo, Xin; Jiao, Jiu Jimmy; Moore, W S; Lee, Chun Ming


    (224)Ra and (223)Ra are adopted as tracers to qualify submarine groundwater discharge (SGD) in Tolo Harbor, a highly urbanized embayment in Hong Kong. Based on the sampling data, a two-layered radium mass balance model is used to estimate lateral SGD and bottom SGD. Total SGD is estimated to be 1.2-3.0 cm d(-1), including lateral SGD of 5.7-7.9 cm d(-1) and bottom SGD of 0.3-2.0 cm d(-1). Fresh SGD is estimated to be (2.1-5.5) × 10(5)m(3)d(-1). Nutrient fluxes (mold(-1)) from SGD are estimated to be (3-7.4) × 10(4) (dissolved inorganic nitrogen), (2.4-6.2) × 10(2) (dissolved inorganic phosphate) and (6.5-16) × 10(4) (dissolved silicate). Primary productivity is estimated to be (1.5-15) × 10(6)gCd(-1), 2-53% of which is supported by SGD-induced phosphate fluxes. The study indicates that SGD is a significant source of nutrients to coastal waters and may cause an obvious increase of primary production. These findings must be considered in future coastal ecological management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Transport and bottom accumulation of fine river sediments under typhoon conditions and associated submarine landslides: case study of the Peinan River, Taiwan (United States)

    Osadchiev, Alexander; Korotenko, Konstantin; Zavialov, Peter; Chiang, Wen-Son; Liu, Cheng-Chi


    A combination of a three-dimensional Eulerian ocean circulation model (POM) and a Lagrangian particle-tracking model (STRiPE) is used to study the fate of fine river sediments discharged by the Peinan River at the south-eastern coast of the Taiwan Island. The composite model is verified against in situ measurements and applied to simulate primary sediment deposition under freshet and typhoon discharge conditions of the Peinan River. It is shown that local wind plays a crucial role in sediment transport and settling at the coastal area through its influence on the river plume dynamics and turbulent mixing in the upper layer. Wind forcing conditions generally determine the location of the sediment deposit area, while its final pattern is defined by coastal circulation as modulated by the geometry of the coast and local bathymetry. In the study, region river-born sediments are deposited to the sea floor mainly in the shallow shelf areas. A significant portion of discharged fine sediments is moved offshore to the deeper ocean where it is further advected and dispersed by strong coastal circulation mainly governed by the Kuroshio Current. The performed numerical experiments showed that sediment accumulation rate under typhoon conditions is about two orders of magnitude greater comparing to freshet condition. Basing on the simulation results, we identified areas of continental shelf and continental slope adjacent to the Peinan River estuary which exhibit high risk of formation of submarine landslides during and shortly after the typhoon events.

  5. Total mercury flux and offshore transport via submarine groundwater discharge and coal-fired power plant in the Jiulong River estuary, China. (United States)

    Wang, Jigang; Liu, Qian; Chen, Jinmin; Chen, Hongzhe; Lin, Hui; Sun, Xiuwu


    A mass balance of total mercury (Hg T , dissolved+particulate) is constructed for China's Jiulong River estuary based on measured Hg T concentrations in the surface water, sediment, porewater, and groundwater for May, August, and November 2009, combined with data from the literature. The Hg T mass budget results show that the dominant source (39-55%) is desulfurized seawater discharged from the Songyu coal-fired power plant. Submarine groundwater discharge (SGD)-derived Hg T flux into the estuary is equivalent to 8-58% of the Hg T input from the Jiulong River, which is remarkable when compared with SGD-derived Hg T fluxes reported in coastal systems worldwide. Hence, SGD is a significant pathway for the transport of Hg T into the Jiulong River estuary. The primary Hg T sinks is export to the Taiwan Strait (53-88%), which has important environmental implications on the Hg cycling and marine ecosystems in marginal seas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Multiple sensor tracking of submarine groundwater discharge: concept study along the Dead Sea. (United States)

    Siebert, Christian; Mallast, Ulf; Rödiger, Tino; Ionescu, Danny; Schwonke, Friedhelm; Hall, John K.; Sade, Aharon R.; Pohl, Thomas; Merkel, Broder


    As a result of the continuously declining water level of the Dead Sea, vast areas of its former lakebed are exposed. That unconsolidated sequence of clay minerals and evaporates (e.g. aragonite, gypsum, halite) generally reacts as aquiclude - preventing direct drainage of the surrounding mountain freshwater aquifers. The high density differences between the hypersaline Dead Sea (1.24 g/cm3) and the approaching fresh water generates a flat dipping and stable Ghyben-Herzberg interface. However, a network of open fissures and cracks enables these freshwaters to regionally penetrate both, aquiclude and interface and to finally enter the Dead Sea on- and offshore. These offshore springs, also termed sublake groundwater discharge (SGD), are neither qualitatively nor quantitatively analysed yet. This is the reason why it is one of the most doubtful variables in existing balances of the lake's water budget and strongly requires improvement. To disclose pathways from the feeding mountain aquifers to the springs, intense hydrochemical and microbial investigations were carried out both, onshore and submarine. The waters have their origin in a variety of hard rock aquifers of Cretaceous age. After draining into the Dead Sea sediments, waters carry the easily soluble components (gypsum, halite) and the abundant organic matter, erodes and transports the hardly soluble minerals (clay and aragonite) and admix with briny pore water, respectively, which are all hosted in the sediment body. Diving campaigns allowed to map at least parts of the submarine spring cluster and to correlate their locations with neo-tectonic patterns. However, comprehensive mapping solely by divers is unfeasible due to the complexity and density of spring locations. The subsurface morphology is characterised by craters, walls, gullies and cones, occasionally nested and intensely anastomosed. To comprehensively understand reasons for specific discharge locations and their shapes, high-precision and high

  7. Possibility of submarine landslide triggering due to dissociation of hydrates - an approach through ring shear tests (United States)

    Fukuoka, Hiroshi; Dok, Atitkagna


    In Japan, the MH21 Research Consortium is developing the advanced technology of mining submarine methane hydrates by reducing pressure of hydrates to induce dissociation and gasification of hydrates. However, assessment and prediction technology of dissociation is still under development through intensive study. On the other hands, authors have pointed out the possibility of large-scale submarine landslides by the sliding surface liquefaction of the hydrate bearing- layers. Author has tested dry-ice and silica-sands mixture specimen as a methane hydrate substitutes in a series of partially-drained high speed / stress-controlled ring shear tests. Their results strongly suggest the possibility of sliding surface liquefaction under strong seismic condition, while the possibility of extensive dissociation especially under mining by reducing pressure is not clear. Author modified the ring shear apparatus DPRI-7 of Kyoto University so that it can cool down the specimen and measure the specimen temperature during shearing. Silica sands #7 submerged in TBAB (Tetra-butyl-ammonium bromide) solution was used for the specimen. This TBAB solution was frozen at around room temperature of 8 - 12 degrees Celsius under 1 atmospheric pressure. A series of constant speed shearing test was conducted to examine the rate-effect. Frictional characteristics was achieved under 0.1 - 10 cm/s of shear speed which was changed in stepping-up and down. The results show rather the temperature effect was obvious than the speed. At the first shearing of the specimen immediately after frozen, extreme high peak stress was obtained. Then the residual shear strength showed medium peak at temperature of about 4 degrees, then gradually decreased up to about 10 degrees. The medium peak of shear strength may come from the generation of angular grains due to crushing the specimen during initial shearing. The decreasing thereafter may have resulted from further crushing, rounding of the hydrates and

  8. Investigation of Submarine Groundwater Discharge along the Tidal Reach of the Caloosahatchee River, Southwest Florida (United States)

    Reich, Christopher D.


    The tidal reach of the Caloosahatchee River is an estuarine habitat that supports a diverse assemblage of biota including aquatic vegetation, shellfish, and finfish. The system has been highly modified by anthropogenic activity over the last 150 years (South Florida Water Management District (SFWMD), 2009). For example, the river was channelized and connected to Lake Okeechobee in 1881 (via canal C-43). Subsequently, three control structures (spillway and locks) were installed for flood protection (S-77 and S-78 in the 1930s) and for saltwater-intrusion prevention (S-79, W.P. Franklin Lock and Dam in 1966). The emplacement of these structures and their impact to natural water flow have been blamed for water-quality problems downstream within the estuary (Flaig and Capece, 1998; SFWMD, 2009). Doering and Chamberlain (1999) found that the operation of these control structures caused large and often rapid variations in salinity during various times of the year. Variable salinities could have deleterious impacts on the health of organisms in the Caloosahatchee River estuary. Flow restriction along the Caloosahatchee has also been linked to surface-water eutrophication problems (Doering and Chamberlain, 1999; SFWMD, 2009) and bottom-sediment contamination (Fernandez and others, 1999). Sources of nutrients (nitrogen and phosphorous) that cause eutrophication are primarily from residential sources and agriculture, though wastewater-treatment-plant discharges can also play a major role (SFWMD, 2009). The pathway for many of these nutrients is by land runoff and direct discharge from stormwater drains. An often overlooked source of nutrients and other chemical constituents is from submarine groundwater discharge (SGD). SGD can be either a diffuse or point source (for example, submarine springs) of nutrients and other chemical constituents to coastal waters (Valiela and others, 1990; Swarzenski and others, 2001; 2006; 2007; 2008). SGD can be composed of either fresh or

  9. Installation of XLPE-Insulated 400 kV Submarine AC Power Cables under the Dardanelles Strait: A 4 GW Turkish Grid Reinforcement

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    Roberto Benato


    Full Text Available This paper describes the 400 kV AC submarine link under the Dardanelles Strait composed of 12 submarine armoured single-core cross-linked polyethylene (XLPE-insulated cables (plus a back-up power cable. The link consists of two parallel-operated double-circuit links named Lâpseki–Sütlüce I and Lâpseki–Sütlüce II. The transmissible power is 4000 MW (1000 MW per circuit and the average length for a single-core cable is about 4.6 km: the submarine cables are part of overhead lines. This paper gives a wide account of the cable installations and, chiefly, of the cable protections on the seabed: different protection choices were extensively used (i.e., water jetting and mattressing.

  10. Transient changes in bacterioplankton communities induced by the submarine volcanic eruption of El Hierro (Canary Islands). (United States)

    Ferrera, Isabel; Arístegui, Javier; González, José M; Montero, María F; Fraile-Nuez, Eugenio; Gasol, Josep M


    The submarine volcanic eruption occurring near El Hierro (Canary Islands) in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1-V3 regions for Bacteria and V3-V5 for Archaea) to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012). Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells) of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70-200 m), coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index) decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria). Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer observed.

  11. Segmentation and tracking of anticyclonic eddies during a submarine volcanic eruption using ocean colour imagery. (United States)

    Marcello, Javier; Eugenio, Francisco; Estrada-Allis, Sheila; Sangrà, Pablo


    The eruptive phase of a submarine volcano located 2 km away from the southern coast of El Hierro Island started on October 2011. This extraordinary event provoked a dramatic perturbation of the water column. In order to understand and quantify the environmental impacts caused, a regular multidisciplinary monitoring was carried out using remote sensing sensors. In this context, we performed the systematic processing of every MODIS and MERIS and selected high resolution Worldview-2 imagery to provide information on the concentration of a number of biological, physical and chemical parameters. On the other hand, the eruption provided an exceptional source of tracer that allowed the study a variety of oceanographic structures. Specifically, the Canary Islands belong to a very active zone of long-lived eddies. Such structures are usually monitored using sea level anomaly fields. However these products have coarse spatial resolution and they are not suitable to perform submesoscale studies. Thanks to the volcanic tracer, detailed studies were undertaken with ocean colour imagery allowing, using the diffuse attenuation coefficient, to monitor the process of filamentation and axisymmetrization predicted by theoretical studies and numerical modelling. In our work, a novel 2-step segmentation methodology has been developed. The approach incorporates different segmentation algorithms and region growing techniques. In particular, the first step obtains an initial eddy segmentation using thresholding or clustering methods and, next, the fine detail is achieved by the iterative identification of the points to grow and the subsequent application of watershed or thresholding strategies. The methodology has demonstrated an excellent performance and robustness and it has proven to properly capture the eddy and its filaments.

  12. Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon

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    W. R. Hunter


    Full Text Available The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii and nitrogen-poor terrigenous (Triticum aestivum phytodetritus. 13C and 15N labels were traced into faunal biomass and bulk sediments, and the 13C label traced into bacterial polar lipid fatty acids (PLFAs. Isotopic labels penetrated to 5 cm sediment depth, with no differences between stations or experimental treatments (substrate or time. Macrofaunal assemblage structure differed between the eastern and western canyon branches. Following deposition of marine phytodetritus, no changes in macrofaunal feeding activity were observed between the eastern and western branches, with little change between 3 and 7 days. Macrofaunal C and N uptake was substantially lower following deposition of terrigenous phytodetritus with feeding activity governed by a strong N demand. Bacterial C uptake was greatest in the western branch of the Whittard Canyon, but feeding activity decreased between 3 and 7 days. Bacterial processing of marine and terrigenous OM were similar to the macrofauna in surficial (0–1 cm sediments. However, in deeper sediments bacteria utilised greater proportions of terrigenous OM. Bacterial biomass decreased following phytodetritus deposition and was negatively correlated to macrofaunal feeding activity. Consequently, this study suggests that macrofaunal–bacterial interactions influence benthic C cycling in the Whittard Canyon, resulting in differential fates for marine and terrigenous OM.


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    Haryadi Permana


    Full Text Available The new bathymetry and seismic data were acquired during the PreTI-Gap marine survey (February 15 to March 6, 2008. The survey was carried out along the NE margin of Mentawai Island using multi-beam swath bathymetry equipment, and 28-channels seismic streamer and four-airgun source. The first target was the Mega Island region near the epicenter of the 2007 great earthquake. The shallow bathymetry is characterized as a flat coral platform suggesting that 200 km elongated plateau is slowly subsiding without any active faults. Further north, from South Pagai to North of Siberut Islands, the seafloor morphology changes significantly. The deep and wide canyons or valleys produce very rough seafloor morphology between 50 and 1100 m water depth. In general, the submarine topography shows two break slopes at different depths. Between slope breaks, the undulating, hilly and circular features dominate, possibly caused by mass movement. A push-up ridge is observed that dams the sediments eroded within a steep slope northeastward side. The seismic reflection data acquired along 14 dip seismic lines at the NE flank of Mentawai Islands, from Siberut to the South of Pagai Islands. We observed a set of southwestward dipping back thrust bounding the NE margin of the Mentawai Island and the push-up ridge observed on bathymetric image, which suggest that Mentawai fault is not pure a strike slip fault, but consists of a set of back thrusts. Such kind of back thrust movement at the flank of Mentawai basin can trigger mass movement or landslide that can produce localized tsunami causing damages to Sumatera mainland such as Padang, Painan or northern Bengkulu provinces and Mentawai Islands. Therefore, it is important to re-design the tsunami warning system, especially in this region, in order to mitigate tsunami risk to coastal region of western Sumatera.

  14. New insights on the petrology of submarine volcanics from the Western Pontine Archipelago (Tyrrhenian Sea, Italy) (United States)

    Conte, A. M.; Perinelli, C.; Bianchini, G.; Natali, C.; Martorelli, E.; Chiocci, F. L.


    The Pontine Islands form a volcanic archipelago in the Tyrrhenian Sea. It consists of two edifices, the islands of Ponza, Palmarola and Zannone and the islands of Ventotene and Santo Stefano, respectively. The Archipelago developed during two main volcanic cycles in the Plio-Pleistocene: 1) the Pliocene episode erupted subalkaline, silica-rich volcanic units, which constitute the dominant products in the western edifice (Ponza and Zannone Islands); 2) the Pleistocene episode erupted more alkaline products, represented by evolved rocks (trachytes to peralkaline rhyolites) in the islands of Ponza and Palmarola and by basic to intermediate rocks in the eastern edifice (Ventotene and Santo Stefano Islands). In this paper we present new geochemical and petrological data from submarine rock samples collected in two oceanographic cruises and a scuba diving survey. The main result is the recovery of relatively undifferentiated lithotypes that provide further insights on the magmatic spectrum existing in the Pontine Archipelago, allowing modelling of the whole suite of rocks by fractional crystallization processes. New major and trace element data and thermodynamic constrains (by the software PELE) indicate the existence of three distinct evolutionary trends corresponding to a HK calcalkaline series in the Pliocene, followed by a transitional and then by a shoshonite series in the Pleistocene. In particular, the transitional series, so far overlooked in the literature, is required in order to explain the genesis of several peralkaline felsic rocks recognized in the Archipelago. On the whole, the new geochemical data i) confirm the orogenic signature of the suites, ii) allow to rule out an anatectic origin for both subalkaline and peralkaline rhyolites and iii) indicate highly heterogeneous mantle sources, due to crustal components variously recycled in the mantle via subduction.

  15. Transient changes in bacterioplankton communities induced by the submarine volcanic eruption of El Hierro (Canary Islands.

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    Isabel Ferrera

    Full Text Available The submarine volcanic eruption occurring near El Hierro (Canary Islands in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1-V3 regions for Bacteria and V3-V5 for Archaea to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012. Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70-200 m, coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria. Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer

  16. Quantification of submarine/intertidal groundwater discharge and nutrient loading from a lowland karst catchment (United States)

    McCormack, T.; Gill, L. W.; Naughton, O.; Johnston, P. M.


    Submarine groundwater discharge (SGD) is now recognised to be a process of significant importance to coastal systems and is of increasing interest within oceanographic and hydrologic research communities. However, due to the inherent difficulty of measuring SGD accurately, its quantification at any particular location is a relatively slow process often involving multiple labour intensive methods. In this paper, the SGD occurring at Kinvara Bay, the outlet of a lowland karst catchment in Western Ireland, is estimated using a hydrological model of the karst aquifer and then further verified by means of a relatively simple salinity survey. Discharge at Kinvara predominantly occurs via two springs, Kinvara West (KW) which serves as the outlet of a major, primarily allogenically fed, karst conduit network and Kinvara East (KE) which discharges water from more diffuse/autogenic sources. Discharge from these springs occurs intertidally and as such, their flow rates cannot be measured using traditional methods. Using the hydrological model, flow rates from KW were seen to vary between 5 and 16 m3/s with a mean value of 8.7 m3/s. Through hydrochemical analysis, this estimated discharge was found to be supplemented by an additional 14-18% via sources not accounted for by the model. Mean discharge at KE was also estimated as approximately 2 m3/s, thus the total mean discharge from both Kinvara Springs was determined to be 11.9-12.3 m3/s. Overall, the range of discharge was found to be lower than previous studies have estimated (as these studies had no means of quantifying attenuation within the conduit network). Combining this discharge with nutrient concentrations from the springs, the nutrient loading from the springs into the bay was estimated as 1230 kg/day N and 24.3 kg/day P. This research illustrates the benefits of a numerical modelling approach to the quantification of SGD when used in the appropriate hydrological scenario.

  17. A reflecting, steepening, and breaking internal tide in a submarine canyon (United States)

    Alberty, M. S.; Billheimer, S.; Hamann, M. M.; Ou, C. Y.; Tamsitt, V.; Lucas, A. J.; Alford, M. H.


    Submarine canyons are common features of the coastal ocean. Although they are known to be hotspots of turbulence that enhance diapycnal transport in their stratified waters, the dynamics of canyon mixing processes are poorly understood. Most studies of internal wave dynamics within canyons have focused on a handful of canyons with along-axis slopes less steep than semidiurnal (D2) internal wave characteristics (subcritical). Here, we present the first tidally resolving observations within a canyon with a steeply sloping axis (supercritical). A process study consisting of two 24 h shipboard stations and a profiling mooring was conducted in the La Jolla Canyon off the coast of La Jolla, CA. Baroclinic energy flux is oriented up-canyon and decreases from 182 ±18 W m-1 at the canyon mouth to 46±5 W m-1 near the head. The ratio of horizontal kinetic energy to available potential energy and the observed group speed of each mode are lower than expected for freely propagating D2 internal waves at each station, indicating partial reflection. Harmonic analysis reveals that variance is dominated by the D2 tide. Moving up-canyon, the relative importance of D2 decreases and its higher harmonics are needed to account for a majority of the observed variance, indicating steepening. Steep internal tides cause large isopycnal displacements (˜50 m in 100 m water depth) and high strain events. These events coincide with enhanced O(10-7-10-5 m2 s-3) dissipation of turbulent kinetic energy at mid-depths.

  18. Biological response to geochemical and hydrological processes in a shallow submarine cave

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    Full Text Available The Croatian coastal karst abounds in submerged caves that host a variety of environmental conditions depending on the geomorphology, depth and submarine groundwater discharge. One example is the Y-Cave, a shallow, mostly submerged, horizontal cave on Dugi Otok Island, on the eastern Adriatic coast. This study was aimed at examining the temporal and spatial variability of the marine cave environment, including temperature, salinity, light intensity, cave morphology and hydrodynamism, along with the dissolutional effect caused by the mixing of sea and freshwater. The general distribution of organisms in the Y-Cave was positively correlated to the light gradient and reduced water circulation, thus the highest species diversity and abundance were recorded in the front part of the cave. The phylum Porifera was the most dominant group, and the poriferan species diversity in the cave ranks among the ten highest in the Mediterranean. The middle part of the cave, although completely dark, hosts an abundant population of the gastropod Homalopoma sanguineum and clusters of the gregarious brachiopod Novocrania anomala, whose presence could be connected to tidal hydrodynamics. The absence/scarcity of sessile marine organisms and pronounced corrosion marks at shallow depths inside the cave suggest a freshwater impact in the upper layers of the water column. A year long experiment with carbonate tablets revealed three different, independent ongoing processes affected by the position in the cave: bioaccumulation, dissolution and mechanical erosion. The results of long-term temperature readings also revealed water column stratification within the cave, which was not disturbed by either tidal or wave action. The shallow, partly submerged and relatively small Y-Cave is characterised by a suite of complex environmental conditions, which, together with the resulting distribution of organisms, are unique to this cave.

  19. Effects of submarine power transmission cables on a glass sponge reef and associated megafaunal community. (United States)

    Dunham, A; Pegg, J R; Carolsfeld, W; Davies, S; Murfitt, I; Boutillier, J


    We examined the effects of submarine power transmission cable installation and operation on glass sponge reef condition and associated megafauna. Video and still imagery were collected using a Remotely Operated Vehicle twice a year for 4 years following cable installation. The effects of cables on glass sponges were assessed by comparing sponge cover along fixed transects and at marked index sites. Megafauna counts along transects were used to explore the effects on associated community. We found no evidence of cable movement across the sponge reef surface. Live sponge cover was found to be consistently lower along cable transects and at cable index sites compared to controls. Live sponge cover was the lowest (55 ± 1.1% decrease) at cable index sites 1.5 years after installation and recovered to 85 ± 30.6% of the original size over the following 2 years. Our data suggest 100% glass sponge mortality along the direct cable footprint and 15% mortality in the surrounding 1.5 m corridor 3.5 years after cable installation. Growth rate of a new glass sponge was 1 and 3 cm/year in first and second year, respectively, and appeared to be seasonal. We observed a diverse megafaunal community with representatives from 7 phyla and 14 classes. Total megafauna, spot prawn, and other Arthropoda abundances were slightly lower along cable transects although the effect of cable presence was not statistically significant. The following measures could be taken to reduce the amount of damage to glass sponge reefs and associated fauna: routing the cable around reefs, whenever possible, minimizing cable movement across the surface of the reef at installation and routine operation, and assessing potential damage to glass sponges prior to decommissioning. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  20. Atribacteria from the Subseafloor Sedimentary Biosphere Disperse to the Hydrosphere through Submarine Mud Volcanoes (United States)

    Hoshino, Tatsuhiko; Toki, Tomohiro; Ijiri, Akira; Morono, Yuki; Machiyama, Hideaki; Ashi, Juichiro; Okamura, Kei; Inagaki, Fumio


    Submarine mud volcanoes (SMVs) are formed by muddy sediments and breccias extruded to the seafloor from a source in the deep subseafloor and are characterized by the discharge of methane and other hydrocarbon gasses and deep-sourced fluids into the overlying seawater. Although SMVs act as a natural pipeline connecting the Earth’s surface and subsurface biospheres, the dispersal of deep-biosphere microorganisms and their ecological roles remain largely unknown. In this study, we investigated the microbial communities in sediment and overlying seawater at two SMVs located on the Ryukyu Trench off Tanegashima Island, southern Japan. The microbial communities in mud volcano sediments were generally distinct from those in the overlying seawaters and in the well-stratified Pacific margin sediments collected at the Peru Margin, the Juan de Fuca Ridge flank off Oregon, and offshore of Shimokita Peninsula, northeastern Japan. Nevertheless, in-depth analysis of different taxonomic groups at the sub-species level revealed that the taxon affiliated with Atribacteria, heterotrophic anaerobic bacteria that typically occur in organic-rich anoxic subseafloor sediments, were commonly found not only in SMV sediments but also in the overlying seawater. We designed a new oligonucleotide probe for detecting Atribacteria using the catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). CARD-FISH, digital PCR and sequencing analysis of 16S rRNA genes consistently showed that Atribacteria are abundant in the methane plumes of the two SMVs (0.58 and 1.5 × 104 cells/mL, respectively) but not in surrounding waters, suggesting that microbial cells in subseafloor sediments are dispersed as “deep-biosphere seeds” into the ocean. These findings may have important implications for the microbial transmigration between the deep subseafloor biosphere and the hydrosphere. PMID:28676800

  1. Submarine groundwater discharge from the South Australian Limestone Coast region estimated using radium and salinity. (United States)

    Lamontagne, S; Taylor, A R; Herpich, D; Hancock, G J


    The Tertiary Limestone Aquifer (TLA) is one of the major regional hydrogeological systems of southern Australia. Submarine groundwater discharge (SGD) of freshwater from the TLA occurs through spring creeks, beach springs and diffusively through beach sands, but the magnitude of the total flux is not known. Here, a range of potential environmental tracers (including temperature, salinity, (222)Rn, (223)Ra, (224)Ra, (226)Ra, (228)Ra, and (4)He) were measured in potential sources of SGD and in seawater along a 45 km transect off the coastline to evaluate SGD from the TLA. Whilst most tracers had a distinct signature in the sources of water to the coastline, salinity and the radium quartet had the most distinct SGD signal in seawater. A one-dimensional advection-dispersion model was used to estimate the terrestrial freshwater component of SGD (Qfw) using salinity and the recirculated seawater component (Qrsw) using radium activity in seawater. Qfw was estimated at 1.2-4.6 m(3) s(-1), similar in magnitude to previously measured spring creek discharge (∼3 m(3) s(-1)) for the area. This suggests that other terrestrial groundwater discharge processes (beach springs and diffuse discharge through beach sands) were no more than 50% of spring creek discharge. The largest component of total SGD was Qrsw, estimated at 500-1000 m(3) s(-1) and possibly greater. The potential for wave, storm, or buoyancy-driven porewater displacement from the seafloor could explain the large recirculation flux for this section of the Southern Ocean Continental Shelf. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  2. Macro- and megafauna recorded in the submarine Bari Canyon (southern Adriatic, Mediterranean Sea using different tools

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    Full Text Available Macro- and megafauna were recorded in the submarine Bari Canyon (southern Adriatic Sea, Mediterranean Sea during an oceanographic cruise carried out in May-June 2012 and an experimental fishing survey conducted in November 2013. During the former, a total of 20 benthic samples were taken using a Van Veen grab at depths between 268 and 770 m and 4 deployments of a baited lander, for about 43 hours of video records, were carried out at depths between 443 and 788 m. During the latter, 8 longline fishing operations were conducted from 338 down to 612 m. Eighty-five living benthic and benthopelagic species were recorded: 29 Porifera, 1 Cnidaria, 2 Mollusca, 11 Annelida, 1 Arthropoda, 19 Bryozoa, 3 Echinodermata and 19 Chordata. A total of 51 species are new records for the Bari Canyon, 29 new records for the Adriatic Sea. Among the Porifera Cerbaris curvispiculifer is a new addition for the Italian Sponge Fauna. The first certain record of living specimens for the bryozoan Crisia tenella longinodata is reported. A total of 6 Mediterranean endemic species have been identified: 4 Porifera and 2 Annelida. The bathymetric range of some species has been extended. New information acquired for deep sea species confirms their importance in the structure of cold-water coral communities. This study has updated the knowledge on the biodiversity of the Adriatic Sea, as well as of the Bari Canyon in particular, one of the sites designated as “jewels of the Mediterranean” for which urgent conservation measures are needed.

  3. Submarine landslide identified in DLW3102 core of the northern continental slope, South China Sea (United States)

    Xu, Yuanqin; Liu, Lejun; Zhou, Hang; Huang, Baoqi; Li, Ping; Ma, Xiudong; Dong, Feiyin


    In this paper, we take DLW3101 core obtained at the top of the canyon (no landslide area) and DLW3102 core obtained at the bottom of the canyon (landslide area) on the northern continental slope of the South China Sea as research objects. The chronostratigraphic framework of the DLW3101 core and elemental strata of the DLW3101 core and the DLW3102 core since MIS5 are established by analyzing oxygen isotope, calcium carbonate content, and X-Ray Fluorescence (XRF) scanning elements. On the basis of the information obtained by analyzing the sedimentary structure and chemical elements in the landslide deposition, we found that the DLW3102 core shows four layers of submarine landslides, and each landslide layer is characterized by high Si, K, Ti, and Fe contents, thereby indicating terrigenous clastic sources. L1 (2.15-2.44 m) occurred in MIS2, which is a slump sedimentary layer with a small sliding distance and scale. L2 (15.48-16.00 m) occurred in MIS5 and is a debris flow-deposited layer with a scale and sliding distance that are greater than those of L1. L3 (19.00-20.90 m) occurred in MIS5; its upper part (19.00-20.00 m) is a debris flow-deposited layer, and its lower part (20.00-20.90 m) is a sliding deposition layer. The landslide scale of L3 is large. L4 (22.93-24.27 m) occurred in MIS5; its upper part (22.93-23.50 m) is a turbid sedimentary layer, and its lower part (23.50-24.27 m) is a slump sedimentary layer. The landslide scale of L4 is large.

  4. Influence of submarine groundwater discharge on (210)Po and (210)Pb bioaccumulation in fish tissues. (United States)

    Garcia-Orellana, J; López-Castillo, E; Casacuberta, N; Rodellas, V; Masqué, P; Carmona-Catot, G; Vilarrasa, M; García-Berthou, E


    This study presents the results of the accumulation of (210)Po and (210)Pb in fish tissues and organs in a brackish-water marshland that is characterized by high concentrations of (222)Rn and (226)Ra supplied by submarine groundwater discharge (SGD). Tissues and organs from Cyprinus carpio, Chelon labrosus and Carassius auratus in the wetland were significantly enriched by both (210)Pb and (210)Po (up to 55 and 66 times, respectively) compared to blanks. The major input route of (210)Pb and (210)Po into the fish body seems to be through ingestion, due to the high levels of (210)Pb and (210)Po found in the gut content as well as in organs involved in digestion and metabolism (i.e. gut, kidney and hepatopancreas). Results showed that (210)Po was more accumulated in all fish tissues and organs except for the spine, which showed a higher affinity for (210)Pb, due to its capacity to replace Ca from apatite in bones. Over all the variables analyzed, fish tissues/organs and, secondarily, fish species were the most important factors explaining the concentration of radionuclides, whereas fish length and the sampling location played a minor role. The relationship of the two radionuclides varied markedly among tissues and their concentration levels were only correlated in gills, gut and, marginally, in spines. In general, the highest values of (210)Pb and (210)Po concentrations in tissues were found on C. labrosus tissues rather C. auratus and C. carpio. This study demonstrates that inputs of natural radionuclides supplied by SGD to coastal semi-enclosed areas (such as marshlands, lagoons or ponds) may significantly increase the contents of (210)Pb and (210)Po in fish tissues/organs. Thus, this study represents one of the first evidences of direct ecological effects derived from SGD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Influence of the Coriolis force on the velocity structure of gravity currents in straight submarine channel systems (United States)

    Cossu, R.; Wells, M. G.; WâHlin, A. K.


    Large-scale turbidity currents in submarine channels often show a significant asymmetry in the heights of their levee banks. In the Northern Hemisphere, there are many observations of the right-hand channel levee being noticeably higher than the left-hand levee, a phenomenon that is usually attributed to the effect of Coriolis forces upon turbidity currents. This article presents results from an analog model that documents the influence of Coriolis forces on the dynamics of gravity currents flowing in straight submarine channels. The observations of the transverse velocity structure, downstream velocity, and interface slope show good agreement with a theory that incorporates Ekman boundary layer dynamics. Coriolis forces will be important for most large-scale turbidity currents and need to be explicitly modeled when the Rossby number of these flows (defined as Ro = ∣U/Wf∣, where U is the mean downstream velocity, W is the channel width, and f is the Coriolis parameter defined as f = 2Ω sin(θ), with Ω being the Earth's rotation rate and θ being the latitude) is less than order 1. When Ro ≪ 1, the flow is substantially slower than a nonrotating flow with the same density contrast. The secondary flow field consists of frictionally induced Ekman transports across the channel in the benthic and interfacial boundary layers and a return flow in the interior. The cross-channel velocities are of the order of 10% of the along-channel velocities. The sediment transport associated with such transverse flow patterns should influence the evolution of submarine channel levee systems.

  6. Sleeping under the Ocean: Despite Total Isolation, Nuclear Submariners Maintain Their Sleep and Wake Patterns throughout Their Under Sea Mission. (United States)

    Trousselard, Marion; Leger, Damien; van Beers, Pascal; Coste, Olivier; Vicard, Arnaud; Pontis, Julien; Crosnier, Sylvain-Nicolas; Chennaoui, Mounir


    To assess the effects of isolation, inadequate exposure to light and specific shift work on the subjective and objective measurements of sleep and alertness of submariners. A strictly controlled randomized crossover study with the polysomnography recorded twice during the mission. Setting: Shift and night work with prolonged (70 days) social isolation from the real world (with no phone or Internet contact with families or friends during a routine mission aboard the "Téméraire" French Strategic Submarine with Ballistic Nuclear missiles (SSBN). Participants: 19 submariners working on a 24-hour shift for three days in a row schedule. Interventions: The participants attended two polysomnographic (PSG) recordings of night sleep on Day 21 (D21) and Day 51 (D51) of the 70-day patrol; urine cortisol levels were also taken after sleep, and subjective assessments of sleep, sleepiness, mood and anxiety on D21 and D51. The light and temperature on board were also recorded. PSG analyses showed that sleep did not significantly vary in length (total sleep time) or in quality between D21 and D51. The mariners reported the same subjective sleep, sleepiness, anxiety or mood (except for a slightly worse score for confusion on D51). Blood cortisol levels did not vary significantly. These results show that humans living in an isolated environment for more than two months with this specific shift schedule do not suffer from any significant effects on sleep, sleepiness and confusion between D21 and D51, when they follow an organized regular shift pattern with controlled light and temperature.

  7. 3D Structural and Stratigraphic Architecture of the Northwest Santa Barbara Channel and Implications for Submarine Landslide Generation (United States)

    Wright, A.; Kluesner, J. W.; Brothers, D. S.; Johnson, S. Y.


    Multiple submarine landslides have been previously documented on the north flank of the Santa Barbara Channel, and such failures are considered capable of generating local tsunamis. 2D seismic-reflection datasets provide a general view of regional framework geology, including faulting and folding associated with north-south compression. However, better understanding of the relationships between faults, folds, stratigraphic architecture, and submarine landslides can be obtained with 3D seismic datasets. In this study we use an industry 3D seismic-reflection volume that encompasses the slope and shelfbreak surrounding the Gaviota submarine landslide (3.8 km2) to investigate structural and stratigraphic controls on slope failure in this region. The depth-migrated seismic volume shows a network of stacked thrust faults, backthrusts, and splays that results in both broad and local zones of compression and folding along the slope and shelf. One localized zone of enhanced folding associated with small-offset thrust faults is located directly beneath the Gaviota landslide headwall, while another zone is located directly below an imaged seafloor fissure. In addition, 3D seismic attribute analysis provides insight into the shallow sedimentary section of the failed and non-failed sedimentary packages. Calculation of RMS amplitude and dominant frequency within a windowed region below the seafloor horizon delineates an apparent zone of gas-charged strata that onlaps onto older folded sediments. The up-dip limit of these gas-charged sediments aligns with the location of a seafloor fissure that extends westward from the Gaviota landslide headwall. We propose that the combination of deformation and fluid charging acted to pre-condition and trigger the failure of the Gaviota landslide, and as a result, the presence of these conditions along the fissure adjacent to the Gaviota landslide suggests this area should be considered landslide prone.

  8. Submarine mass wasting processes along slopes influenced by long-term tectonic erosion: The Middle America Trench (United States)

    Harders, R.; Ranero, C. R.; Weinrebe, W.


    We have studied submarine land-sliding using a seafloor topography and side-scan sonar data along the continental slope of the Middle America Trench. This subduction zone is dominated by tectonic erosion. Studies during the last few decades have shown mass wasting structures at submarine slopes around the world's continental margins, hot-spot volcanic islands, and volcanic island arcs. At Atlantic margins slides initiate at low slope angles and appear triggered by high sediment accumulation rates. At volcanic islands large-scale land-sliding is caused by volcano sector collapse. At subduction zones with accretionary prisms, land-sliding seems associated to contractional tectonics and fluid seepage. Submarine mass movements at subduction zones dominated by tectonic erosion are comparatively limited. However, tectonic erosion is active in about 50% of the world subduction zones. Distinct failures have been studied at slopes in Peru, Costa Rica, Nicaragua and New Zealand but extensive surveys have not been obtained. We present a comprehensive data sets on seafloor mapping on a subduction zone dominated by tectonic erosion. The data covers much of the Middle America Trench (MAT) from the Mexico-Guatemala border to Costa Rica - Panama border. The goal of this contribution is to evaluate how long-term tectonics caused by subduction erosion preconditions the continental slope structure to modulate the generation of land-sliding. We show that changes in subduction erosion processes, interacting with the local topography of the subducting plate correlate to variations in the type and distribution of failures along the slope of the region.

  9. Sleeping under the Ocean: Despite Total Isolation, Nuclear Submariners Maintain Their Sleep and Wake Patterns throughout Their Under Sea Mission.

    Directory of Open Access Journals (Sweden)

    Marion Trousselard

    Full Text Available To assess the effects of isolation, inadequate exposure to light and specific shift work on the subjective and objective measurements of sleep and alertness of submariners.A strictly controlled randomized crossover study with the polysomnography recorded twice during the mission.Setting: Shift and night work with prolonged (70 days social isolation from the real world (with no phone or Internet contact with families or friends during a routine mission aboard the "Téméraire" French Strategic Submarine with Ballistic Nuclear missiles (SSBN. Participants: 19 submariners working on a 24-hour shift for three days in a row schedule. Interventions: The participants attended two polysomnographic (PSG recordings of night sleep on Day 21 (D21 and Day 51 (D51 of the 70-day patrol; urine cortisol levels were also taken after sleep, and subjective assessments of sleep, sleepiness, mood and anxiety on D21 and D51. The light and temperature on board were also recorded.PSG analyses showed that sleep did not significantly vary in length (total sleep time or in quality between D21 and D51. The mariners reported the same subjective sleep, sleepiness, anxiety or mood (except for a slightly worse score for confusion on D51. Blood cortisol levels did not vary significantly.These results show that humans living in an isolated environment for more than two months with this specific shift schedule do not suffer from any significant effects on sleep, sleepiness and confusion between D21 and D51, when they follow an organized regular shift pattern with controlled light and temperature.

  10. Assessment of submarine landslides hazard through geotechnical and rheological analysis of sediments on the French Atlantic continental slope (United States)

    Toucanne, S.; Howlett, S.; Garziglia, S.; Silva Jacinto, R.; Courgeon, S.; Sabine, M.; Riboulot, V.; Marsset, B.


    In the aftermath of the devastating tsunami on the Japanese coast in 2011, a French multi-partnership project called TANDEM has been launched to assess the impact of tsunamis generated or propagated in the vicinity of French Channel and Atlantic coastlines. Tsunami are usually generated by earthquakes, but can also be triggered by submarine landslides. This study focuses on submarine landslides along the French Atlantic continental slope using data that were mainly collected in August 2015 during the GITAN cruise (R/V Pourquoi Pas?). Following geomorphological, geophysical and sedimentological analysis of the Bay of Biscay, efforts were oriented towards the determination of the sediment properties controlling landslide dynamics from in situ and laboratory measurements. Preliminary results show over 700 landslide scars on the French Atlantic continental slope, with most of them occurring between 400 and 1000m water depth and in canyon environments. The Plio-Quaternary sediments draping the majority of the Bay of Biscay are generally normally consolidated and composed of high plasticity clays. They show similar geomechanical properties throughout the area studied, with linear evolutions with depth and good reproducibility for rheological parameters such as Storage and Loss modulus. These similarities allow to extend geotechnical and rheological models to a regional scale in the Bay of Biscay. Our multi-disciplinary approach will provide the tools to assess continental slope failures and submarine landslides generation. Finally, we will aim to qualify and quantify the volumes and flow properties of sediment transported obtained through slope-stability modeling on SAMU-3D and rheology modelling on Nixes-SPH. These results will provide the TANDEM actors with the information necessary to simulate tsunami wave generation.

  11. [Prognostic assessment for formation of a group of cardiovascular high risk among personnel participating in atomic submarines utilization]. (United States)

    Sosiukin, A E; Vasiliuk, V B; Ivanchenko, A V; Saenko, S A; Semenchuk, O A; Dokhov, M A; Verveda, A B


    Ultrasound scanning of main vessels (common carotid, internal carotid, common and superficial femoral, posterior tibial arteries) in staffers of shipyard "Nerpa"--branch of JSC "Shipbuilding center Zvezdochka" (Snezhnogorsk city Murmansk region)--engaged into atomic submarines utilization. Findings are atherosclerotic changes in common carotid and common femoral arteries--increased thickness of intima-media complex over the reference values or atherosclerotic plaque formation. The changes were maximal in a group of males aged over 50 with length of service over 25 years. Discriminant analysis helped to suggest a mathematic model to forecast cardiovascular diseases in personnel of "Nerpa" shipyard.

  12. Higher species richness and abundance of fish and benthic invertebrates around submarine groundwater discharge in Obama Bay, Japan

    Directory of Open Access Journals (Sweden)

    Tatsuya Utsunomiya


    New hydrological insights: Species richness, abundance and biomass of fishes and abundance and biomass of turban snail and hermit crab were significantly higher in the area with high 222Rn concentration. Abundance of gammarids, the most major prey item of the fishes, was 18 times higher in the area with high 222Rn concentration. Since the turban snail, hermit crab and gammarids feed on producers (phytoplankton and benthic microalgae, submarine groundwater are concluded to increase species richness and production of fishes and invertebrates through providing nutrients and enhancing primary production.

  13. Precursory geophysical, geodetic and geochemical signatures of a new 2012 submarine eruption off the northwestern coast of El Hierro, Canary Islands, Spain (United States)

    Pérez, Nemesio M.; Somoza, Luis; González de Vallejo, Luis; Sagiya, Takeshi; León, Ricardo; Hernández, Pedro A.; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Gonzalez-Aller, Daniel; Sánchez de La Madrid, José Luis; Barrancos, José; Ibáñez, Jesús M.; Sumino, Hirochika


    Here we report precursory geophysical, geodetic, and geochemical signatures of a new submarine eruption off the northwestern coast of El Hierro, Canary Islands, which has been detected through acoustic imaging of submarine plumes on June 27, 2012, by the Spanish research vessel "Hespérides". Five distinct acoustic submarine plumes have been recognized in this area at water depths between 64 and 88 m along a submarine platform located in front of the Lomo Negro volcanic cone, northwestern of El Hierro. Submarine plums are characterized by vertical columns of high-amplitude values rising from seafloor. These acoustic imaging data clearly support a new submarine eruption in 2012 associated to the recent magmatic reactivation of El Hierro volcanic system. This new eruption event was preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥ 2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS permanent network (Nagoya University-ITER-GRAFCAN) at El Hierro with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity at HIE02, a geochemical station located in the northwestern of El Hierro, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) the highest observed corrected value of 3He/4He ratio in ground waters (8,5 Ra) from San Simón well at the northwestern of El Hierro on June 16, 2012. These precursory signals have revealed important to improve and optimize the detection of early warning signals of volcanic unrest episodes at El Hierro.

  14. Shelf erosion and submarine river canyons: implications for deep-sea oxygenation and ocean productivity during glaciation

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    I. Tsandev


    Full Text Available The areal exposure of continental shelves during glacial sea level lowering enhanced the transfer of erodible reactive organic matter to the open ocean. Sea level fall also activated submarine canyons thereby allowing large rivers to deposit their particulate load, via gravity flows, directly in the deep-sea. Here, we analyze the effects of shelf erosion and particulate matter re-routing to the open ocean during interglacial to glacial transitions, using a coupled model of the marine phosphorus, organic carbon and oxygen cycles. The results indicate that shelf erosion and submarine canyon formation may significantly lower deep-sea oxygen levels, by up to 25%, during sea level low stands, mainly due to the supply of new material from the shelves, and to a lesser extent due to particulate organic matter bypassing the coastal zone. Our simulations imply that deep-sea oxygen levels can drop significantly if eroded shelf material is deposited to the seafloor. Thus the glacial ocean's oxygen content could have been significantly lower than during interglacial stages. Primary production, organic carbon burial and dissolved phosphorus inventories are all affected by the erosion and rerouting mechanisms. However, re-routing of the continental and eroded shelf material to the deep-sea has the effect of decoupling deep-sea oxygen demand from primary productivity in the open ocean. P burial is also not affected showing a disconnection between the biogeochemical cycles in the water column and the P burial record.

  15. Operational and accident survey of Russian nuclear submarines for risk assessments using statistical models for reliability growth

    Energy Technology Data Exchange (ETDEWEB)

    Reistad, Ole [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Osteras (Norway); Norwegian University of Science and Technology, Trondheim (Norway)], E-mail:; Hustveit, Styrkaar; Roudak, Svetlana [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Osteras (Norway)


    In this study, 165 safety related events involving Russian nuclear submarines from 1959 to 2007 are surveyed with respect to vessel generation, reactor type, various types of initiating event (loss-of-coolant accident (LOCA), transients, common cause initiators (CCI)), safety significance and the release of radioactivity. The survey of vessel operations shows that the accumulated number of vessel operating years (VOY)/reactor operating years (ROY) from 1959 to 2007 is 4991/9335. With respect to the survey of safety related events, out of the 165 events registered, there have been identified 17 accidents, 133 incidents and 15 deviations. As to event characteristics, 14 LOCA and 7 criticality events have been identified. The accident rates for each of the vessel generations exhibit the usual characteristics of a technological system under development, gradually going from a high accident rate to a stable lower level - however, with clear differences between reactor technologies (PWR versus LMC) and vessel generations. The mean-time between failures (MTBF) for various types of safety related events for the Russian nuclear submarines has been calculated for various events using the non-homogeneous Poisson process (NHPP) power-law model. When applied to the complete set of events, this model fails due to a cluster of safety related events that occurred between 1984 and 1987. With respect to releases of radioactivity, the MTBF has been calculated to 893 {+-} 138 VOY. All safety related events identified as part of this study are given in.