Sample records for narrow submarine canyon

  1. Flushing submarine canyons

    Microsoft Academic Search

    Miquel Canals; Pere Puig; Xavier Durrieu de Madron; Serge Heussner; Albert Palanques; Joan Fabres

    2006-01-01

    The continental slope is a steep, narrow fringe separating the coastal zone from the deep ocean. During low sea-level stands, slides and dense, sediment-laden flows erode the outer continental shelf and the continental slope, leading to the formation of submarine canyons that funnel large volumes of sediment and organic matter from shallow regions to the deep ocean1. During high sea-level

  2. Currents in Monterey Submarine Canyon

    Microsoft Academic Search

    J. P. Xu; Marlene A. Noble

    2009-01-01

    Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon

  3. Currents in monterey submarine canyon

    USGS Publications Warehouse

    Xu, J. P.; Noble, M.A.

    2009-01-01

    Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (100-m amplitude isotherm oscillations and associated high-speed rectilinear currents. The 15-day spring-neap cycle and a ???3-day??? band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring-neap cycle of the sea level.

  4. Primary Initiation of Submarine Canyons

    E-print Network

    Herndon, J Marvin

    2011-01-01

    The discovery of close-to-star gas-giant exo-planets lends support to the idea of Earth's origin as a Jupiter-like gas-giant and to the consequences of its compression, including whole-Earth decompression dynamics that gives rise, without requiring mantle convection, to the myriad measurements and observations whose descriptions are attributed to plate tectonics. I propose here another, unanticipated consequence of whole-Earth decompression dynamics: namely, a specific, dominant, non-erosion, underlying initiation-mechanism precursor for submarine canyons that follows as a direct consequence of Earth's early origin as a Jupiter-like gas-giant.

  5. Geomorphic process fingerprints in submarine canyons

    USGS Publications Warehouse

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

    2013-01-01

    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.

  6. Contemporary sediment-transport processes in submarine canyons.

    PubMed

    Puig, Pere; Palanques, Albert; Martín, Jacobo

    2014-01-01

    Submarine canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through canyons. Additionally, internal waves periodically resuspend ephemeral deposits within canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures. PMID:23937169

  7. A submarine canyon as the cause of a mud volcano Liuchieuyu Island in Taiwan

    E-print Network

    Lin, Andrew Tien-Shun

    A submarine canyon as the cause of a mud volcano Ð Liuchieuyu Island in Taiwan J. Chowa,*, J, we also discuss the relationship between a nearby submarine canyon (Kaoping Submarine Canyon¯ection; Submarine canyon; Mud volcano 1. Introduction In the early Pliocene, the paleoenvironment of the offshore

  8. Geomorphic characterization of four shelf-sourced submarine canyons along the U.S. Mid-Atlantic continental margin

    E-print Network

    ten Brink, Uri S.

    Geomorphic characterization of four shelf-sourced submarine canyons along the U.S. Mid Washington Canyon Norfolk Canyon Turbidity flow a b s t r a c t Shelf-sourced submarine canyons are common of major submarine canyons. Submarine canyons on passive margins are primarily the result of erosion

  9. Depositional framework and genesis of Wilcox Submarine Canyon systems, Northwest Gulf Coast

    SciTech Connect

    Galloway, W.F.; Dinqus, W.F.; Paige, R.E.

    1988-01-01

    Wilcox (late Paleocene-early Eocene) slope systems of the Texas coastal plain contain two families of paleosubmarine canyons that exhibit distinctly different characteristics and stratigraphic settings: Yoakum and Lavaca type canyons occur as widely separated features within the generally retrogradational middle Wilcox interval. Four such canyons exhibit high length to width ratios, extend far updip of the contemporaneous shelf edge, were excavated deeply into paralic and coastal-plain deposits, and were filled primarily by mud. Fills consist of a lower onlapping unit and capping progradational deposits that are genetically related to deposition of the upper Wilcox fluvial-deltaic sequence. Significantly, the canyon fills correlate with widespread transgressive marine mudstones (the Yoakum shale-Sabinetown Formation and ''Big Shale''). In contrast, Lavaca-type canyons form a system of erosional features created along the rapidly prograding, unstable lower Wilcox continental margin. Comparative analysis of the two canyon system suggests a general process model for submarine canyon formation on prograding basin margins. Key elements are depositional loading of the continental margin creating instability, initiation of a large-scale slump, family of slumps, or listric bedding-plane fault creating a depression or indentation in the margin, and headward and lateral expansion of the depression by slumping and density-underflow erosion. Extent of canyon evolution varies according to time and submerged space available for maturation; short, broad canyons form on narrow shelves of actively prograding margins, and elongate mature canyons form in retrogradational or transgressive settings.

  10. Origin of Izu-Bonin forearc submarine canyons

    SciTech Connect

    Fujioka, Kantaro (Univ. of Tokyo (Japan)); Yoshida, Haruko (Chiba Univ. (Japan))

    1990-06-01

    Submarine canyons on the Izu-Bonin forearc are morphologically divided from north to south into four types based on their morphology, long profiles, and seismic profiles: Mikura, Aogashima, Sofu, and Chichijima types, respectively. These types of canyons are genetically different from each other. Mikura group is formed by the faults related to bending of the subducting Philippine Sea Plate. Aogashima type genetically relates to the activity of large submarine calderas that supply large amounts of volcaniclastic material to the consequent forearc slope. The third, Sofu group, is thought to be formed by the large-scale mega mass wasting in relation to the recent movement of the Sofugan tectonic line. The last, Chichijima group, is formed by collision of the Uyeda Ridge and the Ogasawara Plateau on the subducting Pacific Plate with Bonin Arc. Long profiles of four types of submarine canyons also support this.

  11. Anatomy of La Jolla submarine canyon system; offshore southern California

    USGS Publications Warehouse

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

    2013-01-01

    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.

  12. Physical modeling of tidal resonance in a submarine canyon

    NASA Astrophysics Data System (ADS)

    Souëf, K. E.; Allen, S. E.

    2014-02-01

    Current observations in submarine canyons poleward of 30° are usually dominated by the semidiurnal (M2) tidal frequency, which is superinertial at these latitudes. Observations from a submarine canyon at 44°N (the Gully, Nova Scotia) suggest that canyons can be dominated by the subinertial (K1) tidal frequency if length scales are correct for resonance of the K1 frequency. A model of the Gully was constructed in a tank on a rotating table and tidal currents generated to determine factors that influence resonance. Resonance curves were fit to measurements from the laboratory canyon for a range of stratifications, background rotation rates, and forcing amplitudes. Dense water was observed upwelling onto the continental shelf on either side of the laboratory canyon and traveled at least one canyon width along the shelf. Friction values measured in the laboratory were much higher than expected, probably due to upwelled water surging onto the shelf on each tidal cycle, similar to a tidal bore. By scaling observations from the laboratory to the ocean and assuming friction in the ocean is also affected by water traveling onto the shelf, a resonance curve for the ocean was created. Because of the broad resonance curve, the diurnal tide remains strong year round at the Gully, even as stratification at the shelf break changes. Dense water surging onto the shelf on tidal frequencies may affect friction and mixing at other nonresonant canyons.

  13. Evolution of surface gravity waves over a submarine canyon

    E-print Network

    Magne, R; Herbers, T H C; Ardhuin, F; O'Reilly, W C; Rey, V; Magne, Rudy; Belibassakis, Kostas; Herbers, Thomas H. C.; Ardhuin, Fabrice; Reilly, William C. O'; Rey, Vincent

    2006-01-01

    The effects of a submarine canyon on the propagation of ocean surface waves are examined with a three-dimensional coupled-mode model for wave propagation over steep topography. Whereas the classical geometrical optics approximation predicts an abrupt transition from complete transmission at small incidence angles to no transmission at large angles, the full model predicts a more gradual transition with partial reflection/transmission that is sensitive to the canyon geometry and controlled by evanescent modes for small incidence angles and relatively short waves. Model results for large incidence angles are compared with data from directional wave buoys deployed around the rim and over Scripps Canyon, near San Diego, California, during the Nearshore Canyon Experiment (NCEX). Wave heights are observed to decay across the canyon by about a factor 5 over a distance shorter than a wavelength. Yet, a spectral refraction model predicts an even larger reduction by about a factor 10, because low frequency components c...

  14. Geology and biology of Oceanographer submarine canyon.

    USGS Publications Warehouse

    Valentine, P.C.; Uzmann, J.R.; Cooper, R.A.

    1980-01-01

    Santonian beds more than 100 m thick are the oldest rocks collected from the canyon. Quaternary silty clay veneers the canyon walls in many places and is commonly burrowed by benthic organisms that cause extensive erosion of the canyon walls, especially in the depth zone (100-1300 m) inhabited by the crabs Geryon and Cancer. Bioerosion is minimal on high, near-vertical cliffs of sedimentary rock, in areas of continual sediment movement, and where the sea floor is paved by gravel. A thin layer of rippled, unconsolidated silt and sand is commonly present on the canyon walls and in the axis. Shelf sediments are transported from Georges Bank over the E rim and in the Canyon by the SW drift and storm currents; tidal currents and internal waves move the sediment downcanyon along the walls and axis.- from Authors

  15. Space-for-time substitution and the evolution of a submarine canyon-channel system in a passive progradational margin

    NASA Astrophysics Data System (ADS)

    Micallef, Aaron; Ribó, Marta; Canals, Miquel; Puig, Pere; Lastras, Galderic; Tubau, Xavier

    2014-09-01

    Space-for-time substitution is a concept that has been widely applied, but not thoroughly tested, in some fields of geomorphology. The objective of this study is to test whether the concept of space-for-time substitution is valid in reconstructing the evolution of a submarine canyon-channel system in a passive progradational margin. We use multibeam echosounder data and in situ measurements from the south Ebro Margin to analyse the morphology and morphometry of a sequence of submarine valleys ordered in terms of increasing valley thalweg length. The morphological model of submarine valley evolution that we can propose from this analysis is very similar to established models in the literature, which leads us to conclude that time can be substituted by space when reconstructing the evolution of submarine canyon and channel systems in the south Ebro Margin. By extracting morphometric information from the application of the space-for-time substitution model to our data, we identify a series of morphological patterns as a submarine canyon evolves in a passive progradational margin. These include the geometric similarity of canyon planform shape, an increase in canyon draining efficiency and in the influence of flank slope failures, and an evolution towards equilibrium between canyon form and imposed water and sediment load without net erosion or deposition taking place. We also observe that canyon elongation is higher downslope and that the canyon undergoes an early stage of rapid incision similar to the process of "erosion narrowing" reported in terrestrial rivers. We demonstrate that the conclusions of our study are not limited to submarine valleys in the south Ebro Margin but are applicable to other margins around the world.

  16. Cyclone-induced hyperpycnal turbidity currents in a submarine canyon

    NASA Astrophysics Data System (ADS)

    Liu, James T.; Wang, Yu-Huai; Yang, Rick J.; Hsu, Ray T.; Kao, Shuh-Ji; Lin, Hui-Ling; Kuo, Fang Hsu

    2012-04-01

    Density currents such as turbidity currents are major transport agents in various terrestrial, lacustrine, and marine environments worldwide. However, a gap exists between those who study the deposits by turbidity currents (turbidite) on a field scale, and those who study turbidity currents using small-scale laboratory experiments and theoretical/numerical models. We report two typhoon-triggered hyperpycnal turbidity current events observed in a submarine canyon. Our findings verify turbidite sequences with the characteristics of suspended sediment carried by passing turbidity currents that displayed distinct waxing and waning phases. Our study also confirms the direct link between typhoon-triggered hyperpycnal flows in a small mountainous river and turbidity currents in a nearby submarine canyon that transport sediment to the deep-sea efficiently.

  17. Transient wind-driven upwelling in a submarine canyon: A process-oriented modeling study

    Microsoft Academic Search

    Jochen Kämpf

    2006-01-01

    A hydrodynamic model is employed to study flow near a submarine canyon during conditions of upwelling-favorable coastal winds. Findings reveal that up-canyon flow is the rapid geostrophic adjustment to barotropic pressure gradients establishing across the canyon. Stratification leads to the formation of a cyclonic eddy within the canyon, trapping neutrally buoyant matter, and limits the upwelling depth only when a

  18. Origin of Florida Canyon and the role of spring sapping on the formation of submarine box canyons

    USGS Publications Warehouse

    Paull, Charles K.; Spiess, Fred N.; Curray, Joseph R.; Twichell, David C.

    1990-01-01

    Florida Canyon, one of a series of major submarine canyons on the southwestern edge of the Florida Platform, was surveyed using GLORIA, SeaBeam, and Deep-Tow technologies, and it was directly observed during three DSRV Alvin dives. Florida Canyon exhibits two distinct morphologies: a broad V-shaped upper canyon and a deeply entrenched, flat-floored, U-shaped lower canyon. The flat- floored lower canyon extends 20 km into the Florida Platform from the abyssal Gulf. The lower canyon ends abruptly at an ?3 km in diameter semicircular headwall that rises 750 m with a >60° slope angle to the foot of the upper canyon. The sides of the lower canyon are less steep than its headwall and are characterized by straight faces that occur along preferred orientations and indicate a strong joint control. The upper canyon is characterized by a gently sloping, straight V-shaped central valley cut into a broad terrace. The flat floor of the upper canyon continues as terraces along the upper walls of the lower canyon. On the flanks of the upper canyon, there are five >50-m-deep, >0.5-km-wide, closed sink-hole-like depressions which indicate subsurface dissolution within the platform. The origin of the lower canyon is difficult to explain with traditional models of submarine canyon formation by external physical processes. The movement of ground water, probably with high salinities and reduced compounds along regional joints, may have focused the corrosive force of submarine spring sapping at the head of the lower canyon to produce the canyon's present shape.

  19. The eect of a submarine canyon on the river sediment dispersal and inner shelf sediment movements in

    E-print Network

    Lin, Andrew Tien-Shun

    The e¡ect of a submarine canyon on the river sediment dispersal and inner shelf sediment movements 2001 Abstract This study examines the influence of a submarine canyon on the dispersal of sediments the head region of the Kao-ping Submarine Canyon whose landward terminus is located approximately 1 km

  20. Ascension Submarine Canyon, California - Evolution of a multi-head canyon system along a strike-slip continental margin

    USGS Publications Warehouse

    Nagel, D.K.; Mullins, H.T.; Greene, H. Gary

    1986-01-01

    Ascension Submarine Canyon, which lies along the strike-slip (transform) dominated continental margin of central California, consists of two discrete northwestern heads and six less well defined southeastern heads. These eight heads coalesce to form a single submarine canyon near the 2700 m isobath. Detailed seismic stratigraphic data correlated with 19 rock dredge hauls from the walls of the canyon system, suggest that at least one of the two northwestern heads was initially eroded during a Pliocene lowstand of sea level ???3.8 m.y. B.P. Paleogeographic reconstructions indicate that at this time, northwestern Ascension Canyon formed the distal channel of nearby Monterey Canyon and has subsequently been offset by right-lateral, strike-slip faulting along the San Gregorio fault zone. Some of the six southwestern heads of Ascension Canyon may also have been initially eroded as the distal portions of Monterey Canyon during late Pliocene-early Pleistocene sea-level lowstands (???2.8 and 1.75 m.y. B.P.) and subsequently truncated and offset to the northwest. There have also been a minimum of two canyon-cutting episodes within the past 750,000 years, after the entire Ascension Canyon system migrated to the northwest past Monterey Canyon. We attribute these late Pleistocene erosional events to relative lowstands of sea level 750,000 and 18,000 yrs B.P. The late Pleistocene and Holocene evolution of the six southeastern heads also appears to have been controlled by structural uplift of the Ascension-Monterey basement high at the southeastern terminus of the Outer Santa Cruz Basin. We believe that uplift of this basement high sufficiently oversteepened submarine slopes to induce gravitational instability and generate mass movements that resulted in the erosion of the canyon heads. Most significantly, though, our results and interpretations support previous proposals that submarine canyons along strike-slip continental margins can originate by tectonic trunction and lateral offset. ?? 1986.

  1. Deep-sea scavenging amphipod assemblages from the submarine canyons of the Western Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Duffy, G. A.; Horton, T.; Billett, D. S. M.

    2012-11-01

    Submarine canyons have often been identified as hotspots of secondary production with the potential to house distinct faunal assemblages and idiosyncratic ecosystems. Within these deep-sea habitats, assemblages of scavenging fauna play a vital role in reintroducing organic matter from large food falls into the wider deep-sea food chain. Free-fall baited traps were set at different depths within three submarine canyons on the Iberian Margin. Amphipods from the traps were identified to species level and counted. Scavenging amphipod assemblages were compared at different depths within each canyon and between individual canyon systems. Using data from literature, abyssal plain assemblages were compared to submarine canyon assemblages. Samples from canyons were found to contain common abyssal plain species but in greater than expected abundances. It is proposed that this is a result of the high organic carbon input into canyon systems owing to their interception of sediment from the continental shelf and input from associated estuarine systems. Community composition differed significantly between the submarine canyons and abyssal plains. The cause of this difference cannot be attributed to one environmental variable due to the numerous inherent differences between canyons and abyssal plains.

  2. Geomorphic process fingerprints in submarine canyons Daniel S. Brothers , Uri S. ten Brink, Brian D. Andrews, Jason D. Chaytor, David C. Twichell

    E-print Network

    ten Brink, Uri S.

    Geomorphic process fingerprints in submarine canyons Daniel S. Brothers , Uri S. ten Brink, Brian D bathymetry regression power law landslide Submarine canyons are common features of continental margins. Though it is known that submarine canyons form pri- marily from erosion induced by submarine sediment

  3. Delaware River: Evidence for its former extension to Wilmington Submarine Canyon

    USGS Publications Warehouse

    Twichell, D.C.; Knebel, H. J.; Folger, D.W.

    1977-01-01

    Seismic-reflection profiles indicate that during the Pleistocene the Delaware River flowed across the continental shelf east of Delaware Bay and emptied into Wilmington Submarine Canyon. The ancestral valley (width, 3 to 8 kilometers; relief, 10 to 30 meters) is buried, is not reflected in the surface topography, and probably predates the formation of the present canyon head.

  4. Hanging canyons of Haida Gwaii, British Columbia, Canada: Fault-control on submarine canyon geomorphology along active continental margins

    NASA Astrophysics Data System (ADS)

    Harris, Peter T.; Barrie, J. Vaughn; Conway, Kim W.; Greene, H. Gary

    2014-06-01

    Faulting commonly influences the geomorphology of submarine canyons that occur on active continental margins. Here, we examine the geomorphology of canyons located on the continental margin off Haida Gwaii, British Columbia, that are truncated on the mid-slope (1200-1400 m water depth) by the Queen Charlotte Fault Zone (QCFZ). The QCFZ is an oblique strike-slip fault zone that has rates of lateral motion of around 50-60 mm/yr and a small convergent component equal to about 3 mm/yr. Slow subduction along the Cascadia Subduction Zone has accreted a prism of marine sediment against the lower slope (1500-3500 m water depth), forming the Queen Charlotte Terrace, which blocks the mouths of submarine canyons formed on the upper slope (200-1400 m water depth). Consequently, canyons along this margin are short (4-8 km in length), closely spaced (around 800 m), and terminate uniformly along the 1400 m isobath, coinciding with the primary fault trend of the QCFZ. Vertical displacement along the fault has resulted in hanging canyons occurring locally. The Haida Gwaii canyons are compared and contrasted with the Sur Canyon system, located to the south of Monterey Bay, California, on a transform margin, which is not blocked by any accretionary prism, and where canyons thus extend to 4000 m depth, across the full breadth of the slope.

  5. Recent sea beam mapping of Ascension-Monterey Submarine Canyon System

    SciTech Connect

    Greene, H.G. (Geological Survey, Menlo Park, CA (USA))

    1990-06-01

    Extensive Sea Beam and Bathymetric Swatch Survey System (BS{sup 3}) data covering the Ascension-Monterey Submarine Canyon system and adjoining areas and canyons were collected offshore central California. Many discovered geomorphological features lead to significant new geologic conclusions about the formation and processes of submarine canyons in general and disclose unique sedimentary and tectonic features of the Ascension-Monterey Canyon system. The highly detailed bathymetric maps constructed from the Sea Beam data indicate that the seafloor topographic pattern is influenced by sedimentary and tectonic processes; both remain active along the central California margin. Interpretations of MOAA composite maps, final raw Sea Beam bathymetric maps, and three-dimensional physiographic renditions from bathymetric data indicate a diverse and complex geomorphology for the Ascension-Monterey Submarine Canyon system and adjoining region. Five distinct geomorphologic provinces and four well-defined geographic areas are mapped. Canyons cut by faults and canyon walls actively undergoing mass wasting are prominently displayed in the Sea Beam data. Sedimentary processes illustrating canyon channel capture and the formation of extensive mega-sedimentary wave fields where the canyons debouch onto the abyssal plain are spectacularly well defined. This new tool of seafloor mapping is contributing significant data for the geological interpretation of continental margins and seafloor in the world's oceans.

  6. Discovery of two new large submarine canyons in the Bering Sea

    USGS Publications Warehouse

    Carlson, P.R.; Karl, Herman A.

    1984-01-01

    The Beringian continental margin is incised by some of the world's largest submarine canyons. Two newly discovered canyons, St. Matthew and Middle, are hereby added to the roster of Bering Sea canyons. Although these canyons are smaller and not cut back into the Bering shelf like the five very large canyons, they are nonetheless comparable in size to most of the canyons that have been cut into the U.S. eastern continental margin and much larger than the well-known southern California canyons. Both igneous and sedimentary rocks of Eocene to Pliocene age have been dredged from the walls of St. Matthew and Middle Canyons as well as from the walls of several of the other Beringian margin canyons, thus suggesting a late Tertiary to Quaternary genesis of the canyons. We speculate that the ancestral Yukon and possibly Anadyr Rivers were instrumental in initiating the canyon-cutting processes, but that, due to restrictions imposed by island and subsea bedrock barriers, cutting of the two newly discovered canyons may have begun later and been slower than for the other five canyons. ?? 1984.

  7. Geomorphic process fingerprints in submarine canyons1 Daniel S. Brothers*, Uri S. ten Brink, Brian D. Andrews, Jason D. Chaytor, David C.2

    E-print Network

    ten Brink, Uri S.

    1 Geomorphic process fingerprints in submarine canyons1 Daniel S. Brothers*, Uri S. ten *Corresponding author: dbrothers@usgs.gov; 508-457-229310 11 Abstract12 Submarine canyons are common from the continents to the deep sea.14 Though it is known that submarine canyons form primarily from

  8. Clast-contact conglomerates in submarine canyons: possible subaqueous sieve deposits

    SciTech Connect

    Fitzgerald, M.S.

    1987-05-01

    Thick, coarse, clast-contact conglomerates in submarine canyon fill have previously been attributed to rock-fall, grain-flow, or winnowing processes. However, these processes do not adequately explain some thick conglomeratic sequences. The proposed process of subaqueous sieve deposition could account for these clast-contact conglomerates. Subaerial sieve deposition has been documented on small-scale fan models and on alluvial fans. A subaerial sieve deposit begins as a debris flow which at some point freezes up. The matrix is then lost by subsequent filtration or outflow, and the emplacement of a clast-contact gravel ensues. A subaqueous sieve deposit would be slightly modified in that the matrix would not be lost by filtration into the submarine canyon floor, but rather by outflow at the terminus of the lobe immediately after deposition, or possibly from the top and/or sides of the freezing flow mass during transport. Besides forming in submarine canyons, subaqueous sieve deposits might also occur in paralic, submarine fan channel, and base-of-the-slope settings. In substantiating the existence of subaqueous sieve deposits, the sedimentary structures and grain-size data from recent sieve deposits on alluvial fans are compared to those of ancient submarine canyon deposits. Numerous similarities are found supporting this new method of deposition. Some discrepancies are encountered, but these are expected due to modifications caused by an aqueous medium.

  9. Cyclones and tides as feeders of a submarine canyon off Bangladesh

    NASA Astrophysics Data System (ADS)

    Kudrass, H. R.; Michels, K. H.; Wiedicke, M.; Suckow, A.

    1998-08-01

    Extremely high annual sedimentation rates of about 50 cm/yr at the head of the submarine canyon “Swatch of No Ground,” which connects the submarine delta of the Ganges-Brahmaputra to the Bengal deep-sea fan were estimated by 210Pb and 137Cs gamma spectrometry. The sediment in the canyon at 228 m water depth consists of graded sand and silt layers and laminated mud. The sand and silt layers are assumed to have been deposited by tropical cyclones, whereas the intercalated laminated mud is thought to have been deposited by daily variations of tidal currents. The graded layers correlate well with the historical record of cyclones and allow an annual fine tuning. The rapid infill of the canyon head is caused by trapping of suspended sediment that has been mobilized by storms and tides on the delta topset. The sediment is stored only temporarily in the canyon head: slides, slumps, and earthquakes occasionally remove and transfer it by turbidity currents to the deep-sea fan. The focusing effect of the canyon and the subsequent stepwise export of sediment, probably combined with erosion of the canyon floor, explain the long-term regional stability of this canyon and probably other shelf canyons.

  10. Spatial distribution of phytoplankton assemblages in the Nazaré submarine canyon region (Portugal): HPLC-CHEMTAX approach

    Microsoft Academic Search

    Carlos Rafael Mendes; Carolina Sá; João Vitorino; Carlos Borges; Virginia Maria Tavano Garcia; Vanda Brotas

    2011-01-01

    The distribution and composition of phytoplankton assemblages were studied in the Nazaré submarine canyon, during an upwelling event, using high-performance liquid chromatography (HPLC) pigment analysis, complemented by microscopic qualitative observations. High chlorophyll a (Chl a) concentrations were recorded in the canyon head, near the coast, where values greater than 4?gL?1 were observed. In contrast, Chl a was relatively low in

  11. Space-for-time substitution and the evolution of submarine canyons in a passive, progradational margin.

    NASA Astrophysics Data System (ADS)

    Micallef, Aaron; Ribó, Marta; Canals, Miquel; Puig, Pere; Lastras, Galderic; Tubau, Xavier

    2013-04-01

    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 slope is inferred as the source of gravity flows driving canyon evolution. Canyon morphology is shown to be maintained over the course of more than one fall and rise in sea-level. Our model of canyon evolution is applicable to other passive margins (e.g. Argentine continental margin).

  12. Demise of a submarine canyon? Evidence for highstand infilling on the Waipaoa River continental margin, New Zealand

    Microsoft Academic Search

    J. P. Walsh; C. R. Alexander; T. Gerber; A. R. Orpin; B. W. Sumners

    2007-01-01

    Submarine canyons are major geomorphologic features on the Earth's surface. Their formation has received considerable debate, but their demise has received less attention. Research of modern canyons with cores and moorings has documented active sediment transport and deposition, but extrapolation of these local observations over larger areas is precluded by complex canyon geomorphology. High-resolution multibeam and chirp data presented here

  13. Submarine canyons and channels in the Lower St. Lawrence Estuary (Eastern Canada): Morphology, classification and recent sediment dynamics

    NASA Astrophysics Data System (ADS)

    Normandeau, Alexandre; Lajeunesse, Patrick; St-Onge, Guillaume

    2015-07-01

    Series of submarine canyons and channels observed in the Lower St. Lawrence Estuary (LSLE) provide an opportunity to analyze in great detail the morphology, spatial distribution and modern activity of such systems in a relatively shallow (? 300 m) semi-enclosed basin. Based on their geomorphology and physical settings, the canyons and channels were classified into four categories according to their feeding sources (ancient or recent): glacially-fed, river-fed, longshore drift-fed and sediment-starved systems. Their activity was interpreted based on geomorphological characteristics such as the presence of bedforms related to gravity flows, backscatter intensity, axial incision and the presence of rapidly deposited layers in surficial sediments. River-fed deltas were interpreted as inactive, mainly because suspended sediment concentrations at river mouths are low, preventing the generation of hyperpycnal currents or delta-lip failures related to high sediment supply. Longshore drift-fed canyons, present where the coastal shelf narrows, were found to be episodically active probably due to earthquakes or extreme storm events. Unlike other longshore drift-fed canyons observed elsewhere in the world, they are active infrequently because of the modern low rates of sediment supply to their heads. The most active canyons are the sediment-starved type and were observed near Pointe-des-Monts. Their activity is probably due to slope failures and to the presence of strong hydrodynamic processes. Therefore, sediment supply is not the main mechanism responsible for modern canyon and channel activity in the LSLE. However, sediment supply has been an important factor during the formation of the submarine channels and canyons. Their quasi-exclusive occurrence on the Québec North Shore is attributed to its larger watershed and important sedimentary delivery during deglaciation. The Québec North Shore watershed is 20 times greater than the Québec South Shore watershed, which favored the transport of greater volumes of sediment during the early-Holocene. Moreover, the slope proximity to the shore led to the formation of longshore-drift fed systems on the North Shore when sediment supplied to rivers were transferred on a narrow shelf.

  14. Marine Protected Area Design and the Spatial and Temporal Distribution of Cetaceans in a Submarine Canyon

    Microsoft Academic Search

    Sascha K. Hooker; Hal Whitehead; Shannon Gowans

    1999-01-01

    The Gully, the largest submarine canyon off the coast of eastern Canada, is currently under consid- eration as a marine conservation area, primarily because of the increasing interest in oil and gas production on the Scotian Shelf. Cetaceans, as a guild of abundant, large organisms that are relatively sensitive to such threats, provide a reliable means to determine the boundaries

  15. Focused sound from three-dimensional sound propagation effects over a submarine canyon.

    PubMed

    Chiu, Linus Y S; Lin, Ying-Tsong; Chen, Chi-Fang; Duda, Timothy F; Calder, Brian

    2011-06-01

    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. PMID:21682362

  16. Sediment dynamics and post-glacial evolution of the continental shelf around the Blanes submarine canyon head (NW Mediterranean)

    NASA Astrophysics Data System (ADS)

    Durán, Ruth; Canals, Miquel; Lastras, Galderic; Micallef, Aaron; Amblas, David; Pedrosa-Pàmies, Rut; Sanz, José Luis

    2013-11-01

    The Blanes submarine canyon (BC) deeply incises the Catalan continental shelf in the NW Mediterranean Sea. As a consequence of the closeness (only 4 km) of its head to the coastline and the mouth of the Tordera River, the canyon has a direct influence on the shelf dispersal system as it collects large amounts of sediment, mainly during high-energy events. Multibeam bathymetry, backscatter imagery and very-high resolution seismic reflection profiles have allowed characterizing the morphology of the continental shelf around the canyon head, also identifying sediment sources and transport pathways into the canyon. The morphological data have also been used to reconstruct the evolution of the continental shelf during the last sea-level transgression so that the current understanding of shelf-to-canyon sediment exchanges through time could be improved. The continental shelf surrounding the BC consists of both depositional and erosional or non-depositional areas. Depositional areas display prominent sediment bodies, a generally smooth bathymetry and variable backscatter. These include: (i) an area of modern coarse-grained sediment accumulation that comprises the inner shelf; (ii) a modern fine-grained sedimentation area on the middle shelf offshore Tossa de Mar; and (iii) a modern sediment depleted area that covers most of the middle and outer shelf to the west of the canyon head. Erosional and non-depositional areas display a rough topography and high backscatter, and occur primarily to the east of the canyon head, where the arrival of river-fed inputs is very small. In agreement with this pattern, the continental shelf north and west of the canyon head likely is the main source of shelf sediment into the canyon. To the north, a pattern of very high backscatter extends from the coastline to the canyon head, suggesting the remobilization and off-shelf export of fines. Additionally, relict near-shore sand bodies developed over the Barcelona shelf that extend to the canyon head rim constitute a source of coarse sediment. High-energy processes, namely river floods and coastal storms, are the main controls over the river-shelf-canyon sediment exchange. River floods increase the delivery of terrigenous particles to the coastal system. Storms, mainly from the east, remobilize the sediment temporarily accumulated on the shelf towards the canyon head, so that the finer fractions are preferentially removed and a coarse lag is normally left on the shelf floor. Exceptionally, very strong storms also remove the coarse fractions from the shelf drive them into the canyon. Processes like dense shelf water cascading, which is much more intense in canyons to the north of BC, and the Northern Current also contribute to the transport of suspended sediment from far distant northern sources. During the last post-glacial transgression the BC had a strong influence on the evolution of the inner continental margin, as it interrupted the shelf sediment dispersal system by isolating the shelves to its north and south, named La Planassa and Barcelona shelves, respectively. The detailed study of the geomorphology and uppermost sediment cover of the continental shelf surrounding the Blanes submarine canyon yields insight into the past and present shelf sediment dynamics and the shelf-to-canyon sediment exchanges. The continental shelf near the canyon head consists of mosaic where erosional, or non-depositional, and depositional zones coexist. East of the canyon and offshore Tossa de Mar, the modern sediment deposition is mostly confined to the inner and middle shelf, whilst most of the La Planassa shelf is sediment depleted with numerous relict morphosedimentary features cropping out. Rocky outcrops, narrow ridges and relict coarse sand deposits suggesting erosion or non-deposition of fine sediments in modern times occupy the middle and outer shelf floor east and northeast of the canyon head. In contrast, north and west of the canyon head, the middle and outer shelf comprises several large relict sand bodies that point out to long-term deposition. However

  17. Small-scale turbidity currents in a big submarine canyon

    USGS Publications Warehouse

    Xu, Jingping; Barry, James P.; Paull, Charles K.

    2013-01-01

    Field measurements of oceanic turbidity currents, especially diluted currents, are extremely rare. We present a dilute turbidity current recorded by instrumented moorings 14.5 km apart at 1300 and 1860 m water depth. The sediment concentration within the flow was 0.017%, accounting for 18 cm/s gravity current speed due to density excess. Tidal currents of ?30 cm/s during the event provided a "tailwind" that assisted the down-canyon movement of the turbidity current and its sediment plume. High-resolution velocity measurements suggested that the turbidity current was likely the result of a local canyon wall slumping near the 1300 m mooring. Frequent occurrences, in both space and time, of such weak sediment transport events could be an important mechanism to cascade sediment and other particles, and to help sustain the vibrant ecosystems in deep-sea canyons.

  18. Modelling bottom trawling-generated sediment flows in La Fonera submarine canyon (Northwestern Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Payo-Payo, Marta; Silva Jacinto, Ricardo; Lastras, Galderic; Canals, Miquel; Puig, Pere; Martín, Jacobo; Sanchez-Vidal, Anna; Rabineau, Marina

    2015-04-01

    Bottom-trawling is one of the anthropogenic activities with a stronger and more widespread impact on the seafloor. Physical processes involved in sediment resuspension due to trawling and the resulting sediment-laden flows are not fully understood. The amount and fate of remobilized sediments are of the utmost relevance for establishing present-day continental margin sediment budgets. Resuspension by bottom trawling leads to massive transfer of sediment from shallower to deeper areas practically worldwide. La Fonera submarine canyon is a large, deeply-incised active canyon in the Northwestern Mediterranean Sea. It presents complex sediment transport dynamics associated to littoral drift and extreme events such as dense shelf water cascading and severe storms. Recent studies have revealed recurrent peaks in near-bottom current speed and suspended sediment concentration in the northern flank of the canyon synchronously with trawling. Aiming at simulating sediment-loaded fluxes triggered by trawling and their interaction with the seafloor in La Fonera canyon, we have implemented a numerical process-based model developed to reproduce such flows. Mooring data have been used both to calibrate the modelled sediment fluxes. Good agreement between model and monitoring data has been found, with modelled peaks of suspended sediment concentration values exceeding 120 mg-l-1 and current speed measurements of up to 40 cm-s-1 at the mooring site. Moreover, we have quantified fishing activity over the canyon flanks through modelling and have obtained the propagation pattern of sediment flows from the fishing ground downward the canyon. Our results confirm the value of numerical models to complete and enlarge our understanding of the sedimentary transfer processes from shallow to deep in the ocean. Besides, they allow establishing quantitative comparisons between trawling impact and natural forcing on the sediments dynamics of La Fonera submarine canyon.

  19. Reconstruction of submarine canyon systems associated with proto-Stockton arch during Late Cretaceous

    SciTech Connect

    Rider, J.

    1986-04-01

    A hypothetical depositional model of the middle Great Valley gas fields of California includes the area from the Southwest Vernalis gas field in the south (T3S) to the Nicolaus gas field in the north (T12N). The model assumes that (1) the early Campanian Dobbins Shale Member was deposited at or near the shelf/slope break, and (2) the absence of the Dobbins Shale Member indicates scouring processes of active submarine canyon systems. A striking correlation exists between the proposed distribution of the Dobbins Shale Member scour channels and the position of river systems operating today in the valley. The model distinguishes six submarine canyon systems: (1) Feather River/Nicolaus, (2) American River/Florin, (3) Cosumnes River/Poppy Ridge, (4) Mokelumne River/Lodi, (5) Calaveras delta/Mulligan Hill, and (6) Stanislaus River/East Collegeville. The model implies that an extensive delta system was associated with the Calaveras River during deposition of the Dobbins Shale Member, before its erosive exit southwest of the Mulligan Hill gas field, just east of the Los Medanos, Concord, and Willow Pass fields. The presence of possible equivalents of the Dobbins Shale Member of this latter area suggests an early Campanian highland, the proto-Stockton arch. Subsequent Forbes Formation deposition appears to involve apronlike drapes or overlaps of the early Campanian canyons. However, during deposition of the Kione Formation, the canyon systems were reactivated, and canyon scour predominated, matching the scour patterns of the Dobbins Shale Member. From these ancestral canyons, younger canyons could have evolved easily.

  20. Sedimentologic evolution of a submarine canyon in a forearc basin, Upper Cretaceous Rosario Formation, San Carlos, Mexico

    SciTech Connect

    Morris, W.R.; Busby-Spera, C.J.

    1988-06-01

    The walls, floor, and fill of a submarine canyon are well-exposed near San Carlos, Mexico, in forecarc strata of the Upper Cretaceous Rosario Formation. The submarine canyon is about 7 km wide and at least 230 m deep and has eroded a minimum of 150 m into underlying fluvial red beds. It is unclear whether subaerial or submarine processes initiated the canyon cutting; however, marine processes, especially debris flows, modified the morphology of the submarine canyon. The submarine canyon fill and overlying slope deposits form two major fining-upward sequences. The first includes a 120 m thick lower conglomerate-sandstone unit (LCSU) at the base of the canyon fill overlain by a 50-110 m thick middle mudstone-sandstone unit (MMSU). The MMSU consists predominantly of mudstone and thin-bedded sandstone, but includes a channel filled with sandstone beds that form a fining- and thinning-upward sequence. This sequence is overlain by the second major sequence, a 0-60 m thick upper conglomerate-sandstone unit (UCSU), which is confined to three channels within the submarine canyon and passes gradationally upward into slope mudstone. Each of the two major fining-upward sequences records a gradual decrease in supply of coarse-grained sediment to the submarine canyon head. The first fining-upward sequence may correspond to a lowstand and subsequent rise in global sea level or, alternatively, may have resulted from local downdropping of the basin. The second fining-upward sequence does not correspond to global sea level fluctuations but is age-correlative with a drop then rise in relative sea level recognized by other workers 300-400 km to the north in the San Diego-Ensenada area. This sea level drop is inferred to have been a regional-scale tectonic event that affect the forearc basin along its length. 18 figures, 2 tables.

  1. Biodiversity of macrofaunal assemblages from three Portuguese submarine canyons (NE Atlantic)

    Microsoft Academic Search

    Marina R. Cunha; Gordon L. J. Paterson; Teresa Amaro; Sabena Blackbird; Henko C. de Stigter; Clarisse Ferreira; Adrian Glover; Ana Hilário; Konstadinos Kiriakoulakis; Lenka Neal; Ascensão Ravara; Clara F. Rodrigues; Áurea Tiago; David S. M. Billett

    2011-01-01

    The macrofaunal assemblages from three Portuguese submarine canyons, Nazaré, Cascais and Setúbal were studied from samples collected at their upper (900–1000m), middle (3200–3500m) and lower sections (4200–4500m) and at the adjacent open slopes (?1000m), during the HERMES cruises D297 (R.R.S. Discovery, 2005) CD179 (R.R.S. Charles Darwin, 2006) and 64PE252 (R.V. Pelagia, 2006). The taxonomic composition and patterns in biodiversity, abundance

  2. Dispersal of natural and anthropogenic lead through submarine canyons at the Portuguese margin

    NASA Astrophysics Data System (ADS)

    Richter, T. O.; de Stigter, H. C.; Boer, W.; Jesus, C. C.; van Weering, T. C. E.

    2009-02-01

    Submarine canyons represent natural conduits for preferential transport of particulate material, including anthropogenic contaminants, from coastal zones directly to the deep sea. To assess related dispersal of natural and anthropogenic lead (Pb), we analyzed Pb concentrations and stable isotope ratios in surface sediments and sediment trap particulate material from the Portuguese margin Nazaré and Setúbal/Lisbon canyons. Geochemical data are integrated with previously obtained data on near-bottom hydrodynamics and processes and pathways of sediment transport. The two canyon systems are located in close geographic proximity to each other, but represent contrasting settings in terms of sediment input and down-canyon sediment transport processes. Concentration-isotope diagrams and three-isotope plots ( 206Pb/ 207Pb vs. 208Pb/ 206Pb) suggest binary mixing between natural and anthropogenic end members. The inferred isotopic signature of pollutant Pb ( 206Pb/ 207Pb=1.143 [1.134-1.149, 95% confidence interval]) is most consistent with industrial Pb; ongoing influence from gasoline Pb additives is at most of minor importance. Two proposed natural end members most likely bracket the isotopic signature of natural Pb. Accordingly, binary mixing calculations indicate that on average 20-45% vs. 35-55% of total Pb is derived from anthropogenic sources in the Nazaré and Setúbal-Lisbon canyon systems, respectively. Enhanced anthropogenic influence in the latter area is consistent with its proximity to heavily populated and industrialized areas and with sediment input from the Tagus and Sado rivers, potential major carriers of pollutant particles. In both canyon systems, the anthropogenic component generally decreases with increasing water depth. Isotopic signatures of sediment trap particulate material are generally consistent with surface sediment data at similar water depth, but show large variability in the upper Nazaré canyon and major deviations from surface sediments in the lower canyon. In the lower canyon, Pb isotopic ratios of sediment trap particulate material mostly reflect low pelagic fluxes from the overlying water column, whereas surface sediment signatures are dominated by episodic down-canyon mass transport events. Such gravity flows appear to incorporate older (pre-industrial) material masking the isotopic signature of pollutant Pb. Large variability in the upper canyon reflects continuous sediment resuspension by bottom currents. Stronger average bottom currents are associated with higher 206Pb/ 207Pb ratios of sediment trap particulate material and hence decreased influence of pollutant Pb. This may reflect preferential resuspension of natural Pb at the canyon floor and/or additional remobilization of older, less-polluted sediment in adjacent areas such as the canyon walls.

  3. Sedimentary regime of deep submarine canyons around Fylla Banke, northeastern Labrador Sea

    NASA Astrophysics Data System (ADS)

    Paulsen, Dorthe; Kuijpers, Antoon; Seidenkrantz, Marit-Solveig; Nielsen, Tove

    2014-05-01

    Sedimentary regime of deep submarine canyons around the Fylla Banke, northeastern Labrador Sea Dorthe Paulsen (1), Antoon Kuijpers (2), Marit-Solveig Seidenkrantz (3) and Tove Nielsen (2) 1) Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K 2) Geological Survey of Denmark and Greenland (GEUS), Øster Voldgde 10, DK-1350 Copenhagen K. 3) Centre for Past Climate Studies, Department of Geoscience, Aarhus University. Hoegh-Guldbergs Gade 2, DK-8000 Aarhus C The southern end of the Davis Strait, the comparatively shallow-water area separating the Labrador Sea from the Baffin Bay, is cut by two deep submarine canyons of west Greenland, on the western and eastern side of the Fylla Banke, respectively. The purpose of this study is to investigate Late Pleistocene sedimentary processes governing the area of the two canyons in order to test if gravity flows or ocean currents are the most important factors governing canyon sedimentary processes in this region. Furthermore, an account is given on the formation of the two canyons in order to explain the significant difference between them. The study was carried out based on seismic profiles combined with bathymetric information, and a single sidescan sonar profile from one of the canyons (western canyon). Sedimentary information and an age model are derived from of a 5-m long gravity core (TTR13-AT-479G) collected from the mouth of the western canyon (southern end). The data indicates that the sedimentary regime is today highly affected by northward transport of the ocean currents and that gravity flows (southward from shallower to deep waters) are only of limited significance today. The deep southern end of the canyons are influenced by the upper parts of the deep North Atlantic Deep Water, but the majority of the sediment transport is linked to the strong northward flow of the lower parts of the West Greenland Current. For comparison the sediment transport is held up against earlier studies from the Davis Strait area, where 2D seismic profiles were carried out several places of the west coast of Greenland. These studies are from a contourite drift complex at the Davis Strait and north of Labrador Sea. A further possible process operating in maintaining active sediment transport through the canyon may be the cascading of dense winter water formed on the West Greenland shelf.

  4. Geomorphic characterization of four shelf-sourced submarine canyons along the U.S. Mid-Atlantic continental margin

    USGS Publications Warehouse

    Obelcz, Jeffrey; Brothers, Daniel S.; Chaytor, Jason D.; ten Brink, Uri S.; Ross, Steve W.; Brooke, Sandra

    2013-01-01

    Shelf-sourced submarine canyons are common features of continental margins and are fundamental to deep-sea sedimentary systems. Despite their geomorphic and geologic significance, relatively few passive margin shelf-breaching canyons worldwide have been mapped using modern geophysical methods. Between 2007 and 2012 a series of geophysical surveys was conducted across four major canyons of the US Mid-Atlantic margin: Wilmington, Baltimore, Washington, and Norfolk canyons. More than 5700 km2 of high-resolution multibeam bathymetry and 890 line-km of sub-bottom CHIRP profiles were collected along the outer shelf and uppermost slope (depths of 80-1200 m). The data allowed us to compare and contrast the fine-scale morphology of each canyon system. The canyons have marked differences in the morphology and orientation of canyon heads, steepness and density of sidewall gullies, and the character of the continental shelf surrounding canyon rims. Down-canyon axial profiles for Washington, Baltimore and Wilmington canyons have linear shapes, and each canyon thalweg exhibits morphological evidence for recent, relatively small-scale sediment transport. For example, Washington Canyon displays extremely steep wall gradients and contains ~100 m wide, 5–10 m deep, v-shaped incisions down the canyon axis, suggesting modern or recent sediment transport. In contrast, the convex axial thalweg profile, the absence of thalweg incision, and evidence for sediment infilling at the canyon head, suggest that depositional processes strongly influence Norfolk Canyon during the current sea-level high-stand. The north walls of Wilmington, Washington and Norfolk canyons are steeper than the south walls due to differential erosion, though the underlying cause for this asymmetry is not clear. Furthermore, we speculate that most of the geomorphic features observed within the canyons (e.g., terraces, tributary canyons, gullies, and hanging valleys) were formed during the Pleistocene, and show only subtle modification by Holocene processes active during the present sea-level high-stand.

  5. Rapid Changes on Sediment Accumulation Rates within Submarine Canyons Caused By Bottom Trawling Activities

    NASA Astrophysics Data System (ADS)

    Puig, P.; Masque, P.; Martin, J.; Paradis, S.; Juan, X.; Toro, M.; Palanques, A.

    2014-12-01

    The physical disturbance of the marine sedimentary environments by commercial bottom trawling is a matter of concern. The direct physical effects of this fishing technique include scraping and ploughing of the seabed and increases of the near-bottom water turbidity by sediment resuspension. However, the quantification of the sediment that has been resuspended by this anthropogenic activity over years and has been ultimately exported across the margin remains largely unaddressed. The analysis of sediment accumulation rates from sediment cores collected along the axes of several submarine canyons in the Catalan margin (northwestern Mediterranean) has allowed to estimate the contribution of this anthropogenic activity to the present-day sediment dynamics. 210Pb chronologies, occasionally supported by 137Cs dating, indicate a rapid increase of sediment accumulation rates since the 1970s, in coincidence with a strong impulse in the industrialization of the trawling fleets of this region. Such increase has been associated to the enhanced delivery of sediment resuspended by trawlers from the shelves and upper slope regions towards the canyon's interior, and to the rapid technical development at that time, in terms of engine power and gear size. This change has been observed in La Fonera (or Palamós) Canyon at depths greater than 1700 m, while in other canyons it is restricted to shallower regions (~1000 m in depth) closer to fishing grounds. Two sampling sites from La Fonera and Foix submarine canyons that exhibited high sediment accumulation rates (0.6-0.7 cm/y) were reoccupied several years after the first chronological analyses. These two new cores reveal a second and more rapid increase of sediment accumulation rates in both canyons occurring circa 2002 and accounting for about 2 cm/y. This second change at the beginning of the XXI century has been attributed to a preferential displacement of the trawling fleet towards slope fishing grounds surrounding submarine canyons, and also to technical improvements in trawling vessels, presumably related to subsidies and aids provided by the European Commission to the fishing industry.

  6. ccsd-00089326,version1-17Aug2006 JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Evolution of surface gravity waves over a submarine canyon

    E-print Network

    Paris-Sud XI, Université de

    .1029/, Evolution of surface gravity waves over a submarine canyon R. Magne1,5 , K. A. Belibassakis2 , T. H. C. Herbers3 , Fabrice Ardhuin1 , W. C. O'Reilly4 , and V. Rey5 Abstract. The effects of a submarine canyon

  7. Spatial distribution of phytoplankton assemblages in the Nazaré submarine canyon region (Portugal): HPLC-CHEMTAX approach

    NASA Astrophysics Data System (ADS)

    Mendes, Carlos Rafael; Sá, Carolina; Vitorino, João; Borges, Carlos; Tavano Garcia, Virginia Maria; Brotas, Vanda

    2011-07-01

    The distribution and composition of phytoplankton assemblages were studied in the Nazaré submarine canyon, during an upwelling event, using high-performance liquid chromatography (HPLC) pigment analysis, complemented by microscopic qualitative observations. High chlorophyll a (Chl a) concentrations were recorded in the canyon head, near the coast, where values greater than 4 ?g L - 1 were observed. In contrast, Chl a was relatively low in offshore regions, with values below 0.5 ?g L - 1 . The most abundant accessory pigments were fucoxanthin, peridinin, diadinoxanthin and 19'-hexanoyloxyfucoxanthin. Pigment data information was analyzed using the CHEMTAX software to estimate the contribution of different taxonomic groups to total Chl a. North of the canyon head, an area with high concentration of peridinin-containing dinoflagellates was identified (with presence of chain-forming toxic dinoflagellates). The presence of these organisms was associated with mixed water columns and phosphate values lower than the ones south of the canyon head, where a dominance of diatoms was recorded. The rest of the study region showed a dominance of prymnesiophytes and a significant contribution of cyanobacteria at oceanic stations. This study demonstrates the usefulness of using pigment analysis to study spatial distribution of phytoplankton groups in relation to a complex physical environment.

  8. 3D seismic interpretation of Plio-Pleistocene headless submarine canyons on the Ebro margin: implications for deepwater sand transport

    Microsoft Academic Search

    C. Bertoni; J. Cartwright; J. Fernandez

    2003-01-01

    Recently acquired 3D seismic data from the Ebro continental margin (Eastern Spain) have been used to study a series of spectacular buried post-Messinian submarine canyons that are restricted to the slope i.e. they do not link to incised valleys on the shelf. Understanding the origin of this type of `headless' canyon is important for overall considerations of shelf by-pass and

  9. Describing the development of submarine canyons using stream-power erosion laws

    NASA Astrophysics Data System (ADS)

    Mitchell, N. C.

    2004-12-01

    The problem of how turbidity currents erode their beds is important for understanding how canyons develop, but is complex because flow power also varies as a result of incorporation and deposition of the current's suspended load. In some canyons where the total sedimentary mass passing through the canyon has been much larger than the excavated mass, the loads of the eroding currents changed little during passage down-canyon. Canyon morphology can then potentially reveal how gradient and other factors affect erosion rate, illustrated here with two datasets from tectonically active margins. The first dataset is from Tenryu Canyon off Japan, which was entrenched by up to 1200 m by steepening of the Tokai accretionary prism. Incision depth and channel gradient S data [Soh and Tokuyama, 2002] suggest an erosion law in which incision rate E~S0.8, which is remarkably similar to laws for detachment-limited erosion of river beds. In the second dataset, folds of the Barbados prism have created knickpoints [Huyghe et al., 2004]. Numerical modeling reveals that the knickpoints have partly smoothed out, a property of transport-limited erosion, but primarily have translated, a property of detachment-limited erosion. This mixed style of knickpoint development has also been inferred from some bedrock eroding streams on land. If scaling arguments for erosion with flow velocity apply here [Hancock et al., 1998], the inferred dependence of erosion rate on gradient implies that plucking and shear failure rather than abrasion are the main mechanisms in these channels. Hancock, G.S., Anderson, R.S., and Whipple, K.X., 1998, Beyond power: bedrock river incision process and form, in Tinkler, K.J., and Wohl, E.E., eds., Rivers over rock: Fluvial processes in bedrock channels, American Geophysical Union Monogr. 107: p. 35-60. Huyghe, P., M. Foata, E. Deville, and the Caramba Working Group, Channel profiles through the active thrust front of the southern Barbados prism, Geology, 32, 429-432, 2004. Soh, W., and H. Tokuyama, Rejuvination of submarine canyon associated with ridge subduction, Tenryu Canyon, off Tokai, central Japan, Mar. Geol., 187, 203-230, 2002.

  10. The surface sediment distribution and sedimentary environment of the Pearl River Submarine Canyon

    NASA Astrophysics Data System (ADS)

    Han, X.; Chu, F.; Li, J.; Xu, D.; Zhang, W.

    2012-12-01

    The grain size composition, particle size parameters, clay mineral, and detrital mineral of surface sediment of this The Pearl River Submarine Canyon (the PRSC, for short) area have been measured and analyzed, which were took sampling in 2005 and 2006 in the northern South China Sea. The results show that the isolines distribution features of these parameters have very good corresponding relation with the geomorphology of the PRSC. On the continental-shelf slope break of the PRSC head (123m-1500m water depth), the close interval isolines of the surface sediment particle size percentage content and size parameters nearly parallel with the water depth isolines. The data of sand percentage content and mean grain size, sorting coefficient and skewness decreases with the increase of water depth. The other way around, the silt and clay percentage content and kurtosis value increase with deeper water. These show that in the canyon head sediment distribution was controlled by the material source (mainly comes from the Pearl River), slope and the northern South China Sea offshore current. In the main PRSC area, the surface sediment grain size composition content and grain size parameter numerical isolines have become a isoline platform which has the similar shape with the main PRSC and extended to the northeast and southwest deep sea basin. This means that the sedimentary environment of main canyon is apparently different with the head environment, that is affected by the high-temperature and high-salt the South China Sea Branch of by the Kuroshio along the 3500 m water depth isoline and alone the canyon to bending. The 25% percentage content isoline of the calcium biological and 45% percentage content isoline of the light mineral show a broadband distribution along the head and upside of the PRSC, and reduces in the entrance with the water depth isolines, apparently influenced by the South China Sea Branch of the Kuroshio. A high value area of the silt, clay mineral, light mineral, heavy mineral, silicon biological, and calcium biological appears to the entrance of the PRSC, which may be controlled by a perennial anticlockwise current. But how the materials passed through the South China Sea Branch of the Kuroshio and sediment here still is not be solved. The distribution of clay minerals close to the distribution of grain size, around the main canyon with more loose and uniform interval value isolines. It is lower of the percentage content isolines value of the Illite, Kaolinite and Chlorite in the canyon than the values around the canyon (specially at northeast, northwest, southwest ). And the Smectite percentage content has the opposite distribution, the value is higher in the canyon than out the canyon. Which means that the Traditional knowledge about ocean clay minerals distribution is influenced by the latitude is not adaptive at submarine canyon area. To sum up, the existence of the PRSC has changed the material transport mode from land to deep ocean basin in the northern South China Sea. Not only it played a transfer passageway, but also it played the role of the sorting and aggregation, which is beneficial to the formation and gathering of certain minerals. This work were supported by the NSFC (41106046), the Youth Ocean Science Fund Project, SOA(2011333) and the Basic Scientific Researching Specific Funds of SIO, SOA (JT1002)

  11. A multidisciplinary study of the role of submarine canyons off western Portugal

    NASA Astrophysics Data System (ADS)

    Vitorino, J.; Oliveira, A.; Rodrigues, A.

    2003-04-01

    A multidisciplinary research aimed to characterise the dominant aspects of the Portuguese canyon systems and their role on the shelf-deep ocean sediment exchanges is being conducted in the framework of EU project Eurostrataform. Three contrasting systems are studied: (1) the Nazaré Canyon is a narrow and deep canyon which extends from the deep ocean and completely cuts the NW Portuguese shelf, with no local riverine sources; (2) the Setubal-Lisbon canyon system affects an area marked by complex topography and coastline configuration and with riverine contributions provided by the Tagus and Sado rivers; (3) the Oporto canyon is restricted to the outer shelf, with a major local riverine source (Douro river). We present preliminary results from the ongoing program of observations, which includes multidisciplinary surveys (CTD, suspended particle matter measurments, shallow seismic) and both long- and short-term moorings. Process studies are extended with the use of system MOCASSIM, an operational system for the forecast of oceanographic conditions off the Portuguese coast, which is presently being developped at Instituto Hidrografico. The system integrates wave and circulation models and makes use of data assimilation methods to provide numerical results which are consistent with the observed conditions.

  12. Tidal-dominated Sediment Transport in the Gaoping Submarine Canyon off Southwestern Taiwan: Radiochemical, Sediment Trap and Current Meter Observations

    Microsoft Academic Search

    C. Huh; J. T. Liu; H. Lin; J. Xu

    2008-01-01

    A sediment trap-CTD-current meter array was deployed ~17 m above the seafloor at 22°21.239'N, 120°16.419'E (water depth: 659 m) in the Gaoping submarine canyon (GPSC) from Jan. 10 to Mar. 20, 2008, a period with relatively quiescent weather conditions off southwestern Taiwan. It resulted in a \\

  13. Muscular and Hepatic Pollution Biomarkers in the Fishes Phycis blennoides and Micromesistius poutassou and the Crustacean Aristeus antennatus in the Blanes Submarine Canyon (NW Mediterranean)

    Microsoft Academic Search

    Montserrat Solé; Bastian Hambach; Verónica Cortijo; David Huertas; Pilar Fernández

    2009-01-01

    Submarine canyons are regarded as a sink for pollutants. In order to determine if this theory applied to deep-sea species\\u000a from an important fishing ground (the Blanes submarine canyon) located in the NW Mediterranean, we sampled the commercial\\u000a fish Phycis blennoides and Micromesistius poutassou and the crustacean Aristeus antennatus. Specimens were sampled inside and outside (in the open continental slope)

  14. Tidal and flood signatures of settling particles in the Gaoping submarine canyon (SW Taiwan) revealed from radionuclide and flow measurements

    USGS Publications Warehouse

    Huh, C.-A.; Liu, J.T.; Lin, H.-L.; Xu, J. P.

    2009-01-01

    Sediment transport and sedimentation processes in the Gaoping submarine canyon were studied using sediment trap and current meter moorings deployed at a location during the winter (January-March) and the summer (July-September) months in 2008. At the end of each deployment, sediment cores were also collected from the canyon floor at the mooring site. Samples from sediment traps and sediment cores were analyzed for 210Pb and 234Th by gamma spectrometry. In conjunction with particle size and flow measurements, the datasets suggest that sediment transport in the canyon is tidally-modulated in the drier winter season and flood (river)-dominated in the wetter summer season. From the magnitude and temporal variation of sediment flux in the canyon with respect to the burial flux and sediment budget on the open shelf and slope region, we reaffirm that, on annual or longer timescales, the Gaoping submarine canyon is an effective conduit transporting sediments from the Gaoping River's drainage basin (the source) to the deep South China Sea (the ultimate sink). ?? 2009 Elsevier B.V.

  15. Suspended sediment fluxes and transport processes in the Gulf of Lions submarine canyons. The role of storms and dense water cascading

    Microsoft Academic Search

    Albert Palanques; Xavier Durrieu de Madron; Pere Puig; Joan Fabres; Jorge Guillén; Antoni Calafat; Miquel Canals; Serge Heussner; Jerôme Bonnin

    2006-01-01

    Contemporary suspended sediment transport was studied in seven submarine canyons of the Gulf of Lions (GoL). Current meters equipped with turbidity sensors were moored 4 m above bottom at 300 m depth in the canyon axis from November 2003 to May 2004. Sediment transport events were monitored and studied in relation to forcing conditions. There was a large flood in early December,

  16. Character, Provenance, and Recurrence Intervals of Holocene Turbidites in the Kushiro Submarine Canyon, Eastern Hokkaido Forearc, Japan

    NASA Astrophysics Data System (ADS)

    Noda, A.; Tsujino, T.; Furukawa, R.; Yoshimoto, N.

    2004-12-01

    Eastern Hokkaido forearc, Japan, is located on the Pacific side of the country along the Kuril Trench where large earthquakes and tsunamis have frequently occurred. The earthquake history in this region during the last few centuries is known, based on the historical literature. In order to examine prehistoric earthquakes, geological approach, such as analysis of seismo-turbidites or tusnami deposits, are effective. Two gravity cores (GH03-1033 and GH03-1034) were collected from the bottom of the Kushiro Submarine Canyon, offshore of Kushiro, eastern Hokkaido forearc. The cores contain evidence of several turbidites. Sedimentological, geochemical, and micropaleontological data and high-resolution seismic data have been used to identify character, provenance, and recurrence intervals of the turbidites. Upstream (< 1000 m of the water depth), the Kushiro Submarine Canyon is presumed not to be a pathway for turbidity currents during Holocene, because an accumulation of thick mud lies in the channel. Tephras of Ta-a (AD1739), Ko-c2 (AD1694), Ta-b (AD1667), and Us-b (AD1663) were identified, and used to define the recurrence ages of the turbidite depositions. The provenance of the turbidites in core GH03-1034 collected from the middle part of the canyon was inferred to be the northern slope of the canyon deeper than the shelf edge, on the basis of sand composition and benthic foraminiferal analysis. Strong seismic shocks would have caused repeated turbidity currents into the Kushiro Submarine Canyon. The determined turbidite recurrences (rate of 68 years) are similar to the historical (rate of 79.7 years) and estimated (rate of 77.4 years) recurrence intervals of the earthquakes along the Kuril Trench.

  17. The engineering and geological constraints of the intraslope basins and submarine canyons of the northwestern Gulf of Mexico

    SciTech Connect

    Bryant, W.R.; Yuh Liu, J. [Texas A& M Univ., College Station, TX (United States); Ponthier, J. [Louisiana State Univ., Baton Rouge, LA (United States)

    1995-10-01

    It is well realized that future hydrocarbon discoveries on the upper and lower continental slope and rise off Texas and Louisiana necessitate innovative methods for the construction of platforms and pipelines in a very difficult engineering and complex geological environment. There are 105 intraslope basins and 5 major submarine canyons on the continental slope of the northwestern Gulf of Mexico, many of which may be prime targets for hydrocarbon production. Examination of the physiographic, geophysical and geotechnical characteristics of the intraslope basins of Pigmy and Vaca basins and the Alaminos submarine canyon are used as examples to typify the various engineering and geological constraints that are most likely to be encountered on the continental slope and rise and along the Sigsbee Escarpment in the northwestern Gulf of Mexico. High-resolution bathymetry identifies such constraints as high-angle intraslope basin walls, walls that exceed 40 degrees are not uncommon. Sediment slumps and other instabilities, such as long-term sediment creep and other affects of halokenesis and contemporaneous faulting, are illustrated and evaluated from high-resolution geophysics. The small canyons and large gullies that dissect the parameter flanks of Alaminos Canyon, that may be the results of both recent and old turbidity currents and debris flows, are structures that require engineering consideration in the implement of seafloor structures in, near or down slope of these features.

  18. Microbial Communities in Sunken Wood Are Structured by Wood-Boring Bivalves and Location in a Submarine Canyon

    PubMed Central

    Fagervold, Sonja K.; Romano, Chiara; Kalenitchenko, Dimitri; Borowski, Christian; Nunes-Jorge, Amandine; Martin, Daniel; Galand, Pierre E.

    2014-01-01

    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. PMID:24805961

  19. Submarine canyon morphologies and evolution on a modern carbonate system: the Northern Slope of Little Bahama Bank (Bahamas).

    NASA Astrophysics Data System (ADS)

    Tournadour, Elsa; Mulder, Thierry; Borgomano, Jean; Hanquiez, Vincent; Ducassou, Emmanuelle; Gillet, Hervé; Sorriaux, Patrick

    2013-04-01

    The recent CARAMBAR cruise (Nov. 2010) on the northern slope of Little Bahama Bank (LBB, Bahamas) provided new seafloor and subsurface data, that improve our knowledge on carbonate slope systems. The new high-resolution multibeam bathymetry data (Kongsberg EM302 echosounder) and very high resolution (3.5 kHz/Chirp subbotom profiler) seismic data show that the upper LBB slope is dissected by 18 canyons. These canyons evolve sharply into short channels opening to depositional fan-shaped lobes. These architectural elements form a narrow carbonate gravity system extending over 40 km along the LBB slope. The features previously described as small linear canyons have a more complex morphology than originally supposed. The several architectural elements that can be distinguished share similar characteristics with siliciclastic canyons. The average morphological features of the canyons are: minimum and maximum water depths of 460 and 970 m resp., mean length = 16.3 km and sinuosity = 1.14. Canyons are floored with flat elongated morphologies interpreted as terraces. Some of these terraces are located at the toe of slide scars on canyon heads and canyon sides which suggest that they result from sediment failures. On the Chirp seismic data, wedge-shape aggrading terraces interpreted as "internal levees" can be observed. These terraces would then be formed by overbanking of the upper part of turbidity currents. Between 530 and 630 m water depth, some canyons exhibit an amphitheater-shaped head with a head wall height ranging from 80 to 100 m. The wall edges of these canyon heads consist of coalescing arcuate slump scars, which suggests that the canyons formed by retrogressive erosion. Other canyons show an amphitheater-shaped head that evolves upslope into linear valleys incising the upper slope between 460 m and 530 m water depth. The onset and the spatial distribution of these linear valleys seem to be influenced by sediments transported from oolitic shoals of Walker Cay located 5 km upstream toward the upper slope. Indeed, upslope the canyon heads, the reflectivity map shows low backscatters characteristic of fine grained sediments within small elongated depressions (3-5 km long, 1-5 m deep) that are probably-formed by the flow of sediments coming the platform. These initial results allow a preliminary model of the canyon evolution to be proposed with two stages: (1) a first stage controlled by retrogressive erosion, generating several slides and collapses finally forming the amphitheater-shaped canyon heads, (2) a second stage of retrogressive erosion influenced on the upper slope by the sediment input from the platform along small erosional depressions located seaward of the carbonate bank. These small depressions can locally merge with the canyon heads.

  20. A delta-fed submarine ramp alternative to the canyon-fed depositional model of the Stevens submarine fan system, southeastern San Joaquin basin, Kern County, California

    SciTech Connect

    Harrison, C.P. (Amoco Production Co., Houston, TX (United States))

    1996-01-01

    Deep-marine sands of the Upper Miocene Stevens Sandstone, one of the most important hydrocarbon-producing units in the United States, were deposited by sediment-gravity flows in the Bakersfield Arch area of the southern San Joaquin basin. The Stevens Sandstone has historically been considered to be a thick turbidite succession shed off the southern Sierra Nevada as four fans in a long-lived submarine fan system fed by several large submarine canyons. Access to previously unavailable proprietary 2-D and 3-D seismic data sets, carefully calibrated by well-log and core data, permits a more complete understanding of the depositional architecture of this highly petroliferous, deep-marine depositional system. This study concludes that these units were deposited in a delta-fed, line- sourced deep-sea system, whose distribution was structurally-controlled. Seismic lines examined in this study show evidence for a large fault-controlled slump feature in the area that has been referred to as [open quotes]Rosedale Canyon,[close quotes] and no evidence supports the existence of submarine canyons feeding the system. The highly progradational Stevens interval consists of thick siliciclastic units separated by thin, intervening biosiliceous shales. Seismically, the upper bounding surfaces of these biosiliceous shales represent major downlap surfaces. As sands were deposited by high-density turbidity currents, the area of the present Bakersfield Arch developed into a deep-sea braid plain. Smaller-scale linear features detected on horizon slices through the 3-D seismic data cube have been interpreted in this study as braided channelform features deposited on the deep-sea braid plain. Hydrocarbon production along these linear trends may be associated with porosity and permeability variations resulting from channelized versus non-channelized sedimentation.

  1. A delta-fed submarine ramp alternative to the canyon-fed depositional model of the Stevens submarine fan system, southeastern San Joaquin basin, Kern County, California

    SciTech Connect

    Harrison, C.P. [Amoco Production Co., Houston, TX (United States)

    1996-12-31

    Deep-marine sands of the Upper Miocene Stevens Sandstone, one of the most important hydrocarbon-producing units in the United States, were deposited by sediment-gravity flows in the Bakersfield Arch area of the southern San Joaquin basin. The Stevens Sandstone has historically been considered to be a thick turbidite succession shed off the southern Sierra Nevada as four fans in a long-lived submarine fan system fed by several large submarine canyons. Access to previously unavailable proprietary 2-D and 3-D seismic data sets, carefully calibrated by well-log and core data, permits a more complete understanding of the depositional architecture of this highly petroliferous, deep-marine depositional system. This study concludes that these units were deposited in a delta-fed, line- sourced deep-sea system, whose distribution was structurally-controlled. Seismic lines examined in this study show evidence for a large fault-controlled slump feature in the area that has been referred to as {open_quotes}Rosedale Canyon,{close_quotes} and no evidence supports the existence of submarine canyons feeding the system. The highly progradational Stevens interval consists of thick siliciclastic units separated by thin, intervening biosiliceous shales. Seismically, the upper bounding surfaces of these biosiliceous shales represent major downlap surfaces. As sands were deposited by high-density turbidity currents, the area of the present Bakersfield Arch developed into a deep-sea braid plain. Smaller-scale linear features detected on horizon slices through the 3-D seismic data cube have been interpreted in this study as braided channelform features deposited on the deep-sea braid plain. Hydrocarbon production along these linear trends may be associated with porosity and permeability variations resulting from channelized versus non-channelized sedimentation.

  2. Multiple drivers of particle fluxes in the Blanes submarine canyon and southern open slope: Results of a year round experiment

    NASA Astrophysics Data System (ADS)

    Lopez-Fernandez, Pilar; Calafat, Antoni; Sanchez-Vidal, Anna; Canals, Miquel; Mar Flexas, M.; Cateura, Jordi; Company, Joan B.

    2013-11-01

    To characterize the temporal and spatial variability of total mass fluxes in the Blanes submarine canyon and the nearby southern open slope, eight near-bottom sediment traps were deployed at 300, 900, 1200 and 1500 m along the canyon axis, and at 900, 1200, 1500 and 1800 m of water depth on the southern open slope from November 2008 to November 2009. The results obtained show that mass fluxes were higher into the canyon, ranging from 0.05 to 82.67 g m-2 d-1, compared with those from the open slope that ranged from 0.01 to 9.91 g m2 d-1. Both environments were highly influenced by atmospheric forcing and showed increased total mass fluxes during autumn and winter months. The spatial distribution of total mass fluxes and major constituents (organic matter, carbonate, opal and lithogenics) highlights the contrasts amongst the two physiographic domains in the study area (canyons vs. open slope). The temporal evolution of particle fluxes shows three distinct situations succeeding each other along the year. These are determined by: (1) storms in autumn and winter, driving 60% of the annual total mass flux in Blanes Canyon and 44% in the open slope stations, and also 60% and 40% of the annual OC flux in Blanes Canyon and the southern open slope, respectively; (2) open sea convection in late winter and spring, which is accompanied by a phytoplankton bloom and drives 13% of the settling OC in the canyon and 34% in the open slope; and (3) dust inputs and resuspension by bottom trawling in late spring and -summer months, driving 17% of the annual OC flux in the canyon and 18% in the slope.

  3. Limited depth zonation among bathyal epibenthic megafauna of the Gully submarine canyon, northwest Atlantic

    NASA Astrophysics Data System (ADS)

    Kenchington, E. L.; Cogswell, A. T.; MacIsaac, K. G.; Beazley, L.; Law, B. A.; Kenchington, T. J.

    2014-06-01

    The Gully is a large submarine canyon incised into the Scotian Shelf, in the northwest Atlantic. A submersible-mounted camera was used to collect 17 km of high resolution video imagery of the soft sediment flanks and floor of the canyon between 1000 and 2500 m depth. A depth-stratified random survey design with two transects per stratum was followed. Depth strata were drawn at 1000-1500 m, 1500-2000 m and 2000-2500 m reflecting global and regional faunal boundaries. The 47,614 individuals or colonies observed on the transects were identified into 49 unique taxa drawn from 7 phyla, while 21 additional taxa were observed between the transect lines. Cnidaria was the most diverse phylum (22 taxa) on the transects, followed by the Echinodermata (15 taxa). Most fauna were sessile or sedentary suspension feeders. A species of Xenophyophorida, likely Syringammina sp., was the most abundant taxon. Cluster analysis of transects based on a Bray-Curtis (BC) matrix of species abundance identified one cluster of five transects and one independent transect - the deepest transect (2406 m average depth). A similarity profile test indicated that this structure is not random. There was a significant change in the megafaunal assemblage with depth over scales of 10s of kilometers, accounting for 65% of the variation in the BC matrix. Both total organic carbon and labile carbon were higher in cores from the 1000-1500 m stratum than at greater depth, consistent with transport of food and sediments into the canyon from shallower waters. The first principal component calculated from species abundances separated the two transects from the 1000-1500 m depth stratum from the others indicating that sediment food supply influences community structure and composition. Over small spatial scales (?10 m), eight groups of species associations were identified. However, the associations between the species within each group were not strong with the highest correlation between the Xenophyophorida and the Pennatulacea (?=0.66). At this spatial scale substrate type was an important factor, with hard and soft bottom species associations being identified.

  4. Modeled alongshore circulation and force balances onshore of a submarine canyon

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  5. Numerical simulation of the circulation within the Perth Submarine Canyon, Western Australia

    Microsoft Academic Search

    Susan J. Rennie; Charitha B. Pattiaratchi; Robert D. McCauley

    2009-01-01

    Surface and sub-surface currents along the ocean boundary of Western Australia were simulated using Regional Ocean Modelling System (ROMS) to examine the circulation within the Perth Canyon. Two major current systems influenced the circulation within the canyon: (1) The Leeuwin current interacted weakly with the canyon as the majority of the canyon was below the depth of the Leeuwin current

  6. Deep flow variability in a deeply incised Mediterranean submarine valley (Blanes canyon)

    NASA Astrophysics Data System (ADS)

    Jorda, G.; Flexas, M. M.; Espino, M.; Calafat, A.

    2013-11-01

    Deep flow variability in Blanes canyon is analyzed by means of a unique dataset in which the canyon was instrumented at its axis and at the two canyon walls, from March 2003 to July 2004. The mean intensity of deep currents range between 3.5 cm s-1 (at the canyon axis, 1500 m) and 5.4 cm s-1 (upstream canyon wall, 900 m). A wavelet analysis shows that the energy is concentrated in the 2-30 day band, and it is mainly associated to single (not periodical, not wave-related) events, uncoupled at the different canyon sites. An empirical orthogonal function analysis shows two main patterns of current variability explaining 65% of the total variance. The first mode represents intensifications of the typical along-bathymetry pattern of currents over the canyon. The second mode corresponds to near-bottom upwelling events along the canyon axis with water exiting the canyon through the canyon head. After discussing possible forcing mechanisms, it is here suggested that such deep upwelling events are associated to offshore displacements of the Northern Current. Namely, the interaction of the current with the particular shape of the canyon topography at large depths (>1800 m) would be responsible for the observed deep upwelling events.

  7. Muscular and hepatic pollution biomarkers in the fishes Phycis blennoides and Micromesistius poutassou and the crustacean Aristeus antennatus in the Blanes Submarine Canyon (NW Mediterranean).

    PubMed

    Solé, Montserrat; Hambach, Bastian; Cortijo, Verónica; Huertas, David; Fernández, Pilar; Company, Joan B

    2009-07-01

    Submarine canyons are regarded as a sink for pollutants. In order to determine if this theory applied to deep-sea species from an important fishing ground (the Blanes submarine canyon) located in the NW Mediterranean, we sampled the commercial fish Phycis blennoides and Micromesistius poutassou and the crustacean Aristeus antennatus. Specimens were sampled inside and outside (in the open continental slope) the submarine canyon; both are regarded as potentially affected by exposure to different anthropogenic chemicals. Several pollution biomarkers in muscle (activity of cholinesterases) and liver/hepatopancreas (catalase, glutathione S-transferases, carboxylesterases, ethoxyresorufin O-deethylase in fish or mixed function oxygenase (MFO)-related reductases in crustacean, and lipid peroxidation levels) were measured. Chemical analysis of the persistent organic pollutants, namely polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) was also performed on the fish and crustacean muscle. Biomarker activities and levels were discussed in relation to pollutant exposure, habitat, and parameters including sex, size, and species. Biochemical responses and chemical analysis of PCBs evidenced interspecies differences as well as sex and size-related ones, mainly in A. antennatus. An indication of higher exposure to pollutants inside the canyon was observed, which was more clearly reflected in the fish than in the crustacean. However, further research is required to confirm this observation. PMID:18941829

  8. Provenance and fate of organic carbon in three submarine canyons from the Portuguese Margin: Implications for transport processes of material in continental margins

    NASA Astrophysics Data System (ADS)

    Kiriakoulakis, Kostas; Wolff, George; Blackbird, Sabena

    2010-05-01

    Submarine canyons are key environments on the continental margin that are affected by unique and dynamic but often episodic and complex processes, and are difficult to study. Canyons are considered hotspots of biodiversity and enhancement of primary productivity at canyon heads has often been postulated to support this, although the evidence is sparse. Additionally canyons are considered to be fast-track corridors for material transported from the land to the deep sea and they are considered major pathways for the transportation and burial of organic carbon, acting as buffers for sediment and carbon storage. Organic geochemical and isotopic markers are often used as reliable indicators for the supply, quality and fate of organic matter in marine systems. In this study they have been used to test the above hypotheses in three contrasting submarine canyons (Nazaré, Setubal/Lisbon and Cascais) of the Portuguese Margin. The elemental and lipid biomarker composition of suspended particulate organic matter of surface waters close to the studied canyon heads had a fresh phytoplankton signal, however there was no clear evidence for enhanced primary productivity by comparison to the neighbouring open slope. By contrast, mid-depth waters (700-1600 m), that are dominated by the northward flowing Mediterranean Outflow Water, had high lipid content and abundant mesozooplankton biomarkers, perhaps reflecting zooplankton activity focused at the boundaries of distinct water masses. In the waters close to the floor of the Nazaré Canyon the presence of elemental sulphur (a product of sediment diagenesis) and high molecular weight hydrocarbons (recalcitrant, terrestrial markers) indicated high levels of resuspended material, particularly at the Upper section (

  9. 78 FR 67086 - Safety Zone, Submarine Cable Replacement Operations, Kent Island Narrows; Queen Anne's County, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ...USCG-2013-0908] RIN 1625-AA00 Safety Zone, Submarine Cable Replacement Operations, Kent Island...their vessels on navigable waters during submarine cable replacement operations at the Kent...This rule involves the installation of a submarine cable within a federal navigation...

  10. Migration–aggradation history and 3-D seismic geomorphology of submarine channels in the Pleistocene Benin-major Canyon, western Niger Delta slope

    Microsoft Academic Search

    Mark E. Deptuck; Zoltan Sylvester; Carlos Pirmez; Ciaran O’Byrne

    2007-01-01

    Several laterally offset and aggradational sinuous submarine channels are contained within a 54km long segment of the Benin-major Canyon. Axial channel deposits produce high amplitude reflections on three-dimensional (3-D) seismic profiles. Some seismic reflections have U- or V-shaped cross-sectional motifs that were correlated with confidence along linear to meandering paths for distances up to 70km. They are referred to here

  11. Defining biological assemblages (biotopes) of conservation interest in the submarine canyons of the South West Approaches (offshore United Kingdom) for use in marine habitat mapping

    NASA Astrophysics Data System (ADS)

    Davies, Jaime S.; Howell, Kerry L.; Stewart, Heather A.; Guinan, Janine; Golding, Neil

    2014-06-01

    In 2007, the upper part of a submarine canyon system located in water depths between 138 and 1165 m in the South West (SW) Approaches (North East Atlantic Ocean) was surveyed over a 2 week period. High-resolution multibeam echosounder data covering 1106 km2, and 44 ground-truthing video and image transects were acquired to characterise the biological assemblages of the canyons. The SW Approaches is an area of complex terrain, and intensive ground-truthing revealed the canyons to be dominated by soft sediment assemblages. A combination of multivariate analysis of seabed photographs (184-1059 m) and visual assessment of video ground-truthing identified 12 megabenthic assemblages (biotopes) at an appropriate scale to act as mapping units. Of these biotopes, 5 adhered to current definitions of habitats of conservation concern, 4 of which were classed as Vulnerable Marine Ecosystems. Some of the biotopes correspond to descriptions of communities from other megahabitat features (for example the continental shelf and seamounts), although it appears that the canyons host modified versions, possibly due to the inferred high rates of sedimentation in the canyons. Other biotopes described appear to be unique to canyon features, particularly the sea pen biotope consisting of Kophobelemnon stelliferum and cerianthids.

  12. A Picture on the Wall: Innovative Mapping Reveals Cold-Water Coral Refuge in Submarine Canyon

    PubMed Central

    Huvenne, Veerle A. I.; Tyler, Paul A.; Masson, Doug G.; Fisher, Elizabeth H.; Hauton, Chris; Hühnerbach, Veit; Le Bas, Timothy P.; Wolff, George A.

    2011-01-01

    Cold-water corals are azooxanthellate species found throughout the ocean at water depths down to 5000 m. They occur in patches, reefs or large mound structures up to 380 m high, and as ecosystem engineers create important habitats for a diverse fauna. However, the majority of these habitats are now within reach of deep-sea bottom trawling. Many have been severely damaged or are under threat, despite recent protection initiatives. Here we present a cold-water coral habitat type that so far has been overlooked – quite literally – and that has received minimal impact from human activities. Vertical and overhanging cliffs in deep-sea canyons, revealed using an innovative approach to marine habitat mapping, are shown to provide the perfect substratum for extensive cold-water coral-based communities. Typical canyon-related processes, including locally enhanced internal tides and focussed downslope organic carbon transport, provide favourable environmental conditions (current regime, food input) to sustain the communities, even outside the optimal depth and density envelopes reported elsewhere in the NE Atlantic. Our findings show that deep-sea canyons can form natural refuges for faunal communities sensitive to anthropogenic disturbance, and have the potential to fulfil the crucial role of larval sources for the recolonisation of damaged sites elsewhere on the margin. PMID:22194903

  13. Impact of Bottom Trawling on Deep-Sea Sediment Properties along the Flanks of a Submarine Canyon

    PubMed Central

    Martín, Jacobo; Puig, Pere; Masqué, Pere; Palanques, Albert; Sánchez-Gómez, Anabel

    2014-01-01

    The offshore displacement of commercial bottom trawling has raised concerns about the impact of this destructive fishing practice on the deep seafloor, which is in general characterized by lower resilience than shallow water regions. This study focuses on the flanks of La Fonera (or Palamós) submarine canyon in the Northwestern Mediterranean, where an intensive bottom trawl fishery has been active during several decades in the 400–800 m depth range. To explore the degree of alteration of surface sediments (0–50 cm depth) caused by this industrial activity, fishing grounds and control (untrawled) sites were sampled along the canyon flanks with an interface multicorer. Sediment cores were analyzed to obtain vertical profiles of sediment grain-size, dry bulk density, organic carbon content and concentration of the radionuclide 210Pb. At control sites, surface sediments presented sedimentological characteristics typical of slope depositional systems, including a topmost unit of unconsolidated and bioturbated material overlying sediments progressively compacted with depth, with consistently high 210Pb inventories and exponential decaying profiles of 210Pb concentrations. Sediment accumulation rates at these untrawled sites ranged from 0.3 to 1.0 cm y?1. Sediment properties at most trawled sites departed from control sites and the sampled cores were characterized by denser sediments with lower 210Pb surface concentrations and inventories that indicate widespread erosion of recent sediments caused by trawling gears. Other alterations of the physical sediment properties, including thorough mixing or grain-size sorting, as well as organic carbon impoverishment, were also visible at trawled sites. This work contributes to the growing realization of the capacity of bottom trawling to alter the physical properties of surface sediments and affect the seafloor integrity over large spatial scales of the deep-sea. PMID:25111298

  14. Trophic relationships at intrannual spatial and temporal scales of macro and megafauna around a submarine canyon off the Catalonian coast (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Cartes, Joan E.; Fanelli, Emanuela; Papiol, Vanesa; Maynou, Francesc

    2010-04-01

    The spatial and temporal changes of near-bottom macrofauna (suprabenthos and macroplankton) and the trophic relationships of megabenthic decapod crustaceans were analyzed off the Catalonian coasts (western Mediterranean) around Berenguera submarine canyon in four periods (April and December 1991, March and July 1992) and four zones (within Berenguera Canyon at ca. 450 m, and on adjacent slope at ca. 400, 600 m and 1200 m). In March 1992, we found the highest macrofauna abundance and the smallest sizes in the canyon, suggesting a positive effect of river discharges on suprabenthos recruitment. By contrast, macroplankton (decapods, fishes and euphausiids) did not show higher recruitment into canyons. After analyzing the diet of 23 decapod crustaceans, we found a significant segregation between guilds feeding on zooplankton and on benthos. Zooplankton (euphausiids and Pasiphaeidae) and infauna (polychaetes, Calocaris macandreae and ophiuoroids) were consistently the main prey exploited by decapod crustaceans around Berenguera Canyon. We also found some macrophyte ( Posidonia oceanica) consumption, which was higher in periods of water column homogeneity (winter-spring and late autumn). Positive correlations between decapods' gut fullness ( F) and decapod abundance indicate feeding aggregations, while positive correlations were also found between F and Llobregat River (situated ca. 18 km from Berenguera head) flow 1 to 2 months before sampling. Increases in F were delayed only 1 month when zooplankton feeders were analyzed alone, while benthos feeders did not show significant relationships with any environmental variables. That indicates that the response of megabenthic decapods feeding on benthos to environmental shifts is slower than that of zooplankton feeders. The importance of river flows in enhancing food supply of macro- and megabenthos dwelling close to submarine canyons was apparent, with a delay in the fauna response of 0-2 months after river flow peaks.

  15. From Kings Peak to the Delgado submarine canyon: Tracking littoral inputs to the deep sea at the Mendocino Triple Junction, California

    NASA Astrophysics Data System (ADS)

    Davidson, C. J.; Di Fiori, R. V.; Smith, M. E.; Mueller, E. R.

    2011-12-01

    Gravel coarse enough to overcome viscous damping and impact bedrock underwater is thought prerequisite for incision of submarine canyons, yet with few exceptions, canyons off the California coast have headwalls >2 km offshore at the shelf edge and below storm wave base. This suggests effective disconnection from modern coarse littoral sediment fluxes, and implies they are relict Pleistocene features only actively incised during glacial periods. North of the Transverse Ranges only five submarine canyons approach shore closer than 500 m, and are coincident areas of rapid uplift. Although canyons occur adjacent to major upland-draining streams that transport coarse sediment, submarine canyon headwalls are often laterally offset from stream mouths by ~1-2 km. Coarse stream sediment thus requires littoral transport to enter canyon heads and induce incision. To better understand the evolution of coarse sediment through the littoral system, we measured the texture and composition of coarse sediment in streams and beaches directly onshore of the Delgado submarine canyon, which lies offshore of the fastest uplifting segment of the King Range and onshore the Mendocino Triple Junction. Adjacent to the Delgado Canyon inlet, coarse (d50 > 360 mm) sediment enters the littoral zone from three streams, and is transported alongshore in a predominantly southeast direction. Stream-derived alluvium is comprised of a poorly to moderately sorted mixture of angular to subrounded clasts of well-cemented sandstone (d50 = 256-725 mm) and fissile siliciclastic mudstone (d50 = 90-256 mm). Well sorted and rounded beach gravels adjacent to stream mouths are similarly coarse, and clasts larger than 1 m diameter extend 200-400 meters eastward from stream mouths. In contrast, sediment entering the littoral zone from hillslope erosion between streams is finer (d50 ~16 mm) and is exclusively comprised of pervasively-folded siliciclastic mudstone. Immediately adjacent the Delgado canyon headwall, beach sediments are nearly two orders of magnitude finer than sediment at stream mouths (d50 = 16 mm). However, sandstone clasts are coarser (d50 = 32 mm), comprise ~30% of the total mass, and approximately 10% of these clasts exceed 128 mm in diameter. The mudstone fraction in contrast is much finer (d50 = 4 mm). Particles finer than 0.25 mm represent less than 10% of beach sediment, consistent with effective removal of fines from the littoral environment. Lithologic contrast between sandstone and mudstone rock types is the basis for a multi-lithologic downstream fining model that routes sediment through the littoral system. Inputs of sediment are calculated according to upstream catchment area for 200 m segments of coastline and scaled according to lithologically based erosion rates, with differential diminuation as it is routed through the littoral zone. Initial model results indicate that differential abrasion of mudstone clasts relative to sandstone clasts is important to achieving grain size and lithologic distributions observed at the canyon head, and the presence of clasts >100 mm diameter ~1 km from their input via stream to the littoral zone provides tools needed for incision submarine bedrock.

  16. Sediment dynamics on the narrow, canyon-incised and current-swept shelf of the northern KwaZulu-Natal continental shelf, South Africa

    NASA Astrophysics Data System (ADS)

    Green, Andrew

    2009-08-01

    Side-scan sonar, multibeam bathymetry, ShipekTM grab, and high- to moderate-resolution sub-bottom data for the northern KwaZulu-Natal continental shelf reveal further insights into the interactions between sediment dynamics, strong western boundary currents and submarine canyon topography. Unlike previously recognised mechanisms for bedload parting on current-swept shelves, bedload partings here are the result of complex interactions between the western boundary poleward-flowing Agulhas Current and submarine canyon topography. This has resulted in bedforms orientated orthogonally to the canyon axis, with sediments entrained equator-wards into the canyon heads before resuming their dominant southerly migration. It is in these zones of parting where the most prominent bedforms occur; these bedform fields are formed by positive feedback in the boundary layer between an increasingly undulatory Agulhas Current and a seafloor incised by regularly spaced submarine canyons. Bedform morphometrics such as wavelength-height, depth-height and distance from thalweg-height relationships show no distinct patterns, indicating that the bedforms are heavily reworked and appear to be out of equilibrium with the inherent oceanographic conditions.

  17. Megalodicopia hians in the Monterey submarine canyon: Distribution, larval development, and culture

    NASA Astrophysics Data System (ADS)

    Havenhand, Jon. N.; Matsumoto, George I.; Seidel, Ed

    2006-02-01

    The exclusively deep-sea ascidian family Octacnemidae comprises several genera in which the oral siphon has hypertrophied to form two large lips which create an "oral hood" capable of capturing motile prey. Megalodicopia hians is typical of this carnivorous family and has been reported to prey upon small epibenthic crustaceans. Distribution of M. hians in the Monterey Canyon system (36°45'N, 122°00'W) (California) was determined with remotely operated vehicles. M. hians was found sparsely to depths of at least 3800 m throughout the canyon; however, abundance was greatest within the oxygen-minimum zone (400-800 m). Eggs, sperm, and recently fertilized embryos were obtained repeatedly from adults returned to the laboratory in vivo, indicating that this species free-spawns routinely. Overall egg diameter (ovum plus chorion, plus follicle cells) was 175-190 ?m—considerably smaller than previously reported for this species. Embryonic development at temperature and oxygen concentrations equivalent to the oxygen-minimum zone was 2-4 d and, embryos gave rise to typical phlebobranch "simple" tadpole larvae. Larval period was extremely variable, and settlement/metamorphosis occurred up to 3 months post-hatching. These results are discussed within the context of settlement-site selection and fertilization ecology of the species.

  18. Delivery of Terrigenous Material to Submarine Fans: Biological Evidence of Local, Staged, and Possibly Full Canyon Sediment Transport Down the Ascension-Monterey Canyon System Off Central California, USA

    NASA Astrophysics Data System (ADS)

    McGann, M.

    2014-12-01

    Submarine canyons are instrumental in transporting sediment from coastal regions to deep-sea fans. Mean grain size, distribution, and sorting have been used to characterize these deposits, but they provide little information on where sediment transport was initiated or the delivery processes involved. Fortunately, the entrained biological constituents have unique environmental signatures that are more precise proxies for source areas than are mineral grains alone. They may identify a single biofacies deposit (SBD) resulting from local sediment transport such as storm waves, peak river discharge, breaking of internal waves, canyon wall sloughing, or hemipelagic deposition, or a displaced, multiple biofacies deposit (MBD) containing several biofacies where sediment is transported from one biofacies to another, is caught behind a slump that acts as a dam, remains there long enough for the local fauna to become established, and then this combined assemblage is transported further downslope when the dam breaks. Multiple episodes of this "staged" storage-and-release process occur sequentially so as to move the sediment progressively down the canyon. Rarely, exceptionally large triggers such as earthquakes, intense storm disturbances, and catastrophic failure of canyon walls result in full canyon flushing events, entraining numerous biofacies during a single rapid descent. These events can be differentiated in recent deposits by the presence of living specimens representing distinct biofacies or in historic records by dating individual biofacies within a turbidite. A 19,000 year record from the Ascension-Monterey Canyon system (core S3-15G, 36°23.53'N, 123°20.52'W; 3491 m) captured hemipelagic mud interspersed with turbiditic sand and silt transported to lower bathyal depths. The relative abundance of displaced benthic foraminifera was found to correlate positively with grain size (75% in cross-bedded turbiditic sands, 39% in laminated turbiditic sands, and 15% in turbiditic muds) and the 65 MBDs recovered originated from the estuarine/inner shelf to the upper middle slope. Sediment bypassing was evident and possibly full canyon flushing as well. Identifying allochthonous biological sediment constituents is a powerful tool in the investigation of sediment transport in submarine canyons.

  19. Sediment transport off Bangladesh: the power of tropical cyclones recorded in a submarine canyon

    NASA Astrophysics Data System (ADS)

    Meyer, I.; Kudrass, H.; Palamenghi, L.

    2011-12-01

    Marine sediments offshore Bangladesh are mainly supplied by the Ganges-Brahmaputra river system and are accumulated on the shelf of Bangladesh. The average sediment discharge of the world's biggest river system is estimated to be 0.8-1 billion tons per year. The shallow shelf is cut by a steep and up to 1000 m deep anaerobic canyon, called the "Swatch of No Ground", which acts as a sediment trap. An extremely high annual sedimentation flux of 20-45 cm was determined for the last 50 years by 137Cs and 210Pb measurements. In order to investigate the sediment transport in the Bay of Bengal a marine sediment core was taken from the mid-part of the Swatch of No Ground (21°18N/89°34E) and analyzed for element composition and grain-size distributions. Results show a sequence of graded fine-sand-silt-clay layers. These sequences can be directly related to the historical record of tropical storms, which move across the northern Bay of Bengal during pre- and post-monsoon flood peak and mobilize huge amounts of the shallow marine and coastal sediments into turbid hyperpycnal water masses. Due to the anti-clockwise rotation of the cyclones and their northward path the main transport direction is westward. The coarse grained sediment, remobilized by storm waves, is supported by cyclone-induced currents toward the canyon while the fine grained fraction follows afterward supported by the storm swell plus the semi-diurnal tidal component. Despite the high riverine input the amount of sediment mobilized during normal weather conditions is minimal compared to the sediment mobilized by the cyclonic high-energy input. Similar cyclone-induced sediment transport probably also governs erosion and deposition in most tropical shelf areas affected by the monsoon regime.

  20. Large-scale stratigraphic architecture and sequence analysis of an early Pleistocene submarine canyon fill, Monte Ascensione succession (Peri-Adriatic basin, eastern central Italy)

    NASA Astrophysics Data System (ADS)

    Di Celma, Claudio; Teloni, Riccardo; Rustichelli, Andrea

    2014-04-01

    The Monte Ascensione succession (c. 2.65-2.1 Ma) is a well-exposed example of an exhumed submarine canyon fill embedded within slope hemipelagic mudstones. This gorge represented a long-lasting pathway for sediment transport and deposition and during the Gelasian delivered Apennine-derived clastic sediment to the adjacent Peri-Adriatic basin. A total of six principal lithofacies types, representing both canyon-confining hemipelagic deposits and canyon-filling turbidity current and mass-transport deposits, can be delineated in the studied sedimentary succession. The canyon-fill deposits display a marked cyclic character and the component lithofacies succeed one another to form at least fifteen fining-upward stratal units, which are interpreted to represent high-frequency, unconformity-bounded depositional sequences. Variability in the vertical repetition of constituent lithofacies allows the identification of three basic styles of sequence architecture that can be interpreted in terms of differing positions along a conceptual down-canyon depositional profile. An integrated chronology, based on biostratigraphic data and on palaeomagnetic polarity measurements, strongly supports a one-to-one correlation between the sequence-bounding surfaces and oxygen isotope stages G2-78, suggesting that the most feasible sequence-engendering mechanism is that of orbitally dictated glacio-eustatic changes in sea level, which regulated timing of sediment storage on the shelf and its redistribution beyond the shelf edge. One of the most significant aspects of this study is the demonstration that processes occurring within upper slope canyons can be expected to be strongly influenced by variations in sea level; that is, the erosional and depositional features evident in these deposits can be strongly controlled by allocyclic processes rather than autocyclic or random processes.

  1. Mapping the Canyon

    NSDL National Science Digital Library

    In this activity, students will learn about the bathymetry of Hudson Canyon, a submarine canyon on the Atlantic coast of North America. As they study Hudson Canyon, they will compare and contrast topographic maps and bathymetric maps, investigate the various ways in which bathymetric maps are made, and learn how to interpret bathymetric maps.

  2. Sedimentology, architecture, and depositional evolution of a coarse-grained submarine canyon fill from the Gelasian (early Pleistocene) of the Peri-Adriatic basin, Offida, central Italy

    NASA Astrophysics Data System (ADS)

    Di Celma, Claudio

    2011-07-01

    The early Pleistocene stratigraphic succession of the Peri-Adriatic basin, eastern central Italy, records the filling of an elongate, N-S oriented piggy-back basin located east of the growing Apennine fold-thrust belt. During the Gelasian (2.588-1.806 Ma), large volumes of gravel, sand and mud derived from the emergent Apennines were redistributed into the basin through a number of slope erosional fairways. These sediment conduits are preserved in the rock record as a series of coarse-grained canyon-fill successions that provide an opportunity for assessing, from an outcrop perspective, how this type of deep-water depositional systems evolves and fills. The present study uses measured stratigraphic sections, photopanels, paleocurrent data, careful lithological mapping, and well-log data from a nearby exploration well to constrain the internal organization of one of these canyon fills, referred to herein as the Offida Canyon. A detailed facies analysis suggests that a variety of gravity-driven subaqueous flows were involved in sediment transport and deposition within the submarine canyon, including slumps, cohesive debris flows, and high- and low-density turbidity currents. Five main lithofacies reflecting both canyon-bounding slope deposits and canyon-filling turbidite and debrite depositional elements have been identified within the exposed succession: (i) clast-supported conglomerates (gravel-rich channel complexes); (ii) medium- to thick-bedded sandstones (overbank lobe); (iii) medium- to very thin-bedded sandstones and mudstones (levee-overbank); (iv) pebbly mudstones and chaotic beds (mudstone-rich mass-transport deposits); and (v) massive mudstones (hemipelagic background deposits). These lithofacies are organized in recurring successions and define fining-upward packages that are regarded as the deep-water expression of high-frequency depositional sequences. Each sequence comprises the sedimentary record of major phases of canyon activity and comprises the following surfaces and systems tracts, in ascending stratigraphic order: (i) a pronounced surface of erosion (sequence boundary) generated by efficient turbidity currents during a period of erosion and complete bypass of sediment to more basinward settings; (ii) a lowstand systems tract composed of a diverse assemblage of genetically related lithofacies (channel-complex conglomerates, levee sandy heterolithics, and overbank lobe sheet-like sandstones) laid down by turbidity currents largely bypassing the area; and (iii) a transgressive to forced regressive systems tract comprising mass-transport deposits produced by instability of shelf-edge staging areas and/or failure of canyon walls when coastal sediment sources were far from the shelf edge. Correlation between sequences and oxygen isotope curve suggests that the recurring fluctuations in sedimentary activity of the submarine canyon are related to the switching on and off of coarse clastic sediments to the slope in response to obliquity-driven (41 ky duration) glacio-eustatic sea-level oscillations, which modulated timing of sediment storage on the shelf and its redistribution beyond the shelf edge.

  3. Structure-Forming Corals and Sponges and Their Use as Fish Habitat in Bering Sea Submarine Canyons

    Microsoft Academic Search

    Robert J. Miller; John Hocevar; Robert P. Stone; Dmitry V. Fedorov

    2012-01-01

    Continental margins are dynamic, heterogeneous settings that can include canyons, seamounts, and banks. Two of the largest canyons in the world, Zhemchug and Pribilof, cut into the edge of the continental shelf in the southeastern Bering Sea. Here currents and upwelling interact to produce a highly productive area, termed the Green Belt, that supports an abundance of fishes and squids

  4. Biophysical factors affecting the distribution of demersal fish around the head of a Submarine Canyon off the Bonney Coast, South Australia.

    PubMed

    Currie, David R; McClatchie, Sam; Middleton, John F; Nayar, Sasi

    2012-01-01

    We sampled the demersal fish community of the Bonney Canyon, South Australia at depths (100-1,500 m) and locations that are poorly known. Seventy-eight species of demersal fish were obtained from 12 depth-stratified trawls along, and to either side, of the central canyon axis. Distributional patterns in species richness and biomass were highly correlated. Three fish assemblage groupings, characterised by small suites of species with narrow depth distributions, were identified on the shelf, upper slope and mid slope. The assemblage groupings were largely explained by depth (?w?=?0.78). Compared to the depth gradient, canyon-related effects are weak or occur at spatial or temporal scales not sampled in this study. A conceptual physical model displayed features consistent with the depth zonational patterns in fish, and also indicated that canyon upwelling can occur. The depth zonation of the fish assemblage was associated with the depth distribution of water masses in the area. Notably, the mid-slope community (1,000 m) coincided with a layer of Antarctic Intermediate Water, the upper slope community (500 m) resided within the core of the Flinders Current, and the shelf community was located in a well-mixed layer of surface water (<450 m depth). PMID:22253907

  5. Habitat associations of deep-water rockfishes in a submarine canyon: an example of a natural refuge

    Microsoft Academic Search

    Mary M. Yoklavich; H. Gary Greene; Gregor M. Cailliet; Deidre E. Sullivan; Robert N. Lea; Milton S. Love

    Abstract.?A multidisciplinary assess- ment,of benthic ,rockfishes,(genus Se- bastes) and associated,habitats,in deep water,was ,conducted ,in Soquel ,Sub- marine Canyon, Monterey Bay, Califor- nia. Rock habitats,at depths,to 300 m

  6. Submarine canyon, slope, and shelf sedimentation in an upper Eocene-Oligocene progradational system (Limnos Island, north Aegean Sea, Greece)

    SciTech Connect

    Roussos, N. (Public Petroleum Corp. of Greece, Athens)

    1988-08-01

    The only well-exposed outcrops of a post-Alpine late Eocene-Oligocene basin in the north Aegean Sea are at Limnos Island. These mostly consist of typical slope deposits overlain by remnants of shallow marine shelf and continental (braided-river) deposits. Three main slope lithofacies are distinguished. Canyon deposits consist of thick-bedded, massive, and pebbly sandstones (facies B), conglomerates (facies A), pebbly mudstone where the matrix shows flow (facies F), rock falls (nummulitic limestones), and zones of slump folds in sandstones (facies F). Channelized facies of massive sandstones, classical turbidites, and thin interbeds of sandstone and mudstone (facies E - probably overbank or levee deposits) are associated with canyon deposits. Pelagic and hemipelagic slope deposits consist of mudstone (facies G) and thin-bedded sandstone (facies D) with occasional small to medium-scale slump folds. These mud-rich slope deposits are incised by several channels filled with conglomerates, thick massive sandstones with well-developed dish structures, and turbidites interbedded with thin layers of mudstone (facies C). This unit composes a typical thinning and fining-upward sequence.

  7. Canyon dynamics and related sedimentary impacts off western Portugal

    NASA Astrophysics Data System (ADS)

    Vitorino, J.; Oliveira, A.; Silva, R.; Quaresma, L.; Marreiros, R.

    2003-04-01

    Submarine canyons are areas of increased exchanges between the continental shelf and the deep ocean. We present preliminary results from a multidisciplinary research focussing the dynamics of several canyon systems that occur along the Portuguese continental margin. The research is being conducted in the framework of EU project Eurostrataform and aims to understand the dominant aspects of the interaction between shelf/slope flows and canyons and to relate those aspects with the exportation of sediments from the shelf. The present work is intended to complement results from previous projects that were focussed on the quasi-inertial dynamics of the Portuguese canyon systems. Three contrasting systems are studied: (1) the Nazaré Canyon, a narrow and deep canyon which completely cuts the shelf, with no local riverine sources; (2) the Setubal-Lisbon canyon system, located in an area of complex topography and coastline configuration, with local riverine sources (Tagus and Sado rivers) and (3) the Oporto canyon, which is restricted to the outer shelf and affected by a major riverine source (Douro river). The ongoing program of observations includes multidisciplinary surveys (CTD, ADCP, suspended particle matter measurements, shallow seismic) and both long-term and short-term currentmeter moorings. The observations will cover both the summer upwelling regime as well as the highly energetic winter conditions. Process studies will combine observations and numerical modeling tools through the use of MOCASSIM system, which is presently being developed at Instituto Hidrografico. The system integrates several numerical models and is intended to characterise the wave and current conditions over the study areas.

  8. Topographic analysis of submarine cable failures offshore southwestern taiwan

    NASA Astrophysics Data System (ADS)

    Hsia, Pei Cheng; Shine Liu, Char; Hsu, Ho Han

    2013-04-01

    In 2006, there was large scale of the submarine cable failures offshore southern Taiwan right after the Pingtung Earthquake. Apparently the December 26 Pingtung Earthquake triggered submarine mass movements which generated turbidity currents in the submarine canyons and damaged cables lying across the canyons. In addition, the Typhoon Morakot on August 8-9, 2009 and the Jiashian Earthquake on March 4, 2010 also caused many submarine cable failures offshore southwestern Taiwan. The most of broken cable sites are along the axis of the Gaoping Submarine Canyon (GPSC) and Fangliao Submarine Canyon (FLSC), topography should be an important factor controlling transport processes of submarine mass movement. The cable broken sites indicate that there were submarine mass movement pass through. Therefore, the topographic factor of the cable broken sites can be the threshold to index submarine mass movement. And as, submarine cables are distributed widely offshore southwestern Taiwan, why only a total of 35 sites of submarine cable failures occurred in 2006, 2009 and 2010? We use bathymetry data, CHIRP (compressed high-intensity radar pulse) sonar profile data and the time series of the cable breakage to investigate the characteristics of submarine mass movement and to develop a model for the series of submarine cable failure. Using the Geographic Information System (GIS) software, we analyze the bathymetric data collected before the 35 sites of submarine cable failures offshore southwestern Taiwan. Applying the hydrology in GIS software, the flow movement could be derived from the factors of slope and aspect. We quantify the transport process of submarine mass movement and combine with the time series of the cable breakage to discuss the effect between submarine cable failures. Based on the CHIRP sonar data, we identified the distinct CHIRP echo character patterns after the submarine cable failures and classify the distinct CHIRP echo characters. Using the threshold of topographic factor to expect where will be potential area of submarine mass movement and evidence the result by CHIRP sonar profile data.

  9. Shallow-water longshore drift-fed submarine fan deposition (Moisie River Delta, Eastern Canada)

    E-print Network

    St-Ong, Guillaume

    ORIGINAL Shallow-water longshore drift-fed submarine fan deposition (Moisie River Delta, Eastern Submarine canyons and associated submarine fans are in some cases located at the end of a littoral cell to the discovery of an unusu- ally shallow submarine fan (60 m) located at the end of a littoral cell. Sediment

  10. Let's Bet on Sediments! Hudson Canyon Cruise--Grades 9-12. Focus: Sediments of Hudson Canyon.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    These activities are designed to teach about the sediments of Hudson Canyon. Students investigate and analyze the patterns of sedimentation in the Hudson Canyon, observe how heavier particles sink faster than finer particles, and learn that submarine landslides are avalanches of sediment in deep ocean canyons. The activity provides learning…

  11. Ryan Canyon Hull Canyon

    E-print Network

    ten Brink, Uri S.

    Geospatial-Intelligence Agency (http://earth-info.nga.mil/gns/html/index.html) Bathymetry is from National:1,500,000 Contour interval 500 meters Depths referenced to Instantaneous Sea Level Canyon names are from National

  12. SUBMARINE GEOLOOY REP

    E-print Network

    Russell, Lynn

    SUBMARINE GEOLOOY REP. Investigation of bead of Monterey Submarine Canyon. Contract N6ori-lll. March 1948. 36p. 2. Shepard, Francis P Erosion '8o."U"d. Teshnieal Hemo- rand'IIJil No.2.3, July 1951. 10. Inman, Douglas L. SUbmarine topoerapey

  13. Submarine landslide hazard off Northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, C. L.; Hsu, S. K.; Tsai, C. H.; Doo, W. B.; Lin, S. S.

    2014-12-01

    In the northern margin of the western end of the Okinawa Trough, three major submarine channels running across the continental margin are distinctive. From east to west, they are the North Mein-Hua Submarine Canyon, Mein-Hua Submarine Canyon and the Keelung Valley. To the east of the Mein-Hua Submarine Canyon, the slope of the continental margin is quite gentle, implying that the risk of slope instability is low. However, between the Keelung Valley and the Mei-Hua Submarine Canyon, the slope is rather steep. We have conducted multi-channel reflection seismics, sub-bottom profilers and multi-beam bathymetry in this area. The results show two general trends of fracture or faulting. The NE-SW trending faults generally follow the major orientation of the Taiwan mountain belt. Thus, these faults could be reverse faults from the former collisional thrust faults to currently post-collisional normal faults. Another almost E-W trending faults are consistent with the N-S extending of the Southern Okinawa Trough. Because the most significant faulting in the northwest end of the study is probably associated with the offshore extension of the Kenchiao Fault or the Sanchiao Fault, we consider either of these two faults as the northeast boundary (headwall) of the potential submarine landslide. Taking the stability slope angle of 0.5 degree as the stable landslide slope as shown in the area to the northeast of the study area, we estimate the total volume of the potential submarine landslide could be 300 cubic kilometers. Such a landslide volume may generate a local tsunami and affect especially the northeast coast of Taiwan.

  14. Development of the Astoria Canyon-Fan physiography and comparison with similar systems

    USGS Publications Warehouse

    Nelson, C.H.; Carlson, P.R.; Byrne, J.V.; Alpha, T.R.

    1970-01-01

    A detailed bathymetric study of Astoria Canyon and Astoria Fan provides a model for typical submarine canyon-fan systems. The present canyon head is 9 miles (17 km) west of the Columbia River mouth but buried Pleistocene channels appear to have connected the two features in the past. The canyon, which is distinguished by its relief, V-shaped profiles, and numerous tributaries, winds sinuously and is coincident with apparent structural trends across the continental shelf and slope. At the fan apex, the canyon mouth merges smoothly into Astoria Channel, which is characterized by its U-shaped profiles, lower walls of even height, and levee development. Astoria Channel and the fan valley at the base of the continental slope are the most recently active of a series of main fan valleys that appear to have: (1) progressively "hooked left"; (2) migrated from north to south across the fan during its formation; and (3) been partly responsible for the asymmetrical shape of the fan. The deep, narrow upper fan valleys that characterize the steep (> 1:100, or 0??35???) and rough (10-30 fathoms, or 18-55 m) upper fan surface break into distributaries on the middle fan, where there is the sharpest change in gradient. The main valleys become broader and shallower down the fan, while the generally concave fan surface grades to nearly a flat seafloor (to gradients < 1:1000, or 0??0.5???), (< 10 fathoms, or 18 m relief). Similarity of Astoria Canyon-Fan system with other deep-sea fan and alluvial fan systems, suggests the hypothesis that size of drainage basin, sediment size, and sediment load control the size, gradient, and valley development of any fan system. Data from bathymetry, seismic refraction stations, and sediment load of the Columbia River indicate that the cutting of Astoria Canyon and the deposition of the unconsolidated sediment layer forming Astoria Fan could have been accomplished during the Pleistocene. A similar history can be suggested for other major submarine canyon-fan systems. ?? 1970.

  15. Shallow-water longshore drift-fed submarine fan deposition (Moisie River Delta, Eastern Canada)

    NASA Astrophysics Data System (ADS)

    Normandeau, Alexandre; Lajeunesse, Patrick; St-Onge, Guillaume

    2013-08-01

    Submarine canyons and associated submarine fans are in some cases located at the end of a littoral cell where they act as conduits for the transfer of eroded terrigenous sediments to the marine environment. Such fans are generally found in deep-water settings at >500 m water depth. Offshore the Moisie River Delta (NW Gulf of St. Lawrence, Eastern Canada), high-resolution multibeam bathymetry and seismic data led to the discovery of an unusually shallow submarine fan (?60 m) located at the end of a littoral cell. Sediment is transported westward on the shallow coastal shelf, as demonstrated by the downcurrent displacement of oblique nearshore sandbars where the shelf narrows to less than 1 km. The steep slope near the end of the littoral cell is incised by a channel that feeds a submarine fan composed of smaller channels and depositional lobes. According to existing Holocene evolution models for the region, the fan formed within the last 5,000 years. Its evolution is largely due to the transport of sediment by longshore drift. Multibeam echosounder and seismic data also reveal that the gravity-driven accretion of the submarine fan is characterized mainly by two processes, i.e., frequent small-scale, downslope migration of sandwaves on the slope, and more episodic slumping/turbidity-current activity in the deeper part of the fan. This study documents that, besides their common deep-water location, smaller-scale submarine fans can occur also in very shallow water, implying that they could be more frequent than previously thought both in modern environments and in the rock record.

  16. Canyon-related undulation structures in the Shenhu area, northern South China Sea

    NASA Astrophysics Data System (ADS)

    Qiao, Shaohua; Su, Ming; Kuang, Zenggui; Yang, Rui; Liang, Jinqiang; Wu, Nengyou

    2015-03-01

    The characteristics and origin of seafloor and subsurface undulations were studied in the Shenhu area, northern South China Sea using high-precision multibeam bathymetric map and high-resolution 2D seismic data. Two undulation structure fields associated with submarine canyons have been identified. One structure field is developed in canyon head areas and shows waveform morphology on the bathymetric map. The waves display wavelengths and wave heights of 1-2 km and 20-50 m, respectively, generally occur on slopes from 1° to 5°, and extend for about 15 km approximately parallel to the canyon's orientation. The other structure field is developed in the lower segment or mouth area of submarine canyons. In general, the waves display wavelengths and wave heights of 1.3-3.6 km and 50-80 m, respectively, occur on slopes of approximately 2°, and extend for more than 20 km. Sediment cores from crests between submarine canyons in the lower segment include predominantly silts and clayey silts. Since undulations in the two fields show differences in morphology and internal architectures, two different formation mechanisms are suggested. Seafloor undulations in the head area of submarine canyons are interpreted as creep folds induced by soft sediment deformation. Undulation structures in the lower segment or the mouth area of submarine canyons are sediment waves constructed by turbidity currents overflows along the submarine canyons.

  17. Canyon-confined pockmarks on the western Niger Delta slope

    NASA Astrophysics Data System (ADS)

    Benjamin, Uzochukwu; Huuse, Mads; Hodgetts, David

    2015-07-01

    Fluid flow phenomena in the deepwater Niger Delta are important for the safe and efficient exploration, development and production of hydrocarbons in the area. Utilizing 3D seismic data from the western Niger Delta slope, we have identified pockmarks that are confined within a NE-SW oriented submarine canyon system that has been active since the early Quaternary. The pockmarks, subdivided into 'canyon-margin' pockmarks and 'intra-canyon' pockmarks, on the basis of their plan-form distribution patterns, are found to be spatially and stratigraphically related to stratigraphic discontinuities created by erosion cuts associated with the submarine canyon system. We infer that stratigraphic discontinuities provided pathways for fluid migration within the buried canyon system, allowing fluids from deeper parts of the basin to reach the seafloor as indicated by abundant pockmarks above the partly buried canyon. The transportation of fluids from deeper parts of the basin into the buried segment of the canyon system was facilitated by carrier beds expressed as high amplitude reflection packages and by extensional normal faults. The prevalence of the 'canyon margin' pockmarks over the 'intra-canyon' pockmarks is attributed to the direct connection of the buried canyon margins with truncated reservoir facies in hydraulic connection with deeper reservoir facies. The formation of the 'intra-canyon' pockmarks is interpreted to have been limited by fluid flow disconnection often caused by stratigraphic alternation of sand-rich and shale-rich channel deposits that constitute the canyon fill. Muddy canyon fill units act as baffles to fluid flow, while connected sandy infill units constitute pathways for fluid migration. Occurrence of pockmarks throughout the length of the submarine canyon system is an indication of shallow fluid flow within buried reservoir facies. Systematic alignment of seafloor pockmarks are clues to buried reservoirs and provide insights into reservoir architecture which could be crucial in frontier exploration of buried deepwater canyons reservoirs and for risk assessment of development activities on top of submarine canyons. A single mega pockmark linked by a gas chimney to a deeper anticlinal structure was discovered to the north of the canyon system. This structure may be indicative of subsurface geo-pressures close to the fracture gradient, highlighting a significant drilling hazard in this part of the study area.

  18. Morphology, structures and seismic characters of the Chimei Canyon-Fan system offshore eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Hsieh, Y. H.; Liu, C. S.

    2014-12-01

    The Chimei submarine canyon located offshore east Taiwan shows a very distinct morphology, it has a wide (9 km in average) and very smooth bottom, a submarine fan was formed at its foot but the northern part of the submarine fan has been washed away. This canyon starts from the Hsiukuluan River estuary, runs eastward across the eastern flank of the Luzon arc, and merges into the Hualien Canyon near the western end of the Ryukyu Trench off NE Taiwan. The Chimei canyon can be divided into two parts: the upper section is a U-shaped canyon with broad and flat bottom and high walls; the lower section meanders across a deep sea fan in the Huatung basin. In this study, we use multichannel seismic reflection profile data together with high resolution bathymetry data to study the topography, basement structures and seismic sequences along the canyon path and in the distal fan. The U-shaped upper Chimei canyon seems to be carved not only by submarine erosion but also by structural uplift of both side-walls. The canyon walls are up to 950 m above the canyon floor, strata truncations along both sides of the canyon walls and many slumps are observed. The upper Chimei canyon was developed along basement lows of the highly deformed Luzon arc, and runs across a series of N-S trending thrusts. Acoustic basement and lower strata are deformed and folded, and young sediments cover the canyon floor smoothly. We find many thrusts run across the upper Chimei canyon, but now the canyon bottom is smooth. The concave thalweg profile seems to reach the equilibrium between erosion and deposition. An east-vergent thrust fault lies at the foot of the eastern flank of the Luzon arc which separates the upper section from the lower section of the Chimei Canyon. The lower section of the Chimei canyon flows over a submarine fan where eight seismic sequences are recognized. The two lower sequences show continuous, parallel to sub-parallel sheet-drape seismic facies which fill the basement low. They are interpreted to be old deep sea sediment. The six upper sequences show chaotic and mounded seismic facies, and also transparent and continuous parallel seismic strata. We interpret those are characters of submarine fan. Some large slumps occurred at northern half of the submarine fan. The northern half of the submarine fan has been eroded away already by canyon and slumps.

  19. Effects of the Western Boundary undercurrent on sediment transport and deposition in the Pamlico Canyon off Cape Hatteras 

    E-print Network

    Jenkins, John Stacy

    1980-01-01

    directions and Alvin dive sites . . Submarine canyons along the continental margin off the northeast United States. Depths are in fathoms Velocity vector of WBU free stream (a), theoretical path taken by geostrophic WBU around Pamlico Canyon (b), radius... by the WBU along the east coast of the United States (Fig. 2). The information gained from this study will, therefore, have general applicability to problems concerning sediment transport in submarine canyons. Previous Work Some attempts have been made...

  20. Exploration models for submarine slope sandstones

    SciTech Connect

    Slatt, R.M.

    1986-09-01

    Recent published studies have demonstrated a far greater potential than previously recognized for submarine slope sandstones to contain significant oil and gas reserves in the Gulf Coast and elsewhere. Comparison of modern slopes with outcrop and subsurface analogs from several areas provided the framework for developing the following submarine slope sandstone exploration models: submarine canyon fill, slope gully/channel fill, slope spillover sand sheets, and intraslope basin fill. Submarine canyon fill is mainly shale, but sandstone beds that form stratigraphic traps may be present. Canyon shale fill juxtaposed against older sandstones can also form stratigraphic traps. Gully/channel fills are sandstones deposited on shallow-gradient slopes or ramps. The proximity of these sandstones to slope shales provides opportunities for stratigraphic traps to develop. Spillover sand sheets are resedimented from a shelf to a shallow-gradient slope and are associated with gully/channel fills. Intraslope basin fill is mainly shale, but elongate, sheetlike, or fan-shaped turbidite sandstones can provide stratigraphic traps. In all of these deposits, slope shales may be sufficiently enriched in organic carbon to be potential hydrocarbon source rocks; the potential for organic-rich shales to accumulate is highest in intraslope basin fill.

  1. Hot Canyon

    SciTech Connect

    None

    2012-06-18

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  2. Hot Canyon

    SciTech Connect

    None

    2012-01-01

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  3. Hot Canyon

    ScienceCinema

    None

    2013-03-01

    This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

  4. Simple Submarine

    NSDL National Science Digital Library

    Using simple, inexpensive items, students build and test submarine models in a single class period. They gain insight into the engineering that's required to make these machines ascend, descend, and hover safely in extreme environments. The printable eight-page handout includes a series of inquiry-based questions that get students thinking about the complex engineering required for submersibles, illustrated experiment directions, and a worksheet that includes thought-provoking questions along with areas for recording experiment data.

  5. The Initiation of Submarine Debris Flow after 2006 Pingtung Earthquake Offshore Southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Su, C. C.; Liu, J. T.; Chiu, H. T.; Li, S. J.

    2014-12-01

    On 26?27 December 2006, a series of submarine cables were damaged offshore southwestern Taiwan from Gaoping Slope to the northern terminus of the Manila Trench. The cable breakages were caused by gravity flows which triggered by the Pingtung earthquake doublet occurred on 26 December 2006 at 20:26 (21.9°N, 120.6°E; ML 7.0) and 20:34 (21.97°N, 120.42°E; ML 7.0) offshore of Fangliao Twonship and meanwhile the local fishermen reported disturbed waters at the head of Fangliao submarine canyon. Although many researchers conjectured the disturbed waters may cause by the eruption of submarine volcanoes which has been widely discovered off the southwestern Taiwan, the actual mechanism is still unclear. In previous studies, a series of faults, liquefaction strata, pockmarks and acoustically transparent sediments with doming structures were observed at the head of Fanliao submarine canyon and may highly related to the submarine groundwater discharge off southwestern Taiwan. Recently, further multi-beam surveys were conducted at the east of Fangliao submarine canyon head and the result shows large area of seafloor subsidence after Pingtung Earthquake. The area of subsidence is over 60 km2 with maximum depth around 5 meters. The north end of the subsidence is connected to the Fangliao submarine canyon where the first cable was failed (CH-US CN-W2-1: 22°13.287'N, 120°33.722'E) after Pingtung Earthquake. All the evidences point out the large earthquake might triggered liquefaction process and generated large debris flow and swept the submarine cables away from the Fangliao submarine canyon head to the abyss.

  6. How Submarines Work

    NSDL National Science Digital Library

    Brain, Marshall

    In this article, presented by HowStuffWorks.com, shows how a submarine dives and surfaces in the water. It also shows how life support is maintained, how the submarine gets its power, how a submarine finds its way in the deep ocean and how submarines might be rescued. The article addresses many points effectively and is a good survey of the topic.

  7. Obstacle avoidance sonar for submarines

    NASA Astrophysics Data System (ADS)

    Dugas, Albert C.; Webman, Kenneth M.

    2002-05-01

    The Advanced Mine Detection Sonar (AMDS) system was designed to operate in poor environments with high biological and/or shallow-water boundary conditions. It provides increased capability for active detection of volume, close-tethered, and bottom mines, as well as submarine and surface target active/passive detection for ASW and collision avoidance. It also provides bottom topography mapping capability for precise submarine navigation in uncharted littoral waters. It accomplishes this by using advanced processing techniques with extremely narrow beamwidths. The receive array consists of 36 modules arranged in a 15-ft-diameter semicircle at the bottom of the submarine sonar dome to form a chin-mounted array. Each module consists of 40 piezoelectric rubber elements. The modules provide the necessary signal conditioning to the element data prior to signal transmission (uplink) through the hull. The elements are amplified, filtered, converted to digital signals by an A/D converter, and multiplexed prior to uplink to the inboard receiver. Each module also has a downlink over which it receives synchronization and mode/gain control. Uplink and downlink transmission is done using fiberoptic telemetry. AMDS was installed on the USS Asheville. The high-frequency chin array for Virginia class submarines is based on the Asheville design.

  8. Tectonic control of Cretaceous gravity deposits and submarine Valleys in the subalpine basin, French western Alps

    SciTech Connect

    Philippe, J.; Beaudoin, B.; Fries, G.; Parize, O.

    1988-08-01

    The Late Jurassic-Early Cretaceous series of the French subalpine basin is characterized by alternating limestones and marls with numerous, thick gravity-flow deposits (carbonate debris flows and slumps, siliciclastic grain flows, turbidites). These gravity deposits originate from platforms and slopes and come through the basin via several parallel canyons and submarine valleys. Some carbonate (Berriasian) and siliciclastic (Aptian) deep-sea fans are built at the canyon mouth during intense activity of the canyons and reworking of the sediments. The tectonic control of the gravity deposits is demonstrated by the position and filling of the submarine valleys all along the Cretaceous. The submarine valleys correspond systematically to the lower part of extensional tilted blocks; the gravity deposits come along the main syn-sedimentary normal faults delimiting these tilted blocks. The gravity deposits go from one tilted block to another through some synsedimentary passes which are induced by slight folding, perhaps related to an early diapirism at some nodes of extensional faults. The canyon-like valleys are due to very strong erosion when a submarine valley cuts of the higher part of a tilted block. The gravity deposits are stacked atop each other and progressively fill the valleys. Thus the cutting and filling of the submarine valleys and canyons on occasions during the Early Cretaceous are explained by a permanent synsedimentary activity. These Jurassic and Cretaceous extensional structures are later reactivated by inversion during Tertiary compressional movements.

  9. Bioavailable organic matter in surface sediments of the Nazaré canyon and adjacent slope (Western Iberian Margin)

    NASA Astrophysics Data System (ADS)

    García, R.; Thomsen, L.

    2008-11-01

    The distribution of bioavailable organic matter in surface sediments of the Nazaré submarine canyon and adjacent open slope was investigated. The concentration of chlorophyll a (chl a), phaeopigments (phaeo), chloroplastic pigment equivalents (CPE) and total hydrolyzable amino acids (THAA) decreased with increasing water depth, and were in general higher within the canyon (specially in the upper regions) than on the open slope. The concentrations were low on the canyon walls, increasing towards the canyon axis. The chl a:phaeo ratio, degradation index (DI), asp:?-ala and glu:?-aba ratios were highest in the upper canyon, and similarly low in the deeper canyon and along the open slope. On the canyon axis and walls these lability indices were similar. chl a:OM ratio indicated that the quality of the bulk organic matter in the upper canyon was higher than on the slope and deeper canyon regions. Bioavailable organic matter enters the canyon through the upper region; it is transported down canyon by the tide circulation, where it is dispersed across a bigger area under a more refractory state. Flume experiments demonstrate that arborescent foraminifera and polychaete pellet mounds, as found in the head of the canyon; increase deposition of phytodetritus under critical shear velocities by a 50%.

  10. Deep Research Submarine

    E-print Network

    Woertz, Jeff

    2002-02-01

    The Deep Sea Research Submarine (Figure 1) is a modified VIRGINIA Class Submarine that incorporates a permanently installed Deep Sea Operations Compartment (Figure 2). Table 1 summarizes the characteristics of the Deep ...

  11. Seismic stratigraphy and development of Avon canyon in Benin (Dahomey) basin, southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Olabode, S. O.; Adekoya, J. A.

    2008-03-01

    Interpretation of a grid of high resolution seismic profiles from the offshore eastern part of the Benin (Dahomey) basin in southwestern Nigeria area permitted the identification of cyclic events of cut and fill associated with the Avon canyon. Seismic stratigraphic analysis was carried out to evaluate the canyon morphology, origin and evolution. At least three generations of ancient submarine canyons and a newly formed submarine canyon have been identified. Seismic reflection parameters of the ancient canyons are characterized by transparent to slightly transparent, continuous to slightly discontinuous, high to moderate amplitude and parallel to sub-parallel reflections. Locally, high amplitude and chaotic reflections were observed. The reflection configurations consist of regular oblique, chaotic oblique, progradational and parallel to sub-parallel types. These seismic reflection characteristics are probably due to variable sedimentation processes within the canyons, which were affected by mass wasting. Canyon morphological features include step-wise and spoon-shaped wall development, deep valley incision, a V-shaped valley, similar orientation in the southeast direction, and simple to complex erosion features in the axial floor. The canyons have a composite origin, caused partly by lowering of the sea level probably associated with the formation of the Antarctic Ice Sheet about 30 Ma ago and partly by complex sedimentary processes. Regional correlation with geological ages using the reflectors show that the canyons cut through the Cretaceous and lower Tertiary sediments while the sedimentary infill of the canyon is predominantly Miocene and younger. Gravity-driven depositional processes, downward excavation by down slope sediment flows, mass wasting from the canyon walls and variation in terrigenous sediment supply have played significant roles in maintaining the canyons. These canyons were probably conduits for sediment transport to deep-waters in the Gulf of Guinea during their period of formation.

  12. Design a Submarine

    NSDL National Science Digital Library

    Museum of Science and Industry, Chicago

    2012-01-01

    Learners act as engineers and design mini submarines that move in the water like real submarines. The submarines must be able to float, sink, and hover steadily without touching the top of the water or resting on the bottom. Use this activity to introduce learners to density and buoyancy.

  13. Canyon Dust

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03682 Canyon Dust

    These dust slides are located on the wall of Thithonium Chasma.

    Image information: VIS instrument. Latitude -4.1N, Longitude 275.7E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Canyon Variety

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03281 Canyon Variety

    This image shows paret of the west end of Melas Chasma. Landslide deposits are visible at the top of the image, with dark dunes appearing at the bottom.

    Image information: VIS instrument. Latitude -8.2N, Longitude 281.0E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Sediment-laden flow induced submarine cable failures off southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Su, C. C.

    2012-04-01

    Taiwan is located on the convergent boundary between the Eurasian and Philippine Sea plates, where has a highly frequency of earthquakes. Furthermore, the interaction between the largest continent (Eurasia Continent) and ocean (Pacific Ocean) leads to torrential-rain-induced flooding in the plume rain (May-June) and typhoon seasons (July-October). According to statistics from Water Resources Agency, in the last few decades, the mean annual sediment load was 384 million tons from the island of Taiwan into the sea. Off southwestern Taiwan, two major submarine canyons, the Gaoping submarine canyon (GPSC) and Fangliao submarine canyon (FLSC), are incising from continental shelf to deep sea floor and both of them transport considerable amounts of sediment to the South China Sea. In contrast to the GPSC which is directly connected to the Gaoping River, the FLSC which is smaller, younger and confined to the slope, does not associate with any river on land. Since 2006, southern Taiwan has been through several big typhoons and earthquakes which triggered submarine landslides and turbidity currents and damaged many submarine cables. The analytical results from sediment cores which taken from the GPSC and FLSC during 2005 to 2010 show these submarine cable break events may caused by different processes. In the upper GPSC, hyperpycnal flow might be the major process which caused the cable damages. On the contrary, cable failures in FLSC are due to sediment liquefaction.

  16. Morphology, paleogeographic setting, and origin of the middle Wilcox Yoakum Canyon, Texas coastal plain

    SciTech Connect

    Dingus, W.F. (Exxon Co., Midland, TX (USA)); Galloway, W.E. (Univ. of Texas, Austin (USA))

    1990-07-01

    The Yoakum canyon is the largest of the Gulf Coast Eocene erosional gorges and is interpreted as a buried submarine channel. The canyon can be traced for 67 mi (108 km) from the Wilcox fault zone, which defines the position of the early Eocene shelf edge, nearly to present outcrop. In this paper, the authors expand on previously published descriptions of the canyon and use a more extensive subsurface database. Decompaction of the canyon shale-fill reveals that original depths of the canyon exceeded 3,500 ft (1,067 m). Apparent canyon-wall slump scarps and a peripheral chaotic zone, interpreted as an incipient slump feature, are comparable to similar features of the late Quaternary Mississippi submarine canyon. The Yoakum canyon formed within the Garwood subembayment to the west of and adjacent to the middle Wilcox Rockdale delta system. Quantitative mapping of facies adjacent to the Yoakum shale indicate the following sequence of events. (1) Muddy, distal deltaic and shelf facies of the lower middle Wilcox subgroup were deposited during a retrogradation. (2) A resurgence of progradation deposited upper middle Wilcox deltaic facies atop the unconsolidated, lower middle Wilcox continental margin muds, loading the shelf edge and initiating slump failure of the continental margin. (3) Headward erosion of the canyon across the shelf occurred contemporaneously with a subsidence-induced transgression that coincided with a disruption in sediment supply. The Yoakum canyon was excavated by a combination of slumping and current scour. (4) The canyon was filled by hemipelagic and prodelta muds of the upper Wilcox subgroup. 19 figs.

  17. 4. DARK CANYON SIPHON VIEW ACROSS DARK CANYON AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DARK CANYON SIPHON - VIEW ACROSS DARK CANYON AT LOCATION OF SIPHON. VIEW TO NORTHWEST - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

  18. Inter-bed fluid triggered slope failures of the Kaoping Canyon upstream area: Results from memorial R/V Ocean Researcher 5

    NASA Astrophysics Data System (ADS)

    Yeh, Yi-Ching; Shen, Tsung-Fu; Liu, Shao-Yung; Yu, Pai-Sen

    2015-04-01

    As a major pathway of the sediment transportation, the submarine canyons sculpture the seafloor then deposit sediments at the deep ocean. The submarine canyons could be classified to two categories: erosive or deposition based on geological environment or fluid flow down to the canyon. The erosive canyons often 'attack' the levee which may result in submarine landslides or mass transportations due to slope failure. Once slope failure occurs at geological weakness area such as gas hydrate dissociation zone, giant mass slumping will be triggered. These kinds of mass transportations will further develop turbidity current or hyperpycnal flow, which could damage the submarine cables or pipes. The giant mass transportation even triggers devastated tsunami. In this study, a latest swath bathymetric map was compiled by comprising seven cruises between December, 2012 and March 2013. The result shows that regressive erosion may take a place north of 500 meters contour (gas hydrate dissociation region), southwest off Taiwan. Moreover, high resolution seismic image (acquired by Edgetech SB-424 sub-bottom profiler) show that gas rich sediments co-exist with submarine landslide deposits in the edge of the upstream of Kaoping submarine canyon. It implies that slope failures in the study area might be caused by weaken sediment collapse.

  19. Submarine cable route survey

    SciTech Connect

    Herrouin, G.; Scuiller, T.

    1995-12-31

    The growth of telecommunication market is very significant. From the beginning of the nineties, more and more the use of optical fiber submarine cables is privileged to that of satellites. These submarine telecommunication highways require accurate surveys in order to select the optimum route and determine the cable characteristics. Advanced technology tools used for these surveys are presented along with their implementation.

  20. Submarine neutrino communication

    Microsoft Academic Search

    Patrick Huber

    2010-01-01

    We discuss the possibility to use a high energy neutrino beam from a muon storage ring to provide one way communication with a submerged submarine. Neutrino interactions produce muons which can be detected either, directly when they pass through the submarine or by their emission of Cerenkov light in sea water, which, in turn, can be exploited with sensitive photo

  1. Paint-Stirrer Submarine

    ERIC Educational Resources Information Center

    Young, Jocelyn; Hardy, Kevin

    2007-01-01

    In this article, the authors discuss a unique and challenging laboratory exercise called, the paint-stir-stick submarine, that keeps the students enthralled. The paint-stir-stick submarine fits beautifully with the National Science Education Standards Physical Science Content Standard B, and with the California state science standards for physical…

  2. THE SUBMARINE REVIEW SUMMER 2012

    E-print Network

    THE SUBMARINE REVIEW 1 SUMMER 2012 SPURRING INNOVATION AT THE DECKPLATE LEVEL IN THE SUBMARINE FORCE LT Ryan P. Hilger, USN Submarine Student at the Naval Postgraduate School he phenomenal success to alter how we design and operate our submarines. Vice Admiral Richardson happily announced after

  3. Bryce Canyon Natural Bridge

    USGS Multimedia Gallery

    The Bryce Canyon Natural Bridge. Technically, this is not a natural bridge, which forms when running water erodes a tunnel into a rock formation. Instead, this is a natural arch, similar to the ones in nearby Arches National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is...

  4. Bryce Canyon Rim

    USGS Multimedia Gallery

    The rim of Bryce Canyon, viewed from Rainbow Point. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms ...

  5. Bryce Canyon Hoodoos

    USGS Multimedia Gallery

    Sandstone hoodoos in Bryce Canyon National Park. In the background, Grand Staircase-Escalante National Monument can be seen. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different er...

  6. Depositional environment and reservoir morphology of Guadalupian Bell Canyon sandstones, Scott field, Ward and Reeves counties, Texas 

    E-print Network

    Kashatus, Gerard Paul

    1986-01-01

    Canyon divisions separated by thinner interchannel portions of the same division. Sands from later submarine flows filled in the topographi- cally lower interchannel areas of previous flows. The lack of erosion- al surfaces has led... the shelves to attain current velocities high enough to produce an unstable fluid interface causing extensive mixing at the top of the submarine currents. A low density turbid cloud that behaved as a separate transport mode could have formed above...

  7. Submarine neutrino communication

    E-print Network

    Huber, Patrick

    2009-01-01

    We discuss the possibility to use a high energy neutrino beam from a muon storage ring to provide one way communication with a submerged submarine. Neutrino interactions produce muons which can be detected either, directly when they pass through the submarine or by their emission of Cerenkov light in sea water, which, in turn, can be exploited with sensitive photo detectors. Due to the very high neutrino flux from a muon storage ring, it is sufficient to mount either detection system directly onto the hull of the submersible. The achievable data transfer rates compare favorable with existing technologies and do allow for a communication at the usual speed and depth of submarines.

  8. Submarine neutrino communication

    E-print Network

    Patrick Huber

    2010-08-20

    We discuss the possibility to use a high energy neutrino beam from a muon storage ring to provide one way communication with a submerged submarine. Neutrino interactions produce muons which can be detected either, directly when they pass through the submarine or by their emission of Cerenkov light in sea water, which, in turn, can be exploited with sensitive photo detectors. Due to the very high neutrino flux from a muon storage ring, it is sufficient to mount either detection system directly onto the hull of the submersible. The achievable data transfer rates compare favorable with existing technologies and do allow for a communication at the usual speed and depth of submarines.

  9. Shear-wave velocity of slope sediments near Hudson Canyon from analysis of ambient noise

    NASA Astrophysics Data System (ADS)

    Miller, N. C.; Ten Brink, U. S.; Collins, J. A.; McGuire, J. J.; Flores, C. H.

    2014-12-01

    We present new ambient noise data that help constrain the shear strength of marine sediments on the continental slope north of Hudson Canyon on the U.S. Atlantic margin. Sediment shear strength is a key parameter in models of potentially tsunamigenic, submarine slope failures, but shear strength is difficult to measure in situ and is expected to evolve in time with changes in pore pressure. The ambient noise data were recorded by 11 short-period, ocean-bottom seismometers and hydrophones deployed in a ~1 by 1.5 km array for ~6 months on the continental slope. These high frequency (~0.1 - 50 Hz), narrow-aperture data are expected to record noise propagating as interface waves and/or resonating in the upper ~500 m of sediment. Propagation of interface waves is controlled by the shear-wave velocity of the sediment, which we measure by calculating lag-times in cross-correlations of waveforms recorded by pairs of receivers. These measurements of shear-wave velocity will be used to constrain shear strength. The data also appear to record wind-generated noise resonating in layered sediment. We expect this resonance to also be sensitive to shear-wave velocity, and spectral analysis and modeling of harmonics may provide a second constraint on sediment shear strength. Both the correlogram- and spectral-based measurements can be made using hour- to day-long segments of data, enabling us to constrain temporal evolution of shear-wave velocity and potential forcing mechanisms (e.g., tidal and storm loading and submarine groundwater discharge) through the ~6 month deployment.

  10. Snake Hells Canyon Subbasin Inventory

    E-print Network

    Snake Hells Canyon Subbasin Inventory May 2004 Prepared for the Northwest Power and Conservation .................................................................................................................................. 62 8 APPENDIX A APRE SUMMARIES FOR HELLS CANYON SUBBASIN.................. 63 Snake Hells Canyon Subbasin Inventory i May 2004 #12;LIST OF FIGURES FIGURE 1.LAND MANAGEMENT IN THE SNAKE HELLS CANYON

  11. Refraction and reflection of infragravity waves near submarine canyons

    Microsoft Academic Search

    Jim Thomson; Steve Elgar; T. H. C. Herbers; Britt Raubenheimer; R. T. Guza

    2007-01-01

    The propagation of infragravity waves (ocean surface waves with periods from 20 to 200 s) over complex inner shelf (water depths from about 3 to 50 m) bathymetry is investigated with field observations from the southern California coast. A wave-ray-path-based model is used to describe radiation from adjacent beaches, refraction over slopes (smooth changes in bathymetry), and partial reflection from

  12. Constraining the timing of turbidity current driven sediment transport down Monterey Canyon, offshore California

    NASA Astrophysics Data System (ADS)

    McGann, M.; Stevens, T.; Paull, C. K.; Ussler, W.; Buylaert, J.

    2013-12-01

    Turbidity currents are responsible for transport of sand down the Monterey Submarine Canyon, offshore California, from the shoreline to Monterey Fan. However the timing of sediment transport events and their frequencies are not fully understood despite recent monitoring of canyon events and AMS 14C dating of foraminifera from hemipelagic sediments bracketing sand deposited during turbidity flows. Quartz optically stimulated luminescence (OSL) dating in sand sequences provides a complementary means of dating sand transport. OSL dates reflect the time interval since the sand grains were last exposed to sunlight. However, the technique has never been applied extensively to canyon sediments before. Here we report both quartz OSL ages of sand deposits and benthic foraminifera ages sampled from the axial channel within Monterey Submarine Canyon and Fan via ROV-collected vibracores. This allows a rare opportunity to directly test the frequency and timing of turbidity current events at different points in the canyon. We use both single-grain and small (~2 mm area) single aliquot regeneration OSL approaches on vibracore samples from various water depths to determine sand transport frequency. Within the upper canyon (<2,000 m water depths) the OSL data require sub-decadal to decadal transit times. Sand bearing fining upward sequences yielding middle Holocene to last few hundred year ages indicate turbidity currents occur at 150 to 250 year event frequencies within the fan channel out to 3,600 m water depth. We suggest that turbidity currents have been active during the current sea-level high stand and that the submarine fan has recorded turbidity currents over the entire Holocene. The increased age spread in single grain OSL dates with water depth provides evidence of sediment mixing and reworking during turbidity flows. Apparently, sand is stored within the canyon for various amounts of time while it is in route to its current location on the fan.

  13. The Grand Canyon

    NSDL National Science Digital Library

    Brieske, Joel A.

    2002-01-01

    The first site from PBS.org, called Lost in the Canyon (1), offers an excellent online learning experience. Visitors learn about John Wesley Powell's expedition down the Colorado River, covered in transcripts from the companion television show and a timeline of Powell's life. Other features include an interactive lesson on running rapids and a look at the unique geologic history of the area. Next, from StudyWorks! Online comes the lesson entitled Sleuthing at the Grand Canyon: Using Rocks to Tell Us About the Past (2). Through basic descriptions, photographs, and illustrations, students learn how rocks form, how scientists use them to find out about past environments, and much more. The third site is provided by the Grand Canyon Monitoring and Research Center called The Grand Canyon Monitoring and Research Center Fiscal Year 2000-2004 Monitoring and Research Strategic Plan (3). Readers will discover the mission of the center, history of monitoring in the area, management strategies, research activities, and much more. Next is a site offered by Richard S. Naylor of Northeastern University's Department of Geology called Unconformities in the Grand Canyon (4). Visitors will find descriptions and photographs of several sites in the Grand Canyon that exhibit geologic unconformities or surfaces that represent a break in the geologic record. The fifth site is maintained by kaibob.org called the Geology of Grand Canyon (5). This site contains basic information on how the canyon was formed, where all the rock came from, why it looks like it does, and when it all happened. From NASA's Visible Earth Web site comes the 3-D View of Grand Canyon (6) page. The canyon can be viewed in a low or high resolution JPEG format, which shows the surrounding area, part of the Colorado river, and the canyon itself in dynamic colors. Part of Northern Arizona University, the seventh site is entitled Canyons, Culture, and Environmental Change: An Introduction to the Land Use History of the Colorado Plateau (7). The site provides an introduction to the environmental history of the Colorado Plateau and summarizes a vast body of research from multiple disciplines in an easily accessible format. The last site from NOAA's Colorado River Basin Forecast Center is the River Forecasts and Data page (8). Provided are data from various sites along the river that offer a wide range of relevant information such as simulated hydrographs.

  14. Redistribution ofmulti-phase particulate organic carbon in a marine shelf and canyon system during an exceptional river flood: Effects of Typhoon Morakot on the Gaoping River–Canyon system

    E-print Network

    Sparkes, Robert B.; Lin, In-Tian; Hovius, Niels; Galy, Albert; Liu, James T.; Xu, Xiaomei; Yang, Rick

    2015-02-25

    , transport and deposition that can be difficult to study in detail. Here we present data from the Gaoping submarine canyon system, off SW Taiwan, which was perturbed in 2009 by the addition of flood deposits following Typhoon Morakot and sampled by gravity...

  15. Tlie Submarine Caves of Bermuda

    E-print Network

    Iliffe, Thomas M.

    Tlie Submarine Caves of Bermuda ThomasM. Iliffe Bermuda Biological Station, Ferry Reach 1-15 #12;The SubmarineCavesofBermuda ThomasM.Iliffe BermudaBiological Station,Ferry Reach 1-15 Abstract Bermuda the volcanic pedistal. Three types of submarine limestone cave morphology have so far been identified

  16. Submarine Coaxial Cable Pressure Characteristics

    Microsoft Academic Search

    K. Aida; M. Aiki

    1978-01-01

    In equalization design of submarine coaxial cable system, the cable attenuation deviation due to pressure in deep sea bottom has significant weight. This paper treats the submarine coaxial cable characteristics pressure dependency. By using an artificial ocean test facility, 1.7 inch submarine coaxial cable attenuation, phase, capacitance and insulator core diameter were studied and their pressure coefficients under a pressure

  17. Superelevation and overspill control secondary flow dynamics in submarine channels

    NASA Astrophysics Data System (ADS)

    Dorrell, R. M.; Darby, S. E.; Peakall, J.; Sumner, E. J.; Parsons, D. R.; Wynn, R. B.

    2013-08-01

    In subaerial and submarine meander bends, fluid flow travels downstream in a helical spiral, the structure of which is determined by centrifugal, hydrostatic, baroclinic, and Coriolis forces that together balance frictional stresses generated by the flow. The sense of rotation of this helical flow, and in particular, whether the near bed flow is directed toward the inner bank, e.g., "river-normal," or outer bank, e.g., "river-reversed," is crucial to the morphodynamic evolution of the channel. However, in recent years, there has been a debate over the river-normal or river-reversed nature of submarine flows. Herein, we develop a novel three-dimensional closure of secondary flow dynamics, incorporating downstream convective material transport, to cast new light on this debate. Specifically, we show that the presence of net radial material transport, arising from flow superelevation and overspill, exerts a key control on the near bed orientation of secondary flow in submarine meanders. Our analysis implies that river-reversed flows are likely to be much more prevalent throughout submarine-canyon fan systems than prior studies have indicated.

  18. Seven years of geomorphic change in the head of Monterey Canyon, CA: Steady state equilibrium or monotonic change?

    Microsoft Academic Search

    D. P. Smith; R. G. Kvitek; E. Ross; P. Iampietro; C. K. Paull; M. Sandersfeld

    2010-01-01

    The head of Monterey submarine canyon has been surveyed with high-precision multibeam sonar at least once each year since September 2002. This poster provides a summary of changes between September 2002 and September 2008. Data were collected with a variety of Reson mulitbeam sonar heads, and logged with an ISIS data acquisition system. Vessel attitude was corrected using an Applanix

  19. Newly recognized submarine slide complexes in the southern California Bight

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    New high-resolution bathymetric and seismic-reflection surveys have imaged large (<0.5 km3) submarine landslides offshore southern California that have not been previously recognized in the Borderland. The new data show several large slides or slide complexes that include: 1) a slide complex consisting of numerous (>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 terrestrial sediment input from fluvial sources, as are most other previously recognized submarine slides in the Borderland. Only the SPS slide, which lies adjacent to the San Gabriel Canyon submarine channel, is associated with a significant fluvial sediment source.

  20. Submarine: Soda Cup Lander

    NSDL National Science Digital Library

    James Cameron

    2013-01-01

    In this activity (on page 2), learners create a submarine using a plastic cup. This is a fun way to learn about buoyancy and density. Extensions for this activity, such as adding a propeller or manometer, are also included.
    Note: You will also need access to a tank or swimming pool to watch your submarine dive.
    Safety note: Learners will need an adult's help to drill holes in the film canister. Learners will also need an adult's help if they use a glue gun to attach the film canister to the plastic cup.

  1. Paint-Stirrer Submarine

    NSDL National Science Digital Library

    Jocelyn Young

    2007-02-01

    In today's fast-paced, technological world, it is a constant struggle for teachers to find new and exciting ways to challenge and engage our students. The Paint-Stirrer Submarine is a unique and challenging laboratory exercise that keeps the students enthralled. They won't even realize they are learning because they will be having too much fun. This inquiry-based, hands-on experience in building a submarine allows the students to learn about buoyancy, buoyant force, Archimedes' principle, and motion in an engaging manner. It will be an experience neither you nor your students will ever forget.

  2. Paleogene canyons of Tethyan margin and their hydrocarbon potential, Czechoslovakia

    SciTech Connect

    Picha, F.J. (Chevron Overseas Petroleum Inc., San Ramon, CA (United States))

    1991-03-01

    Two Paleogene canyons buried below the Neogene foredeep and the Carpathian thrust belt in Southern Moravia have been outlined by drilling and seismic profiling. The features, as much as 12 km wide and over 1000 m deep, have been traced for 40 km. They are cut into Mesozoic and Paleozoic carbonate and clastic deposits and underlying Precambrian crystalline rocks. The sedimentary fill is made of late Eocene and early oligocene marine deposits, predominantly silty mudstones and siltstones. Sandstones and conglomerates are distributed mainly in the lower axial part of the valleys. Proximal and distal turbidites, grain-flow and debris-flow deposits have been identified in the fill. The common occurrence of slump folds, pebbly mudstones, and chaotic slump deposits indicate that mass movement played a significant role in sediment transport inside the canyons. The canyons are interpreted as being cut by rivers, then submerged and further developed by submarine processes. The organic rich mudstones of the canyon fill are significant source rocks (1-10% TOC). They reached the generative stage only after being tectonically buried below the Carpathian thrust belt in middle Miocene time. Channelized sandstones and proximal turbidities provide reservoirs of limited extent, although more substantial accumulations of sands are possible further downslope at the mouth of these canyons. Several oil fields have been discovered both within the canyon fill and the surrounding rocks. Similar Paleogene valleys may be present elsewhere along the ancient Tethyan margins buried below the Neogene foredeeps and frontal zones of the Alps and Carpathians. Their recognition could prove fruitful in the search for hydrocarbons.

  3. Snake Hells Canyon Subbasin Assessment

    E-print Network

    Snake Hells Canyon Subbasin Assessment May 2004 Prepared for the Northwest Power and Conservation, Ecovista Angela Sondenaa, Nez Perce Tribe Darin Saul, Ecovista #12;Snake Hells Canyon Subbasin Assessment Table of Contents 0 INTRODUCTION TO SNAKE HELLS CANYON SUBBASIN ASSESSMENT............ 1 1 SUBBASIN

  4. Fiber Optic Submarine Cables

    NASA Astrophysics Data System (ADS)

    Oestreich, Ulrich H. P.

    1990-01-01

    Submarine communication cables have one of the longest history in the field of technics. During the last 20 years their importance showed a drastic decay in favour of satellites. Presently their future looks bright again as they contain now optical fibers instead of coaxial pairs.

  5. Bathymetrical distribution and size structure of cold-water coral populations in the Cap de Creus and Lacaze-Duthiers canyons (northwestern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Gori, A.; Orejas, C.; Madurell, T.; Bramanti, L.; Martins, M.; Quintanilla, E.; Marti-Puig, P.; Lo Iacono, C.; Puig, P.; Requena, S.; Greenacre, M.; Gili, J.

    2012-12-01

    Submarine canyons are known as one of the seafloor morphological features where living cold-water coral (CWC) communities develop in the Mediterranean Sea. We investigated the CWC community of the two westernmost submarine canyons of the Gulf of Lions canyon system: the Cap de Creus Canyon (CCC) and Lacaze Duthiers Canyon (LDC). Coral associations have been studied through video material recorded by means of a manned submersible and a remotely operated vehicle. Video transects have been conducted and analyzed in order to obtain information on (1) coral bathymetric distribution and density patterns, (2) size structure of coral populations, and (3) coral colony orientation with respect to the substrate. Madrepora oculata was the most abundant CWC in both canyons, while Lophelia pertusa and Dendrophyllia cornigera mostly occurred as isolated colonies or in small patches. An important exception was detected in a vertical cliff in LDC where a large Lophelia pertusa framework was documented. This is the first record of such an extended L. pertusa framework in the Mediterranean Sea. In both canyons coral populations were dominated by medium and large colonies, but the frequent presence of small-sized colonies also indicate active recruitment. The predominant coral orientation with respect to the substrate (90° and 135°) is probably driven by the current regime as well as by the sediment load transported by the current flows. In general no clear differences were observed between the CWC populations from CCC and LDC, despite large differences in particulate matter between canyons.

  6. Bathymetrical distribution and size structure of cold-water coral populations in the Cap de Creus and Lacaze-Duthiers canyons (northwestern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Gori, A.; Orejas, C.; Madurell, T.; Bramanti, L.; Martins, M.; Quintanilla, E.; Marti-Puig, P.; Lo Iacono, C.; Puig, P.; Requena, S.; Greenacre, M.; Gili, J. M.

    2013-03-01

    Submarine canyons are known as one of the seafloor morphological features where living cold-water coral (CWC) communities develop in the Mediterranean Sea. We investigated the CWC community of the two westernmost submarine canyons of the Gulf of Lions canyon system: the Cap de Creus Canyon (CCC) and Lacaze-Duthiers Canyon (LDC). Coral associations have been studied through video material recorded by means of a manned submersible and a remotely operated vehicle. Video transects have been conducted and analyzed in order to obtain information on (1) coral bathymetric distribution and density patterns, (2) size structure of coral populations, and (3) coral colony position with respect to the substrate. Madrepora oculata was the most abundant CWC in both canyons, while Lophelia pertusa and Dendrophyllia cornigera mostly occurred as isolated colonies or in small patches. An important exception was detected in a vertical cliff in LDC where a large L. pertusa framework was documented. This is the first record of such an extended L. pertusa framework in the Mediterranean Sea. In both canyons coral populations were dominated by medium and large colonies, but the frequent presence of small-sized colonies also indicate active recruitment. The predominant coral orientation (90° and 135°) is probably driven by the current regime as well as by the sediment load transported by the current flows. In general, no clear differences were observed in the abundance and in the size structure of the CWC populations between CCC and LDC, despite large differences in particulate matter between canyons.

  7. Grand Canyon Explorer

    NSDL National Science Digital Library

    Maintained by Bob Ribokas, Grand Canyon Explorer is quite extraordinary for a unaffiliated Web site. Updated regularly, it contains everything from stunning photography and geologic descriptions to information about hiking permits and park trials for users planning a trip. A highlight of the site is the guided tour, which provides descriptions and pictures from the park entrance to the Grand Canyon's spectacular formations like Mohave Point on the South Rim. The author has even provided a downloadable version of the Web site for Pocket PC's and PDA's, enabling users to have all the information at their finger tips when visiting the park.

  8. High-Resolution Acoustic Imaging in the Agadir-Canyon Region, NW-Africa: Morphology, Processes and Geohazards

    NASA Astrophysics Data System (ADS)

    Krastel, S.; Wynn, R. B.; Feldens, P.; Unverricht, D.; Huehnerbach, V.; Stevenson, C.; Glogowski, S.; Schuerer, A.

    2014-12-01

    Agadir Canyon is one of the largest submarine canyons in the World, supplying giant submarine sediment gravity flows to the Agadir Basin and the wider Moroccan Turbidite System. While the Moroccan Turbidite System is extremely well investigated, almost no data from the source region, i.e. the Agadir Canyon, are available. Understanding why some submarine landslides remain as coherent blocks of sediment throughout their passage downslope, while others mix and disintegrate almost immediately after initial failure, is a major scientific challenge, which was addressed in the Agadir Canyon source region during Cruise MSM32. We collected ~ 1500 km of high-resolution seismic 2D-lines in combination with a dense net of hydroacoustic data. About 1000 km2 of sea floor were imaged during three deployments of TOBI (deep-towed sidescan sonar operated by the National Oceanography Centre Southampton). A total of 186 m of gravity cores and several giant box cores were recovered at more than 50 stations. The new data show that Agadir canyon is the source area of the world's largest submarine sediment flow, which occurred about 60,000 years ago. Up to 160 km3 of sediment was transported to the deep ocean in a single catastrophic event. For the first time, sediment flows of this scale have been tracked along their entire flow pathway. A major landslide area was identified south of Agadir Canyon. Landslide material enters Agadir canyon in about 2500 m water depth; the material is transported as debrite for at least another 200 km down the canyon. Initial data suggest that the last major slide from this source entered Agadir canyon at least 130,000 years ago. A large field of living deep-water corals was imaged north of Agadir canyon. To our knowledge, these are the first living cold water corals recovered off the coast of Morocco (except for the Gulf of Cadiz). They represent an important link between the known cold-water coral provinces off Mauritania and in the Gulf of Cádiz.

  9. Variability in turbidity current frequency within a central Portuguese margin canyon

    NASA Astrophysics Data System (ADS)

    Allin, Joshua R.; Talling, Peter J.; Hunt, James E.; Clare, Michael E.; Pope, Ed

    2015-04-01

    Submarine canyons constitute one of the most important pathways for sediment transport into ocean basins. For this reason, understanding canyon architecture and sedimentary processes has significance for oil and gas reservoir characterisation, carbon budgets and geohazard assessment. Canyon sedimentation in the form of turbidity-currents is known to operate on a variety of scales and result from a number of different processes, including landslides, river-derived hyperpycnal flows and tidal or storm resuspension. Despite the expanding knowledge of turbidity current triggers, the spatial variability in turbidity current frequency within most canyon systems is not well defined. Here, new chronologies from cores in the lower reaches of Nazaré Canyon illustrate changes in turbidity current frequency and their relationship to sea level. These flows were relatively frequent during the last glacial maximum and the last deglaciation, with an average recurrence interval of ~70 years. Mid to early Holocene slowdown in activity (avg. recurrence of 1625 years) appears to occur later than other systems along the Iberian margin. Cores from the Iberian Abyssal Plain also provide the first recurrence interval estimates for large run-out turbidity currents from the central Portuguese margin. These large turbidity currents have an average recurrence interval of 2750 years, broadly comparable to modern turbidity flow events in the lower Nazaré Canyon. This indicates that Nazaré Canyon acted as a depocentre, capturing large volumes of sediment during glacial periods prior to large scale canyon flushing events. However, this sediment capture has largely been restricted to the middle and upper canyon since stabilisation of Holocene sea level. Recurrence intervals suggest that large turbidity flows which flush the canyon operate on a timescale independent of the sea level forcing evident in the lower canyon. While instability-triggered landsliding and tidal/storm resuspension are likely responsible for canyon restricted turbidity flows, a different trigger may exist for long run-out turbidity flows capable of travelling several hundred kilometres. Canyon flushing events in other systems have been suggested as resulting from landslides triggered by regional earthquakes. However, turbidites from the Iberian Abyssal Plain do not correlate well with previously suggested earthquake-triggered landslides in the Tagus Abyssal Plain to the south. The inconclusiveness of a test for synchronous deposition in distinct basins makes identifying a seismic trigger problematic. The Nazaré fault, which intersects the canyon head, may have a distinct return time for large earthquakes that is different from seismically active areas to the south. This further suggests the need for caution in the use of turbidites as a palaeo-seismological indicator along the Iberian margin.

  10. Mars: Canyon and Volcanoes

    NSDL National Science Digital Library

    This image of Mars includes a brief description and a zoom-in feature to view the image at closer range. The center of the scene shows the entire Valles Marineris canyon system. An audio option allows one to listen to the caption. A glossary is also provided.

  11. Sandbar in Grand Canyon

    USGS Multimedia Gallery

    Picture showing the size of the sandbar before the November 2012 controlled flood from the Glen Canyon Dam. This location is 65 miles downstream from Lees Ferry and the view is looking downstream. These and additional photographs depicting the results of the recent controlled floods can be viewed on...

  12. Submarine Paleoseismology Based on Turbidite Records

    E-print Network

    Goldfinger, Chris

    Submarine Paleoseismology Based on Turbidite Records Chris Goldfinger College of Oceanic trigger processes such as turbidity currents, submarine landslides, tsunami (which may be recorded both counterparts. This article reviews the use of submarine turbidite deposits for paleoseismology, focuses

  13. Exo-enzymatic activities and organic matter properties in deep-sea canyon and slope systems off the southern Cretan margin

    NASA Astrophysics Data System (ADS)

    Polymenakou, Paraskevi N.; Lampadariou, Nikolaos; Tselepides, Anastasios

    2008-10-01

    Enzymatic activities of aminopeptidase and ?- D-glucosidase were investigated in sediments collected from deep-sea canyon (Samaria) and slope systems of the unexplored southern Cretan margin (Eastern Mediterranean Sea). Stations were grouped in defined regions, inside the canyon, in nearby slopes and in open slope systems. Redox potential values, organic carbon concentrations, C/N ratios, chlorophyll- a, phaeopigments, prokaryotic abundances and carbon (C) mineralization rates were also estimated. The main aim of this investigation was to examine the links among prokaryotic abundance and activities and organic matter parameters along the axis of a submarine canyon (Samaria), and laterally along the slopes of the deep southern Cretan margin (Eastern Mediterranean Sea). The recorded aminopeptidase activities exhibited elevated values near the mouth of the canyon and the nearby slope systems and were found to be comparable to those reported for mesotrophic ecosystems. Statistical comparisons revealed that chloroplastic pigment equivalents, C/N ratios and carbon mineralization rates did not differ significantly between the deep stations in and outside the canyon (of either 2000 or 3500 m water depth). On the other hand, organic carbon and nitrogen content, prokaryotic abundances, and enzymatic activities differ substantially between the canyon and slope stations. It is suggested that the deep basins at the outlet of the submarine canyon of Samaria and the nearby slope systems are promising targets for the identification of microbial hotspots.

  14. The Grand Canyon

    NSDL National Science Digital Library

    This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on the ecology of the Grand Canyon area. Students act as scientists investigating the damming of the Colorado River by the Glen Canyon dam and experimental flooding that took place in 1996. They then write a proposal as to whether or not more experimental flooding should be done on the area considering the ecological effects. It includes objectives, materials, procedures, discussion questions, evaluation ideas, extensions, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

  15. Evidence for submarine landslides and continental slope erosion related to fault reactivation during the last glaciation offshore eastern Canada

    NASA Astrophysics Data System (ADS)

    Saint-Ange, F.; Campbell, C.; MacKillop, K.; Mosher, D. C.; Piper, D. J.; Roger, J.

    2012-12-01

    Many studies have proposed that reactivation of dormant faults during deglaciation is a source of neotectonic activity in glaciated regions, but few have demonstrated the relationship to submarine landslides. In this study, seabed morphology and shallow geology of the outer continental margin adjacent to the Charlie Gibbs Fracture Zone off Newfoundland, Canada was investigated for evidence of this relationship. The glacial history and morphology of the margin suggest that the entire continental shelf in the area, coincident with major continental crustal lineaments, was ice-covered during the Last glacial cycle, and transverse troughs delineate the paleo-icestream drainage patterns. A recent investigation of Notre Dame Trough revealed the existence of large sediment failures on the shelf. The current study investigates complex seafloor erosion and widespread mass transport deposition (MTD) on the continental slope seaward of Notre Dame Trough, using recently-acquired high resolution seismic reflection data and piston cores. The new data reveal that a trough mouth fan (TMF) is present on the slope seaward of Notre Dame Trough. The Notre Dame TMF is characterized by a succession of stacked debris flows, but does not show a lobate shape in plan view like other classic TMFs. Instead, the Notre Dame TMF has abruptly-truncated margins suggesting post-depositional failure and erosion of the fan deposits. Seismic reflection data show that the locations of the failures along the TMF margin are coincident with a set of shallow faults; however the current dataset does not image the deeper portion of the faults. On the upper slope immediately south of the TMF, a narrow and deeply incised canyon is located along-trend with the Notre Dame Trough. The location of this canyon appears to be controlled by a fault. Downslope from this canyon, along the southern margin of the TMF, a 25 km wide, flat-floored, U-shaped valley was eroded into a succession of stacked MTD-filled channels. Seismic stratigraphic analysis shows that the valley developed around the same time as the adjacent TMF, however, the valley morphology and evidence for repeated slope failure suggests that the processes responsible for its formation were different than the processes that formed the nearby TMF. Age control provided from piston cores suggest that the last major slope failure that contributed to valley formation probably occurred at ~29 ka. Geotechnical measurements from piston cores show slightly underconsolidated sediments. The results indicate that this part of the margin is more unstable than Orphan Basin and Labrador slope regions. Given the low factor of safety and the complex fault system, low energy earthquake from the surrounding area could be enough to potentially trigger landslides.

  16. Submarine landslides: advances and challenges

    Microsoft Academic Search

    Jacques Locat; Homa J. Lee

    2002-01-01

    Due to the recent development of well-integrat ed surveying techniques of the sea-floor, significant improvements were achieved in mapping and describing the morphology 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 found on land. Submarine mass movements however, can have run out

  17. Submarine Landslides: A Multidisciplinary Crossroad

    NASA Astrophysics Data System (ADS)

    Moscardelli, L. G.

    2014-12-01

    The study of submarine landslides has advanced considerably in the last decade. A multitude of geoscience disciplines, including marine, petroleum and planetary geology, as well as geohazard assessments, are concerned with the study of these units. Oftentimes, researchers working in these fields disseminate their findings within their own communities and a multidisciplinary approach seems to lack. This presentation showcases several case studies in which a broader approach has increased our understanding of submarine landslides in a variety of geologic settings. Three-dimensional seismic data from several continental margins (Trinidad, Brazil, Morocco, Canada, GOM), as well as data from outcrop localities are shown to explore geomorphological complexities associated with submarine landslides. Discussion associated with the characterization and classification of submarine landslides is also part of this work. Topics that will be cover include: 1) how data from conventional oil and gas exploration activities can be used to increase our understanding of the dynamic behavior of submarine landslides, 2) analogies between terrestrial submarine landslides and potential Martian counterparts, 3) impact of submarine landslides in margin construction, as well as their economic significance and 4) the importance of quantifying the morphology of submarine landslides in a systematic fashion.

  18. Submitted to Journal of Hydraulic Research, June, 2004 The Response of Turbidity Currents to a Canyon-Fan Transition: Internal Hydraulic

    E-print Network

    Parker, Gary

    Turbidity currents often carve canyons into the continental slope, and then deposit submarine fans on lower of sediment brought in by rivers or littoral drift to the ocean floor. On relatively steep slopes they can fans are commonly found at and beyond the transition between the continental slope and rise (Bouma et

  19. Submarine laser communications

    NASA Astrophysics Data System (ADS)

    McConathy, D. R.

    The Department of the Navy and the Defense Advanced Research Projects Agency (DARPA) are sponsoring a joint study to investigate the use of blue-green laser technology to comunicate with submarines at operating depths. Two approaches are under investigation - one in which the laser itself is space-based, and the other in which the laser is ground-based with its beam redirected to the earth's surface by an orbiting mirror. This paper discusses these two approaches, and presents a brief history of activities which led to the current studies.

  20. Optimizing submarine berthing with a persistence incentive

    Microsoft Academic Search

    Gerald G. Brown; Kelly J. Cormican; Siriphong Lawphongpanich; Daniel B. Widdis

    1997-01-01

    Submarine berthing plans reserve mooring locations for inbound U.S. Navy nuclear submarines prior to their port entrance. Once in port, submarines may be shifted to different berthing locations to allow them to better receive services they require or to make way for other shifted vessels. However, submarine berth shifting is expensive, labor inten- sive, and potentially hazardous. This article presents

  1. Active submarine volcano sampled

    NASA Astrophysics Data System (ADS)

    Taylor, Brian

    On June 4, 1982, two full dredge hauls of fresh olivine basalt were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, from water depths of 400 and 900 m. The shallower dredge site was within one-half mile of the active submarine vent evidenced at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano located on the ‘trench-slope break’ or ‘outer-arc high’ of the New Georgia Group, approximately 35 km seaward of the main volcanic line and only 30 km landward of the base of the trench inner wall. The volcano has been observed to erupt every year or two for at least the last 30 years (see cover photographs). An island formed in 1952, 1961, 1965, and 1978, but in each case it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982.

  2. California State Waters Map Series--Hueneme Canyon and vicinity, California

    USGS Publications Warehouse

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Krigsman, Lisa M.; Endris, Charles A.; Clahan, Kevin B.; Sliter, Ray W.; Wong, Florence L.; Yoklavich, Mary M.; Normark, William R.

    2012-01-01

    In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Hueneme Canyon and vicinity map area lies within the eastern Santa Barbara Channel region of the Southern California Bight. The area is part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation - at least 90° - since the early Miocene has been proposed for the Western Transverse Ranges, and the region is presently undergoing north-south shortening. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area, which is offshore of the Oxnard plain and west of and along the trend of the south flank of the Santa Monica Mountains, lies at the east end of the Santa Barbara littoral cell, characterized by west-to-east littoral transport of sediment derived mainly from coastal watersheds. The Hueneme Canyon and vicinity map area in California's State Waters is characterized by two major physiographic features: (1) the nearshore continental shelf, and (2) the Hueneme and Mugu Submarine Canyon system, which, in the map area, includes Hueneme Canyon and parts of three smaller, unnamed headless canyons incised into the shelf southeast of Hueneme Canyon. The shelf is underlain by tens of meters of interbedded upper Quaternary shelf, estuarine, and fluvial deposits that formed as sea level fluctuated in the last several hundred thousand years. Hueneme Canyon extends about 15 km offshore from its canyon head near the dredged navigation channel of the Port of Hueneme. The canyon is relatively deep (about 150 m at the California's State Waters limit) and steep (canyon flanks as steep as 25° to 30°). Historically, Hueneme Canyon functioned as the eastern termination of the Santa Barbara littoral cell by trapping all eastward littoral drift, not only feeding the large Hueneme submarine fan but acting as the major conduit of sediment to the deep Santa Monica Basin; however, recent dredging programs needed to maintain Channel Islands Harbor and the Port of Hueneme have moved the nearshore sediment trapped by jetties and breakwaters to an area southeast of the Hueneme Canyon head. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Hueneme Canyon and vicinity map area are related directly to the geomorphology and sedimentary processes that are the result of its Quaternary geologic history. The two basic megahabitats in the map area are Shelf (continental shelf) and Flank (continental slope). The flat seafloor of the continental shelf in the Hueneme Canyon and vicinity map area is dynamic, as indicated by mobile sand sheets and coarser grained scour depressions. The active Hueneme Canyon provides considerable relief to the continental shelf in the map area, and its irregular morphology of eroded walls, landslide scarps, and deposits and gullies provide promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms. Most invertebrates observed in the map area durin

  3. Sunset over Red Rock Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  4. Sunset over Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  5. Yuccas in Pine Creek Canyon

    USGS Multimedia Gallery

    The Mojave Desert, home to drought-tolerant plants like yuccas, gradually mixes with loblolly pine ecosystems in Pine Creek Canyon. Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Cany...

  6. Chollas in Pine Creek Canyon

    USGS Multimedia Gallery

    The Mojave Desert, home to drought-tolerant plants like Cholla cacti, gradually mixes with loblolly pine ecosystems in Pine Creek Canyon. Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Roc...

  7. Sunset in Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  8. Manzanita in Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  9. Yucca in Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  10. Bryce Canyon's Navajo Loop Trail

    USGS Multimedia Gallery

    Views along the Navajo Loop Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandston...

  11. Cedar Forest in Bryce Canyon

    USGS Multimedia Gallery

    A cedar forest in Bryce Canyon National Park, viewed from Rainbow Point. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the ...

  12. Cedar Tree in Bryce Canyon

    USGS Multimedia Gallery

    A cedar tree in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their ba...

  13. Snow-covered Bryce Canyon

    USGS Multimedia Gallery

    Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their base. Bryce Canyon is also home to large numbe...

  14. Submarine ramp facies model for delta-fed, sand-rich turbidite systems

    SciTech Connect

    Heller, P.L.; Dickinson, W.R.

    1985-06-01

    Some sandy turbidite successions contain facies that differ in significant ways from those predicted by the canyonfed submarine fan depositional model. The key differences are the absence of a master slope channel or canyon through which sediment is transported to the basin, and the lack of facies segregation into distinct channel and overbank or interchannel facies associations within the turbidite sequence. These types of sequences can be better described using a delta-fed submarine ramp depositional model. The primary components of this model are: a sandy deltaic system that has prograded to the shelf-slope break; an abbreviated section of mud-rich slope deposits traversed by multiple shallow channels that transport sand from the delta front to the deeper basin; very sandy proximal ramp deposits composed dominantly of laterally continuous sheets of Facies B turbidites; and less sandy distal ramp deposits characterized by an increase in the abundance of Facies C and D turbidites. Ramp turbidites characteristically display statistically random patterns of bed thickness. Submarine ramp development requires rapid sediment accumulation (>800 ft or 250 m/m.y.) in turbidite basins of shallow to moderate depth where deltaic progradation is rapid enough to mask the structural relief along basin margins. The delta-fed submarine ramp facies model may be useful in describing short-lived sandy depositonal episodes in some rapidly aggrading and prograding basinal sequences. As such, they represent one member in a spectrum of submarine fan depositional styles.

  15. Timing of occurrence of large submarine landslides on the Atlantic Ocean margin

    USGS Publications Warehouse

    Lee, H.J.

    2009-01-01

    Submarine landslides are distributed unevenly both in space and time. Spatially, they occur most commonly in fjords, active river deltas, submarine canyon-fan systems, the open continental slope and on the flanks of oceanic volcanic islands. Temporally, they are influenced by the size, location, and sedimentology of migrating depocenters, changes in seafloor pressures and temperatures, variations in seismicity and volcanic activity, and changes in groundwater flow conditions. The dominant factor influencing the timing of submarine landslide occurrence is glaciation. A review of known ages of submarine landslides along the margins of the Atlantic Ocean, augmented by a few ages from other submarine locations shows a relatively even distribution of large landslides with time from the last glacial maximum until about five thousand years after the end of glaciation. During the past 5000??yr, the frequency of occurrence is less by a factor of 1.7 to 3.5 than during or shortly after the last glacial/deglaciation period. Such an association likely exists because of the formation of thick deposits of sediment on the upper continental slope during glacial periods and increased seismicity caused by isostatic readjustment during and following deglaciation. Hydrate dissociation may play a role, as suggested previously in the literature, but the connection is unclear.

  16. Canyon in DCS Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released July 26, 2004 This image shows two representations of the same infra-red image covering a portion of Ganges Chasma. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    The northern canyon at the top of this image is dominated by a bright red/magenta area consisting primarly basaltic materials on the floor of the canyon and atmospheric dust. Within that area, there are patches of purple, on the walls and in the landslides, that may be due to an olivine rich mineral layer. In the middle of the image, the green on the mesa between the two canyons is from a layer of dust. The patchy blue areas in the southern canyon are likely due to water ice clouds.

    Image information: IR instrument. Latitude -6.6, Longitude 316 East (44 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. Obstacle avoidance sonar for submarines

    Microsoft Academic Search

    Albert C. Dugas; Kenneth M. Webman

    2002-01-01

    The Advanced Mine Detection Sonar (AMDS) system was designed to operate in poor environments with high biological and\\/or shallow-water boundary conditions. It provides increased capability for active detection of volume, close-tethered, and bottom mines, as well as submarine and surface target active\\/passive detection for ASW and collision avoidance. It also provides bottom topography mapping capability for precise submarine navigation in

  18. Wind and topographic effects on the Labrador Current at Carson Canyon

    NASA Astrophysics Data System (ADS)

    Kinsella, E. Douglas; Hay, Alex E.; Denner, Warren W.

    1987-09-01

    We present results from an experimental investigation of the interaction between a shelf break jet and a submarine canyon and of the response of this system to a single upwelling favorable wind event. The field site was Carson Canyon, located at the edge of the Grand Bank of Newfoundland. The shelf break jet is the Labrador Current. The time-averaged current measurements indicate that the interaction between the Labrador Current and the canyon topography is nonlinear and that the mean current crosses isobaths to flow into the canyon on the upstream side but is steered off shelf on the downstream side. The mean flow vorticity balance in the near field and far field is examined, using a two-layer model with the lower layer at rest. In the far field we obtain an interesting result which suggests that the cross-stream shear in combination with bottom friction can drive a significant on-shelf flow. This flow is equivalent to a volume transport of about 60 m3 s-1 per 100 m of along-shelf distance, which is comparable to typical wind-driven Ekman transports on and off continental shelves and which appears to have important implications for the on-off-shelf transport of icebergs in the Grand Banks region. In the near field the Rossby number is of order unity and bottom friction is less important. Many of the observed flow properties can be explained qualitatively in terms of an upstream inertial boundary layer and potential vorticity conservation. The time-dependent response to upwelling favorable winds was registered by current meters in the canyon and at the shelf break at the canyon perimeter. These observations indicate an amplified upwelling response at the shelf break and vertical ascent rates within the canyon of about 0.7 cm s-1.

  19. Grand Canyon Explorer: The Geology of the Grand Canyon

    NSDL National Science Digital Library

    Bob Ribokas

    This site provides an overview of how the Grand Canyon was formed. Concepts discussed include erosion by water, ice and wind, continental drift, and deposition. A photo gallery and stratigraphic figures support the text.

  20. Northern Current variability and its impact on the Blanes Canyon circulation: A numerical study

    NASA Astrophysics Data System (ADS)

    Ahumada-Sempoal, M.-A.; Flexas, M. M.; Bernardello, R.; Bahamon, N.; Cruzado, A.

    2013-11-01

    A high-resolution (?1.2 km) 3D numerical model was used to analyze the interaction of the Northern Current (a right-bounded flow) with the Blanes submarine canyon (BC, NW Mediterranean). Although it refers to a climatological simulation the model properly suites our purpose since it simulates the Northern Current (NC) mesoscale variability, as well as its seasonal variability. Model results were validated with satellite sea surface temperature and current-meter data. The simulated NC tends to be faster and deeper in winter, and slower and shallower in summer. According to our results, NC meanders and eddies are recurrent in the BC area and produce highly fluctuating three-dimensional circulation patterns within the canyon. We found that NC meanders and anticyclonic eddies propagating along the current pathway tend to be deep and, consequently, their effects extend down to the deeper part of the BC. We also found that the meandering of the NC plays a key role in enhancing vertical motions inside the BC. Upwelling and downwelling events occurring on timescales of 4-20 days are associated with NC meanders crests and troughs passing over the BC. Net upwelling/downwelling events are accordingly influenced by the NC seasonality. They are more predominant in winter, while damped in summer. Our results show the importance of NC meanders in creating local net upwelling/downwelling and strengthen the evidence that continuous right-bounded (downwelling favorable) flows can also produce net upwelling inside submarine canyons.

  1. Submarine daylight and ecology

    Microsoft Academic Search

    S. Weinberg

    1976-01-01

    The different parameters acting upon daylight before it reaches underwater organisms are discussed. Methods for measuring these parameters are reviewed, and lightsensing units equipped with hemispherical collectors and possessing a narrow spectral sensitivity band are recommended for use in marine biology. A new formula relating Secchi-disk readings to attenuation coefficients is proposed. A method is suggested which makes it possible

  2. New York Canyon Stimulation

    SciTech Connect

    Raemy, Bernard

    2012-06-21

    The New York Canyon Stimulation Project was to demonstrate the commercial application of Enhanced Geothermal System techniques in Buena Vista Valley area of Pershing County, Nevada. From October 2009 to early 2012, TGP Development Company aggressively implemented Phase I of Pre-Stimulation and Site/Wellbore readiness. This included: geological studies; water studies and analyses and procurement of initial permits for drilling. Oversubscription of water rights and lack of water needed for implementation of EGS were identified and remained primary obstacles. Despite extended efforts to find alternative solutions, the water supply circumstances could not be overcome and led TGP to determine a "����No Go"��� decision and initiate project termination in April 2012.

  3. Repainting decontaminated canyon cranes

    SciTech Connect

    Not Available

    1984-08-23

    The paint on the H-area hot canyon crane is expected to be at least partially removed during the planned decontamination with high pressure Freon/reg sign/ blasting. Tests to evaluate two candidate finishes, DuPont Imron/reg sign/ polyurethane enamel and DuPont Colar/reg sign/ epoxy were carried out at Quadrex Co., Oak Ridge, TN, March 1984. Three types of 304L stainless steel surface finishes were included in the test (ASTM No. 1, bead blasted ASTM No. 1, and ASTM No. 2B). Two types of contamination were used (diluted dissolver solution, the type of contamination encountered in existing canyons; and raw sludge plus volatiles, the type of contamination expected in DWPF). Some specimens were coated with the type of grease (Mystic JT-6) used on cranes in SRP separations areas. The results of the test indicate that smoother surfaces are easier to decontaminate than rougher surfaces. Statistical analysis of the data from this experiment by R.L. Postles leads to the following conclusions: There is no statistical difference between the decontamination properties of DuPont Imron/reg sign/ polyurethane enamel and DuPont Colar/reg sign/ epoxy; DuPont Imron/reg sign/ polyurethane enamel and perhaps Type 304L stainless steel with an ASTM No. 2B surface finish are easier to decontaminate than Type 304L stainless steel with an ASTM No. 1 surface finish; dilute dissolver solution is harder to remove than raw sludge plus volatiles; specimens with grease are easier to decontaminate than specimens with no grease; and, Freon/reg sign/ blasting pressure has no statistically significant effect. 2 refs., 1 fig., 4 tabs.

  4. Grand Canyon: The Hidden Secrets

    NSDL National Science Digital Library

    Summertime means vacations for many people, and for many of these sojourning to the American Southwest, this may mean a trip to the brilliance that is the Grand Canyon in northern Arizona. The people at National Geographic certainly know this area quite well, as they have sponsored a number of research expeditions there over the past century or so. Designed as a way to publicize the film that the organization plays at their canyon visitor center, this site contains a number of helpful features for those persons who may be visiting the canyon. First, visitors will want to look at the interactive map of the South Rim offered here. The map allows visitors to learn about selected features of the area, such as the famous bald eagles, the various outlooks, and the plants indigenous to the region. The site also includes a section for young people, a number of free screensavers and wallpapers, along with a travel guide to visiting the Grand Canyon.

  5. 1996 Grand Canyon Flood Analysis

    NSDL National Science Digital Library

    Mark Manone

    Mark Manone, Northern Arizona University Summary Analyze the effect of a 1996 controlled flood on a sandbar in Grand Canyon. This exercise uses Spatial Analyst and 3D Analyst Context Type and level of course ...

  6. Submarine landslides in French Polynesia SUBMARINE LANDSLIDES IN SOCIETY AND AUSTRAL ISLANDS,

    E-print Network

    Clouard, Valerie

    Submarine landslides in French Polynesia 1 SUBMARINE LANDSLIDES IN SOCIETY AND AUSTRAL ISLANDS of numerous submarine landslides in French Polynesia. This inventory shows an evolution of the landslide type with the age of oceanic islands. Submarine active volcanoes are subject to superficial landslides of fragmental

  7. Plio-Quaternary canyons evolution on South Colombian convergent margin : Tectonic causes and implications

    NASA Astrophysics Data System (ADS)

    Ratzov, Gueorgui; Sosson, Marc; Collot, Jean-Yves; Migeon, Sebastien

    2010-05-01

    Investigations of seafloor morphology and sediment deposits associated with the incision of the South Colombia active margin by a major submarine canyon system are used to reveal out-of-sequence fault activity at least since the Middle Pleistocene. The South Colombian convergent margin is located along Northwestern South America, where the Nazca plate underthrusts eastward the South America plate with a 58 mm.yr-1 convergence rate. The morphology and deep multichannel seismic reflection lines obtained across the margin reflect a frontal accretionnary wedge, as well as antiform and faulted internal structural highs that locally extend up to near the continental shelf, suggesting wide-spread Plio-Quaternary tectonic activity. The Amadeus cruise conduced in 2005 brought new seismic and sedimentary data together with 150m and 60m-resolution EM12D multibeam bathymetry. The newly mapped Mira and Patia canyons system incises the South Colombian margin slope over a distance of ~90 and ~150 km respectively, forming an unequivocal Z-shape in map view, breaching the deformation front and feeding a 30-km wide trench fan system. The morphology of the canyon exhibits meanders, steep over-incised walls (~25-30 degrees), alternation between concave-up and convex-up downstream profiles, slope failures scars, and buried channels. These features reflect interactions between tectonics, sedimentation and the canyon evolution. A synthesis of all the data reveals that: A) Uplifting structural highs control canyons path and incision stages. B) Canyons developed asynchronously across the upper, mid and lower margin slopes according to three main stages: a) upper slope incision by downward cutting during Pleistocene, and possibly by retrogressive headward erosion, b) infill of a mid-slope basin bounded by uplifting structural highs, and c) overspill of the slope basin, and breaching its seaward bounding ridge, and the accretionary prism ~150 kyr ago. These processes led to the construction of sedimentary lobes in the trench, and then to a well-developed channel-levees system. C) Occurrences of antecedence, canyon walls over steepening, and convex-up bathymetric profiles of the canyons imply uplift of the fault-controlled structural highs at least during the last ~150 kyr supporting active out-of-sequence tectonic shortening. The long-term causes of the out-of-sequence tectonic could be linked to interplate coupling and basal friction variations. This study strongly reflects the interplay between tectonic deformation and canyon evolution thus providing a good example of the use of canyon morphology and associated deposits as markers of active tectonic deformation

  8. Habitat characterization of deep-water coral reefs in La Gaviera Canyon (Avilés Canyon System, Cantabrian Sea)

    NASA Astrophysics Data System (ADS)

    Sánchez, Francisco; González-Pola, Cesar; Druet, María; García-Alegre, Ana; Acosta, Juan; Cristobo, Javier; Parra, Santiago; Ríos, Pilar; Altuna, Álvaro; Gómez-Ballesteros, María; Muñoz-Recio, Araceli; Rivera, Jesus; del Río, Guillermo Díaz

    2014-08-01

    Surveys conducted at the complex Avilés Canyon System (southern Bay of Biscay) in order to identify vulnerable habitats and biological communities revealed the presence of noteworthy deep-water coral reefs in one of the tributaries of the system (La Gaviera Canyon). The aim of the present study is to determine why this deep-sea canyon provides suitable environmental conditions for corals to grow. This hanging canyon is characterized by an irregular U-shaped floor with two narrow differentiated flanks. Sand ripples and rocky outcrops structured in diverse W-E directed steps are observed on the canyon floor, suggesting intense hydrodynamic activity. Accordingly, high-frequency near-bottom current and thermal structure profiles showed that there occur strong shifts in currents/hydrography behaving as front-like features at each tidal cycle. These involve the sudden increase of along-axis velocities to over 50 cm/s and vertical velocities of over 5 cm/s in each tidal cycle associated with the passage of sharp thermal fronts and thermal inversions suggesting overturning. A year-long near-bottom current record showed events with near-bottom velocities well over 1 m/s lasting for several days. Three cold-water coral settings were distinguished: a dense coral reef located on stepped rocky bottoms of the eastern and western flanks, carbonate mounds (20-30 m high) located on the canyon floor, and a cluster of shallower water dead coral framework at the head sector of the canyon. Video and still images from a towed sled and ROV verified the presence of dropstones and rippled sand sheets surrounding the mounds and revealed changes in the coral population (alive or dead; total or patchy coverage) in coral reef and carbonate mound areas. The dominant species of the reef are Lophelia pertusa and Madrepora oculata, which considerably increase the habitat?s complexity and biodiversity in relation to other facies described in the canyon. The presence of living cold-water reefs is directly related to a high-energy environment at depths between 700 and 1200 m in the levels between the lower bound of Eastern North Atlantic Central Water (ENACW) and the core of Mediterranean Water (MW). Such level matches the water density range ??=27.35-27.65 kg m-3 which has been identified as limits for cold-water coral distribution in the North Atlantic.

  9. The Dangeard and Explorer canyons, South Western Approaches UK: Geology, sedimentology and newly discovered cold-water coral mini-mounds

    NASA Astrophysics Data System (ADS)

    Stewart, Heather A.; Davies, Jaime S.; Guinan, Janine; Howell, Kerry L.

    2014-06-01

    The Celtic Margin is a complex area in terms of sedimentary dynamics and evolution, with a number of submarine canyons dissecting the continental slope and outer continental shelf. The complex terrain and diverse range of sea-bed sediments play a part in submarine canyons being described as areas of high habitat heterogeneity. This study has concentrated on the heads of two canyons: Dangeard (also known as Dangaard) and Explorer (first named here) located in UK territorial waters, in water depths between 138 and 1165 m. Multibeam echosounder, 2D reflection seismic and photographic ground-truthing data have been combined to map the sea-bed geomorphology, sedimentary features and canyon megafauna of these canyons. In addition, two previously unknown provinces of cold-water coral (CWC) mini-mounds were discovered on the interfluves of the Dangeard and Explorer canyons. The study area comprises a dendritic network of gullies feeding into the canyon thalwegs. Amphitheatre rims, where slope angles are commonly in excess of 20°, occur along the margins and heads of both canyons and are interpreted as drainage basins indicative of retrogressive mass-wasting in a shelfward direction. The CWC mini-mounds occur in water depths between 250 m and 410 m, with more than 400 mounds identified. They are up to 3 m in height and 50-150 m in diameter with no sub-surface expression, suggesting these mounds are, in geological terms, relatively young and possibly Holocene in age. Biological analyses revealed that the mounds form a habitat for ophiuroids and Munida associated with Lophelia pertusa coral rubble, suggesting these mini-mounds are not present-day living features.

  10. Direct measures of Submarine Groundwater Discharge (SGD)

    E-print Network

    Page: 1 Direct measures of Submarine Groundwater Discharge (SGD) over a fractured rock aquifer of submarine groundwater discharge (SGD) have been made, but measurements along the South American coast of submarine, freshwater springs have been recognized in the folk wisdom of millennia, the scientific inquiry

  11. THE SUBMARINE REVIEW FIXED SONAR SYSTEMS

    E-print Network

    THE SUBMARINE REVIEW 1 APRIL 2011 FIXED SONAR SYSTEMS THE HISTORY AND FUTURE OF THE UNDEWATER Undersea Warfare Department Executive Summary One of the most challenging aspects of Anti-Submarine War water and intended to monitor the growing submarine threat of the Soviet Union. SOSUS provided cueing

  12. Submarine Warfare in the A Bibliography

    E-print Network

    Submarine Warfare in the 20th & 21st Centuries: A Bibliography Compiled by Michaele Lee Huygen 3D, 1966. p. 205. This bibliography is a revised edition of the bibliography Submarine Warfare in the 20th & 21st Centuries, 2003, which is in turn a revised and expanded version of Submarine Warfare in the 20

  13. Implications for the Removal of Invasive Species in Canyon de Chelly National Monument

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of a study to investigate the causes of channel narrowing and incision in Canyon de Chelly National Monument, the effects of Tamarisk and Russian-olive on streambank stability were evaluated. Root tensile strengths and distributions in streambanks were measured and used in combination in a r...

  14. Red Canyon Terrace Project

    NSDL National Science Digital Library

    Dennis Dahms

    We know that glacial cycles produce changes in stream regimens downstream from the active ice margin, and that successive glacial cycles often result in separate (and usually lower) floodplains that become terraces following each cycle of stream incision. Using a suite of 4-5 glacio-fluvial terraces outside the mouth of Little PopoAgie Canyon on the east flank of Wyoming's Wind River Range, students do the following: (1) produce a map of the major terrace landforms, (2) observe the geomorphic characteristics of each map unit (this includes height above present stream, depth of fine overbank material above coarse bedload, and general weathering characteristics of the units, and whether the unit is a cut or fill terrace), and (3) measure the characteristics of soil profiles dug into each unit (including horizons Id's, depth and thickness of horizons, and carbonate morphology). Students use all this information to place the terrace units into the regional glacio-fluvial chronology by matching the relative age-data with the Pinedale/Bull Lake/Pre-Bull Lake regional sequence. Final project must include a graphic representation of stream heights that fit their interpretations of the regional glacio-fluvial stratigraphy.

  15. Canyon Floor Deposits

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03598 Canyon Floor Deposits

    The layered and wind eroded deposits seen in this VIS image occur on the floor of Chandor Chasma.

    Image information: VIS instrument. Latitude 5.2S, Longitude 283.4E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  16. Geology Fieldnotes: Grand Canyon National Park, Arizona

    NSDL National Science Digital Library

    Visitors can access park geology information, photographs, related links, visitor information, multimedia resources, and resources for teaching geology with National Park examples. The park geology section discusses the Grand Canyon's geologic history, structural geology, and features a question-and-answer section about the canyon. The history of the canyon as a park and environmental issues surrounding it are also discussed. A geologic cross section of the canyon showing the various rock layers is included.

  17. DEVIL CANYON-BEAR CANYON PRIMITIVE AREA, CALIFORNIA.

    USGS Publications Warehouse

    Crowder, Dwight F.; Fillo, Paul V.

    1984-01-01

    The Devil Canyon-Bear Canyon Primitive Area, located about 10 mi northeast of Pasadena in the Angeles National Forest, Los Angeles County, California, is an area about 8 mi long by 6 mi wide. To evaluate the mineral-resource potential of the area, geologic examinations were made by foot traverses. Samples of fresh, altered, and mineralized rocks, of sand, gravel, and other sediments, and of some panned concentrates from stream sediments were collected and analyzed. The mineral-resource survey concluded that there is little promise for the occurrence of metallic resources.

  18. Seven years of geomorphic change in the head of Monterey Canyon, CA: Steady state equilibrium or monotonic change?

    NASA Astrophysics Data System (ADS)

    Smith, D. P.; Kvitek, R. G.; Ross, E.; Iampietro, P.; Paull, C. K.; Sandersfeld, M.

    2010-12-01

    The head of Monterey submarine canyon has been surveyed with high-precision multibeam sonar at least once each year since September 2002. This poster provides a summary of changes between September 2002 and September 2008. Data were collected with a variety of Reson mulitbeam sonar heads, and logged with an ISIS data acquisition system. Vessel attitude was corrected using an Applanix POS MV equipped with an auxillary C-Nav 2050 GPS receiver. Data were processed and filtered and cleaned in Caris HIPS. Depth changes for various time spans were determined through raster subtraction of pairs of 3-m resolution bathymetric grids in ArcMap. The depth change analyses focused on the canyon floor, except where a landslide occurred on a wall, and where obvious gullying near the headwall had occurred during the time of our study. Canyon walls were generally excluded from analysis. The analysis area was 1,414,240 sq meters. The gross changes between 2002 and 2008 include net erosion of 2,300,000 m^3 +/- 800,000 m^3 of material from the canyon. The annualized rate of net sediment loss from this time frame agrees within an order of magnitude with our previously published estimates from earlier (shorter) time frames, so the erosion events seem to be moderate magnitude and frequent, rather than infrequent and catastrophic. The greatest sediment loss appears to be from lateral erosion of channel-bounding terraces rather than deepening or scouring of the existing channel axis. A single landslide event that occurred in summer 2003 had an initial slide scar (void) volume of 71,000 m^3. The scar was observed to increase annually, and had grown to approximately 96,000 m^3 by 2008. The initial slide was too small to be tsunamigenic. In contrast to the monotonic canyon axis widening, the shoreward terminus of the canyon (canyon lip) appears to be in steady state equilibrium with sediment supply entering the canyon from the littoral zone. The lip position, indicated by the clearly defined shelf/slope break, typically oscillates offshore and onshore about 20 m to 30 m annually, but a 50 m change was measured. This oscillation likely represents cycles of sediment wedge progradation followed by slope failure and shoreward lip retreat. At this time, it appears that buildings along Moss Landing strand are not at risk from net shoreward canyon growth. The canyon appears to be excavating material that was previously stored in the canyon during an era when sediment supply outcompeted submarine transport processes. Published ages and pollen analyses from the canyon walls indicate that an enormous volume of sediment entered the canyon in post-European settlement time, with up to 1.6 m of sediment drape occurring after 1945 (presence of trace DDT). Likewise, 1930’s-era bathymetric charts indicate that major depositional features now located in the canyon were not present in the 1930’s, again suggesting a very young age for the deposits now being excavated from the canyon. One possible source of the young deposits is the construction of nearby Moss Landing Harbor in 1946, which has led to very high erosion rates in adjacent Elkhorn Slough.

  19. Human powered submarine propeller design

    Microsoft Academic Search

    B. Ellis; D. Wacholder

    2003-01-01

    While all parts of a submarine contribute to its overall performance, the propeller blade design is often neglected due to the difficulties in analyzing the impact in design changes combined with a lack of previous research in blade designs for the power and speed requirements as dictated by a human powered vehicle. To aid us in the design of our

  20. Digital Transmission over Submarine Cables

    Microsoft Academic Search

    W. Litchman

    1965-01-01

    The problems of transoceanic transmission of large volumes of information have been raised increasingly over the past few years. Lately, the need for transoceanic digital communications has been of interest. This paper discusses the significance of these trends and examines the technical prospects for handling large volumes of digital traffic using submarine cables. Concentrating on transatlantic traffic, an argument is

  1. Seismic Methods in Submarine Geology

    Microsoft Academic Search

    E. C. Bullard; T. F. Gaskell

    1938-01-01

    PROF. MAURICE EWING has shown that it is possible to use the seismic method for investigating submarine geology, and has used the method to show that, in the continental shelf off the coast of Virginia, many thousands of feet of sediments overlie the Palæozoic or pre-Cambrian rocks.

  2. Submarine structure of Reunion Island (Indian Ocean) inferred from gravity

    NASA Astrophysics Data System (ADS)

    Gailler, L.; Lénat, J.

    2008-12-01

    La Reunion is a large (diameter: 220 km; height: 7 km), mostly immerged (97%) oceanic volcanic system. New land and marine gravity data are used to study the structure of its submarine part. The gravity models are interpreted jointly with the published geology interpretations and compared with magnetic models. This allows us to derive a new model of the shallow and internal structure of the submarine flanks. Recent cruises have collected high quality gravity, magnetic and multi-beam swath bathymetry data over the submarine flanks of La Réunion and the surrounding oceanic plate. A new Bouguer anomaly map has been computed for a reduction density of 2.67.103 kg m-3. A magnetic anomalies map covering the same area has been also built. Studies based on bathymetric and acoustic data have previously shown the presence of different types of submarine features: a coastal shelf, huge bulges built by debris avalanches and sediment deposits, erosion canyons, volcanic constructions near the coast, isolated seamounts offshore, and elongate volcanic ridges on the Mascarene plate. On the new Bouguer anomaly map, all these features are associated with negative anomalies. They have been modeled using 2 3/4 D modeling techniques. The short wavelength anomalies over the coastal shelf area can be explained by piles of low density layers. This suggests that they are mostly built by hyaloclastites which are generally characterized by lower densities than lava flows. The voluminous debris avalanche deposits which formed the huge Submarine Bulges to the east, north, west, and south of the island have also been modeled as low density formations. Each bulge is modeled with an overall density less than 2.67.103 kg m-3, in order to account for its long wavelength anomaly. Some shorter wavelength features are superimposed on these long wavelength negative anomalies. They probably represent heterogeneities within the bulges. Some shallow ones can be associated with observed surface geological features such as secondary landslide deposits or sedimentary areas. The interpretation of the negative short wavelength gravity anomalies associated with the seamounts and the volcanic ridges is less simple. Available data indicate that they are more likely built by lava flows than by low density pyroclastites or breccias. The observed negative anomalies can be accounted for if we consider an isostatic compensation of the surface constructions. Finally, a joint analysis of the gravity and magnetic anomalies allows us to refine the structural models of particular areas. Reversely magnetized formations near the seashore can be associated with volcanic constructions. Conversely, the deeper submarine flanks are poorly magnetized. This is coherent with the interpretation of the bulges as piles of mass-wasting deposits. 3D models have been then calculated in order to provide a first insight of the internal structure of the Reunion complex submarine part.

  3. 30. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONNECTICUT. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONNECTICUT. 2 JUNE 1930. SUBMARINE TRAINING TANK - STEELWORK 98% COMPLETE; BRICKWORK 95% COMPLETE, PIPING 10% IN PLACE. LOOKING NORTH. CONTRACT NO. Y-1539-ELEVATOR, SUBMARINE ESCAPE TANK.' - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  4. Attributes and origins of ancient submarine slides and filled embayments: Examples from the Gulf Coast basin

    SciTech Connect

    Morton, R.A. (Univ. of Texas, Austin (United States))

    1993-06-01

    Large submarine slides and associated shelf margin embayments represent an intermediate member in the continuum of unstable shelf margin features. On seismic profiles, they may resemble submarine canyons, but are different in their size, morphology, origin, and hydrocarbon exploration potential. Two large Neogene submarine slides, located in the northwestern Gulf Coast Basin, formed on the upper slope and flanks of prominent shelf-margin deltas. The basal detachment surface of each slide is a structural discontinuity that may be misinterpreted as an erosional unconformity and misidentified as a stratigraphic boundary separating depositional sequences. Regional stratigraphic correlations indicate that both slides were initiated after the continental platform was flooded. The condensed sections deposited during the rise in relative sea level contain the basal detachment surfaces. The relationships between the slides and sea level fluctuations are uncertain. The shelf-margin embayments created by the slides apparently were partly excavated during periods of lowered relative sea level and were filled during sea level rise and highstand. Eventually the preslide morphology of the shelf margin was restored by coalsced prograding deltas. Submarine slides exhibit landward dipping, wavy, mounded, and chaotic seismic reflection that are manifestations of slump blocks and other mass transport material. Composition of these internally derived slide deposits depends on th composition of the pre-existing shelf margin. Embayment fill above the slide consists mostly of externally derived mudstones and sandstones deposited by various disorganized slope processes, as well as more organized submarine channel-level systems. Thickest slope sandstones, which are potential hydrocarbon reservoirs, commonly occur above the basal slide mudstones where seismic reflections change from chaotic patterns to overlying wavy or subhorizontal reflections. 46 refs., 10 figs., 1 tab.

  5. Submarine Silicic Explosive Eruptions: what can submarine pyroclasts tell us?

    NASA Astrophysics Data System (ADS)

    Carey, R.; Allen, S.; McPhie, J.; Fiske, R. S.; Tani, K.

    2014-12-01

    Our understanding of submarine volcanism is in its infancy with respect to subaerial eruption processes. Two fundamental differences between eruptions in seawater compared to those on land are that (1) eruptions occur at higher confining pressures, and (2) in a seawater medium, which has a higher heat capacity, density and viscosity than air. Together with JAMSTEC collaborators we have a sample suite of submarine pumice deposits from modern volcanoes of known eruption depths. This sample suite spans a spectrum of eruption intensities, from 1) powerful explosive caldera-forming (Myojin Knoll caldera); to 2) weakly explosive cone building (pre-caldera Myojin Knoll pumice and Kurose-Nishi pumice); to 3) volatile-driven effusive dome spalling (Sumisu knoll A); to 4) passive dome effusion (Sumisu knoll B and C). This sample suite has exceptional potential, not simply because the samples have been taken from well-constrained, sources but because they have similar high silica contents, are unaltered and their phenocrysts contain melt inclusions. Microtextural quantitative analysis has revealed that (i) clast vesicularities remain high (69-90 vol.%) regardless of confining pressure, mass eruption rate or eruption style , (ii) vesicle number densities scale with inferred eruption rate, and (iii) darcian and inertial permeabilities of submarine effusive and explosive pyroclasts overlap with explosively-erupted subaerial pyroclasts.

  6. 34. VIEW OF SUBMARINE ESCAPE TRAINING TANK PRIOR TO ADDITION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. VIEW OF SUBMARINE ESCAPE TRAINING TANK PRIOR TO ADDITION OF BLISTERS IN 1959, LOOKING SOUTHEAST - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  7. EXPLORATION OF VOLCANISM ALONG The PACIFIC "SUBMARINE RING OF FIRE"

    E-print Network

    EXPLORATION OF VOLCANISM ALONG The PACIFIC "SUBMARINE RING OF FIRE" · NOAA Office of Ocean Systematic, interdisciplinary exploration of submarine magmatic arcs and diverse ecosystems - Spatial of submarine volcanoes are generated within subduction zones Volatile Release ~200 Km forearc ocean crust

  8. Submarines, spacecraft and exhaled breath.

    PubMed

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another 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 extend the underwater endurance to 2-3 weeks. These propulsion engineering changes also reduce per

  9. Saga is largest commercial submarine ever

    SciTech Connect

    Not Available

    1985-05-01

    The long-range autonomous submarine, Saga, went nuclear last year with an agreement between the French and two Canadian companies. The agreement to convert the prototype from Swedish Stirling closed-cycle combustion engines to a nuclear power supply will make Saga the first non-defense nuclear submarine. With an external hull displacement of 500 tons, Saga will be the largest commercial submarine ever built.

  10. Tsunami Modeling from Submarine Landslides

    NSDL National Science Digital Library

    Kenji Satake

    This paper describes a kinematic model that computes tsunamis generated from submarine landslides. The model is based on bathymetric (ocean floor modeling) data and historical tsunami data. The papers' main focus is the application of the model to the 1741 Oshima-Oshima Tsunami in Japan and landslide events around the Hawaiian Islands. This paper was presented at the U.S. National Tsunami Hazard Mitigation Program Review and International Tsunami Symposium in Seattle, Washington on August 10, 2001.

  11. The role of upper-regime flow bedforms in the morphodynamics of submarine channels

    NASA Astrophysics Data System (ADS)

    Covault, Jacob A.; Kostic, Svetlana; Fildani, Andrea

    2014-05-01

    Advances in acoustic imaging of submarine canyons and channels have provided accurate renderings of seafloor geomorphology. Still, a fundamental understanding of channel inception, evolution, sediment transport, and the nature of the currents traversing these channels remains elusive. Here, we review a mosaic of geomorphology, shallow stratigraphy, and morphodynamics of channelized deep-water depositional systems of tectonically active slopes offshore of California, USA. These systems are imaged in high-resolution multi-beam sonar bathymetry (dominant frequency ~200 kHz) and seismic-reflection (2-16 kHz) data. From north to south, the Monterey East, Lucia Chica, and San Mateo channelized deep-water depositional systems show a breadth of geomorphology and stratigraphic architecture, including channel reaches of varying sinuosity, levees, terraces within channels, and crescent-shaped bedforms, especially in the thalwegs of incipient channel elements. Morphodynamic numerical modeling is combined with interpretations of seafloor and shallow subsurface stratigraphic imagery to demonstrate that the crescent-shaped bedforms common to channel thalwegs are likely to be cyclic steps. We propose that net-erosional and net-depositional cyclic steps play a fundamental role in the formation, filling, and maintenance phases of submarine channels in continental margins with high gradient, locally rugose bathymetry. These margins include passive-margin slopes subjected to gravity-driven tectonic deformation. In such settings, high gradients support the development of densimetric Froude-supercritical turbidity currents, and abrupt slope breaks can promote hydraulic jumps and the spontaneous evolution of an erodible seabed into cyclic steps. This morphodynamic investigation of turbidity currents and the seafloor has the potential to enhance prediction of the locations, stratigraphic evolution, and architecture of submarine canyon-channel systems.

  12. Turkish Straits System and Southern Black Sea: Exchange. Mixing and Shelf / Canyon Interactions

    NASA Astrophysics Data System (ADS)

    Özsoy, Emin; Gürses, Özgür; Tutsak, Ersin

    2015-04-01

    Based largely on an experiment employing high-resolution measurements carried out in June-July 2013 and re-interpretation of past experiments, the oceanographic variability of the exchange through the Turkish Straits System (TSS) and the interactions with the southern Black Sea are revealed through CTD, ADCP, oxygen and light transmission measurements. The exchange flow is primarily governed by the complex topography spanning two narrow straits, wide continental shelf regions, steep slopes and numerous canyons connecting deep basins. Water properties and currents in the high energy environment depends on the mosaic of fine-scale processes and pathways. The TSS, often approximated as a two-layer system has a hydraulically controlled, upper ocean and straits intensified regime, leading to surface jets and bottom plumes participating in mixing and renewal processes. The exit of the 'Mediterranean effluent' onto the Black Sea past a sill overflow from the Bosphorus passes through two subsequent hydraulic jumps and proceeds along a narrow canyon that veers to the west clear of the greater Bosphorus Canyon finally cascading down the few small canyons. A diffusive spread from the bottom vein of salty water reforms to the east and spills down the Bosphorus Canyon. The suspended particulate signature of the cascade, as well as its influence in hydrography is traced over the shelf and slope waters and through the numerous canyons into deep water where the reformed flow is found to sustain signatures of the past evolution of intrusive waters. An evaluation of the processes is given with reference to model development carried out in parallel to the analyses of the measurements.

  13. Carbonate apron models: Alternatives to the submarine fan model for paleoenvironmental analysis and hydrocarbon exploration

    USGS Publications Warehouse

    Mullins, H.T.; Cook, H.E.

    1986-01-01

    Sediment gravity flow deposition along the deep-water flanks of carbonate platforms typically does not produce submarine fans. Rather, wedge-shaped carbonate aprons develop parallel to the adjacent shelf/slope break. The major difference between submarine fans and carbonate aprons is a point source with channelized sedimentation on fans, versus a line source with sheet-flow sedimentation on aprons. Two types of carbonate aprons may develop. Along relatively gentle (< 4??) platform-margin slopes, aprons form immediately adjacent to the shallow-water platform and are referred to as carbonate slope aprons. Along relatively steep (4-15??) platform margin slopes, redeposited limestones accumulate in a base-of-slope setting, by-passing an upper slope via a multitude of small submarine canyons, and are referred to as carbonate base-of-slope aprons. Both apron types are further subdivided into inner and outer facies belts. Inner apron sediments consist of thick, mud-supported conglomerates and megabreccias (Facies F) as well as thick, coarse-grained turbidites (Facies A) interbedded with subordinate amounts of fine-grained, peri-platform ooze (Facies G). Outer apron sediments consist of thinner, grain-supported conglomerates and turbidites (Facies A) as well as classical turbidites (Facies C) with recognizable Bouma divisions, interbedded with approximately equal proportions of peri-platform ooze (Facies G). Seaward, aprons grade laterally into basinal facies of thin, base-cut-out carbonate turbidites (Facies D) that are subordinate to peri-platform oozes (Facies G). Carbonate base-of-slope aprons grade shelfward into an upper slope facies of fine-grained peri-platform ooze (Facies G) cut by numerous small canyons that are filled with coarse debris, as well as intraformational truncation surfaces which result from submarine sliding. In contrast, slope aprons grade shelfward immediately into shoal-water, platform-margin facies without an intervening by-pass slope. The two carbonate apron models presented here offer alternatives to the submarine-fan model for paleoenvironmental analysis and hydrocarbon exploration for mass-transported carbonate facies. ?? 1986.

  14. Revisiting submarine mass movements along the U.S. Atlantic Continental Margin: implications for tsunami hazards

    USGS Publications Warehouse

    Chaytor, J.D.; Twichell, D.C.; ten Brink, U.S.; Buczkowski, B.J.; Andrews, B.D.

    2007-01-01

    Interest in the generation of tsunamis by submarine mass movements has warranted a reassessment of their distribution and the nature of submarine landslides offshore of the eastern U.S. The recent acquisition and analysis of multibeam bathymetric data over most of this continental slope and rise provides clearer view into the extent and style of mass movements on this margin. Debris flows appear to be the dominant type of mass movement, although some translational slides have also been identified. Areas affected by mass movements range in size from less than 9 km2 to greater than 15,200 km2 and reach measured thicknesses of up to 70 m. Failures are seen to originate on either the open-slope or in submarine canyons. Slope-sourced failures are larger than canyonsourced failures, suggesting they have a higher potential for tsunami generation although the volume of material displaced during individual failure events still needs to be refined. The slope-sourced failures are most common offshore of the northern, glaciated part of the coast, but others are found downslope of shelf-edge deltas and near salt diapirs, suggesting that several geological conditions control their distribution.

  15. 77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-16

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  16. 76 FR 24516 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  17. 77 FR 43117 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-23

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  18. 77 FR 22801 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  19. 78 FR 7810 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  20. 78 FR 21415 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  1. De-Stabilization of Streambanks by Removal of Invasive Species in Canyon de Chelly National Monument, Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of a study to investigate the causes of channel narrowing and incision in Canyon de Chelly National Monument, the effects of Tamarisk and Russian-olive on streambank stability were evaluated. The National Park Service (NPS) is currently engaged in an experimental program to remove the invasi...

  2. Bell Canyon test and results

    SciTech Connect

    Christensen, C.L.; Hunter, T.O.

    1980-01-01

    The purposes of the Borehold Plugging Program are: to identify issues associated with sealing boreholes and shafts; to establish a data base from which to assess the importance of these issues; and to develop sealing criteria, materials, and demonstrative test for the Waste Isolation Pilot Plant (WIPP). The Bell Canyon Test described in this report is one part of that program. Its purpose was to evaluate, in situ, the state of the art in borehole plugs and to identify and resolve problems encountered in evaluating a typical plug installation in anhydrite. The test results are summarized from the work of Peterson and Christensen and divided into two portions: system integrity and wellbore characterization tests prior to plug installation, and a series of tests to evaluate isolation characteristics of the 1.8-m-long plug. Conclusions of the Bell Canyon Test are: brine and fresh-water grouts, with acceptable physical properties in the fluid and hardened states, have been developed; the field data, taken together with laboratory data, suggest that the predominant flow into the test region occurs through the cement plug/borehold interface region, with lesser contributions occurring through the wellbore damage zone, the plug core, and the surrounding undisturbed anhydrite bed; and the 1.8-m-long by 20-cm-diameter grout plug, installed in anhydrite at a depth of 1370 m in the AEC-7 borehole, limits flow from the high pressure Bell Canyon aquifer to 0.6 liters/day.

  3. Snake Hells Canyon Subbasin Management Plan

    E-print Network

    ...............................................................9 4.1 Vision Statement...............................................................................8 4 VISION FOR THE SNAKE HELLS CANYON SUBBASIN........................................................................................................9 5 PROBLEM STATEMENTS, OBJECTIVES, AND STRATEGIES

  4. Biological Inventory Colorado Canyons National Conservation Area

    E-print Network

    Biological Inventory of the Colorado Canyons National Conservation Area Prepared by: Joe Stevens............................................................................................................................. 1 II. The Natural Heritage Network and Biological Diversity ...................................................... 3 What is Biological Diversity

  5. Submarine landslide geomorphology, US continental slope

    Microsoft Academic Search

    B. g. Mcadoo; L. f. Pratson; D. l. Orange

    2000-01-01

    The morphometric analysis of submarine landslides in four distinctly different tectonic environments on the continental slopes of Oregon, central California, Texas, and New Jersey provides useful insight into submarine process, including sediment transport mechanisms and slope stability. Using Geographic Information System (GIS) software, we identify landslides from multibeam bathymetric and GLORIA sidescan surveys based solely on surficial morphology and reflectivity.

  6. Dynamics Modeling for Submarine Pipeline Oil Spill

    Microsoft Academic Search

    Ming Xiao; Qingjun Gao; Jianguo Lin; Wei Li; Xiao Liang

    2010-01-01

    The present oil spill models are usually based on sea surface, while few of them are for submarine oil spill. Therefore, modeling and simulation for submarine pipeline oil spill is discussed by FLUENT in this paper to forecast the trajectory of oil. The coupling of pressure and velocity under unsteady-state condition is solved by pressure implicit with splitting of operators

  7. Submarine landslide flows simulation through centrifuge modelling

    E-print Network

    Gue, Chang Shin

    2012-05-08

    SUBMARINE LANDSLIDE FLOWS SIMULATION THROUGH CENTRIFUGE MODELLING by Chang Shin GUE A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge Churchill College January... “Continuous effort – not strength or intelligence – is the key to unlocking our potential” - Winston Churchill ABSTRACT SUBMARINE LANDSLIDE FLOWS SIMULATION THROUGH CENTRIFUGE MODELLING Chang Shin GUE Landslides occur both onshore...

  8. Computer simulation of submarine motion 

    E-print Network

    Zurflueh, Jeffery Alan

    1991-01-01

    and gM = d (Id)). The right hand side, i. e. , the ma terms and the d d(Itu) dt dt terms, were derived and verified to be equal to the same terms in Feldman's equations. It was not possible to verify the ~ and PM terms as they are determined from... of gravity (CG) m = mass of the submarine g = gt'avlty. Figure 13 shows plots of the roll angle (Q) vs. time for the propulsion torque values of -1000, -2000, and -4000 Newton*meter (N*m). Table 1(pg. 23) displays the comparison between the simulated...

  9. Chirp seismic-reflection data from the Baltimore, Washington, and Norfolk Canyons, U.S. mid-Atlantic margin

    USGS Publications Warehouse

    Obelcz, Jeffrey B.; Brothers, Daniel S.; ten Brink, Uri S.; Chaytor, Jason D.; Worley, Charles R.; Moore, Eric M.

    2014-01-01

    A large number of high-resolution geophysical surveys between Cape Hatteras and Georges Bank have been conducted by federal, state, and academic institutions since the turn of the century. A major goal of these surveys is providing a continuous view of bathymetry and shallow stratigraphy at the shelf edge in order to assess levels of geological activity during the current sea level highstand. In 2012, chirp seismic-reflection data was collected by the U.S. Geologial Survey aboard the motor vessel Tiki XIV near three United States mid-Atlantic margin submarine canyons. These data can be used to further our understanding of passive continental margin processes during the Holocene, as well as providing valuable information regarding potential submarine geohazards.

  10. 29. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION AT POINT JUST ABOVE THE SUBMARINE SECTION AT THE 110-FOOT LEVEL 1929-1930 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  11. 32. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONN. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONN. OCTOBER 3, 1932. COMPLETION OF ERECTION OF STEELWORK FOR ELEVATOR. LOOKING NORTH. CONTRACT NO. Y-1539-ELEVATOR, SUBMARINE ESCAPE TANK.' - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  12. Following the Cantabrian (Ventaniella) fault into the Bay of Biscay: a deeply incised canyon, a change of trend, and 20002 km of unstable continental slope

    NASA Astrophysics Data System (ADS)

    Fernandez Viejo, G.; Lopez-Fernandez, C.; Dominguez-Cuesta, M.

    2012-12-01

    The Cantabrian fault, known traditionally with the local name of Ventaniella fault is a long-lived rectilinear feature that runs in a NW-SE direction for more than 200 km across northwest Spain. Its origins are linked to the end of the Variscan orogeny, but its important role took place during the extensional processes of the Mesozoic that led Iberia to become a microplate separated from Europe and Africa. With the initiation of the alpine orogeny Iberia converges with Europe pushed from the south by Africa, and the Ventaniella fault acted as a dextral strike slip fault with an important reverse component. It has a relatively low topographic expression, although its NE block is slightly uplifted with respect to the SW one. Traditionally it has been mapped offshore following the trace of the Aviles canyon, a deeply incised canyon 7 miles from the coast, oblique to the E-W coast trend and which descents from 160 m in the continental shelf , down to 4750 m in the abyssal plain of the Bay of Biscay . All this incision occurs along just 50 km length of the narrow continental shelf in this area, making the Aviles canyon one of the steepest in the Atlantic. Through seismic reflection lines across the continental shelf and slope, a bathymetric model up to date and a 3D geological model the fault has been mapped into the sea integrating the seismicity associated to its SW block and the newest geological mapping on land. At the same time, what is observed in the northwest prolongation and termination of the fault against the oceanic crust of the abyssal plain is a continental slope that is full of mass-wasting processes along more than 80 km length, showing gravitational and submarine slide processes in an area that roughly occupies 2000 km 2 and involves a volume of unstable mass estimated in more than 1000 km3 . One of the biggest displaced masses made the Aviles canyon change its trend to N-S in an almost 90° bend close to the middle slope. Although the displaced masses are big, it does not seem to pose an immediate hazard, as they all show a short run-out distance and, being the actual seismicity of low grade, it is not enough to trigger the fall of the unstable slope. The Ventaniella fault runs in the continental shelf and slope in NW-SE direction, but it also has been deduced with the new data a secondary fault trace slightly more W-E, interpreted as a termination in horsetail of the main strike-slip feature. Both structures seem to be responsible for the seismicity and the mass wasting processes observed along this strip of the Cantabrian margin.

  13. Nicolas and Eel submarine fans, California continental borderland

    SciTech Connect

    Reynolds, S.; Gorsline, D.S.

    1987-04-01

    Nicolas and Eel Submarine Fans occur in the San Nicolas basin - an outer basin of the California continental borderland that has a low sedimentation rate. Nicolas Fan lies southeast of San Nicolas Island and the broad San Nicolas Bank. The upper fan is characterized by numerous channels. The midfan region may be divided into three distinct areas: a central midfan and two subfans. The central midfan deposition system is typical of Normark's suprafan. The subfans are essentially flat, sandy lobes. Eel Fan lies west of San Clemente Island and is fed by an erosional valley. Its midfan region may also be characterized as a flat, sandy lobe. Box-core data show that holocene turbidity currents have occurred on the central Nicolas Fan, whereas the subfans and Eel Fan are nearly inactive. The local tectonic regime influences these fans by determining slope trends, creating bathymetric obstacles, controlling canyon location, and triggering mass movements. Sea level changes affect sedimentation patterns of the fans by increasing the mean grain size and the amount of sediment delivered to the fan during lowstands. These changes may, in turn, affect the morphology of the fan. The characteristics of these fans represent variations of the generalized fan models described in the literature. 12 figures, 1 table.

  14. Marine neotectonic investigation of the San Gregorio Fault Zone on the northern flank of Monterey Canyon, offshore central California

    NASA Astrophysics Data System (ADS)

    Maier, K. L.; Paull, C. K.; Brothers, D. S.; McGann, M.; Caress, D. W.; Lundsten, E. M.; Anderson, K.; Gwiazda, R.

    2014-12-01

    The San Gregorio Fault Zone (SGFZ) is part of the North American-Pacific plate boundary and is thought to accommodate right-lateral offset up to 10 mm/yr. Because much of the SGFZ in Monterey Bay, central California, lies offshore in steep submarine canyon bathymetry, little is known of its recent activity. We provide initial direct evidence for faulting where the SGFZ has been interpreted based on canyon morphology to cross the northern flank of Monterey Canyon. High-resolution multibeam bathymetry and chirp subbottom profiles were acquired during 13 dives with the Monterey Bay Aquarium Research Institute's (MBARI) Autonomous Underwater Vehicle (AUV) from 2009-2014 on the northern flank of Monterey Canyon, extending from the shelf edge ~15 km offshore Santa Cruz to ~1850 m water depth. Chirp profiles resolve layered sediments up to ~40 m subsurface in this region, and no fault scarps or seafloor lineaments are visible in the 1-m resolution multibeam bathymetry. At least one subsurface fault is identified within the SGFZ by offset reflections across a discrete, nearly vertical fault. However, this fault is only imaged where mass wasting has exhumed older strata to within ~25 m of the seafloor. Numerous slumps scars on the seafloor and packages of chaotic internal reflectivity in chirp profiles suggest that submarine landslide processes dominate the study area. To constrain the age of reflections offset by the fault, MBARI's Remotely Operated Vehicle (ROV) Doc Ricketts, sampled faces of slump scars where the offset reflections crop out using vibracores and horizontal push cores. Radiocarbon dating of foraminifera within these core samples is being used to constrain the last recorded movement on the fault. Application of AUV and ROV methods allows detailed neotectonic investigation of significant offshore structures, like the SGFZ, that contribute to hazard assessment.

  15. Urban street canyons: Coupling dynamics, chemistry and within-canyon chemical processing of emissions

    NASA Astrophysics Data System (ADS)

    Bright, Vivien Bianca; Bloss, William James; Cai, Xiaoming

    2013-04-01

    Street canyons, formed by rows of buildings in urban environments, are associated with high levels of atmospheric pollutants emitted primarily from vehicles, and substantial human exposure. The street canyon forms a semi-enclosed environment, within which emissions may be entrained in a re-circulatory system; chemical processing of emitted compounds alters the composition of the air vented to the overlying boundary layer, compared with the primary emissions. As the prevailing atmospheric chemistry is highly non-linear, and the canyon mixing and predominant chemical reaction timescales are comparable, the combined impacts of dynamics and chemistry must be considered to quantify these effects. Here we report a model study of the coupled impacts of dynamical and chemical processing upon the atmospheric composition in a street canyon environment, to assess the impacts upon air pollutant levels within the canyon, and to quantify the extent to which within-canyon chemical processing alters the composition of canyon outflow, in comparison to the primary emissions within the canyon. A new model for the simulation of street canyon atmospheric chemical processing has been developed, by integrating an existing Large-Eddy Simulation (LES) dynamical model of canyon atmospheric motion with a detailed chemical reaction mechanism, a Reduced Chemical Scheme (RCS) comprising 51 chemical species and 136 reactions, based upon a subset of the Master Chemical Mechanism (MCM). The combined LES-RCS model is used to investigate the combined effects of mixing and chemical processing upon air quality within an idealised street canyon. The effect of the combination of dynamical (segregation) and chemical effects is determined by comparing the outputs of the full LES-RCS canyon model with those obtained when representing the canyon as a zero-dimensional box model (i.e. assuming mixing is complete and instantaneous). The LES-RCS approach predicts lower (canyon-averaged) levels of NOx, OH and HO2, but higher levels of O3, compared with the box model run under identical chemical and emissions conditions. When considering the level of chemical detail implemented, segregation effects were found to reduce the error introduced by simplifying the reaction mechanism. Chemical processing of emissions within the canyon leads to a significant increase in the Ox flux from the canyon into the overlying boundary layer, relative to primary emissions, for the idealised case considered here. These results demonstrate that within-canyon atmospheric chemical processing can substantially alter the concentrations of pollutants injected into the urban canopy layer, compared with the raw emission rates within the street canyon. The extent to which these effects occur is likely to be dependent upon the nature of the domain (canyon aspect ratio), prevailing meteorology and emission/pollution scenario considered.

  16. Barrel Cactus in Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  17. Sunset Panorama in Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  18. Loblolly Pines in Pine Creek Canyon

    USGS Multimedia Gallery

    Pine Creek Canyon is a remnant ecosystem of loblolly pines. A remnant ecosystem is the last vestige of an ecosystem type that used to be more widespred. Red Rock Canyon is a National Conservation Area managed by the Bureau of Land Management, located just outside of Las Vegas, Nevada. It is part of...

  19. Environmental assessment: Davis Canyon site, Utah

    SciTech Connect

    Not Available

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Davis Canyon site in Utah as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high- level radioactive waste. To determine their suitability, the Davis Canyon site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EA. The Davis Canyon site is in the Paradox Basin, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains one other potentially acceptable site -- the Lavender Canyon site. Although the Lavender Canyon site is suitable for site characterization, the DOE has concluded that the Davis Canyon site is the preferred site in the Paradox Basin. On the basis of the evaluations reported in this EA, the DOE has found that the Davis Canyon site is not disqualified under the guidelines. Furthermore, the DOE has found that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Davis Canyon site as one of the five sites suitable for characterization.

  20. Environmental assessment: Davis Canyon site, Utah

    SciTech Connect

    Not Available

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Davis Canyon site in Utah as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Davis Canyon site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EA. The Davis Canyon site is in the Paradox Basin, which is one of five distinct geohydrologic settings considering for the first repository. This setting contains one other potentially acceptable site -- the Lavender Canyon site. Although the Lavender Canyon site is suitable for site characterization, the DOE has concluded that the Davis Canyon site is the preferred site in the Paradox Basin. On the basis of the evaluations reported in this EA, the DOE has found that the Davis Canyon site is not disqualified under the guidelines. Furthermore, the DOE has found that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Davis Canyon site as one of five sites suitable for characterization.

  1. ACCELERATED PILOT PROJECT FOR U CANYON DEMOLITION

    SciTech Connect

    KEHLER KL

    2011-01-13

    At the U.S. Department of Energy's Hanford Site in southeast Washington State, CH2M HILL Plateau Remediation Company (CH2M HILL) is underway on a first-of-a-kind project with the decommissioning and demolition of the U Canyon. Following the U.S. Environmental Protection Agency's Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) Record of Decision for the final remediation of the canyon, CH2M HILL is combining old and new technology and techniques to prepare U Canyon for demolition. The selected remedial action called first for consolidating and grouting equipment currently in the canyon into lower levels of the plant (openings called cells), after which the cell galleries, hot pipe trench, ventilation tunnel, drains and other voids below the operating deck and crane-way deck levels will be filled with approximately 20,000 cubic yards of grout and the canyon roof and walls demolished down to the approximate level of the canyon deck. The remaining canyon structure will then be buried beneath an engineered barrier designed to control potential contaminant migration for a 500-year life. Methods and lessons learned from this project will set the stage for the future demolition of Hanford's four other canyon-type processing facilities.

  2. Grand Canyon Monitoring and Research Center

    USGS Publications Warehouse

    Hamill, John F.

    2009-01-01

    The Grand Canyon of the Colorado River, one of the world's most spectacular gorges, is a premier U.S. National Park and a World Heritage Site. The canyon supports a diverse array of distinctive plants and animals and contains cultural resources significant to the region's Native Americans. About 15 miles upstream of Grand Canyon National Park sits Glen Canyon Dam, completed in 1963, which created Lake Powell. The dam provides hydroelectric power for 200 wholesale customers in six western States, but it has also altered the Colorado River's flow, temperature, and sediment-carrying capacity. Over time this has resulted in beach erosion, invasion and expansion of nonnative species, and losses of native fish. Public concern about the effects of Glen Canyon Dam operations prompted the passage of the Grand Canyon Protection Act of 1992, which directs the Secretary of the Interior to operate the dam 'to protect, mitigate adverse impacts to, and improve values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established...' This legislation also required the creation of a long-term monitoring and research program to provide information that could inform decisions related to dam operations and protection of downstream resources.

  3. Big Canyon Creek Ecological Restoration Strategy

    Microsoft Academic Search

    Lynn Rasmussen; Shannon Richardson

    2007-01-01

    He-yey, Nez Perce for steelhead or rainbow trout (Oncorhynchus mykiss), are a culturally and ecologically significant resource within the Big Canyon Creek watershed; they are also part of the federally listed Snake River Basin Steelhead DPS. The majority of the Big Canyon Creek drainage is considered critical habitat for that DPS as well as for the federally listed Snake River

  4. Snow-covered Sandstone at Bryce Canyon

    USGS Multimedia Gallery

    Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their base. Bryce Canyon is also home to large numbe...

  5. NOAA Explorations: Submarine Ring of Fire 2004

    NSDL National Science Digital Library

    NOAA's 2004 Submarine Ring of Fire expedition's goals are to examine over a 1,000 km stretch of submarine volcanoes and sea-floor hot springs in the Mariana Island Arc. At this website, users can find general information about the Mariana Arc, the research, and the scientists involved. Educators can find intriguing lesson plans about volcanoes and the chemistry of hydrothermal vents for grades fifth through twelfth. The site presents fascinating materials about seafloor mapping, volcanism, and vent chemistry. Visitors can view amazing satellite images of the overall Mariana Arc Volcanic Chain, its sea floor, and the NW Uracas and Ahyi submarine volcanoes.

  6. Supplement to The Snake Hells Canyon Subbasin Plan Introduction

    E-print Network

    1 Supplement to The Snake Hells Canyon Subbasin Plan Introduction This document was written draft Snake Hells Canyon Subbasin Assessment and Snake Hells Canyon Subbasin Management Plan prepared species in the Snake Hells Canyon subbasin. Section II summarizes the prioritization of these limiting

  7. Prehistoric deforestation at Chaco Canyon?

    PubMed Central

    Wills, W. H.; Drake, Brandon L.; Dorshow, Wetherbee B.

    2014-01-01

    Ancient societies are often used to illustrate the potential problems stemming from unsustainable land-use practices because the past seems rife with examples of sociopolitical “collapse” associated with the exhaustion of finite resources. Just as frequently, and typically in response to such presentations, archaeologists and other specialists caution against seeking simple cause-and effect-relationships in the complex data that comprise the archaeological record. In this study we examine the famous case of Chaco Canyon, New Mexico, during the Bonito Phase (ca. AD 860–1140), which has become a prominent popular illustration of ecological and social catastrophe attributed to deforestation. We conclude that there is no substantive evidence for deforestation at Chaco and no obvious indications that the depopulation of the canyon in the 13th century was caused by any specific cultural practices or natural events. Clearly there was a reason why these farming people eventually moved elsewhere, but the archaeological record has not yet produced compelling empirical evidence for what that reason might have been. Until such evidence appears, the legacy of Ancestral Pueblo society in Chaco should not be used as a cautionary story about socioeconomic failures in the modern world. PMID:25071220

  8. Comparative naval architecture analysis of diesel submarines

    E-print Network

    Torkelson, Kai Oscar

    2005-01-01

    Many comparative naval architecture analyses of surface ships have been performed, but few published comparative analyses of submarines exist. Of the several design concept papers, reports and studies that have been written ...

  9. Capacity upgrade in WDM submarine cable system

    Microsoft Academic Search

    Eiichi Shibano; Hidenori Taga; Toshio Kawazawa; Koji Goto

    1999-01-01

    The capacity upgrade from 20 Gbit\\/s to 160 Gbit\\/s in a WDM submarine cable system has been designed based on the experimental study of the dependency of the repeater output power and the number of wavelength

  10. Baltimore Canyon Trough, a clastic-carbonate system

    SciTech Connect

    Edson, G.M. (Minerals Management Service, Herndon, VA (USA))

    1990-05-01

    Baltimore Canyon Trough is similar in age, architecture, and sedimentary framework to neighboring marginal basins offshore from eastern North America. The other basins are the Scotian and Georges Bank basins and the Carolina Trough. All contain a Jurassic-earliest Cretaceous clastic-carbonate sedimentary section composed of terrigenous basin fill and a shallow-water limestone platform. In Baltimore Canyon Trough, the platform is believed to be over 10 km thick. Upward through the Jurassic System, the platform progrades seaward and narrows. The platform top is earliest Cretaceous (Berriasian) and only about 5-15 km wide. Width of the base is indeterminate but apparently much wider. At the seaward edge of the platform is a limestone buildup and reef complex that consists of bioclastic wackestones, packstones, grainstones, and sponge-stromatoporoid-algal bindstones. Foreslope deposits are thrombolitic stromatactis-pelletal carbonate mudstones. Landward of the buildup, the platform contains numerous siliciclastic interbeds, consisting of mostly calcareous shale and siltstone with inertinite. The calciclastic lime mudstone beds of the platform contain terrigenous siliciclasts and kerogens. All units are oxidized and show considerable sedimentary reworking. Through the Jurassic System and into the Cretaceous, terrigenous clastic sediments became increasingly dominant in the basin and erosional-depositional cycles continually reworked carbonate, as well as siliciclastic, units.

  11. Addressing submarine geohazards through scientific drilling

    Microsoft Academic Search

    A. Camerlenghi

    2009-01-01

    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

  12. High-Resolution Multibeam, Sidescan, and Subbottom Surveys in and Around Monterey Canyon Using the MBARI Mapping AUV

    NASA Astrophysics Data System (ADS)

    Caress, D. W.; Thomas, H.; McEwen, R.; Henthorn, R.; Kirkwood, W. J.; Thompson, D.; Paull, C. K.; McGill, P.

    2005-12-01

    During 2004 and 2005, MBARI has conducted several high-resolution bathymetry, sidescan, and subbottom profiler surveys in and around Monterey Canyon, Monterey Bay, California. These surveys were conducted using the new MBARI Mapping Autonomous Underwater Vehicle (AUV). This torpedo-shaped, 6000 m deep rated vehicle is equipped with a 200 kHz multibeam sonar, 110 kHz and 410 kHz chirp sidescan sonar, and a 2-16 kHz sweep subbottom profiler. The sonar package can also be mounted on ROV Ventana, allowing near-bottom bathymetric surveys of sites where extreme topography (e.g. the Monterey Canyon axis) preclude safe autonomous operation. The Mapping AUV is being used to monitor sediment transport through Monterey Canyon by conducting repeated high-resolution bathymetric surveys in the upper canyon. Upper Monterey Canyon is known to have frequent sediment transport events. Four sites have been selected with canyon axis depths of 300 m, 520 m, 1000 m, and 1400 m, respectively. Each survey nominally covers a 600 m by 600 m area with a 35 m line spacing and a 20 m altitude. We are achieving sub-meter lateral resolution and a vertical precision of 0.3 m. The combined bathymetry and backscatter successfully image fine scale channel features, including bedforms, small scarps and plunge pools, and undercutting of the inner canyon walls. All four sites have been surveyed at least once, and we will revisit these sites three times annually for the foreseeable future. We have also collected in excess of 170 km of subbottom profiles around and across the upper canyon. The subbottom profiler successfully images sediment structure to subsurface depths of as much as 50 m. These profiles demonstrate that the upper canyon walls are draped with sediment rather than exposing an erosional surface. Another Mapping AUV survey target is Smooth Ridge, located immediately north of Monterey Canyon and west of Soquel canyon. The upper reaches of Smooth Ridge are connected to the shelf across a narrow ridge, or neck, known from ROV dives to have scattered carbonate outcrops and numerous 1-2 m high scarps. We are scheduled to autonomously survey the upper neck of Smooth Ridge during October 2005, and will present initial results from these data.

  13. Submarine landslides: processes, triggers and hazard prediction.

    PubMed

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

    2006-08-15

    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. PMID:16844646

  14. The Grand Canyon: How It Formed

    NSDL National Science Digital Library

    Today, in the deepest part of the Grand Canyon, the Colorado River flows past rocks that are 1.7 billion years old. This video describes how the river cut vertically through layers of pre-existing rock as the plateau beneath it was uplifted by tectonic forces. It also explains that other forces worked to widen the canyon, particluarly the activity of tributary streams and debris flows caused by flash flooding from intense rainfall or rapid snowmelt moving loose rock and boulders down canyon walls and side channels. A background essay and list of discussion questions are also provided.

  15. Human-Powered Submarine Competition: World Submarine International 1996 [and] Design Technology Exhibit: A School Model.

    ERIC Educational Resources Information Center

    Hibberd, John C.; Edwards, Don

    1996-01-01

    Hibbard describes the process used by students at Millersville University to build a human-powered submarine for entry in an international submarine competition. Edwards discusses the Design Technology Exhibit held at Lu Sutton Elementary School, the purpose of which was to challenge students to design a useful structure and provide them with the…

  16. Riparian vegetation of the Black Canyon of the Gunnison River, Colorado: composition and response to selected hydrologic regimes based on a direct gradient assessment model

    USGS Publications Warehouse

    Auble, Gregor T.; Friedman, Jonathan M.; Scott, Michael L.

    1991-01-01

    The Black Canyon of the Gunnison National Monument is located along the Gunnison River on the western slope of the Rocky Mountains in Montrose County, Colorado. The canyon is narrow because it is cut into resistant pre-Cambrian gneiss: it has a maximum depth of 900m and a minimum width of 300m from rim to rim (Hansen 1987). The watershed is 10,000 square km. A 450-m study reach was selected by the National Park Service (Fig. 1). The width of the canyon bottom within the study reach varies from 40 to 90 m, the gradient is 0.0128, and the elevation is approximately 1707 m. Average annual precipitation is 370 m (Colorado Climate Center 1984). Because of the steep canyon walls the study reach is inaccessible to livestock and has probably never been grazed.

  17. Simulating Submarine Channels in Flume Experiments: Aspects of the Channel Incision Dynamic

    NASA Astrophysics Data System (ADS)

    Lancien, P.; Metivier, F.; Lajeunesse, E.; Cacas, M.

    2004-12-01

    We report the results of thirty laboratory experiments reproducing submarine straight canyons as well as meandering ones. Our experimental setup consists in 2 m X 0.5 m flume filled with fresh water. The flume bottom simulates a sub-marine ramp draped by a sediment blanket. A sustained density flow is simulated by a continuous brine stream injected at the top of the ramp. We control the three main parameters of the experiment: the slope of the plane, the input flow rate, and the brine density. It allowed us to test the reproducibility of the phenomenon and to roughly delineate a phase diagram specifying the channel incision conditions. An optical acquisition technique enables us to measure instantaneously the topography of the sediment surface at successive times, during the canyon formation and frontal lobe deposition. In this way we can define and then measure physical quantities representative of different channel types in order to visualize their evolution. Here we present a few aspects of the channel incision dynamic. After a development phase in which the bottom density current spreads over the bed, the channel inception phase suddenly begins, followed by a positive feedback mechanism facilitating further erosion. Then a phase of regressive erosion appears, and in some cases a steady state can be finally obtained. By computing the difference between successive maps, we can elaborate time-varying maps of sedimentation and erosion rates in the system. Stacking of these maps produce a 3D cube of sedimentation rates showing autocyclic phases of incision, by-pass and sedimentation. Cross-sections through this 3D cube show morphologies very similar to those observed on seismic acquisitions performed in the Recent Orenoque channel system.

  18. Submarine Landslide Morphology of Box Slides Present on the Continental Slope Offshore Fraser Island, Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Fletcher, M. J. A.; Hubble, T.; Clarke, S. L.; Airey, D.; Yu, P. W. C.

    2014-12-01

    The Fraser Island slide complex is located on eastern Australia's continental slope. Two potentially tsunamigenic submarine landslides identified here as the 'North Fraser Island Upper Slope Slide' (25km2 in area, 100m thick) and the 'Middle Fraser Island Middle Slope Slide' (12km2 in area, 50m thick) are described. Morphologic, sedimentologic and geomechanical properties for these slides are compared to data reported for existing submarine landslides located to the south in New South Wales (NSW). The two Fraser Island slides are translational, box-shaped, slab slides. We suspect that the slabs remained intact during downslope transport. The upper slope slide is situated at a water depth of approximately 750m at the northern end of the Fraser Canyon complex. The head of this slide has apparently detached from a structural surface comprised of a Miocene reef complex located beneath the continental shelf edge. The middle slope slide is situated on a large plateau to the south of the Fraser Canyon complex in 1500m of water. Cores taken in the continental slope within both slides are long and present hemipelagic muds. Cores taken adjacent to both slides are short and terminate in stiff muds of suspected Miocene or Pliocene age. Additionally, the core adjacent to the upper slope slide presents a near surface layer of upper-fining of coarse to fine shelly sand which we interpret to be a turbidite deposit. This layer was deposited above hemipelagic muds which are ubiquitously present on the upper eastern Australian continental slope in NSW and Southern Queensland.

  19. Mars Science Laboratory at Canyon

    NASA Technical Reports Server (NTRS)

    2003-01-01

    December 2, 2003

    NASA's Mars Science Laboratory travels near a canyon on Mars in this artist's concept. The mission is under development for launch in 2009 and a precision landing on Mars in 2010.

    Once on the ground, the Mars Science Laboratory would analyze dozens of samples scooped up from the soil and cored from rocks as it explores with greater range than any previous Mars rover. It would investigate the past or present ability of Mars to support life. NASA is considering nuclear energy for powering the rover to give it a long operating lifespan.

    NASA's Jet Propulsion Laboratory, Pasadena, Calif., is managing development of the Mars Smart Laboratory for the NASA Office of Space Science, Washington, D.C.

  20. Flow Structure in a Bedrock Canyon (Invited)

    NASA Astrophysics Data System (ADS)

    Venditti, J. G.; Rennie, C. D.; Church, M. A.; Bomhof, J.; Lin, M.

    2013-12-01

    Bedrock canyon incision is widely recognized as setting the pace of landscape evolution. A variety of models link flow and sediment transport processes to the bedrock canyon incision rate. The model components that represent sediment transport processes are quite well developed in some models. In contrast, the model components that represent fluid flow remain rudimentary. Part of the reason is that there have been relatively few observations of flow structure in a bedrock canyon. Here, we present observations of flow obtained using an array of three acoustic Doppler current profilers during a 524 km long continuous centerline traverse of the Fraser River, British Columbia, Canada as it passes through a series of bedrock canyons. Through this portion of the river, the channel alternates between gravel-bedded reaches that are deeply incised into semi-consolidated glacial deposits and solid bedrock-bound reaches. We present observations of flow through 41 bedrock bound reaches of the river, derived from our centerline traverses and more detailed three-dimensional mapping of the flow structure in 2 canyons. Our observations suggest that flow in the most well-defined canyons (deep, laterally constrained, completely bedrock bound) is far more complex than that in a simple prismatic channel. As flow enters the canyon, a high velocity core plunges from the surface to the bed, causing a velocity inversion (high velocities at the bed and low velocities at the surface). This plunging flow then upwells along the canyon wall, resulting in a three-dimensional flow with counter-rotating, along-stream eddies that diverge near the bed. We observe centerline ridges along the canyon floors that result from the divergence and large-scale surface boils caused by the upwelling. This flow structure causes deep scour in the bedrock channel floor, and ensures the base of the canyon walls are swept of debris that otherwise may be deposited due to lower shear stresses abutting the walls. The observations suggest that the modeling approaches currently included in landscape evolution theories may be inadequate to capture the morphodynamics of bedrock canyons.

  1. Structure of Flow in a Bedrock Canyon

    NASA Astrophysics Data System (ADS)

    Venditti, J. G.; Rennie, C. D.; Church, M. A.; Bomhof, J.; Lin, M.

    2012-12-01

    Bedrock canyon incision is widely recognized as setting the pace of landscape evolution. A variety of models link flow and sediment transport processes to the bedrock canyon incision rate. The model components that represent sediment transport processes are quite well developed in some models. In contrast, the model components that represent fluid flow remain rudimentary. Part of the reason is that there have been relatively few observations of flow structure in a bedrock canyon. Here, we present observations of flow obtained using an array of three acoustic Doppler current profilers during a 524 km long continuous centerline traverse of the Fraser River, British Columbia, Canada as it passes through a series of bedrock canyons. Through this portion of the river, the channel alternates between gravel-bedded reaches that are deeply incised into semi-consolidated glacial deposits and solid bedrock-bound reaches. We present observations of flow through 41 bedrock bound reaches of the river, derived from our centerline traverses and more detailed three-dimensional mapping of the flow structure in 2 canyons. Our observations suggest that flow in the most well-defined canyons (deep, laterally constrained, completely bedrock bound) is far more complex than that in a simple prismatic channel. As flow enters the canyon, a high velocity core plunges from the surface to the bed, causing a velocity inversion (high velocities at the bed and low velocities at the surface). This plunging flow then upwells along the canyon wall, resulting in a three-dimensional flow with counter-rotating, along-stream eddies that diverge near the bed. We observe centerline ridges along the canyon floors that result from the divergence and large-scale surface boils caused by the upwelling. This flow structure causes deep scour in the bedrock channel floor, and ensures the base of the canyon walls are swept of debris that otherwise may be deposited due to lower shear stresses abutting the walls. The observations suggest that the rudimentary modeling approaches currently included in landscape evolution theories are inadequate to capture the morphodynamics of bedrock canyons.

  2. Environmental assessment: Davis Canyon site, Utah

    SciTech Connect

    Not Available

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Davis Canyon site in Utah as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Davis Canyon site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EA. The Davis Canyon site is in the Paradox Basin, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains one other potentially acceptable site -- the Lavender Canyon site. Although the Lavender Canyon site is suitable for site characterization, the DOE has concluded that the Davis Canyon site is the preferred site in the Paradox Basin. On the basis of the evaluations reported in this EA, the DOE has found that the Davis Canyon site is not disqualified under the guidelines. Furthermore, the DOE has fond that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Davis Canyon site as one of five sites suitable for characterization. 181 figs., 175 tabs.

  3. Hudson Canyon Offshore New York and New Jersey: Active Circular Depressions, Fans, Ravines, Methane Discharge and Water Masses

    NASA Astrophysics Data System (ADS)

    Rona, P. A.; Guida, V.; Scranton, M. I.; Gong, D.; Haag, S.; Macelloni, L.; Simonetti, A.; James, J.; Diercks, A.; Asper, V. L.

    2009-12-01

    We investigated Hudson Canyon from where it begins at the seaward edge of the continental shelf (water depth 100 m) to ~30 km seaward (100-700 m) using high-resolution bathymetry (AUV Eagle Ray; ISE Explorer; EM2000 sonar) and standard oceanographic methods. We find features and processes that create varied distinctive habitats in submarine canyons on passive continental margins, as follows: 1)Sediment conduit: The initial 10 km- long section of the canyon head connects with cross-shelf sediment transport and is smoothed by sediment accumulation indicating that it is presently inactive as a sediment conduit, in contrast to its active role during prior intervals of lowered sea level. 2)Circular depressions: A population of circular depressions with diameters from 50 to 400 m, rim-to-floor relief up to 20 m increasing directly with diameter, flat rough floors and steep walls (15-25 degrees) occur in sediment near the base of both walls of the canyon. The number of circular depressions increases with water depth with one at 325 m in the initial 10 km-long NW-SE section of the canyon, two at 350 m in the next 10 km N-S section, and nineteen at 300 to 500 m at the SW wall of the next 10 km NW-SE section. The sharp shape of the depressions suggests that they are actively forming. Larger circular depressions (diameter <800 m) exhibit different characteristics. 3)Methane chemistry: A methane anomaly (50 nmol) ten times background was measured in August 2008 in the near-bottom water column adjacent to one of the two circular depressions in the middle canyon section. In August 2009 water samples were recovered at other circular depressions and are being analyzed to test for methane discharge. We suggest that the circular depressions are gas release-collapse features possibly produced by dissociation of underlying gas hydrates. 4)Fans and ravines: Sediment fans with intervening ravines about 1 km apart extend orthogonal to the canyon axis down the two walls of the canyon in the second and third sections. 5)Hydrography: A dynamic system of multiple layers of inter-leaved shelf (cold, fresh) and slope (warm, salty) water masses was observed in the canyon head in summers 2007, 2008 and 2009 and found to produce shifting fronts and strong currents. Dynamic interactions between the hydrography and different terrains create a wide range of habitat conditions in the canyon critical for biodiversity. Enhanced shelf-slope exchange of water masses facilitated by the complex canyon topography may influence adjacent shelf circulation, and impact ecosystems including commercial fish stocks well beyond the canyon. We thank NOAA National Marine Fisheries Service(NMFS), National Institute of Science and Technology (NIUST), and National Undersea Research Program (NURP) for support.

  4. Open architecture framework for improved early stage submarine design

    E-print Network

    Sewell, Eli A. (Eli Anthony)

    2010-01-01

    Could transparency between current disparate methods improve efficiency in early stage submarine design? Does the lack of transparency between current design methods hinder the effectiveness of early stage submarine design? ...

  5. Mathematical modelling of submarine landslide motion

    NASA Astrophysics Data System (ADS)

    Burminskij, A.

    2012-04-01

    Mathematical modelling of submarine landslide motion The paper presents a mathematical model to calculate dynamic parameters of a submarine landslide. The problem of estimation possible submarine landslides dynamic parameters and run-out distances as well as their effect on submarine structures becomes more and more actual because they can have significant impacts on infrastructure such as the rupture of submarine cables and pipelines, damage to offshore drilling platforms, cause a tsunami. In this paper a landslide is considered as a viscoplastic flow and is described by continuum mechanics equations, averaged over the flow depth. The model takes into account friction at the bottom and at the landslide-water boundary, as well as the involvement of bottom material in motion. A software was created and series of test calculations were performed. Calculations permitted to estimate the contribution of various model coefficients and initial conditions. Motion down inclined bottom was studied both for constant and variable slope angle. Examples of typical distributions of the flow velocity, thickness and density along the landslide body at different stages of motion are given.

  6. Combining Seismic Geomorphology and Physical Sedimentology to Resolve Depositional Processes within Submarine Channel Bends

    NASA Astrophysics Data System (ADS)

    Fernandes, A. M.; Mohrig, D.; Petter, A. L.; Steel, R. J.; Henriksen, S.

    2012-12-01

    Turbidity currents display exaggerated super-elevation at the outer banks of channel bends because they have low excess densities relative to the ambient sea-water. Low-velocity zones form where flows separate from the inner banks of bends. Depositional processes associated with the development of bank-attached bars in these flow-separation zones are evaluated using: a) measurements of geometries of bank-attached bars and their positions along channel curvature from two buried submarine channels, imaged in a high-resolution seismic data-set from the continental margin of West Africa, and b) detailed measurements of bed geometry, sedimentary structures and grain-sizes of a bank-attached bar in an exposed submarine channel complex from the Permian Brushy Canyon Formation, in west Texas. The 226 bar surfaces mapped in the seismic volume have high median slopes (10-11 degrees), occupy less than 30% of channel width, and are associated with weak channel incision and small amounts of lateral migration equal to less that 70% of a channel width. The mapped bank-attached bar outcrop shows a 17m-thick set of steeply inclined (median dip=10 degrees) fine-grained sandstone beds. Sub- to super-critically climbing ripple-lamination is abundant with paleo-transport oriented at 20-120 degrees relative to the dip azimuths of interpreted bar surfaces. Sedimentary structures, grain-size distributions and paleo-transport reconstructions from deposits in the bar and those filling the main channel reveal that this bar was constructed from fully-suspended sediment. These observations suggest that bank-attached bars constructed from fully-suspended sediment in submarine channels have been under-recognized on passive continental margins thus far. This data also defines the connection between the large scale morphologies of depositional elements, the processes responsible for their construction and the fine-scale attributes of the resulting stratigraphy.

  7. Variability of the underwater light field and chlorophyll a in the Blanes Canyon (NW Mediterranean Sea) during the MERIS- ENVISAT calibration exercise

    Microsoft Academic Search

    Nixon Bahamon; Antonio Cruzado; Zoila Velásquez

    Time variation of spectral downwelling irradiance (Ed), upwelling radiance (Lu), chlorophyll a (Chla) and density was monitored above 200 m depth from June through September 2002 at the head of the Blanes Canyon located in a narrow shelf section of the NW Mediterranean Sea. The water column showed typical stratified oligotrophic conditions with no signals of freshwater intrusions. The thermocline

  8. 31. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION OF THE ELEVATOR AND PASSAGEWAYS TO THE 18- AND 50-FOOT LOCKS AND CUPOLA 1932 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  9. 36. VIEW OF CUPOLA, SUBMARINE ESCAPE TRAINING TANK, SHOWING ROVING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. VIEW OF CUPOLA, SUBMARINE ESCAPE TRAINING TANK, SHOWING ROVING RESCUE BELL SUSPENDED ABOVE TANK, WITH TWO-LOCK RECOMPRESSION CHAMBER AT REAR, LOOKING WEST. Photo taken after installation of recompression chamber in 1956. - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  10. 35. INTERIOR VIEW OF EQUIPMENT HOUSE, SUBMARINE ESCAPE TRAINING TANK, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. INTERIOR VIEW OF EQUIPMENT HOUSE, SUBMARINE ESCAPE TRAINING TANK, PRIOR TO ENLARGEMENT OF ROOM AND INSTALLATION OF TRIPLE-LOCK RECOMPRESSION CHAMBER IN 1957 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  11. Introduction Deep-sea deposits from submarine landslides, debris

    E-print Network

    Introduction Deep-sea deposits from submarine landslides, debris flows, and turbidity currents have with submarine mass-wasting. An example is the Storegga landslide on the Norwegian margin, which occurred about 9 detached from the front of slowing-down submarine landslides. With a runout ratio of the order 0

  12. On the frontal dynamics and morphology of submarine debris flows

    E-print Network

    On the frontal dynamics and morphology of submarine debris flows Trygve Ilstada,*, Fabio V. De, MN 55414, USA Accepted 30 September 2004 Abstract Several submarine debris flows show an apparently reserved. Keywords: submarine slide; debris flow; Morphology; outrunner blocks; experiment 1. Introduction

  13. Geomechanical Characterization of Submarine Volcano-Flank Sediments, Martinique, Lesser

    E-print Network

    Manga, Michael

    Chapter 7 Geomechanical Characterization of Submarine Volcano-Flank Sediments, Martinique, Lesser of Montagne Pel´ee that generated large submarine mass wasting deposits. Here, we evaluate the preconditioning.), Submarine Mass Movements and Their Consequences, Advances in Natural and Technological Hazards Research 37

  14. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Command of a submarine. 700.1058 Section 700.1058 National...Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in...

  15. Submarine Floating Antenna Model for LORAN-C Signal

    E-print Network

    Monin, André

    Submarine Floating Antenna Model for LORAN-C Signal Processing A. MONIN LAAS-CNRS France An electromagnetic model of the floating antenna used by submarines for LORAN-C radionavigation and very low The antenna used by submarines, for LORAN-C radionavigation and very low frequency (VLF) communications

  16. Optimal control design for the nonlinear manoeuvrability of a submarine

    E-print Network

    Optimal control design for the nonlinear manoeuvrability of a submarine Javier Garc´ia , Diana M, submarine, optimal control, gradient descent method. 1 Introduction In the development of a naval architecture tool for the guidance and autopilot of a submarine is important to choose both an accurate

  17. Numerical simulation of tsunami waves generated by deformable submarine landslides

    E-print Network

    Kirby, James T.

    Numerical simulation of tsunami waves generated by deformable submarine landslides Gangfeng Ma a 2013 Accepted 4 July 2013 Available online 15 July 2013 Keywords: Submarine landslide Nonhydrostatic wave model Tsunami wave Numerical modeling a b s t r a c t This paper presents a new submarine

  18. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Command of a submarine. 700.1058 Section 700.1058 National...Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in...

  19. Tidal Conversion at a Submarine Ridge FRANOIS PTRLIS

    E-print Network

    Young, William R.

    Tidal Conversion at a Submarine Ridge FRANÇOIS PÉTRÉLIS Laboratoire de Physique Statistique, Ecole-dimensional submarine ridge is computed using an integral-equation method. The problem is characterized by two tide over submarine topography is a main source of the mechanical energy required to power the internal

  20. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Command of a submarine. 700.1058 Section 700.1058 National...Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in...

  1. Non-cooperative Diagnosis of Submarine Cable Faults

    E-print Network

    Chang, Rocky Kow-Chuen

    Non-cooperative Diagnosis of Submarine Cable Faults Edmond W. W. Chan, Xiapu Luo, Waiting W. T. Fok|csxluo|cswtfok|csweicli|csrchang}@comp.polyu.edu.hk Abstract. Submarine cable faults are not uncommon events in the In- ternet today. However, their impacts of the performance degradation. 1 Introduction Submarine cables are critical elements of the Internet today, because

  2. Deep submarine pyroclastic eruptions: theory and predicted landforms and deposits

    E-print Network

    Head III, James William

    Deep submarine pyroclastic eruptions: theory and predicted landforms and deposits James W. Head III October 2001; received in revised form 19 August 2002; accepted 19 August 2002 Abstract Submarine and illustrate the full range of submarine eruption styles, we model several possible scenarios for the ascent

  3. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Command of a submarine. 700.1058 Section 700.1058 National...Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in...

  4. Mass wasting on the submarine Lomonosov Ridge, central Arctic Ocean

    E-print Network

    Kristoffersen, Yngve

    Mass wasting on the submarine Lomonosov Ridge, central Arctic Ocean Yngve Kristoffersen a,, Bernard particulate matter in the water column accumulate as a uniform drape on submarine plateaus and ridges Lomonosov Ridge is a submarine feature of alpine proportions which rises 3 km above the adjacent abyssal

  5. 32 CFR 700.1058 - Command of a submarine.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Command of a submarine. 700.1058 Section 700.1058 National...Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in...

  6. Reducing Unsteady Loads on a Piggyback Miniature Submarine

    NASA Technical Reports Server (NTRS)

    Lin, John

    2009-01-01

    A small, simple fixture has been found to be highly effective in reducing destructive unsteady hydrodynamic loads on a miniature submarine that is attached in piggyback fashion to the top of a larger, nuclear-powered, host submarine. The fixture, denoted compact ramp, can be installed with minimal structural modification, and the use of it does not entail any change in submarine operations.

  7. Effects of Wall Heating on Flow Characteristics in a Street Canyon

    NASA Astrophysics Data System (ADS)

    Cai, Xiao-Ming

    2012-03-01

    We develop a large-eddy simulation (LES) model based on a meteorological numerical model for a real scale street-canyon flow with rough building facets heated by a given temperature. The model is applied to a canyon with the aspect ratio of unity for two idealized heating scenarios: (1) the roof and the entire upstream wall are heated, named as `assisting cases', and (2) the roof and the entire downstream wall are heated, named as `opposing cases'. These facets were heated up to 15 K above the air temperature. A wall function for temperature is proposed for a rough facet with an assumption that the thermal roughness length, z 0T, is much smaller than the aerodynamic roughness length, z 0. It is demonstrated that the sensible heat flux and canyon-air temperature are significantly influenced by the near-facet process that is parametrized by z 0T as the primary factor; other processes such as in-canyon mixing and roof-level exchange are secondary. This new finding strongly suggests that it is vital to choose an appropriate value of z 0T in a numerical simulation of street-canyon flows with the facet-air exchange processes of heat or any scalar. The finding also raises an awareness of the demand for carefully designed laboratory or field experiments of quantifying z 0T values for various urban surfaces. For the opposing cases, an unsteady penetrating narrow updraft zone appears occasionally along the heated wall and this feature is consistent field observations. The unique result indicates the superior capability of LES. The results of this study can be used to guide the parametrization of turbulent processes inside the urban canopy layer.

  8. Karst hydrology of Grand Canyon, Arizona, USA

    NASA Astrophysics Data System (ADS)

    Hill, C. A.; Polyak, V. J.

    2010-09-01

    SummaryCaves in Grand Canyon, Arizona, USA fall into two main categories: those formed under unconfined conditions and those formed under confined conditions. This study focuses on the hydrology and paleohydrology of the confined caves in the Redwall-Muav aquifer, where the aquifer is overlain by rocks of the Supai Group and underlain by the Bright Angel Shale. Unconfined caves are discussed only in their relation to confined caves. Discharge for confined groundwater was, as it is today, primarily from the Redwall Limestone where it has been incised by the main canyon or its tributaries and where it has converged along a structural low or fault. Descent of the potentiometric surface (or water table) over time is recorded by one ore episode and six cave episodes: (1) emplacement of Cu-U ore, (2) precipitation of iron oxide in cavities, (3) dissolution of cave passages, (4) precipitation of calcite-spar linings over cave passage walls, (5) precipitation of cave mammillary coatings, (6) minor replacement of cave wall and ceiling limestone by gypsum, and (7) deposition of subaerial speleothems. The mammillary episode records the approximate position of the water table when the incision of the canyon was at that level. Discharge toward spring points has reorganized and adjusted with respect to ongoing canyon and side-canyon incision. The dissolution of Grand Canyon confined caves was the result of the mixing of epigene waters with hypogene waters so that undersaturation with respect to calcite was achieved. The karst hydrology of Grand Canyon may be unique compared to other hypogene cave areas of the world.

  9. A model for the submarine depthkeeping team

    NASA Technical Reports Server (NTRS)

    Ware, J. R.; Best, J. F.; Bozzi, P. J.; Kleinman, D. W.

    1981-01-01

    The most difficult task the depthkeeping team must face occurs during periscope-depth operations during which they may be required to maintain a submarine several hundred feet long within a foot of ordered depth and within one-half degree of ordered pitch. The difficulty is compounded by the facts that wave generated forces are extremely high, depth and pitch signals are very noisy and submarine speed is such that overall dynamics are slow. A mathematical simulation of the depthkeeping team based on the optimal control models is described. A solution of the optimal team control problem with an output control restriction (limited display to each controller) is presented.

  10. Overview of the Colorado River Canyon from the helicopter pad. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overview of the Colorado River Canyon from the helicopter pad. View of the Nevada side where new bridge will cross canyon, view northwest - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  11. 43. and Design, Grand Canyon National Park, dated August 23, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. and Design, Grand Canyon National Park, dated August 23, 1934, and September 17, 1934 (original located at Federal Records Center, Denver, Colorado, #113/3084-set of 2) SEWAGE PLANT ADDITION. - Water Reclamation Plant, Grand Canyon, Coconino County, AZ

  12. Metazoan meiofauna in deep-sea canyons and adjacent open slopes: A large-scale comparison with focus on the rare taxa

    NASA Astrophysics Data System (ADS)

    Bianchelli, S.; Gambi, C.; Zeppilli, D.; Danovaro, R.

    2010-03-01

    Metazoan meiofaunal abundance, total biomass, nematode size and the richness of taxa were investigated along bathymetric gradients (from the shelf break down to ca. 5000-m depth) in six submarine canyons and on five adjacent open slopes of three deep-sea regions. The investigated areas were distributed along >2500 km, on the Portuguese to the Catalan and South Adriatic margins. The Portuguese and Catalan margins displayed the highest abundances, biomass and richness of taxa, while the lowest values were observed in the Central Mediterranean Sea. The comparison between canyons and the nearby open slopes showed the lack of significant differences in terms of meiofaunal abundance and biomass at any sampling depth. In most canyons and on most slopes, meiofaunal variables did not display consistent bathymetric patterns. Conversely, we found that the different topographic features were apparently responsible for significant differences in the abundance and distribution of the rare meiofaunal taxa (i.e. taxa accounting for <1% of total meiofaunal abundance). Several taxa belonging to the temporary meiofauna, such as larvae/juveniles of Priapulida, Holothuroidea, Ascidiacea and Cnidaria, were encountered exclusively on open slopes, while others (including the Tanaidacea and Echinodea larvae) were found exclusively in canyons sediments. Results reported here indicate that, at large spatial scales, differences in deep-sea meiofaunal abundance and biomass are not only controlled by the available food sources, but also by the region or habitat specific topographic features, which apparently play a key role in the distribution of rare benthic taxa.

  13. 6. DARK CANYON SIPHON Photographic copy of historic photo, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DARK CANYON SIPHON - Photographic copy of historic photo, January 29, 1907 (original print filed in Record Group 115, National Archives, Washington, D.C.) W.J.Lubken, photographer 'RIPRAP AT THE ENTRANCE END OF DARK CANYON PRESSURE PIPE' - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

  14. 5. DARK CANYON SIPHON Photographic copy of historic photo, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DARK CANYON SIPHON - Photographic copy of historic photo, November 11, 1906 (original print located at the Carlsbad Irrigation District offices, Carlsbad, New Mexico) photographer unknown 'LOWER END OF DARK CANYON SIPHON CONSTRUCTION' - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

  15. THE ORIGI N ANDSEDIMENTOLOGYOF THE PUNASUBMARINE CANYON,HAhIAII

    E-print Network

    Luther, Douglas S.

    THE ORIGI N ANDSEDIMENTOLOGYOF THE PUNASUBMARINE CANYON,HAhIAII A DISSERTATIONSUBMITTEDTO Submarrne Canyon lres oFf the east coast of Lhe rsland of Hawarr, the youngest rsland of the Hawallan Charn. The canyon has a length of 7, km and a varrable wrdth, reachrng a maxrmum of t5 km at a posrtron abouL 25 km

  16. 75 FR 34476 - Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose...respect to the operation of Glen Canyon Dam and the exercise of other authorities...

  17. Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam

    E-print Network

    Kemner, Ken

    Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Years 2006 Canyon Dam during Water Years 2006 through 2010 ANL/DIS-11-4 by L.A. Poch,1 T.D. Veselka,1 C.S. Palmer,2 Canyon Dam (GCD) conducted for the U.S. Department of Energy's Western Area Power Administration (Western

  18. 27 CFR 9.152 - Malibu-Newton Canyon.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Malibu-Newton Canyon. 9.152 Section 9.152...Viticultural Areas § 9.152 Malibu-Newton Canyon. (a) Name. The name of...described in this petition is “Malibu-Newton Canyon.” (b) Approved maps....

  19. 27 CFR 9.152 - Malibu-Newton Canyon.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Malibu-Newton Canyon. 9.152 Section 9.152...Viticultural Areas § 9.152 Malibu-Newton Canyon. (a) Name. The name of...described in this petition is “Malibu-Newton Canyon.” (b) Approved maps....

  20. 27 CFR 9.152 - Malibu-Newton Canyon.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Malibu-Newton Canyon. 9.152 Section 9.152...Viticultural Areas § 9.152 Malibu-Newton Canyon. (a) Name. The name of...described in this petition is “Malibu-Newton Canyon.” (b) Approved maps....

  1. 7. DARK CANYON SIPHON Photographic copy of construction drawing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DARK CANYON SIPHON - Photographic copy of construction drawing c1907 (from Record Group 115, Box 17, Denver Branch of the National Archives, Denver) DARK CANYON SIPHON PLAN, ELEVATION, AND SECTIONS - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

  2. Authigenic clay minerals in sandstones of the Delaware Mountain Group: Bell Canyon and Cherry Canyon Formations, Waha Field, West Texas

    E-print Network

    Walling, Suzette Denise

    1992-01-01

    AUTHIGENIC CLAY MINERALS IN SANDSTONES OF THE DELAWARE MOUNTAIN GROUP: BELL CANYON AND CHERRY CANYON FORMATIONS, WAHA FIELD, WEST TEXAS A Thesis by SUZETTE DENISE WALLING Submitted to the Office of Graduate Studies of Texas A&M University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1992 Major Subject: Geology AUTHIGENIC CLAY MINERALS IN SANDSTONES OF THE DELAWARE MOUNTAIN GROUP: BELL CANYON AND CHERRY CANYON FORMATIONS, WAHA FIELD, WEST TEXAS...

  3. Submarine Thermal Springs on the Galapagos Rift

    Microsoft Academic Search

    John B. Corliss; Jack Dymond; Louis I. Gordon; John M. Edmond; Richard P. von Herzen; Robert D. Ballard; Kenneth Green; David Williams; Arnold Bainbridge; Kathy Crane; Tjeerd H. van Andel

    1979-01-01

    The submarine hydrothermal activity on and near the Galapagos 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

  4. Morphology of Quench Crystals in Submarine Basalts

    Microsoft Academic Search

    Wilfred B. Bryan

    1972-01-01

    Submarine basalts from the mid-Atlantic ridge, Red Sea rift, and Joides site 105 in the western Atlantic have been studied in ultra thin, doubly polished thin sections. Most of the samples are pillow lava fragments containing a variety of skeletal crystal growth forms that can be related to three major textural zones in the pillows. Olivine appears as diffuse, lattice-like

  5. Analogues of stealth: Submarines and aircraft

    Microsoft Academic Search

    Robert P. Haffa JR; James H. Patton JR

    1991-01-01

    “Analogues of Stealth “ questions whether stealth technologies (measures designed to reduce the observable signature of a weapons platform) now being applied to aircraft will prove as successful as low?observable technologies and tactics employed by the submarine. To address that question, the article briefly explores the history of antisubmarine warfare, notes the failures of various technologies designed to counter the

  6. Submarine granular flows down inclined planes

    Microsoft Academic Search

    C. Cassar; M. Nicolas; O. Pouliquen

    2005-01-01

    Submarine flows of granular material down a rough inclined plane are experimentally investigated. We focus on the dense flow regime when the whole sediment layer is flowing down the slope and when no deposition nor entrainment occurs. In this regime, steady uniform flows are observed for which we systematically measure the depth-averaged velocity, the thickness, and the excess pore pressure

  7. Arctic Ocean warming: submarine and acoustic measurements

    Microsoft Academic Search

    P. Mikhalevsky; A. Gavrilov; M. S. Moustafa; B. Sperry

    2001-01-01

    In 1993 the USS Pargo made the first Submarine Science Expedition (SCICEX) to the Arctic Ocean. In April 1994 the first Transarctic Acoustic Propagation (TAP) experiment designed to measure Arctic Ocean temperature was conducted. SCICEX cruises to the Arctic followed annually from 1995 to 2000. Expendable CTDs and on some cruises standard CTDs were deployed along or close to the

  8. Gold plating in submarine telephone cable repeaters

    Microsoft Academic Search

    D. S. Girling

    1973-01-01

    Thousands of miles of submarine telephone cables form an important and growing part of the world pattern of communications.\\u000a Repeaters every few miles along these cables maintain signal strengths, and many of the components in these repeaters are\\u000a gold plated to ensure freedom from deterioration or failure in service.

  9. AI Planning for Robotic Submarine Exploration

    E-print Network

    Yao, Xin

    AI Planning for Robotic Submarine Exploration Zeyn Saigol School of Computer Science University of Birmingham PG Seminar Series 22nd January 2009 PG Seminar, 22 Jan 2009 Planning for AUV ExplorationPlanning for AUV Exploration #12;Planning for AUV ExplorationPG Seminar, 22 Jan 2009 Planning for AUV Exploration

  10. Monitoring corrosion in submarine sonar domes

    Microsoft Academic Search

    C. J. Sandwith; R. L. Ruedisueli; K. G. Booth; J. P. Papageorge; B. A. Eng

    1993-01-01

    The Applied Physics Laboratory at the University of Washington (APL-UW) and the Naval Sea Systems Command (NAVSEA) are involved in a long-term study to reduce corrosion in submarine sonar domes. Besides periodically inspecting the structures in tile domes and recommending improvements in their design, materials, and maintenance, APLUW has recently developed an instrument package to monitor selected parameters of the

  11. Researchers Find Japanese Submarine at Pearl Harbor

    NSDL National Science Digital Library

    Green, Marcia.

    2002-01-01

    Earlier this week, researchers from the University of Hawaii and the Hawaii Underwater Research Lab located the remains of a Japanese midget submarine. Found in 1200 feet of water, the submarine was sunk by the USS Ward just an hour before the aerial attack on Pearl Harbor on December 7, 1941. Most important, the discovery of the midget submarine offers concrete physical evidence that the United States did fire the first shot against the Japanese. Previous expeditions to locate the sub, including an effort made in 2000 by the National Geographic Society, had been unsuccessful, largely due to the fact that the area is a military "junkyard" with tons of debris on the ocean floor.For more in-depth information on this story, readers may find the first four news links particularly helpful. The fifth link leads to the Hawaii Underwater Research Lab's Web site that features photographs of the midget sub from the expedition earlier this week. The sixth link is to a Web site dealing with the history and missions of the USS Ward. The final link contains detailed information about the 2000 expedition led by Robert Ballard, with support from the National Geographic Society, to find the midget submarine.

  12. Chemical environments of submarine hydrothermal systems

    NASA Technical Reports Server (NTRS)

    Shock, Everett L.

    1992-01-01

    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 determinations rely on studies of pieces of deep oceanic crust uplifted by tectonic forces such as along the Southwest Indian Ridge, or more complete sections of oceanic crust called ophiolite sequences which are presently exposed on continents owing to tectonic emplacement. Much of what is thought to happen in submarine hydrothermal systems is inferred from studies of ophiolite sequences, and especially from the better-exposed ophiolites in Oman, Cyprus and North America. The focus of much that follows is on a few general features: pressure, temperature, oxidation states, fluid composition and mineral alteration, because these features will control whether organic synthesis can occur in hydrothermal systems.

  13. HELLS CANYON STUDY AREA, OREGON AND IDAHO.

    USGS Publications Warehouse

    Simmons, George C.; Close, Terry J.

    1984-01-01

    The Hells Canyon study area occupies nearly 950 sq mi along and near Hells Canyon of the Snake River in northeast Oregon and west-central Idaho. Geologic, geochemical, aeromagnetic, and mine and prospect investigations to determine the mineral-resource potential of the area were carried out. As a result, 42 sq mi or about 4 percent of the lands, in 21 separate areas, were classified as having probable or substantiated resource potential for base and precious metals, molybdenum, and tungsten. No energy resource potential was identified in this study.

  14. Morphology of Neptune Node Sites, Barkley Canyon, Cascadia Margin

    NASA Astrophysics Data System (ADS)

    Lundsten, E. M.; Anderson, K.; Paull, C. K.; Caress, D. W.; Thomas, H. J.; Riedel, M.

    2014-12-01

    High-resolution multibeam bathymetry and chirp seismic reflection profiles collected with MBARI's mapping autonomous underwater vehicle reveal the fine-scale morphology and shallow seafloor structure of the flanks and floor of Barkley Canyon on the Cascadia continental margin off British Columbia. The surveys characterize the environment surrounding three nodes on the Neptune Canada cabled observatory located within the canyon. The canyon floor between 960 and 1020 m water depth lacks channeling and contains ? 24 m of acoustically uniform sediment fill, which is ponded between the canyon's steep sidewalls. The fill overlies a strong reflector that outlines an earlier, now buried, canyon floor channel system. Debris flow tongues contain meter scale blocks sticking-up through the fill. Apparently the present geomorphology surrounding the Canyon Axis node in 985 m is attributable to local debris flows, rather than organized down canyon processes. In the survey area the canyon sidewalls extend ~300 m up and in places the slope of the canyons sides exceed 40°. Both the Hydrate node in 870 m water depths and the Mid-Canyon node at 890 m are located on a headland that forms intermediate depth terraces on the canyon's western flank. While the seafloor immediately surrounding the Mid-canyon node is smooth, the Hydrate node is marked by 10 circular mounds up to 2 m high and 10 m in diameter, presumable associated with hydrate formation. Although wedges of sediment drape occur in places on the canyon sides, the chirp profiles show no detectible sediment drape at either node site and suggest these nodes are situated on older, presumably pre-Quaternary strata. The lack of reflectors in the chirp profiles indicates most of the canyon's sidewalls are largely sediment-bare. Lineations in the bathymetry mark the exposed edges of truncated beds. Rough, apparently fresh textures, within slide scarps show the importance of erosion on the development of the canyon flanks.

  15. The origin of Messinian canyons in the Mediterranean: the role of brine-related dense shelf water cascading currents

    NASA Astrophysics Data System (ADS)

    Roveri, Marco; Bergamasco, Andrea; Marcello Falcieri, Francesco; Gennari, Rocco; Lugli, Stefano; Manzi, Vinicio; Schreiber, B. Charlotte

    2013-04-01

    Recent studies on modern deep-sea environments have documented the role of submarine processes, such as turbidity currents, fluvial flood-related hyperpycnal flows and dense shelf water cascading (DSWC), in the genesis and evolution of canyons and gullies. These processes are largely independent from sea-level fluctuations and significant erosion has been shown to occur even at present-day sea-level highstand conditions. The study of ancient deep-marine environments and processes may take great advantage from the knowledge produced during the last decade in this field of research. The study of some exceptional events of the past is an exciting issue for a common effort of specialists from different disciplines (geomorphology, geology, physical oceanography) in the understanding of modern and ancient deep seascape. An example is provided by the genesis of the widespread Messinian erosional surface (MES) and the associated gullies and canyons, which have been recognized through seismic data along the Mediterranean shelves and slopes. These features are commonly related to subaerial fluvial processes that imply a 1500 m drawdown and the desiccation of the Mediterranean Sea during what has been called the "Messinian salinity crisis" (MSC). Such an interpretation is one of the main arguments for the shallow-water deep-basin model (Hsü et al., 1973), which is the current paradigm for the MSC. However, no unquestionable evidence for subaerial deposits associated with the MES has been ever documented. We suggest that fully submarine erosional processes played a significant role in shaping the Mediterranean slopes also during the MSC; thus, no desiccation is needed to explain canyon formation and/or rejuvenation. We want to stress here the importance of the processes, driven by evaporative fluxes in shallow areas, that lead to the formation of seasonal high-density contrasts and cause the development of cascading along the continental slopes (Shapiro et al., 2003). These processes are active today in the Mediterranean margins where they produce large-scale erosional features within canyons (Canals et al., 2006; Palanques et al., 2012). On the basis of modelling of cascading events that recently occurred in the Gulf of Lions, we performed numerical simulations of Messinian brine-related cascading currents at different water density contrasts. Our results show that the activation of downslope flow of hypersaline dense waters may well account for both significant slope erosion and progressive salinity rise leading to the accumulation of deep-seated supersaturated brines. These findings support a "deep-water deep-basin" model thus implying that the evaporite deposition occurred in a non-desiccated basin with strongly reduced connections with the global ocean. References Canals M. et al., 2006. Flushing submarine canyons, Nature, 444, 354-357. Hsü K.J., Ryan W.B.F. and Cita M.B., 1973 Late Miocene desiccation of the Mediterranean. Nature, 242, 240-244. Palanques A. et al., 2012. Sediment transport to the deep canyons and open-slope of the western Gulf of Lyon during 2006 intense cascading and open-sea convection period, Progress in Oceanography, 106, 1-15. Shapiro G.I., Huthnance J.M. and Ivanov V.V., 2003 Dense water cascading off the continental shelf, J. Geophys. Res., 108, 3390.

  16. Geohydrology of White Rock Canyon of the Rio Grande from Otowi to Frijoles Canyon

    SciTech Connect

    Purtymun, W.D.; Peters, R.J.; Owens, J.W.

    1980-12-01

    Twenty-seven springs discharge from the Totavi Lentil and Tesuque Formation in White Rock Canyon. Water generally acquires its chemical characteristics from rock units that comprise the spring aquifer. Twenty-two of the springs are separated into three groups of similar aquifer-related chemical quality. The five remaining springs make up a fourth group with a chemical quality that differs due to localized conditions in the aquifer. Localized conditions may be related to recharge or discharge in or near basalt intrusion or through faults. Streams from Pajarito, Ancho, and Frijoles Canyons discharge into the Rio Grande in White Rock Canyon. The base flow in the streams is from springs. Sanitary effluent in Mortandad Canyon from the treatment plant at White Rock also reaches the Rio Grande.

  17. Bioavailable compounds in sinking particulate organic matter, Blanes Canyon, NW Mediterranean Sea: Effects of a large storm and sea surface biological processes

    NASA Astrophysics Data System (ADS)

    Lopez-Fernandez, Pilar; Bianchelli, Silvia; Pusceddu, Antonio; Calafat, Antoni; Danovaro, Roberto; Canals, Miquel

    2013-11-01

    To ascertain whether the Blanes submarine canyon functions as a conduit of labile organic compounds to the deep margin, we analyzed phytopigment, protein, carbohydrate and lipid contents of sinking particles during a 6-months period comprised between a large storm event and the spring phytoplankton bloom. Four sediment traps were deployed, at 300, 900, 1200, and 1500 m depth along the axis of the canyon from November 2008 to April 2009. Fluxes of all study variables (organic carbon, proteins, carbohydrates and lipids) peaked from mid to late December. Afterwards, organic matter fluxes in the upper canyon decreased to values comparable (BC1200) or much lower (BC900) than those observed at the beginning of the monitoring period. The algal fraction of biopolymeric C (i.e. the percentage contribution of phytopigments to biopolymeric C utilized here as an indicator of particles’ freshness), ranging from 14 to about 100%, was generally low (median value about 32%), and showed the highest values from November to early December 2008 at all stations, except for the station at 1200 m which peaks in April 2009. A severe storm that occurred the 26th of December 2008 determined a strong increase in the downward transport of organic matter along the Blanes Canyon, though associated with a decrease in its nutritional quality. Values of the protein to carbohydrate ratio (utilized here as an indicator of particles’ nutritional quality) ranged from 0.4 to >2.0, increasing from late winter to early spring at 900 and 1200 m depth in association with the spring phytoplankton bloom in superficial waters. The material collected by sediment traps in spring had a higher nutritional value than in autumn-winter at both stations. According to the optimal foraging theory, the results of this study suggest that, following winter episodic events, deep-sea detritus feeders would need to ingest more detritus to fulfill their requirements for labile food than in spring, when fresher material is derived from sinking particles associated with phytoplankton blooms. We conclude that whilst submarine canyons like the Blanes Canyon act as major conduits for material exported from the continental shelf after high-energy episodic events, the supply of labile food to the deep-sea benthic ecosystem is connected to biological processes occurring at the sea surface.

  18. Map Your Way to the Grand Canyon

    ERIC Educational Resources Information Center

    Yoder, Holly

    2005-01-01

    In the introductory assignment, each randomly assigned group spends about 10 to 15 minutes at each station. The author incorporates as much sensory stimulation in the activity as possible. At the first station, students view a PowerPoint show from a geology class the author participated in at the Grand Canyon. At station two, students look at a…

  19. The Colorado River in the Grand Canyon.

    ERIC Educational Resources Information Center

    Speece, Susan

    1991-01-01

    An assessment of the water quality of the Colorado River in the Grand Canyon was made, using the following parameters: dissolved oxygen, water temperature, hydrogen ion concentration, total dissolved solids, turbidity, and ammonium/nitrogen levels. These parameters were used to provide some clue as to the "wellness" and stability of the aquatic…

  20. Sandbar growth Grand Canyon following controlled flood

    USGS Multimedia Gallery

    Picture showing the increased size of the sandbar after the November 2012 controlled flood from the Glen Canyon Dam. This location is 65 miles downstream from Lees Ferry and the view is looking downstream. These and additional photographs depicting the results of the recent controlled floods can be ...

  1. Evidence of clastic evaporites in the canyons of the Levant basin (Israel): implications for the Messinian salinity crisis

    NASA Astrophysics Data System (ADS)

    Lugli, Stefano; Schreiber, B. Charlotte; Gvirtzman, Zohar; Manzi, Vinicio; Roveri, Marco

    2013-04-01

    The recognition of widespread and thick evaporite deposits below the floor of the Mediterranean Sea has boosted a long standing controversy concerning their depositional setting (shallow versus deep) and their correlation with the onshore sequences. Until a new scientific campaign might be launched to cross those deposits, the discussion is still open to speculation. Many Messinian evaporitic deposits have been interpreted as primary precipitates in very shallow-water or coastal environments, thus favouring the idea of a desiccated Mediterranean basin (Hsu et al., 1973). Recent studies have questioned this interpretation (Hardie and Lowenstein, 2004) and widespread, thick, clastic evaporite facies have been identified in the Mediterranean (Manzi et al., 2005). These clastic deposits are not compatible with a desiccation model as they were clearly emplaced by fully subaqueous, deep-water processes, ranging from submarine slides, to high- and low-density gravity flows. One of the most relevant areas for the understanding of the salinity crisis is the Levant basin where the Messinian evaporites partially fill some of the erosional features (canyons) considered to have formed as a consequence of significant drawdown related to the desiccation of the Mediterranean Sea (up to - 850 m, Druckman et al., 1995). Our complete revisitation of the available cores from onshore Israel cutting through the sedimentary filling of the Messinian canyons (Afiq 1, Ashdod 2, Be'eri Sh1, Be'eri Sh4, Jaffa 1 and Talme-Yaffe 3) revealed exclusively clastic sulfate facies. This is the first direct evidence that the Lower Evaporite Unit offshore Israel may actually consist of deep-water resedimented evaporites that were originally deposited on the margin of the Levant Basin. References Druckman Y., Buchbinder B., Martinotti G.M., Tov R.S., Aharon P., 1995. The buried Afiq Canyon (eastern Mediterranean, Israel): a case study of a Tertiary submarine canyon exposed in Late Messinian times. Marine Geology, 123, 167-185. Hardie L.A. & Lowenstein T.K., 2004. Did the Mediterranean Sea dry out during the Miocene? A reassessment of the evaporite evidence from DSDP Legs 13 and 42A cores. JSR, 74, 453-461. Hsu, K.J., Cita, M.B., and Ryan, W.B.F, 1973. The origin of the Mediterranean evaporites, in Ryan, W.B.F., et al. eds., Initial Reports of the Deep Sea Drilling Project, v. 13, Washington, 1203-1231. Manzi V., Lugli S., Ricci Lucchi F., Roveri M., 2005. Deep-water clastic evaporites deposition in the Messinian Adriatic foredeep (northern Apennines, Italy): did the Mediterranean ever dry out? Sedimentology, 52, 875-902.

  2. 16. INTERIOR VIEW OF SUBMARINE SECTION AT 110FOOT LEVEL, ESCAPE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. INTERIOR VIEW OF SUBMARINE SECTION AT 110-FOOT LEVEL, ESCAPE TRAINING TANK, SHOWING LADDER TO ESCAPE TANK, LOOKING SOUTH - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  3. 50. PIPING FOR SUBMARINE SECTION, Y&D No. 107728 Scale 3/8' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. PIPING FOR SUBMARINE SECTION, Y&D No. 107728 Scale 3/8' = 1'; August 26, 1929 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  4. Determining Spatial and Temporal Inputs of Freshwater, Including Submarine Groundwater Discharge,

    E-print Network

    Miami, University of

    Determining Spatial and Temporal Inputs of Freshwater, Including Submarine Groundwater Discharge. Florida . Submarine groundwater discharge Introduction The timing and sources of freshwater delivery systems while submarine groundwater discharge (SGD) has largely been ignored due, in part, as a result

  5. Supplementary Material A submarine landslide is required to explain the 2011 Tohoku tsunami

    E-print Network

    Kirby, James T.

    1 Supplementary Material A submarine landslide is required to explain the 2011 Tohoku tsunami]. In contrast, tsunamis generated by a submarine mass failure (SMF; i.e., a submarine landslide), which are more

  6. 33 CFR 209.310 - Representation of submarine cables and pipelines on nautical charts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Representation of submarine cables and pipelines on nautical charts. 209.310 Section...Representation of submarine cables and pipelines on nautical charts. (a) The policy...the locations of submarine cables and pipelines on nautical charts published by the...

  7. 33 CFR 209.310 - Representation of submarine cables and pipelines on nautical charts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Representation of submarine cables and pipelines on nautical charts. 209.310 Section...Representation of submarine cables and pipelines on nautical charts. (a) The policy...the locations of submarine cables and pipelines on nautical charts published by the...

  8. 33 CFR 209.310 - Representation of submarine cables and pipelines on nautical charts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Representation of submarine cables and pipelines on nautical charts. 209.310 Section...Representation of submarine cables and pipelines on nautical charts. (a) The policy...the locations of submarine cables and pipelines on nautical charts published by the...

  9. 33 CFR 209.310 - Representation of submarine cables and pipelines on nautical charts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Representation of submarine cables and pipelines on nautical charts. 209.310 Section...Representation of submarine cables and pipelines on nautical charts. (a) The policy...the locations of submarine cables and pipelines on nautical charts published by the...

  10. 33 CFR 209.310 - Representation of submarine cables and pipelines on nautical charts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Representation of submarine cables and pipelines on nautical charts. 209.310 Section...Representation of submarine cables and pipelines on nautical charts. (a) The policy...the locations of submarine cables and pipelines on nautical charts published by the...

  11. Seismically induced rock slope failures resulting from topographic amplification of strong ground motions: The case of Pacoima Canyon, California

    USGS Publications Warehouse

    Sepulveda, S.A.; Murphy, W.; Jibson, R.W.; Petley, D.N.

    2005-01-01

    The 1994 Northridge earthquake (Mw = 6.7) triggered extensive rock slope failures in Pacoima Canyon, immediately north of Los Angeles, California. Pacoima Canyon is a narrow and steep canyon incised in gneissic and granitic rocks. Peak accelerations of nearly 1.6 g were recorded at a ridge that forms the left abutment of Pacoima Dam; peak accelerations at the bottom of the canyon were less than 0.5 g, suggesting the occurrence of topographic amplification. Topographic effects have been previously suggested to explain similarly high ground motions at the site during the 1971 (Mw = 6.7) San Fernando earthquake. Furthermore, high landslide concentrations observed in the area have been attributed to unusually strong ground motions rather than higher susceptibility to sliding compared with nearby zones. We conducted field investigations and slope stability back-analyses to confirm the impact of topographic amplification on the triggering of landslides during the 1994 earthquake. Our results suggest that the observed extensive rock sliding and falling would have not been possible under unamplified seismic conditions, which would have generated a significantly lower number of areas affected by landslides. In contrast, modelling slope stability using amplified ground shaking predicts slope failure distributions matching what occurred in 1994. This observation confirms a significant role for topographic amplification on the triggering of landslides at the site, and emphasises the need to select carefully the inputs for seismic slope stability analyses. ?? 2005 Elsevier B.V. All rights reserved.

  12. Accident Risk Associated with Fueled Decommissioned Nuclear Powered Submarines

    Microsoft Academic Search

    S. Kupca; A. Natalizio

    \\u000a Many nuclear powered submarines have been removed from active duty during the past decade. Common practice when retiring such\\u000a submarines from active duty is to remove the fuel from the reactor vessel, thereby rendering the submarine relatively harmless,\\u000a from a radiation risk perspective, to workers, the public and the environment. In Russia, the defueling process is progressing\\u000a slowly and a

  13. VIRGINIA-Class Submarine: Two for Four in 2012 (A)

    Microsoft Academic Search

    Tom Cross

    The VIRGINIA-class submarine was one of the largest naval-acquisition projects in history, involving the construction of 30 submarines at an acquisition cost of $93 billion. By FY05, the VIRGINIA-class program was in its 10th year. Construction had begun on seven submarines. Unit costs were running 41% over the base-line budget, and production goals were not being met. Ship construction budget

  14. VIRGINIA-Class Submarine: Two for Four in 2012 (B)

    Microsoft Academic Search

    Tom Cross

    The VIRGINIA-class submarine was one of the largest naval-acquisition projects in history, involving the construction of 30 submarines at an acquisition cost of $93 billion. By FY05, the VIRGINIA-class program was in its 10th year. Construction had begun on seven submarines. Unit costs were running 41% over the base-line budget, and production goals were not being met. Ship construction budget

  15. Whale Entanglements With Submarine Telecommunication Cables

    Microsoft Academic Search

    Matthew Peter Wood; Lionel Carter

    2008-01-01

    Before 1955-1966, 16 instances of whale entanglement with submarine telegraphic cables were reported in the scientific literature. Here we present new information, derived from global cable fault databases, that reveals an absence of whale entanglements since 1959. This cessation coincided with the transition from telegraphic to coaxial telecommunication cables followed by the change to fiber-optic systems in the 1980s. We

  16. Earth Currents in Short Submarine Cables

    Microsoft Academic Search

    D. W. Cherry; A. T. Stovold

    1946-01-01

    PRIOR to 1940, faults on submarine telephone cables between Great Britain and the Continent were normally located by direct-current methods employing a good wire in another cable. Confirmatory tests were usually made by the impedance-frequency method1. When the time came in 1944 to restore telephone communications, no good wires were available. The impedance-frequency method was employed for fault localization with

  17. Submarine Mass Movements and Their Consequences

    Microsoft Academic Search

    D. C. Mosher; L. Moscardelli; R. C. Shipp; J. D. Chaytor; C. D. P. Baxter; H. J. Lee; R. Urgeles

    \\u000a In 1929, an earthquake off the Grand Banks of Newfoundland initiated a submarine mass movement that sheared undersea communication\\u000a cables and generated a tsunami that resulted in deaths of 27 people along the south coast of Newfoundland. This event initiated\\u000a the modern realization that the seafloor is a dynamic environment with potential to do harm. More recent catastrophic examples\\u000a include

  18. New constraints on oceanographic vs. seismic control on submarine landslide initiation: a geotechnical approach off Uruguay and northern Argentina

    NASA Astrophysics Data System (ADS)

    Ai, Fei; Strasser, Michael; Preu, Benedict; Hanebuth, Till J. J.; Krastel, Sebastian; Kopf, Achim

    2014-10-01

    Submarine landslides are common along the Uruguayan and Argentinean continental margin, but size, type and frequency of events differ significantly between distinct settings. Previous studies have proposed sedimentary and oceanographic processes as factors controlling slope instability, but also episodic earthquakes have been postulated as possible triggers. However, quantitative geotechnical slope stability evaluations for this region and, for that matter, elsewhere in the South Atlantic realm are lacking. This study quantitatively assesses continental slope stability for various scenarios including overpressure and earthquake activity, based on sedimentological and geotechnical analyses on three up to 36 m long cores collected on the Uruguayan slope, characterized by muddy contourite deposits and a locus of landslides (up to 2 km3), and in a canyon-dominated area on the northern Argentinean slope characterized by sandy contourite deposits. The results of shear and consolidation tests reveal that these distinct lithologies govern different stability conditions and failure modes. The slope sectors are stable under present-day conditions (factor of safety >5), implying that additional triggers would be required to initiate failure. In the canyon area, current-induced oversteepening of weaker sandy contourite deposits would account for frequent, small-scale slope instabilities. By contrast, static vs. seismic slope stability calculations reveal that a peak ground acceleration of at least 2 m/s2 would be required to cause failure of mechanically stronger muddy contourite deposits. This implies that, also along the western South Atlantic passive margin, submarine landslides on open gentle slopes require episodic large earthquakes as ultimate trigger, as previously postulated for other, northern hemisphere passive margins.

  19. Submarine tower escape decompression sickness risk estimation.

    PubMed

    Loveman, G A M; Seddon, E M; Thacker, J C; Stansfield, M R; Jurd, K M

    2014-01-01

    Actions to enhance survival in a distressed submarine (DISSUB) scenario may be guided in part by knowledge of the likely risk of decompression sickness (DCS) should the crew attempt tower escape. A mathematical model for DCS risk estimation has been calibrated against DCS outcome data from 3,738 exposures of either men or goats to raised pressure. Body mass was used to scale DCS risk. The calibration data included more than 1,000 actual or simulated submarine escape exposures and no exposures with substantial staged decompression. Cases of pulmonary barotrauma were removed from the calibration data. The calibrated model was used to estimate the likelihood of DCS occurrence following submarine escape from the United Kingdom Royal Navy tower escape system. Where internal DISSUB pressure remains at - 0.1 MPa, escape from DISSUB depths < 200 meters is estimated to have DCS risk < 6%. Saturation at raised DISSUB pressure markedly increases risk, with > 60% DCS risk predicted for a 200-meter escape from saturation at 0.21 MPa. Using the calibrated model to predict DCS for direct ascent from saturation gives similar risk estimates to other published models. PMID:25109085

  20. Big Canyon Creek Ecological Restoration Strategy.

    SciTech Connect

    Rasmussen, Lynn; Richardson, Shannon

    2007-10-01

    He-yey, Nez Perce for steelhead or rainbow trout (Oncorhynchus mykiss), are a culturally and ecologically significant resource within the Big Canyon Creek watershed; they are also part of the federally listed Snake River Basin Steelhead DPS. The majority of the Big Canyon Creek drainage is considered critical habitat for that DPS as well as for the federally listed Snake River fall chinook (Oncorhynchus tshawytscha) ESU. The Nez Perce Soil and Water Conservation District (District) and the Nez Perce Tribe Department of Fisheries Resources Management-Watershed (Tribe), in an effort to support the continued existence of these and other aquatic species, have developed this document to direct funding toward priority restoration projects in priority areas for the Big Canyon Creek watershed. In order to achieve this, the District and the Tribe: (1) Developed a working group and technical team composed of managers from a variety of stakeholders within the basin; (2) Established geographically distinct sub-watershed areas called Assessment Units (AUs); (3) Created a prioritization framework for the AUs and prioritized them; and (4) Developed treatment strategies to utilize within the prioritized AUs. Assessment Units were delineated by significant shifts in sampled juvenile O. mykiss (steelhead/rainbow trout) densities, which were found to fall at fish passage barriers. The prioritization framework considered four aspects critical to determining the relative importance of performing restoration in a certain area: density of critical fish species, physical condition of the AU, water quantity, and water quality. It was established, through vigorous data analysis within these four areas, that the geographic priority areas for restoration within the Big Canyon Creek watershed are Big Canyon Creek from stream km 45.5 to the headwaters, Little Canyon from km 15 to 30, the mainstem corridors of Big Canyon (mouth to 7km) and Little Canyon (mouth to 7km). The District and the Tribe then used data collected from the District's stream assessment and inventory, utilizing the Stream Visual Assessment Protocol (SVAP), to determine treatment necessary to bring 90% of reaches ranked Poor or Fair through the SVAP up to good or excellent. In 10 year's time, all reaches that were previously evaluated with SVAP will be reevaluated to determine progress and to adapt methods for continued success. Over 400 miles of stream need treatment in order to meet identified restoration goals. Treatments include practices which result in riparian habitat improvements, nutrient reductions, channel condition improvements, fish habitat improvements, invasive species control, water withdrawal reductions, improved hydrologic alterations, upland sediment reductions, and passage barrier removal. The Nez Perce Soil and Water Conservation District (District) and the Nez Perce Tribe Department of Fisheries Resource Management Watershed Division (Tribe) developed this document to guide restoration activities within the Big Canyon Creek watershed for the period of 2008-2018. This plan was created to demonstrate the ongoing need and potential for anadromous fish habitat restoration within the watershed and to ensure continued implementation of restoration actions and activities. It was developed not only to guide the District and the Tribe, but also to encourage cooperation among all stakeholders, including landowners, government agencies, private organizations, tribal governments, and elected officials. Through sharing information, skills, and resources in an active, cooperative relationships, all concerned parties will have the opportunity to join together to strengthen and maintain a sustainable natural resource base for present and future generations within the watershed. The primary goal of the strategy is to address aquatic habitat restoration needs on a watershed level for resident and anadromous fish species, promoting quality habitat within a self-sustaining watershed. Seven objectives have been developed to support this goal: (1) Identify factors limiting quality

  1. 3D View of Grand Canyon, Arizona

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Grand Canyon is one of North America's most spectacular geologic features. Carved primarily by the Colorado River over the past six million years, the canyon sports vertical drops of 5,000 feet and spans a 445-kilometer-long stretch of Arizona desert. The strata along the steep walls of the canyon form a record of geologic time from the Paleozoic Era (250 million years ago) to the Precambrian (1.7 billion years ago).

    The above view was acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument aboard the Terra spacecraft. Visible and near infrared data were combined to form an image that simulates the natural colors of water and vegetation. Rock colors, however, are not accurate. The image data were combined with elevation data to produce this perspective view, with no vertical exaggeration, looking from above the South Rim up Bright Angel Canyon towards the North Rim. The light lines on the plateau at lower right are the roads around the Canyon View Information Plaza. The Bright Angel Trail, which reaches the Colorado in 11.3 kilometers, can be seen dropping into the canyon over Plateau Point at bottom center. The blue and black areas on the North Rim indicate a forest fire that was smoldering as the data were acquired on May 12, 2000.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

  2. Engineering Geologic Assessment of Risk to Visitors: Canyon Lake Gorge, Texas 

    E-print Network

    Kolkmeier, Benjamin D.

    2010-07-14

    Presented here are the results of a study of geological hazards conducted in Canyon Lake Gorge of Central Texas. Canyon Lake Gorge formed in 2002 when the emergency spillway of Canyon Lake was overtopped. Since that time, ...

  3. 75 FR 71102 - Jones Canyon Hydro, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-22

    ...Regulatory Commission [Project No. 13860-000] Jones Canyon Hydro, LLC; Notice of Preliminary Permit...Applications November 12, 2010. On October 14, 2010, Jones Canyon Hydro, LLC (Jones Canyon Hydro) filed an application for a...

  4. 75 FR 20381 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group (AMWG...SUMMARY: The Glen Canyon Dam Adaptive Management Program (AMP) was...Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement...

  5. 78 FR 54482 - Charter Renewal, Glen Canyon Dam Adaptive Management Work Group

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-04

    ...4073000] Charter Renewal, Glen Canyon Dam Adaptive Management Work Group AGENCY...renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose...concerning the operation of Glen Canyon Dam and the exercise of other authorities...

  6. 75 FR 439 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group (AMWG...SUMMARY: The Glen Canyon Dam Adaptive Management Program (AMP) was...Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement...

  7. 76 FR 584 - Glen Canyon Dam Adaptive Management Program Work Group (AMWG)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-05

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Program Work Group...SUMMARY: The Glen Canyon Dam Adaptive Management Program (AMP) was...Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement...

  8. 75 FR 44809 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-29

    ...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group (AMWG...SUMMARY: The Glen Canyon Dam Adaptive Management Program (AMP) was...Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement...

  9. Characteristics of wind field in a street canyon

    Microsoft Academic Search

    Vu Thanh Ca; Takashi Asaeda; Manabu Ito; Steve Armfield

    1995-01-01

    Characteristics of the wind field in a North-South oriented street canyon were studied by a numerical model to couple the heat and mass transfer processes. The heat fluxes were traced in and out of the street canyon, and the feedback of the heating processes inside the street canyon to the atmosphere was simulated by simultaneous solutions of the two-dimensional Navier-Stokes

  10. Flood Geology and the Grand Canyon: A Critique

    Microsoft Academic Search

    Carol A. Hill; Stephen O. Moshier

    2009-01-01

    Four claims of Flood Geology—as they are related to the Grand Canyon and specifically to the book Grand Canyon: A Different View—are evaluated by directly addressing Young Earth Creationist arguments, by showing rock features that belie these claims, and by presenting the most up-to-date scientific theories on the origin of the Grand Canyon. We conclude that Young Earth Creationism promotes

  11. Lake Powell, Colorado River, Utah and Grand Canyon, Arizona

    NASA Technical Reports Server (NTRS)

    1973-01-01

    In this stark desert scene, Lake Powell, the Colorado River and the Grand Canyon (36.5N, 111.5W) provide the only relief and source of water. The creation of Lake Powell by the building of the Glen Canyon High Dam led directly to the establishment of a National Recreation Area surrounding the lakes. To the south, following the course of the Colorado River, the NE corner of Grand Canyon can be seen.

  12. Integrated study of Mediterranean deep canyons: Novel results and future challenges

    NASA Astrophysics Data System (ADS)

    Canals, M.; Company, J. B.; Martín, D.; Sànchez-Vidal, A.; Ramírez-Llodrà, E.

    2013-11-01

    This volume compiles a number of scientific papers resulting from a sustained multidisciplinary research effort of the deep-sea ecosystem in the Mediterranean Sea. This started 20 years ago and peaked over the last few years thanks to a number of Spanish and European projects such as PROMETEO, DOS MARES, REDECO, GRACCIE, HERMES, HERMIONE and PERSEUS, amongst others. The geographic focus of most papers is on the NW Mediterranean Sea including the Western Gulf of Lion and the North Catalan margin, with a special attention to submarine canyons, in particular the Blanes and Cap de Creus canyons. This introductory article to the Progress in Oceanography special issue on “Mediterranean deep canyons” provides background information needed to better understand the individual papers forming the volume, comments previous reference papers related to the main topics here addressed, and finally highlights the existing relationships between atmospheric forcing, oceanographic processes, seafloor physiography, ecosystem response, and litter and chemical pollution. This article also aims at constituting a sort of glue, in terms of existing knowledge and concepts and novel findings, linking together the other twenty papers in the volume, also including some illustrative figures. The main driving ideas behind this special issue, particularly fitting to the study area of the NW Mediterranean Sea, could be summarized as follows: (i) the atmosphere and the deep-sea ecosystem are connected through oceanographic processes originating in the coastal area and the ocean surface, which get activated at the occasion of high-energy events leading to fast transfers of matter and energy to the deep; (ii) shelf indented submarine canyons play a pivotal role in such transfers, which involve dense water, sedimentary particles, organic matter, litter and chemical pollutants; (iii) lateral inputs (advection) from the upper continental margin contributes significantly to the formation of intermediate and deep-water masses, and the associated fluxes of matter and energy are a main driver of deep-sea ecosystems; (iv) deep-sea organisms are highly sensitive to the arrival of external inputs, starting from the lowest food web levels and propagating upwards as time passes, which also relies upon the biology, nutritional needs and life expectancy of each individual species; and (v) innovative knowledge gained through such multidisciplinary research is of the utmost significance for an improved management of deep-sea living resources, such as the highly priced red shrimp Aristeus antennatus, for which a pilot management plan largely based in the findings described here and in related articles has been recently published (BOE, 2013). The researchers involved in such challenging endeavour have learnt tremendously from the results obtained so far and from each other, but are fully aware that there are still many unsolved questions. That is why this introductory article also includes “Future challenges” both in the title and as an individual section at the end, to express that there is still a long way to go.

  13. Atmospheric Flow through Urban Street Canyons

    Microsoft Academic Search

    H. J. S. Fernando

    2005-01-01

    Flow and turbulence through a network of urban street canyons (streets located within large buildings) were studied during two large-scale field experiments: the Mock Urban Setting Test (MUST-2000) at the US Army Dugway Proving Grounds and the Joint-Urban 2003 field experiment in Oklahoma City. Instrumented towers and tethersondes deployed by the authors and several other groups were analyzed in the

  14. Aggradation and degradation of alluvial sand deposits, 1965 to 1986, Colorado River, Grand Canyon National Park, Arizona; executive summary

    USGS Publications Warehouse

    Schmidt, J.C.; Graf, J.B.

    1988-01-01

    High discharges that occurred in 1983-85 resulted in redistribution of sand stored in zones of recirculating current in the Colorado River in Grand Canyon National Park. Redistribution resulted in net loss in the number of reattachment deposits in narrow reaches and aggradation of some separation deposits. Separation deposits were more stable than other types of deposits. Alluvial sand deposits that are large enough and of sufficient areal extent for use as campsites were more stable than smaller lower-elevation deposits. Fluctuating flows between October 1985 and January 1986 caused erosion throughout the Grand Canyon and caused erosion of some deposits created by the high flows of 1983-85. (Author 's abstract)

  15. Ocean circulation promotes methane release from gas hydrate outcrops at the NEPTUNE Canada Barkley Canyon node

    NASA Astrophysics Data System (ADS)

    Thomsen, Laurenz; Barnes, Christopher; Best, Mairi; Chapman, Ross; Pirenne, Benoît; Thomson, Richard; Vogt, Joachim

    2012-08-01

    The NEPTUNE Canada cabled observatory network enables non-destructive, controlled experiments and time-series observations with mobile robots on gas hydrates and benthic community structure on a small plateau of about 1 km2 at a water depth of 870 m in Barkley Canyon, about 100 km offshore Vancouver Island, British Columbia. A mobile Internet operated vehicle was used as an instrument platform to monitor and study up to 2000 m2 of sediment surface in real-time. In 2010 the first mission of the robot was to investigate the importance of oscillatory deep ocean currents on methane release at continental margins. Previously, other experimental studies have indicated that methane release from gas hydrate outcrops is diffusion-controlled and should be much higher than seepage from buried hydrate in semipermeable sediments. Our results show that periods of enhanced bottom currents associated with diurnal shelf waves, internal semidiurnal tides, and also wind-generated near-inertial motions can modulate methane seepage. Flow dependent destruction of gas hydrates within the hydrate stability field is possible from enhanced bottom currents when hydrates are not covered by either seafloor biota or sediments. The calculated seepage varied between 40-400 ?mol CH4 m-2 s-1. This is 1-3 orders of magnitude higher than dissolution rates of buried hydrates through permeable sediments and well within the experimentally derived range for exposed gas hydrates under different hydrodynamic boundary conditions. We conclude that submarine canyons which display high hydrodynamic activity can become key areas of enhanced seepage as a result of emerging weather patterns due to climate change.

  16. Detail of conning tower atop the submarine. Note the wire ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of conning tower atop the submarine. Note the wire rope wrapped around the base of the tower, which may have been used in an attempt to pull the submarine offshore. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ

  17. Sensitivity of Greenland outlet glacier dynamics to submarine melting

    NASA Astrophysics Data System (ADS)

    Beckmann, Johanna; Siegrfied, Merten; Perrette, Mahé; Carlov, Reinhard; Ganopolski, Andrey

    2015-04-01

    Over the last few decades Greenland ice mass loss has strongly increased due to surface melt and dynamic changes in marine-terminating outlet glaciers. A major reason for the retreat of these glaciers is believed to be related to increased submarine melting, which in turn is caused by surrounding ocean warming and the enhanced subglacial water discharge. These complex physical processes are not yet fully understood. Inspecting the sensitivities of submarine melting to model formulation and model parameters is crucial for investigations of outlet glacier response to future climate change. Different approaches have been used to compute submarine melt rates of outlet glaciers using experimental data, numerical modelling and simplified analytical solutions. To model the process of submarine melting for a selection of Greenland outlet glaciers, a simple submarine melt parameterization is incorporated into a one-dimensional dynamic ice-flow model. The behaviour of this submarine melt parameterization is demonstrated by running a suite of simulations to investigate the sensitivity of submarine melt to changes in ocean properties and the amount and distribution of subglacial water discharge. A comparison of the simple parameterization with three-dimensional models and experimental data is conducted to assess the quality of parameterization and improve the parameterization of submarine melting.

  18. Identification of a ship or submarine from its magnetic signature

    NASA Technical Reports Server (NTRS)

    Ioannidis, G.

    1977-01-01

    The relationship between the measured time fluctuations of the ambient magnetic field due to the passage of a ship or submarine and the characteristic magnetization properties of this vessel are derived. This relationship would be useful in identifying or classifying ships and submarines according to their magnetization properties.

  19. Processing of Ice Draft Measurements From Submarine Upward Looking Sonar

    Microsoft Academic Search

    M. R. Wensnahan; D. L. Bentley; D. A. Rothrock; W. B. Tucker; Y. Yu; R. Weaver; F. Fetterer

    2001-01-01

    In the last several years the US Navy has agreed to release data on ice draft taken using submarine-mounted upward looking sonar. This data spans more than 40 years, from 1957 to present, and represents a significant resource for climate researchers. Currently, the data are being processed by the Navy's Arctic Submarine Lab, the Applied Physics Lab at the University

  20. Optical Fiber Submarine Cable System Development at KDD

    Microsoft Academic Search

    YASUHIKO NIIRO

    1983-01-01

    An optical fiber submarine cable system using longwavelength and single-mode optical fiber is expected to provide economical long-haul digital transmission. This paper describes the recent research and development on an optical fiber submarine cable system for international communication at the KDD Research and Development Laboratories. An experimental model including cable and repeaters has been designed and manufactured. An experimental repeater

  1. Submarine communications cable for deep-sea application

    Microsoft Academic Search

    Gary Waterworth; I. Watson

    2003-01-01

    This paper details the design and qualification of high reliability submarine cables specifically developed for the telecommunications industry. These cables are now readily available to support various offshore applications where multi low loss optical fibers and medium voltage power is required. The paper covers the design requirements specific to submarine application, such as pressure, water and gaseous ingress and installation

  2. Technologies required for the future submarine cable networks

    Microsoft Academic Search

    Shu Yamamoto

    2002-01-01

    The progress of DWDM transoceanic transmission technologies enabled the immense capacity transport of the submarine cable networks and dramatically decreased the unit capacity cost. However, in order to cost-ffectively transport the large capacity traffic using the submarine cable link, the study on the network architecture will be of great importance in terms of the reduction of the system installation cost

  3. The Place of the Submarine Cable in Aeronautical Communication

    Microsoft Academic Search

    J. J. Gilbert; Cable COW

    1956-01-01

    Difficulty in satisfying increased requirements for aeronautical communication channels appears to justify investigating the potentialities of various means of submarine cable communication as a means of easing the burden on long radio links. Relief might be found by using submarine cables to connect strategic and widely separated land stations and thus materially reduce the length of radio links required. As

  4. Submarine escape trials 1999-2001--provision of medical support.

    PubMed

    Benton, Peter

    2002-01-01

    Since the early 1960s all Royal Navy submarines have been fitted with an escape system comprising a single escape tower (SET) and submarine escape immersion suit (SEIS). This system enables escape from a submarine at a depth of 180 metres (1.9 MPa) provided that the submarine compartment is at a pressure of no greater than 1 bar (0.1 MPa). Due to a variety of causes which may include flooding and leakage of high pressure air systems it is the highly probable that the submarine compartment will be at a pressure in excess of 1 bar (0.1 MPa) at the time of the escape. To investigate and determine what constitutes a 'safe' maximum escape depth from any given compartment pressure (the safe to escape curve), a purpose built chamber complex, the Submarine Escape Simulator (SES) has been constructed at the QinetiQ, formerly the Defence Evaluation and Research Agency (DERA), Alverstoke site. Unlike escapes from a submarine where once released from the submarine the escapee's ascent can not be halted, within the SES it is possible to halt the ascent phase. This article describes the systems and procedures developed to enable medical support to be provided rapidly to a subject at any stage of the compression decompression profile. The article also provides details of the results to date that have been obtained from this work. PMID:12838773

  5. Feasibility of Iceland\\/United Kingdom HVDC Submarine Cable Link

    Microsoft Academic Search

    T. J. Hammons; A. Olsen; T. Gudnundsson

    1989-01-01

    This paper addresses the viability of a submarine cable connection from Iceland to the North of Scotland extended by HVDC overhead line to the South of England. Hydro development, submarine cables, HVDC overhead transmission lines, rectifier\\/invertor stations, investment cost attributable to a power sale, availability of the connection, technical considerations and cost comparisons is discussed.

  6. Design considerations of a submarine laser communications system

    Microsoft Academic Search

    Larry B. Stotts

    1992-01-01

    It is pointed out that the US Navy appears to be ready to initiate the development of an optical communication system between satellites and submarines. This system will operate in the blue\\/green region of the spectrum. A great deal of the pat work has been to develop the critical components that will allow operations through clouds and water to submarines

  7. Ancient impact structures on modern continental shelves: The Chesapeake Bay, Montagnais, and Toms Canyon craters, Atlantic margin of North America

    USGS Publications Warehouse

    Poag, C. Wylie; Plescia, J.B.; Molzer, P.C.

    2002-01-01

    Three ancient impact craters (Chesapeake Bay - 35.7 Ma; Toms Canyon - 35.7 Ma; Montagnais - 51 Ma) and one multiring impact basin (Chicxulub - 65 Ma) are currently known to be buried beneath modern continental shelves. All occur on the passive Atlantic margin of North America in regions extensively explored by seismic reflection surveys in the search for oil and gas reserves. We limit our discussion herein to the three youngest structures. These craters were created by submarine impacts, which produced many structural and morphological features similar in construction, composition, and variability to those documented in well-preserved subaerial and planetary impact craters. The subcircular Chesapeake Bay (diameter 85 km) and ovate Montagnais (diameter 45-50 km) structures display outer-rim scarps, annular troughs, peak rings, inner basins, and central peaks similar to those incorporated in the widely cited conceptual model of complex impact craters. These craters differ in several respects from the model, however. For example, the Montagnais crater lacks a raised lip on the outer rim, the Chesapeake Bay crater displays only small remnants of a raised lip, and both craters contain an unusually thick body of impact breccia. The subtriangular Toms Canyon crater (diameter 20-22 km), on the other hand, contains none of the internal features of a complex crater, nor is it typical of a simple crater. It displays a prominent raised lip on the outer rim, but the lip is present only on the western side of the crater. In addition, each of these craters contains some distinct features, which are not present in one or both of the others. For example, the central peak at Montagnais rises well above the elevation of the outer rim, whereas at Chesapeake Bay, the outer rim is higher than the central peak. The floor of the Toms Canyon crater is marked by parallel deep troughs and linear ridges formed of sedimentary rocks, whereas at Chesapeake Bay, the crater floor contains concentric faults and compression ridges formed in rocks of the crystalline basement. The Chesapeake Bay crater is distinguished further by its cluster of at least 23 adjacent secondary craters. The North American tektite strewn field, a widespread deposit of distal ejecta, is thought to be derived from the Chesapeake Bay impact, perhaps with a small contribution from the Toms Canyon impact. No ejecta field is known to be associated with the Montagnais impact. No immediate major extinction event is directly linked to any of these three impacts. There is evidence, however, that the Chesapeake Bay and Toms Canyon impacts helped initiate a long-term pulse of warm global climate, whose eventual dissipation coincided with an early Oligocene mass extinction event, 2 Ma after the impacts.

  8. Miniature Robotic Submarine for Exploring Harsh Environments

    NASA Technical Reports Server (NTRS)

    Behar, Alberto; Bruhn, Fredrik; Carsey, Frank

    2004-01-01

    The miniature autonomous submersible explorer (MASE) has been proposed as a means of scientific exploration -- especially, looking for signs of life -- in harsh, relatively inaccessible underwater environments. Basically, the MASE would be a small instrumented robotic submarine (see figure) that could launch itself or could be launched from another vehicle. Examples of environments that might be explored by use of the MASE include subglacial lakes, deep-ocean hydrothermal vents, acidic or alkaline lakes, brine lenses in permafrost, and ocean regions under Antarctic ice shelves.

  9. Dynamic and instability of submarine avalanches

    E-print Network

    F. Malloggi; J. Lanuza; B. Andreotti; E. Clément

    2005-04-21

    We perform a laboratory-scale experiment of submarine avalanches on a rough inclined plane. A sediment layer is prepared and thereafter tilted up to an angle lower than the spontaneous avalanche angle. The sediment is scrapped until an avalanche is triggered. Based on the stability diagram of the sediment layer, we investigate different structures for the avalanche front dynamics. First we see a straight front descending the slope, and then a transverse instability occurs. Eventually, a fingering instability shows up similar to rivulets appearing for a viscous fluid flowing down an incline. The mechanisms leading to this new instability and the wavelength selection are discussed.

  10. Hydrogen isotope systematics of submarine basalts

    USGS Publications Warehouse

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

    1984-01-01

    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.

  11. Narrow Angle movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief three-frame movie of the Moon was made from three Cassini narrow-angle images as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. The purpose of this particular set of images was to calibrate the spectral response of the narrow-angle camera and to test its 'on-chip summing mode' data compression technique in flight. From left to right, they show the Moon in the green, blue and ultraviolet regions of the spectrum in 40, 60 and 80 millisecond exposures, respectively. All three images have been scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is the same in each image. The spatial scale in the blue and ultraviolet images is 1.4 miles per pixel (2.3 kilometers). The original scale in the green image (which was captured in the usual manner and then reduced in size by 2x2 pixel summing within the camera system) was 2.8 miles per pixel (4.6 kilometers). It has been enlarged for display to the same scale as the other two. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS) at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  12. The hydroacoustic record of activity at Monowai and its implications for submarine volcanism

    E-print Network

    Watts, A. B. "Tony"

    The hydroacoustic record of activity at Monowai and its implications for submarine volcanism A. B active submarine volcanism. One submarine volcano with a record of activity extending back to 1977 and collapse of a submarine magmatic cone. The main aim of this project is to use geophysical data analysis

  13. Did a submarine landslide contribute to the 2011 Tohoku tsunami? David R. Tappin a,

    E-print Network

    Kirby, James T.

    Did a submarine landslide contribute to the 2011 Tohoku tsunami? David R. Tappin a, , Stephan T September 2014 Accepted 15 September 2014 Available online 28 September 2014 Keywords: tsunami submarine that the most likely additional tsunami source was a submarine mass failure (SMF--i.e., a submarine landslide

  14. Geology Fieldnotes: Canyon De Chelly National Monument, Arizona

    NSDL National Science Digital Library

    This canyon cuts through the sandstones of the De Chelly formation, of Permian age (200 million years old). The river forming the canyon is the Rio De Chelly, which begins in the nearby Chuska Mountains. Details on this site include some geology, visitor information, photographs, and area maps. Also discussed are details on seeing the park, and Native American history of the area.

  15. Aquatic macroinvertebrates and water quality in Sandia Canyon

    Microsoft Academic Search

    1994-01-01

    In 1990, field studies of water quality and stream macroinvertebrate communities were initiated in Sandia Canyon at Los Alamos National Laboratory. The studies were designed to establish baseline data and to determine the effects of routine discharges of industrial and sanitary waste. Water quality measurements were taken and aquatic macroinvertebrates sampled at three permanent stations within the canyon. Two of

  16. Wind-tunnel study of concentration fields in street canyons

    Microsoft Academic Search

    P Kastner-Klein; E. J Plate

    1999-01-01

    The paper presents results from a case study of gaseous pollutant dispersion in street canyons. Tracer-gas experiments were performed in a neutrally stratified wind tunnel. Vehicle emissions were simulated as line sources. Concentration profiles along building walls were measured. A two-dimensional street canyon was considered as the reference case. The influence of systematic parameter variations on the concentration field is

  17. The Grand Canyon: The Top Two Rock Layers

    NSDL National Science Digital Library

    2006-01-01

    Watch this short video clip to learn more about the rock layers of the Grand Canyon. This video discusses the two sandstone formations that comprise the uppermost part of the canyon. The video also discusses how the two sandstone layers were formed.

  18. Formation of Amphitheater-Headed Canyons Michael Patrick Lamb

    E-print Network

    . Dietrich, Chair Professor Michael M. Manga Professor Mark Stacey Spring 2008 #12;Formation of Amphitheater Dissertation Committee Chair #12;i Contents Contents Acknowledgements Chapter 1. Introduction 1.1. Why Study Amphitheater-Headed Canyons? 1.2. Summary of Chapters 2 ­ 6 1.3. References Chapter 2. Can Springs Cut Canyons

  19. 4. VISTA POINT AND INTERPRETIVE PLAQUE AT LEE VINING CANYON. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VISTA POINT AND INTERPRETIVE PLAQUE AT LEE VINING CANYON. NOTE ROAD CUT ON CANYON WALL. LOOKING NNE. GIS: N-37 56 30.3 / 119 13 44.8 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

  20. The Grand Canyon of the Yellowstone Online Tour

    NSDL National Science Digital Library

    Yellowstone National Park

    This Yellowstone National Park website offers an online tour of the Grand Canyon of the Yellowstone. Prominent viewpoints of the canyon are highlighted with photos and information concerning their history. Other stops include information on giant glacial boulders and waterfalls. Similar tours of the Old Faithful area, the Norris Geyser Basin, the Fountain Paint Pots, and the Mammoth Hot Springs are also available online.

  1. Deep-Sea Submarine 'Ben Franklin'

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The deep-sea submarine 'Ben Franklin' is being docked in the harbor. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life. It also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effect of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.

  2. Submarine 'safe to escape' studies in man.

    PubMed

    Jurd, K M; Seddon, F M; Thacker, J C; Blogg, S L; Stansfield, M R D; White, M G; Loveman, G A M

    2014-01-01

    The Royal Navy requires reliable advice on the safe limits of escape from a distressed submarine (DISSUB). Flooding in a DISSUB may cause a rise in ambient pressure, increasing the risk of decompression sickness (DCS) and decreasing the maximum depth from which it is safe to escape. The aim of this study was to investigate the pressure/depth limits to escape following saturation at raised ambient pressure. Exposure to saturation pressures up to 1.6 bar (a) (160 kPa) (n = 38); escapes from depths down to 120 meters of sea water (msw) (n = 254) and a combination of saturation followed by escape (n = 90) was carried out in the QinetiQ Submarine Escape Simulator, Alverstoke, United Kingdom. Doppler ultrasound monitoring was used to judge the severity of decompression stress. The trials confirmed the previously untested advice, in the Guardbook, that if a DISSUB was lying at a depth of 90 msw, then it was safe to escape when the pressure in the DISSUB was 1.5 bar (a), but also indicated that this advice may be overly conservative. This study demonstrated that the upper DISSUB saturation pressure limit to safe escape from 90 msw was 1.6 bar (a), resulting in two cases of DCS. PMID:25109084

  3. Deep-Sea Research Submarine 'Ben Franklin'

    NASA Technical Reports Server (NTRS)

    1969-01-01

    This is an aerial view of the deep-sea research submarine 'Ben Franklin' at dock. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life, and also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effects of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.

  4. Diffusion-induced Ramsey narrowing

    E-print Network

    Yanhong Xiao; Irina Novikova; David F. Phillips; Ronald L. Walsworth

    2005-07-19

    A novel form of Ramsey narrowing is identified and characterized. For long-lived coherent atomic states coupled by laser fields, the diffusion of atoms in-and-out of the laser beam induces a spectral narrowing of the atomic resonance lineshape. Illustrative experiments and an intuitive analytical model are presented for this diffusion-induced Ramsey narrowing, which occurs commonly in optically-interrogated systems.

  5. The rate and pattern of bed incision and bank adjustment on the Colorado River in Glen Canyon downstream from Glen Canyon Dam, 1956-2000

    USGS Publications Warehouse

    Grams, P.E.; Schmidt, J.C.; Topping, D.J.

    2007-01-01

    Closure of Glen Canyon Dam in 1963 transformed the Colorado River by reducing the magnitude and duration of spring floods, increasing the magnitude of base flows, and trapping fine sediment delivered from the upper watershed. These changes caused the channel downstream in Glen Canyon to incise, armor, and narrow. This study synthesizes over 45 yr of channel-change measurements and demonstrates that the rate and style of channel adjustment are directly related to both natural processes associated with sediment deficit and human decisions about dam operations. Although bed lowering in lower Glen Canyon began when the first cofferdam was installed in 1959, most incision occurred in 1965 in conjunction with 14 pulsed high flows that scoured an average of 2.6 m of sediment from the center of the channel. The average grain size of bed material has increased from 0.25 mm in 1956 to over 20 mm in 1999. The magnitude of incision at riffles decreases with distance downstream from the dam, while the magnitude of sediment evacuation from pools is spatially variable and extends farther downstream. Analysis of bed-material mobility indicates that the increase in bed-material grain size and reduction in reach-average gradient are consistent with the transformation of an adjustable-bed alluvial river to a channel with a stable bed that is rarely mobilized. Decreased magnitude of peak discharges in the post-dam regime coupled with channel incision and the associated downward shifts of stage-discharge relations have caused sandbar and terrace erosion and the transformation of previously active sandbars and gravel bars to abandoned deposits that are no longer inundated. Erosion has been concentrated in a few pre-dam terraces that eroded rapidly for brief periods and have since stabilized. The abundance of abandoned deposits decreases downstream in conjunction with decreasing magnitude of shift in the stage-discharge relations. In the downstream part of the study area where riffles controlling channel elevation have not incised, channel narrowing has resulted from decreased magnitude of peak discharges and minor post-dam deposition. These physical changes to the aquatic and riparian systems have supported the establishment and success of an artifact ecosystem dominated by non-native species. Models for the channel response downstream from large dams typically consider factors such as the degree of sediment deficit, the pre-dam surface and subsurface grain size, and the magnitude of post-dam average flows. These results suggest that it is also necessary to consider (1) the possibility of variable responses among different channel elements and (2) the potential importance of exceptional flows resulting from management decisions. ?? 2007 Geological Society of America.

  6. A potential submarine landslide tsunami in South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Zhang, Y.; Switzer, A. D.

    2010-12-01

    Submarine earthquakes and submarine landslides are two main sources of tsunamis. Tsunami hazard modeling in the South China Sea has been primarily concerned with the potential large submarine earthquakes in the Manila trench. In contrast, evaluating the regional risk posed by tsunamis generated from submarine landslide is a new endeavor. At offshore south central Vietnam, bathymetric and seismic surveys show evidence of potentially tsunamigenic submarine landslides although their ages remain uncertain. We model two hypothetical submarine landslide events at a potential site on the heavily sediment laden, seismically active, steep continental slope offshore southeast Vietnam. Water level rises along the coast of Vietnam are presented for the potential scenarios, which indicate that the southeast coastal areas of Vietnam are at considerable risk of tsunami generated offshore submarine landslides. Key references: Kusnowidjaja Megawati, Felicia Shaw, Kerry Sieh, Zhenhua Huang, Tso-Ren Wu, Y. Lin, Soon Keat Tan and Tso-Chien Pan.(2009). Tsunami hazard from the subduction megathrust of the South China Sea, Part I, Source characterization and the resulting tsunami, Journal of Asian Earth Sciences, Vol. 36(1), pp. 13-20. Enet, F., Grilli, S.T. and Watts, P. (2003). Laboratory experiments for tsunami generated by underwater landslides: comparison with numerical modeling, In: Proceedings of 13th International Conference on Offshore and Polar Engineering, Honolulu, Hawaii, USA, pp. 372-379.

  7. Active geologic processes in Barrow Canyon, northeast Chukchi Sea

    USGS Publications Warehouse

    Eittreim, S.; Grantz, A.; Greenberg, J.

    1982-01-01

    Circulation patterns on the shelf and at the shelf break appear to dominate the Barrow Canyon system. The canyon's shelf portion underlies and is maintained by the Alaska Coastal Current (A.C.C.), which flows northeastward along the coast toward the northeast corner of the broad Chukchi Sea. Offshelf and onshelf advective processes are indicated by oceanographic measurements of other workers. These advective processes may play an important role in the production of bedforms that are found near the canyon head as well as in processes of erosion or non-deposition in the deeper canyon itself. Coarse sediments recovered from the canyon axis at 400 to 570 m indicate that there is presently significant flow along the canyon. The canyon hooks left at a point north of Point Barrow where the A.C.C. loses its coastal constriction. The left hook, as well as preferential west-wall erosion, continues down to the abyssal plain of the Canada Basin at 3800 m. A possible explanation for the preferential west-wall erosion along the canyon, at least for the upper few hundred meters, is that the occasional upwelling events, which cause nutrient-rich water to flow along the west wall would in turn cause larger populations of burrowing organisms to live there than on the east wall, and that these organisms cause high rates of bioerosion. This hypothesis assumes that the dominant factor in the canyon's erosion is biological activity, not current velocity. Sedimentary bedforms consisting of waves and furrows are formed in soft mud in a region on the shelf west of the canyon head; their presence there perhaps reflects: (a) the supply of fine suspended sediments delivered by the A.C.C. from sources to the south, probably the Yukon and other rivers draining northwestern Alaska; and (b) the westward transport of these suspended sediments by the prevailing Beaufort Gyre which flows along the outer shelf. ?? 1982.

  8. Glen Canyon Dam, Fluctuating Water Levels, and Riparian Breeding Birds: The Need for Management Compromise

    E-print Network

    I ;'. I Glen Canyon Dam, Fluctuating Water Levels, and Riparian Breeding Birds: The Need.--Large water releases from Glen Canyon Dam in May and June are harmful to riparian breeding birds along' INTRODUCTION 100,000,.... COLORAOQ RIVER NEAR GRAND CANYON (PHANTOM RANCHi The completion of Glen Canyon Dam

  9. 28. Fern Canyon (Meier 1979) This established RNA is on the San Dimas

    E-print Network

    Standiford, Richard B.

    28. Fern Canyon (Meier 1979) Location This established RNA is on the San Dimas Experimental Forest of bigcone Douglas-fir (BDF) at Fern Canyon have burned recently (1975). Poor reproduction suggestsUSDA Forest Service General Technical Report PSW-GTR-188. 2004. 28. Fern Canyon Figure 58--Fern Canyon

  10. Hells Canyon Environmental Investigation : Summary, 1984.

    SciTech Connect

    Not Available

    1984-07-01

    The Northwest Electric Power Planning and Conservation Act of 1980 provided for the establishment of a Regional Power Planning Council (Regional Council) and mandated the development of a Columbia River Basin Fish and Wildlife Program (F and W Program). The F and W Program was adopted in November 1982, and is intended to mitigate fish and wildlife losses resulting from the development of hydroelectric dams on the Columbia and Snake Rivers. One element of the F and W Program is the Water Budget. It calls for additional flows in the Columbia and Snake Rivers between April 15 and June 15 to improve the survival of juvenile salmon and steelhead migrating downstream. The Snake River's contribution to the Water Budget is 20,000 cubic feet per second-months over and above water that would normally flow for power production. The water for the Water Budget would come out of Idaho Power Company's (IPCo) Hells Canyon Complex (Brownlee Reservoir) and the Corps of Engineers' (Corps) Dworshak Reservoir. IPCo's participation in the Water Budget could affect the level of the Brownlee Reservoir and flows downstream of the Hells Canyon Complex on the Snake River. The potential changes that could occur to the environment are summarized in the following areas: (1) natural features, water use, and air and water quality; (2) fish, wildlife, and vegetation; (3) land use, recreation, and aesthetics; and (4) historical and archaeological resources.

  11. Hells Canyon Environmental Investigation : Final Report.

    SciTech Connect

    United States. Bonneville Power Administration.

    1985-01-01

    The Water Budget plan would provide additional flows in the Columbia and Snake Rivers between April 15 and June 15 to improve the survival of downstream migrating salmon and steelhead. The plan calls for 20,000 cubic feet per second-months (beyond the firm power flow) to be delivered to Lower Granite pool as the Snake River contribution to the Water Budget. This water would come from Idaho Power Company's (IPCo) Hells Canyon Complex (principally, Brownlee Reservoir) and the US Army Corps of Engineers' Dworshak Reservoir. This report contains the results of an environmental investigation of the nonpower impacts on the Hells Canyon Complex investigation. The environmental investigation evaluated three Water Budget scenarios, or levels of participation, developed by IPCo. These scenarios involve drawdowns of Brownlee Reservoir to three elevations, or floor levels (2036, 2050, and 2065), for Water Budget flows. A total of nine discipline areas were studied. These include natural features (geology); water use; water quality; fish, botanical, and wildlife resources; air quality; land use; historical and archeological resources; recreational resources; and aesthetic resources. Within each discipline, the report presents the existing conditions, the potential impacts associated with each scenario, information deficiencies and needed studies, and references.

  12. Atmospheric Flow through Urban Street Canyons

    NASA Astrophysics Data System (ADS)

    Fernando, H. J. S.

    2005-11-01

    Flow and turbulence through a network of urban street canyons (streets located within large buildings) were studied during two large-scale field experiments: the Mock Urban Setting Test (MUST-2000) at the US Army Dugway Proving Grounds and the Joint-Urban 2003 field experiment in Oklahoma City. Instrumented towers and tethersondes deployed by the authors and several other groups were analyzed in the framework of flow regimes corresponding to each of the sites (``isolated roughness'' at Dugway and ``skimming flow'' at OKC). The results show that the flow patterns are highly sensitive to the approach angle for angles greater than about 5 deg, and that when the flow is normal to the building cluster the canyons are dominated by recirculating flow. The production of turbulence is highest near the ground and near the top of the buildings, and the variations of turbulent shear stresses could be scaled using local similarity variables. The mean flow in the roughness and inertial layers were compared with available theoretical formulations, and the flow in MUST was also studied using numerical simulations.

  13. Atmospheric Fragmentation of the Canyon Diablo Meteoroid

    NASA Technical Reports Server (NTRS)

    Pierazzo, E.; Artemieva, N. A.

    2005-01-01

    About 50 kyr ago the impact of an iron meteoroid excavated Meteor Crater, Arizona, the first terrestrial structure widely recognized as a meteorite impact crater. Recent studies of ballistically dispersed impact melts from Meteor Crater indicate a compositionally unusually heterogeneous impact melt with high SiO2 and exceptionally high (10 to 25% on average) levels of projectile contamination. These are observations that must be explained by any theoretical modeling of the impact event. Simple atmospheric entry models for an iron meteorite similar to Canyon Diablo indicate that the surface impact speed should have been around 12 km/s [Melosh, personal comm.], not the 15-20 km/s generally assumed in previous impact models. This may help explaining the unusual characteristics of the impact melt at Meteor Crater. We present alternative initial estimates of the motion in the atmosphere of an iron projectile similar to Canyon Diablo, to constraint the initial conditions of the impact event that generated Meteor Crater.

  14. Surface Composition Differences in Martian Canyon

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Color differences in this daytime infrared image taken by the camera on NASA's Mars Odyssey spacecraft represent differences in the mineral composition of the rocks, sediments and dust on the surface.

    The image shows a portion of a canyon named Candor Chasma within the great Valles Marineris system of canyons, at approximately 5 degrees south latitude, 285 degrees east (75 degrees west) longitude. The area shown is approximately 30 by 175 kilometers (19 by 110 miles).

    The image combines exposures taken by Odyssey's thermal emission imaging system at three different wavelengths of infrared light: 6.3 microns, 7.4 microns and 8.7 microns.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The thermal emission imaging system was provided by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and JPL. JPL is a division of the California Institute of Technology in Pasadena.

  15. Directional VLF antenna for communicating with submarines

    NASA Astrophysics Data System (ADS)

    King, Ronold W. P.

    1997-01-01

    High-power, very low frequency transmitters for communicating with submarines use electrically short, top-loaded, vertical monopoles. These are efficient radiators of the lateral surface wave, but since they are omnidirectional, they expose residents of neighboring urban areas to possibly harmful effects. A possible alternative, the horizontal traveling-wave antenna of the Beverage type, is analyzed, and the design for the frequency range from 10 to 30 kHz is described. The antenna is highly directive in the horizontal plane. Although the field of the unit horizontal dipole over the earth is much smaller than that of the unit vertical dipole, the large effective length of the traveling-wave antenna makes its field comparable to that of the electrically short vertical monopole. Furthermore, since the radiated field in all directions except within a 30° to 60° angle out to sea is small, there is no exposure risk when the electrically long horizontal antenna is located near inhabited areas.

  16. Submarine landslides around the Canary Islands

    NASA Astrophysics Data System (ADS)

    Krastel, Sebastian; Schmincke, Hans-Ulrich; Jacobs, Colin L.; Rihm, Roland; Le Bas, Timothy P.; AlibéS, BáRbara

    2001-01-01

    The morphology and structure of the submarine flanks of the Canary Islands were mapped using the GLORIA long-range side-scan sonar system, bathymetric multibeam systems, and sediment echosounders. Twelve young (<2 Ma) giant landslides have been identified on the submarine flanks of the Canary Islands up to now. Older landslide events are long buried under a thick sediment cover due to high sedimentation rates around the Canary Islands. Most slides were found on the flanks of the youngest and most active islands of La Palma, El Hierro, and Tenerife, but young giant landslides were also identified on the flanks of the older (15-20 Ma) but still active eastern islands. Large-scale mass wasting is an important process during all periods of major magmatic activity. The long-lived volcanic constructive history of the islands of the Canary Archipelago is balanced by a correspondingly long history of destruction, resulting in a higher landslide frequency for the Canary Islands compared to the Hawaiian Islands, where giant landslides only occur late in the period of active shield growth. The lower stability of the flanks of the Canaries is probably due to the much steeper slopes of the islands, a result of the abundance of highly evolved intrusive and extrusive rocks. Another reason for the enhanced slope instability is the abundance of pyroclastic deposits on Canary Islands resulting from frequent explosive eruptions due to the elevated volatile contents in the highly alkalic magmas. Dike-induced rifting is most likely the main trigger mechanism for destabilization of the flanks. Flank collapses are a major geological hazard for the Canary Islands due to the sector collapses themselves as well as triggering of tsunamis. In at least one case, a giant lateral blast occurred when an active magmatic or hydrothermal system became unroofed during flank collapse.

  17. Three-dimensional grid generation about a submarine

    NASA Technical Reports Server (NTRS)

    Abolhassani, Jamshid Samareh; Smith, Robert E.

    1988-01-01

    A systematic multiple-block grid method has been developed to compute grids about submarines. Several topologies are proposed, and an oscillatory transfinite interpolation is used in the grid construction.

  18. A Pareto Frontier for Full Stern Submarines via Genetic Algorithm

    E-print Network

    Coello, Carlos A. Coello

    by : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Justin E. Kerwin Professor of Naval Architecture Thesis Supervisor Accepted: Professor of Naval Architecture #12; #12; A Pareto Frontier for Full Stern Submarines via Genetic Algorithm Institute of Technology, 1996 Naval Engineer, Massachusetts Institute of Technology, 1996 Submitted

  19. Surfacing Rescue Container concept design for trident submarines

    E-print Network

    LaPenna, Joshua J. (Joshua Jonathan)

    2009-01-01

    In the wake of the KURSK tragedy, world navies have brought their full attention to the submarine rescue problem. While many rescue systems exist, none have been able to sufficiently address the gamut of scenarios that ...

  20. Fine-scale predictive mapping of Cold Water Coral species in the Cap de Creus Canyon (NW Mediterranean): first insights

    NASA Astrophysics Data System (ADS)

    Lo Iacono, Claudio; Gonzalez-Villanueva, Rita; Gori, Andrea; Orejas, Covadonga; Gili, Josep Maria

    2013-04-01

    Cold-water corals (CWC) are azooxanthellate species which develop in a complex environment ruled out by a delicate interplay between geological, biological and oceanographic conditions.High impact deep-sea bottom trawling activities are seriously compromising the health and state of conservation of CWC habitats. It has been recently discovered that submarine canyons can act as hosting areas for benthic communities dominated by CWCs. Favorable environmental conditions along the canyons coupled with the rough seafloor morphology can foster their development and facilitate their preservation from the trawling threat. The aim of this study is to statistically predict the distribution of three CWC species (Madrepora oculata, Lophelia pertusa, Dendrophyllia cornigera) in the Cap de Creus Canyon (NW Mediterranean) based on high-resolution swath-bathymetry data (pixel resolution: 5m) and video observations from the submersible JAGO (IFM-GEOMAR). Species distribution models have been constructed with a Maximum Entropy approach (MaxEnt model) using the presence data from video imagery and layers derived from multibeam bathymetry such as slope, geomorphologic category, rugosity, aspect (orientation of the pixel respect to the North) and backscatter. For the three species the predictive model performance is outstanding, with the area under the curve (AUC) from the sensitivity-specificity approach of 0.98 for M. oculata and D. cornigera and of 0.99 for L. pertusa. The most relevant variables responsible for the CWC distribution are the slope and aspect for M. oculata and L. pertusa, and rugosity and aspect for D. cornigera. According to the models, CWC species are most likely to be found on the medium to steep rough walls of the southern flank of the Cap de Creus Canyon and almost exclusively along the regions facing the North and the North-West, from where strong organic sediment-rich currents flow. Results are coherent with previous observations and quantitative studies performed in the area. Insights coming out from the application of geo-spatial statistical models could represent the basis for the development of a scientifically-based approach in the planning and management of Marine Protected Areas.

  1. Risk Assessments for Non-Defuelled, Decommissioned Nuclear Submarines

    Microsoft Academic Search

    Steinar Høibråten; IBRA TEN

    \\u000a One of the topics currently under study in Phase II of the NATO\\/CCMS\\/NACC Pilot Study on Cross-Border Environmental Problems Emanating from Defence-Related Installations and Activities is known as Environmental Risk Assessments for NonDefuelled,Decommissioned Nuclear Submarines. In Phase I of the Pilot Study, problems related to such submarines were identified as one of the potentially largest defence-related\\u000a sources of radionuclide contamination

  2. Computational Simulation of Submarine Oil Spill with Current

    Microsoft Academic Search

    Wei Li; Yongjie Pang; Hongwei Li

    2011-01-01

    \\u000a Nowadays, the oil spill models are usually based on the sea surface and few of them are for submarine oil spill. Therefore,\\u000a the simulation for submarine pipeline oil spill is discussed by FLUENT in this paper to forecast the trajectory of oil. The\\u000a coupling of pressure and velocity under unsteady-state condition is solved by pressure implicit with splitting of operators

  3. 33 CFR 165.1103 - Security Zone; Naval Mine Anti Submarine Warfare Command; San Diego Bay, San Diego, CA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...false Security Zone; Naval Mine Anti Submarine Warfare Command; San Diego Bay, San...1103 Security Zone; Naval Mine Anti Submarine Warfare Command; San Diego Bay, San...water adjacent to the Naval Mine Anti Submarine Warfare Command, bound by the...

  4. 47 CFR 1.768 - Notification by and prior approval for submarine cable landing licensees that are or propose to...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Notification by and prior approval for submarine cable landing licensees that are or...Notification by and prior approval for submarine cable landing licensees that are or...licensee”) to land or operate a submarine cable landing in a particular...

  5. Selfsimilar long profiles of aggrading submarine leveed channels: Analytical solution and its application to the Amazon channel

    E-print Network

    Paris-Sud XI, Université de

    Selfsimilar long profiles of aggrading submarine leveed channels: Analytical solution and its submarine fans are coursed by welldefined leveed channels constructed by turbidity currents. The channels Submarine Fan, shows encouraging comparisons. The generality and shortcomings of the model assumptions

  6. 47 CFR 1.768 - Notification by and prior approval for submarine cable landing licensees that are or propose to...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Notification by and prior approval for submarine cable landing licensees that are or...Notification by and prior approval for submarine cable landing licensees that are or...licensee”) to land or operate a submarine cable landing in a particular...

  7. 76 FR 56973 - Office of National Marine Sanctuaries Final Policy and Permit Guidance for Submarine Cable Projects

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-15

    ...Final Policy and Permit Guidance for Submarine Cable Projects AGENCY: Office of National...final policy and permitting guidance for submarine cable projects proposed in national marine...applications to install and maintain submarine cables in sanctuaries are reviewed...

  8. 47 CFR 1.768 - Notification by and prior approval for submarine cable landing licensees that are or propose to...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Notification by and prior approval for submarine cable landing licensees that are or...Notification by and prior approval for submarine cable landing licensees that are or...licensee”) to land or operate a submarine cable landing in a particular...

  9. Report Summary, Final Hells Canyon Environmental Investigation.

    SciTech Connect

    United States. Bonneville Power Administration.

    1985-01-01

    The Northwest Electric Power Planning and Conservation Act of 1980 provided for the establishment of a Regional Power Planning Council (Regional Council) and mandated the development of a Columbia River Basin Fish and Wildlife Program (F&W Program). The F&W Program was adopted by the Regional Council in November 1982. and is intended to mitigate fish and wildlife losses resulting from the development of hydroelectric dams on the Columbia and Snake Rivers. One element of the FLW Program is the Water Budget. It calls for additional flows in the Columbia and Snake Rivers between April 15 and June 15 to improve the survival of juvenile salmon and steelhead migrating downstream. The Snake River's contribution to the Water Budget is 20,000 cubic feet per second-months (A volume of water equal to a flow of 20.000 cubic feet per second, 24 hours per day, for a period of a month) over and above water that would normally flow for power production. The water for the Water Budget would come out of Idaho Power Company's (IPCo) Hells Canyon Complex and the Corps of Engineers' (Corps) Dvorshak Reservoir. IPCo's Hells Canyon Complex consists of three dams, Brownlee, Oxbow, and Hells Canyon. Brownlee, at the upstream end, contains a large reservoir and controls flow to the lower dams. IPCo's participation in the Water Budget could affect the level of the Brownlee Reservoir and flows downstream of the Hells Canyon Complex on the Snake River. In light of this, Bonneville Power Administration (BPA) and IPCo contracted with the consulting firm of CH2!4 Hill to study the potential changes that could occur to the environment. The Environmental Investigation (EI) takes into account concerns that were expressed by the public at a series of public meetings held in the Snake River area during June 1983 and again during September 1984. Existing information and consultations with agencies which have management responsibilities in the project area formed the basis for the data used in the EI. This document summarizes the findings of the final EI in the following areas: (1) natural features, water use, and air and water quality; (2) fish, wildlife, and vegetation; (3) land use, recreation, and aesthetics; and (4) historical and archaeological resources. The EI provides information to be used by IPCo as they assess the effect on the system operations (power and nonpower) resulting from Water Budget participation. BPA and IPCo are continuing to discuss the prospects for IPCo's involvement in implementation of the Water Budget on the Snake River. When IPCo reaches a decision on whether and to what extent it wishes to participate in a Water Budget agreement with BPA, the proposed agreement will be subject to analysis under the National Environmental Policy Act (NEPA). That analysis will consider alternatives, significance of impacts to the environment, and mitigative measures.

  10. Lynch Canyon combination thermal drive project. [Termination

    SciTech Connect

    Stair, J. R.

    1980-11-01

    The following report provides a summary of the Lynch Canyon Thermal Drive Project. This demonstration project was begun in 1978 and terminated in 1980. The project originally was divided into four phases; Geologic Evaluation, Injectivity Test, Field Development Combined with Air-Water Injection, and a Project Review. Following the First Phase operations, which included drilling of four wells for geologic evaluation, a joint decision to cancel the project was made. The conditions which were thought to exist at the initiation of the project, would have provided an excellent opportunity to conduct a Pilot Combination Thermal Drive. However, potential problems which were discovered in the Phase One Operations significantly altered the economics of the project and removed the favorable conditions under which the project was begun.

  11. Cryogenic Detectors (Narrow Field Instruments)

    Microsoft Academic Search

    H. Hoevers; P. Verhoeve

    2003-01-01

    Two cryogenic imaging spectrometer arrays are currently considered as focal plane instruments for XEUS. The narrow field imager 1 (NFI 1) will cover the energy range from 0.05 to 3 keV with an energy resolution of 2 eV, or better, at 500 eV. A second narrow field imager (NFI 2) covers the energy range from 1 to 15 keV with

  12. Controls on plan-form evolution of submarine channels

    NASA Astrophysics Data System (ADS)

    Imran, J.; Mohrig, D. C.

    2014-12-01

    Vertically aggrading sinuous channels constitute a basic building block of modern submarine fans and the greater continental slope. Interpretation of seismically imaged channels reveals a significant diversity in internal architecture, as well as important similarities and differences in the evolution of submarine channels relative to better studied rivers. Many submarine channel cross sections possess a 'gull wing' shape. Successive stacking of such channels demonstrates that systematic bank erosion is not required in order for lateral migration to occur. The lateral shift of such aggrading channels, however, is expected to be much less dynamic than in the case of terrestrial rivers. Recent high-resolution 3D seismic data from offshore Angola and an upstream segment of the Bengal Submarine Fan show intensely meandering channels that experience considerable lateral shifting during periods of active migration within submarine valleys. The cross sections of the actively migrating channels are similar to meandering river channels characterized by an outer cut-bank and inner-bank accretion. In submarine channels, the orientation of the secondary flow can be river-like or river-reverse depending on the channel gradient, cross sectional shape, and the adaptation length of the channel bend. In river channels, a single circulation cell commonly occupies the entire channel relief, redistributing the bed-load sediment across the channel, and influencing the thread of high velocity and thus the plan-form evolution of the channel. In submarine environments, the height of the circulation cell will be significantly smaller than channel relief, thus leading to development of lower relief point bars from bed-load transport. Nevertheless these "underfit" bars may play an important role in plan-form evolution of submarine channels. In rivers and submarine channels, the inclined surface accretion can be constructed via pure bed-load, suspended-load, or a combination of both transport types. The in-channel suspended-load deposition occurs at sites of flow separation along the inner banks of bends. The relative contribution of inner-bank deposition from bed-load versus suspended load affects the plan-form evolution of both river and submarine channels.

  13. Early Cretaceous shelf-edge deltas of the Baltimore Canyon Trough: Principal sources for sediment gravity deposits of the northern Hatteras Basin

    NASA Astrophysics Data System (ADS)

    Poag, C. Wylie; Swift, B. Ann; Schlee, John S.; Ball, Mahlon M.; Sheetz, Linda L.

    1990-02-01

    We present evidence that the principal sources for Early Cretaceous (Berriasian-Valanginian) gravity-flow deposits of the northern Hatteras Basin were three large shelf-edge deltas located along the outer margin of the Baltimore Canyon Trough, ˜ 100 km southeast of Cape Charles, Virginia, Ocean City, Maryland, and Long Branch, New Jersey. Sedimentary detritus from the central Appalachian highlands and the Maryland-Virginia coastal plain was transported across the Early Cretaceous continental shelf to form the Cape Charles and Ocean City deltas, whereas deposits of the Long Branch delta came chiefly from the Adirondack and New England highlands. Each delta supplied sediment gravity flows to large slope aprons and submarine-fan complexes on the Early Cretaceous continental slope and rise. The most conspicuous distributary of sediment on the Early Cretaceous continental rise extends 500 km basinward from the Ocean City delta, where its distal deposits were cored at Deep Sea Drilling Project Site 603.

  14. Early Cretaceous shelf-edge deltas of the Baltimore Canyon Trough: principal sources for sediment gravity deposits of the northern Hatteras Basin

    USGS Publications Warehouse

    Poag, C. Wylie; Swift, B. Ann; Schlee, John S.; Ball, Mahlon M.; Sheetz, Linda L.

    1990-01-01

    We present evidence that the principal sources for Early Cretaceous (Berriasian-Valanginian) gravity-flow deposits of the northern Hatteras Basin were three large shelf-edge deltas located along the outer margin of the Baltimore Canyon Trough, ? 100 km southeast of Cape Charles, Virginia, Ocean City, Maryland, and Long Branch, New Jersey. Sedimentary detritus from the central Appalachian highlands and the Maryland-Virginia coastal plain was transported across the Early Cretaceous continental shelf to form the Cape Charles and Ocean City deltas, whereas deposits of the Long Branch delta came chiefly from the Adirondack and New England highlands. Each delta supplied sediment gravity flows to large slope aprons and submarine-fan complexes on the Early Cretaceous continental slope and rise. The most conspicuous distributary of sediment on the Early Cretaceous continental rise extends 500 km basinward from the Ocean City delta, where its distal deposits were cored at Deep Sea Drilling Project Site 603.

  15. 14. MAIN CANAL CANAL CHECKGATES, JUST BELOW DARK CANYON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. MAIN CANAL - CANAL CHECKGATES, JUST BELOW DARK CANYON SIPHON, VIEW TO NORTHEAST - Carlsbad Irrigation District, Main Canal, 4 miles North to 12 miles Southeast of Carlsbad, Carlsbad, Eddy County, NM

  16. 37. PRATER CANYON AND CIVILIAN CONSERVATION CORPS CAMP SITE FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. PRATER CANYON AND CIVILIAN CONSERVATION CORPS CAMP SITE FROM PRATER GRADE, FACING E. SAME CAMERA LOCATION AS No. 35 AND No. 36. - Mesa Verde National Park Main Entrance Road, Cortez, Montezuma County, CO

  17. Fossil Woodwardia virginica Foliage From the Middle Miocene Yakima Canyon

    NSDL National Science Digital Library

    Kathleen B. Pigg (Arizona State University; Department of Plant Biology ADR; POSTAL)

    2004-03-09

    Fossil Woodwardia virginica foliage from the middle Miocene Yakima Canyon flora of central Washington State, USA. Vegetative and fertile features of this fossil are remarkably similar to those of the modern ""Virginia chain fern"" of the Atlantic coastal region, USA.

  18. A view in Lapwai Canyon at Milepost 18 of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    A view in Lapwai Canyon at Milepost 18 of the grade cut through basalt - Camas Prairie Railroad, Second Subdivision, From Spalding in Nez Perce County, through Lewis County, to Grangeville in Idaho County, Spalding, Nez Perce County, ID

  19. THE SIGNIFICANCE OF ODOR FOR BEES ORIENTING ACROSS A CANYON

    E-print Network

    Boyer, Edmond

    the « odor population hypothesis » would apply in a crosswind situation. MATERIALS AND METHODS crosswind of about 5-10 m/s that blew at a 90° angle to the line across the canyon. The expe- riments were

  20. Sandbar on the Colorado River in Grand Canyon

    USGS Multimedia Gallery

    Sandbar on the Colorado River in Grand Canyon deposited by the 2008 controlled flood. The view is looking downstream and the location is approximately 65 miles downstream from Lees Ferry, Arizona.  ...

  1. Sandbar on the Colorado River in Grand Canyon

    USGS Multimedia Gallery

    Sandbar on the Colorado River in Grand Canyon deposited by 2008 controlled flood. The river is flowing from left to right and the location is approximately 64 miles downstream from Lees Ferry, Arizona....

  2. View of Inverted Siphon crossing Hot Water (or White) Canyon. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Inverted Siphon crossing Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  3. 1. GENERAL VIEW OF SHOSHONE HYDROELECTRIC PLANT IN GLENWOOD CANYON, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF SHOSHONE HYDROELECTRIC PLANT IN GLENWOOD CANYON, VIEW TO THE NORTHEAST ALONG U.S. 6 AND THE COLORADO RIVER. - Shoshone Hydroelectric Plant Complex, 60111 U.S. Highway 6, Glenwood Springs, Garfield County, CO

  4. The Shape of Trail Canyon Alluvial Fan, Death Valley

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Dohrenwend, John C.

    1993-01-01

    A modified conic equation has been fit to high-resolution digital topographic data for Trail Canyon alluvial fan in Death Valley, California. Fits were accomplished for 3 individual fan units of different age.

  5. H CANYON PROCESSING IN CORRELATION WITH FH ANALYTICAL LABS

    SciTech Connect

    Weinheimer, E.

    2012-08-06

    Management of radioactive chemical waste can be a complicated business. H Canyon and F/H Analytical Labs are two facilities present at the Savannah River Site in Aiken, SC that are at the forefront. In fact H Canyon is the only large-scale radiochemical processing facility in the United States and this processing is only enhanced by the aid given from F/H Analytical Labs. As H Canyon processes incoming materials, F/H Labs provide support through a variety of chemical analyses. Necessary checks of the chemical makeup, processing, and accountability of the samples taken from H Canyon process tanks are performed at the labs along with further checks on waste leaving the canyon after processing. Used nuclear material taken in by the canyon is actually not waste. Only a small portion of the radioactive material itself is actually consumed in nuclear reactors. As a result various radioactive elements such as Uranium, Plutonium and Neptunium are commonly found in waste and may be useful to recover. Specific processing is needed to allow for separation of these products from the waste. This is H Canyon's specialty. Furthermore, H Canyon has the capacity to initiate the process for weapons-grade nuclear material to be converted into nuclear fuel. This is one of the main campaigns being set up for the fall of 2012. Once usable material is separated and purified of impurities such as fission products, it can be converted to an oxide and ultimately turned into commercial fuel. The processing of weapons-grade material for commercial fuel is important in the necessary disposition of plutonium. Another processing campaign to start in the fall in H Canyon involves the reprocessing of used nuclear fuel for disposal in improved containment units. The importance of this campaign involves the proper disposal of nuclear waste in order to ensure the safety and well-being of future generations and the environment. As processing proceeds in the fall, H Canyon will have a substantial number of samples being sent to F/H Labs. All analyses of these samples are imperative to safe and efficient processing. The important campaigns to occur would be impossible without feedback from analyses such as chemical makeup of solutions, concentrations of dissolution acids and nuclear material, as well as nuclear isotopic data. The necessity of analysis for radiochemical processing is evident. Processing devoid of F/H Lab's feedback would go against the ideals of a safety-conscious and highly accomplished processing facility such as H Canyon.

  6. CHAMA RIVER CANYON WILDERNESS AND CONTIGUOUS ROADLESS AREA, NEW MEXICO.

    USGS Publications Warehouse

    Ridgley, Jennie L.; Light, Thomas D.

    1984-01-01

    Results of mineral surveys indicate that the Chama River Canyon Wilderness and contiguous roadless area in new Mexico have a probable mineral-resource potential for copper with associated uranium and silver. Gypsum occurs throughout the area, exposed in the canyon walls. Further study of the wilderness should concentrate on exploratory drilling to test the oil and gas potential of Pennsylvanian strata and evaluate vanadium anomalies in the Todilto as a prospecting guide for locating uranium.

  7. Properties of Saltstone Prepared Containing H-Canyon Waste

    Microsoft Academic Search

    Cozzi

    2005-01-01

    Saltstone slurries were prepared from solutions made from H-Canyon waste and evaluated for processing properties. Salt solutions prepared with a 1:1 ratio of Tank 50H simulant and H-Canyon blended waste produced slurries that met the processing requirements in Table 2 of the Task Technical and Quality Assurance Plan (TTQAP). Additions of set retarder and antifoam were necessary to meet these

  8. Safety Evaluation for Packaging (onsite) T Plant Canyon Items

    SciTech Connect

    OBRIEN, J.H.

    2000-07-14

    This safety evaluation for packaging (SEP) evaluates and documents the ability to safely ship mostly unique inventories of miscellaneous T Plant canyon waste items (T-P Items) encountered during the canyon deck clean off campaign. In addition, this SEP addresses contaminated items and material that may be shipped in a strong tight package (STP). The shipments meet the criteria for onsite shipments as specified by Fluor Hanford in HNF-PRO-154, Responsibilities and Procedures for all Hazardous Material Shipments.

  9. 77 FR 67391 - Notice of Proposed Supplementary Rules on Public Land in Water Canyon, Humboldt County, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ...Proposed Supplementary Rules on Public Land in Water Canyon, Humboldt County, NV AGENCY...and resources on public land within the Water Canyon Recreation Area. These proposed...restrictions included within the decisions of the Water Canyon Recreation Area Management...

  10. 76 FR 47237 - Notice of Public Meeting for the Glen Canyon Dam Adaptive Management Work Group Federal Advisory...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ...Notice of Public Meeting for the Glen Canyon Dam Adaptive Management Work Group Federal Advisory...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

  11. A Central-Upwind Scheme for Nonlinear Water Waves Generated by Submarine Landslides

    E-print Network

    Kurganov, Alexander

    A Central-Upwind Scheme for Nonlinear Water Waves Generated by Submarine Landslides Alexander. In this paper, we study submarine landslides, which are capable of generating several types of long waves

  12. Explicit homogeneous time-varying stabilizing control of a submarine vehicle (ROV)

    E-print Network

    Paris-Sud XI, Université de

    Explicit homogeneous time-varying stabilizing control of a submarine vehicle (ROV) Adel Khadhraoui1. Abstract: The stabilizing control problem of a Remotely Operated Vehicle (ROV) for a submarine observing

  13. Submarine Ring of Fire 2003 Mariana Arc R/V T. G. Thompson Cruise TN-153

    E-print Network

    #12;i Submarine Ring of Fire 2003 ­ Mariana Arc R/V T. G. Thompson Cruise TN-153 February 9 - March: Susan Merle, Robert Embley, Edward Baker and Bill Chadwick TABLE OF CONTENTS 1.0 Submarine Ring of Fire

  14. Numerical Methods in Offshore Geotechnics: Applications to Submarine Landslides and Anchor Plates 

    E-print Network

    Nouri, Hamid Reza

    2013-05-08

    communities and the offshore industry can be impacted directly by geohazards, such as submarine slope failures, or by tsunamis generated by the failed mass movements. This study aims at evaluating the triggering mechanisms of submarine landslide under cyclic...

  15. Research Article Evolution of West Rota Volcano, an extinct submarine volcano in the

    E-print Network

    Stern, Robert J.

    submarine eruption. The youngest unit consists of 1­2 m diam- eter spheroids of rhyolite pumice, interpreted mineralization, Mariana Arc, pumice, Quaternary volcano, submarine caldera. INTRODUCTION The 3000-km long Izu

  16. Near-synchronous and delayed initiation of long run-out submarine sediment flows from a record-breaking river flood, offshore Taiwan

    NASA Astrophysics Data System (ADS)

    Carter, L.; Milliman, J. D.; Talling, P. J.; Gavey, R.; Wynn, R. B.

    2012-06-01

    Subsea fiber-optic telecommunication cables can break under fast sediment flows that travel 100s of kilometers through the deep ocean in response to earthquakes and submarine landslides. Similar flows are inferred to form from major river floods whose sediment-laden waters plunge and travel along the seabed. However, the complex initiation of flood-related flows and their hazard potential have not been observed until now. Here we use cable fault data from the Gaoping Canyon/Manila Trench off Taiwan to show that a major river flood, formed during Typhoon Morakot (2009), generated two, long run-out, destructive sediment flows; one during peak flood and the other 3 days later. The latter flow was more damaging with speeds and run-out similar to that of landslide-triggered turbidity currents formed in the same catchment. If the second flow was due to remobilized canyon sediment, it occurred during low earthquake (>Mw 2.0) activity, suggesting other triggering mechanisms.

  17. Navy review of nasopharyngeal radium treatments of submarine candidates.

    PubMed

    George, J D

    1996-11-01

    From approximately 1945 through 1960 nasopharyngeal radium treatments were used to treat barotrauma incurred during submarine escape training by submarine candidates. Concern has been expressed that the treatments placed submarine candidates at significantly increased risk of having brain cancer develop. The concern is based on brain cancer incidence rates reported in a study of Washington County children. Using comparable populations' risk coefficients and secondary brain tumor incidence rates, the excess number of brain cancers per 10,000 subjects during the 42.5 years after treatment was calculated to be 0.5 to 2.8 cases and 1 case, respectively. Personnel records of a sample of those treated and others whose treatment status was unknown were reviewed to determine the feasibility of an epidemiologic study to confirm the cancer risk. The records indicated treatments were not consistently documented to confirm who was treated. In addition, social security numbers are not known to aid in determination of vital status. In conclusion, nasopharyngeal irradiation does not appear to pose a significant risk to submariners, and it is not feasible to use the submariner population to do a meaningful epidemiologic study to clarify the cancer risk. PMID:8903444

  18. Maximizing the probability an aerial anti-submarine torpedo detects its target

    Microsoft Academic Search

    Zhi-Jie Wang

    2009-01-01

    As a result of the high speed of anti-submarine patrol aircraft as well as their wide range, high efficiency and other characteristics,\\u000a aerial torpedoes released by anti-submarine patrol aircraft have become the key anti submarine tool. In order to improve operational\\u000a efficiency, a deep study was made of the target detection probabilities for aerial torpedoes released by anti-submarine patrol\\u000a aircraft.

  19. SRTM Anaglyph: Pinon Canyon region, Colorado

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Erosional features are prominent in this view of southern Colorado taken by the Shuttle Radar Topography Mission (SRTM). The area covers about 20,000square kilometers and is located about 50 kilometers south of Pueblo, Colorado. The prominent mountains near the left edge of the image are the Spanish Peaks, remnants of a 20 million year old volcano. Rising 2,100 meters (7,000 feet) above the plains to the east, these igneous rock formations with intrusions of eroded sedimentary rock historically served as guiding landmarks for travelers on the Mountain Branch of the Santa Fe Trail.

    Near the center of the image is the Pinon Canyon Maneuver Site, a training area for soldiers of the U.S. Army from nearby Fort Carson. The site supports a diverse ecosystem with large numbers of big and small game, fisheries, non-game wildlife, forest, range land and mineral resources. It is bounded on the east by the dramatic topography of the Purgatoire River Canyon, a 100 meter (328 feet) deep scenic red canyon with flowing streams, sandstone formations and exposed geologic processes.

    This anaglyph was produced by first shading a preliminary SRTM elevation model. The stereoscopic effect was then created by generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

    Size: 177.8 x 111.3 kilometers ( 110.5 x 69.2 miles) Location: 37.5 deg. North lat., 104 deg. West lon. Orientation: North toward the top Original Data Resolution: SRTM 1 arcsecond (30 meters or 99 feet) Image Data: Shaded and colored SRTM elevation model

  20. Regional depositional history of the miocene-pleistocene Louisiana slope, Green Canyon-Mississippi Canyon

    SciTech Connect

    Risch, D.L.; Choudhury, A.N.; Hannan, A.E. [Geco-Prakla, Houston, TX (United States)

    1994-12-31

    A regional sequence stratigraphic analysis was recently completed for the Tertiary slope sediments in Green Canyon, Ewing Bank, and Mississippi Canyon to provide a chronostratigraphic framework for basin reconstructions and to predict lithofacies distributions of reservoir and seal rocks. Sixteen third-order sequences of lowstand deepwater deposits were interpreted for the Middle Miocene-Pleistocene section. Thirty regional lithofacies maps were made of predominantly lowstand deposits showing the distribution of shale and sand-prone sediments, slumps, channel/levee systems, and fan lobes based on distinctive seismic reflection and well log patterns. These maps were combined with isochrons of selected sequences to identify depositional fairways, depocenters, and paleosalt positions that constantly changed through time. Depositional trends were principally north-south but were also observed to be east-west as salt modified the gradient on the gently dipping slope. In some cases, the structural and stratigraphic trends could be projected under allochthonous tabular salt. Miocene channel and fan lobe sands were concentrated on the middle-lower paleoslope across the study area. The sedimentation rate doubled to 2.3 m/1000 yr in the early Middle Pliocene, which caused large-scale salt movements and trapped sand-prone turbidities along the upper to middle slope. A four-fold decrease in sediment influx during the Late Pliocene-Early Pleistocene produced a stacked condensed section of four sequences over the eastern Louisiana slope. A return to rapid sedimentation (up to 6.9 m/1,000 yr) during the Late Pleistocene reactivated salt movements and depocenters in the Green Canyon, Ewing Bank, and Mississippi Trough areas.

  1. Regional depositional history of the Miocene-Pleistocene Louisiana Slope, Green Canyon and Mississippi Canyon

    SciTech Connect

    Risch, D.L.; Chowdhury, A.N.; Hannan, A.E. [Geco-Prakla, Houston, TX (United States)

    1994-09-01

    A regional sequence-stratigraphic analysis was recently completed for the Tertiary slope sediments in Green Canyon, Ewing Bank, and Mississippi Canyon to provide a chronostratigraphic framework for basin reconstructions and predict lithofacies distributions of reservoir and seal rocks. Sixteen third-order sequences of lowstand deep-water deposits were interpreted for the middle Miocene-Pleistocene section. Thirty regional lithofacies maps were made of predominantly lowstand deposits showing the distribution of shale and sand-prone sediments, slumping, channel levee systems, and fan lobes based on distinctive seismic reflection and well log patterns. These maps were combined with isochrons of selected sequences to identify depositional fairways, depocenters, and paleosalt positions that constantly changed through time. Depositional trends were principally north to south but were also observed to be east-west as salt modified the gradient on the gently dipping slope. In some cases, the structural and stratigraphic trends could be projected under allochthonous tabular salt. Miocene channel and fan lobe sands were found concentrated on the middle-lower paleoslope across the study area. The sedimentation rate doubled (0.7 m/1000 yr) in the early-middle Pliocene, which caused large-scale salt movements and trapped sand-prone turbidites along the upper-middle slope. A four-fold decrease in sediment influx during the late Pliocene-early Pleistocene produced a stacked condensed section of four sequences over the eastern Louisiana slope. A return to rapid sedimentation (up to 2.1 m/1000 yr.) during the Pleistocene reactivated salt movements and depocenters in the Green Canyon, Ewing Bank, and Mississippi Trough areas.

  2. Composition and evolution of submarine volcanic rocks from the central and western Canary Islands

    NASA Astrophysics Data System (ADS)

    Abratis, M.; Schmincke, H.-U.; Hansteen, T. H.

    2002-08-01

    Submarine volcanic rocks dredged during RV Meteor cruise M43-1 comprise alkali basalts, basanites, nephelinites and their differentiates representing both basement-shield and young post-shield volcanics of Gran Canaria, Tenerife, La Palma and El Hierro. The primitive lavas vary widely in trace element composition (e.g., Zr/Y=6.6-11.7, (La/Sm)N=2.3-5.4, and Ba/Yb=71-311), and they are characterized by steep, rare-earth element patterns with mean (La/Yb)N=16, and by pronounced, positive primitive mantle-normalized Nb and Ta and negative K anomalies similar to HIMU-type basalts. Rocks from the submarine flanks west and north of Gran Canaria are isotopically and geochemically identical to rocks of the subaerial Miocene shield stage, but they are distinct from rocks of the post-shield stages (Zr/Nb=6.3-8.9, 87Sr/86Sr=0.70327-0.70332, 143Nd/144Nd=0.51289-0.51293, 206Pb/204Pb=19.55-19.88). Most rocks dredged from the submarine flanks of Tenerife are isotopically and geochemically similar to rocks of the adjacent subaerial shield remnants, but a few resemble rocks of the subaerial post-shield stages (total range in Zr/Nb=4.6-6.1, 87Sr/86Sr=0.70300-0.70329, 143Nd/144Nd=0.51281-0.51292, 206Pb/204Pb=19.51-19.96). Rocks from the southern submarine ridge of La Palma cover the entire compositional range of the subaerial rocks of that ridge. Additionally, they comprise a high Zr/Nb group which resembles rocks of the ca. 1-Ma-old Taburiente shield of northern La Palma (total range in Zr/Nb=3.0-6.4, 87Sr/86Sr=0.70297-0.70314, 143Nd/144Nd=0.51288-0.51296, 206Pb/204Pb=19.21-19.79). Rocks from the southern submarine ridge of El Hierro compositionally resemble subaerial rocks of the island (Zr/Nb=4.1-6.2, 87Sr/86Sr=0.70296-0.70314, 143Nd/144Nd=0.51291-0.51297, 206Pb/204Pb=19.25-19.91). The degree of melting in the subcanarian mantle is interpreted to decrease from east to west across the archipelago whereas the proportion of depleted mantle component in the melting anomaly increases, as illustrated by Sr, Nd and Pb isotopes. The isotopic characteristics of the mantle source beneath the Canary Islands represents a mixture of HIMU, DMM and EM I. The overall isotopic signature is intermediate between that of Madeira to the north, which trends towards more depleted compositions, and that of the Cape Verde Islands to the south which shows a pronounced trend towards enriched mantle compositions. A clear trend towards the EM II component is only evident in more evolved rocks dredged from a seamount between Tenerife and Gran Canaria, some of which contain terrigenous sedimentary xenoliths. We propose a genetic model which relates similar mantle source signatures of volcanic archipelagos off West Africa to a common, large-scale lower mantle upwelling which, according to geophysical data, becomes more diffuse in the upper mantle. Narrow plumes or blobs feeding the volcanic centers along the passive margin may rise from this thermal anomaly due to upwelling in small, continent-parallel upper-mantle convection cells.

  3. 49. DETAILS OF SUBMARINE SECTION, Y&D No. 107727 Scale 3/8' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. DETAILS OF SUBMARINE SECTION, Y&D No. 107727 Scale 3/8' and 1-1/2' = 1'; July 2, 1929 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  4. Hydroplaning and submarine debris flows Fabio V. De Blasio,1,2

    E-print Network

    Hydroplaning and submarine debris flows Fabio V. De Blasio,1,2 Lars Engvik,3 Carl B. Harbitz,4; published 3 January 2004. [1] Examination of submarine clastic deposits along the continental margins; KEYWORDS: debris flows, hydroplaning, submarine slides Citation: De Blasio, F. V., L. Engvik, C. B. Harbitz

  5. 2006 Nature Publishing Group Long-term eruptive activity at a submarine arc

    E-print Network

    Chadwick, Bill

    © 2006 Nature Publishing Group Long-term eruptive activity at a submarine arc volcano Robert W , Douglas A. Wiens12 & Yoshihiko Tamura13 Three-quarters of the Earth's volcanic activity is submarine of submarine eruptions have been indirect, made from surface vessels or made after the fact1­6 . We describe

  6. 33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Thames River, Naval Submarine Base New London, restricted area...REGULATIONS § 334.75 Thames River, Naval Submarine Base New London, restricted area...notified by personnel of the New London Submarine Base that such use will interfere...

  7. 76 FR 78159 - Safety Zone; Submarine Cable Installation Project; Chicago River South Branch, Chicago, IL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ...USCG-2011-1122] RIN 1625-AA00 Safety Zone; Submarine Cable Installation Project; Chicago...South Branch due to the installation of submarine cables in the vicinity of the Madison...hazards associated with the installation of submarine cables in the vicinity of the...

  8. 33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Bangor Naval Submarine Base, Bangor, WA. 165.1302 Section...District § 165.1302 Bangor Naval Submarine Base, Bangor, WA. (a) Location...Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...

  9. Coastal karst aquifers in Mediterranean regions. 2. A methodology for exploring, exploiting and monitoring submarine springs.

    E-print Network

    Paris-Sud XI, Université de

    and monitoring submarine springs. BAKALOWICZ M.(1) , FLEURY P.(2) , JOUVENCEL B.(3) , PROMÉ J.J.(4) , BECKER P.(5 investigation axis deals with the exploration of fresh water plumes from submarine karst springs. An Autonomous and depth) along its trajectory. The submarine discharge may be estimated by modelling. The second axis

  10. Seafloor seismic monitoring of an active submarine volcano: Local seismicity at Vailulu'u Seamount, Samoa

    E-print Network

    Shearer, Peter

    Seafloor seismic monitoring of an active submarine volcano: Local seismicity at Vailulu'u Seamount'u; volcano; seismic monitoring; volcanic activity; submarine. Index Terms: 3025 Marine Geology and Geophysics of an active submarine volcano: Local seismicity at Vailulu'u Seamount, Samoa, Geochem. Geophys. Geosyst., 5, Q

  11. Submarine Location Estimation via a Network of Detection-Only Sensors

    E-print Network

    Zhou, Shengli

    Submarine Location Estimation via a Network of Detection-Only Sensors Shengli Zhou and Peter by the source/target receive-geometry and the target aspect can detect the return signal. Thus, submarines can. Traditional Approach and Low-Visibility Targets Submarine detection and localization is one major applica

  12. 33 CFR 165.1328 - Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. 165.1328 Section...Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. (a) Location...Washington whenever any U.S. Navy submarine is operating in the Hood Canal and is being...

  13. Using Ambient Noise Fields for Submarine Team #525 for the Mathematical Contest in Modeling

    E-print Network

    Mitchener, W. Garrett

    Using Ambient Noise Fields for Submarine Location Team #525 for the Mathematical Contest or click, and storms. Our job is to determine if this noise can be used to detect a submarine, and determine its location, direction of travel, speed, and size. The submarine is assumed not to make any noise

  14. Submarine Landslides Along the Algerian Margin: A Review of Their Occurrence and

    E-print Network

    Déverchère, Jacques

    Submarine Landslides Along the Algerian Margin: A Review of Their Occurrence and Potential Link submarine landslides are present along these structures, as well as asso- A. Cattaneo ( ) and N. Sultan.C. Mosher et al. (eds.), Submarine Mass Movements and Their Consequences, 515 Advances in Natural

  15. Submarine pingoes: Indicators of shallow gas hydrates in a pockmark at Nyegga, Norwegian Sea

    E-print Network

    Svensen, Henrik

    Submarine pingoes: Indicators of shallow gas hydrates in a pockmark at Nyegga, Norwegian Sea Martin the features as true submarine pingoes, formed by the local accumulation of hydrate (ice) below the sediment the pockmark. We suggest that these submarine hydrate-pingoes manifest the exact locations where fluid flow

  16. 33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Bangor Naval Submarine Base, Bangor, WA. 165.1302 Section...District § 165.1302 Bangor Naval Submarine Base, Bangor, WA. (a) Location...Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...

  17. Estimation of submarine groundwater discharge and associated nutrient fluxes in Tolo Harbour, Hong Kong

    E-print Network

    Jiao, Jiu Jimmy

    Estimation of submarine groundwater discharge and associated nutrient fluxes in Tolo Harbour, Hong 2012 Keywords: Submarine groundwater discharge Nutrients Radium isotope Groundwater Estuary Tolo of algal blooms and red tides. An attempt was made to first quantify the submarine groundwater discharge

  18. Submarine landslide as the source for the October 11, 1918 Mona Passage tsunami: Observations and modeling

    E-print Network

    ten Brink, Uri S.

    Submarine landslide as the source for the October 11, 1918 Mona Passage tsunami: Observations Passage October 11, 1918 Puerto Rico submarine landslide tsunami modeling The October 11, 1918 ML 7 Passage show a fresh submarine landslide 15 km northwest of Rinon in northwestern Puerto Rico

  19. 33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Bangor Naval Submarine Base, Bangor, WA. 165.1302 Section...District § 165.1302 Bangor Naval Submarine Base, Bangor, WA. (a) Location...Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...

  20. Numerical Modeling of Submarine Mass-Movement Generated Waves Using RANS Model

    E-print Network

    Yim, Solomon C.

    Numerical Modeling of Submarine Mass-Movement Generated Waves Using RANS Model D. YUK and S. YIM model for predicting waves generated by nearshore submarine mass-movements is described. The model of fluid (VOF) method is employed to track the free surface. The submarine mass movement is prescribed

  1. A COUPLED NUMERICAL MODEL FOR TSUNAMIS GENERATED BY SUBAERIAL AND SUBMARINE MASS FAILURES

    E-print Network

    Grilli, Stéphan T.

    A COUPLED NUMERICAL MODEL FOR TSUNAMIS GENERATED BY SUBAERIAL AND SUBMARINE MASS FAILURES Stéphane-seismic bottom displacement due to earthquakes. Landslides, however, either submarine or subaerial, can trigger with good success to simulate submarine landslide-induced waves. By contrast, the case of subaerial

  2. SUBMARINE MASS MOVEMENTS IN THE BETSIAMITES AREA, GENEVIEVE CAUCHON-VOYER1

    E-print Network

    St-Ong, Guillaume

    SUBMARINE MASS MOVEMENTS IN THE BETSIAMITES AREA, GENEVIEVE CAUCHON-VOYER1 , JACQUES LOCAT1 A complex submarine geomorphology was revealed from multibeam bathymetry and seismic reflection surveys. Introduction Investigating submarine mass movements in order to evaluate slope stability for a region

  3. Submarine landslides of San Pedro Escarpment, southwest of Long Beach, California

    E-print Network

    New Hampshire, University of

    Submarine landslides of San Pedro Escarpment, southwest of Long Beach, California Robert G greater Los Angeles metropolitan area would be profoundly affected by a large tsunami. Submarine slope. ß 2003 Elsevier B.V. All rights reserved. Keywords: tsunamis; California; submarine environment

  4. 33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Thames River, Naval Submarine Base New London, restricted area...REGULATIONS § 334.75 Thames River, Naval Submarine Base New London, restricted area...notified by personnel of the New London Submarine Base that such use will interfere...

  5. Non-Hydrostatic Wave Model NHWAVE User's Guide for Modeling Submarine Landslide Tsunami

    E-print Network

    Kirby, James T.

    Non-Hydrostatic Wave Model NHWAVE User's Guide for Modeling Submarine Landslide Tsunami ( Version 1 of submarine landslide-induced tsunami waves. NHWAVE was de- veloped by Ma et al. (2012) for modeling fully a surface and terrain in the sigma co- ordinate system. Tsunami waves generated by a prescribed submarine

  6. Submarine venting of liquid carbon dioxide on a Mariana Arc volcano

    E-print Network

    Chadwick, Bill

    Submarine venting of liquid carbon dioxide on a Mariana Arc volcano John Lupton NOAA/Pacific Marine, California, 92065, USA [1] Although CO2 is generally the most abundant dissolved gas found in submarine CO2-rich hydrothermal system at 1600-m depth near the summit of NW Eifuku, a small submarine volcano

  7. 33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Thames River, Naval Submarine Base New London, restricted area...REGULATIONS § 334.75 Thames River, Naval Submarine Base New London, restricted area...notified by personnel of the New London Submarine Base that such use will interfere...

  8. 33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Bangor Naval Submarine Base, Bangor, WA. 165.1302 Section...District § 165.1302 Bangor Naval Submarine Base, Bangor, WA. (a) Location...Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...

  9. BASICS OF DESIGN AND CONSTRUCTION OF A HUMAN POWERED SUBMARINE 'CharlesR. Lockert

    E-print Network

    Wood, Stephen L.

    BASICS OF DESIGN AND CONSTRUCTION OF A HUMAN POWERED SUBMARINE 'CharlesR. Lockert Florid used by the author on the design and construction of the human powered submarine "Sea Panther Though there may The design procedure for the human powered submarine I1SeaPanther" is best represented

  10. 33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Thames River, Naval Submarine Base New London, restricted area...REGULATIONS § 334.75 Thames River, Naval Submarine Base New London, restricted area...notified by personnel of the New London Submarine Base that such use will interfere...

  11. Size distribution of submarine landslides and its implication to tsunami hazard in Puerto Rico

    E-print Network

    Size distribution of submarine landslides and its implication to tsunami hazard in Puerto Rico Uri frequency distribution for carbonate submarine slope failures. Using detailed bathymetry along the northern (2006), Size distribution of submarine landslides and its implication to tsunami hazard in Puerto Rico

  12. 33 CFR 165.1328 - Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. 165.1328 Section...Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. (a) Location...Washington whenever any U.S. Navy submarine is operating in the Hood Canal and is being...

  13. Submarine mass movements on continental margins HOMA J. LEE*, JACQUES LOCAT, PRISCILLA DESGAGNS, JEFFREY D. PARSONS,

    E-print Network

    Lin, Andrew Tien-Shun

    Submarine mass movements on continental margins HOMA J. LEE*, JACQUES LOCAT, PRISCILLA DESGAGNÉS **Institut de Ciències del Mar, Barcelona 08003, Spain ABSTRACT Submarine landslides can be important currents. Recent submarine land- slide research has: shown that landslides and sediment waves may generate

  14. 33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Thames River, Naval Submarine Base New London, restricted area...REGULATIONS § 334.75 Thames River, Naval Submarine Base New London, restricted area...notified by personnel of the New London Submarine Base that such use will interfere...

  15. Size distributions and failure initiation of submarine and subaerial landslides U.S. ten Brink a,

    E-print Network

    ten Brink, Uri S.

    Size distributions and failure initiation of submarine and subaerial landslides U.S. ten Brink a distributions of submarine landslides along the U.S. Atlantic continental slope follow a lognormal distribution and not an inverse power law. Using Monte Carlo simulations, we generated area distributions of submarine landslides

  16. Size distribution of submarine landslides along the U.S. Atlantic margin Jason D. Chaytor a,

    E-print Network

    ten Brink, Uri S.

    Size distribution of submarine landslides along the U.S. Atlantic margin Jason D. Chaytor a, , Uri­normal distribution submarine geomorphology landslide volume Assessment of the probability for destructive landslide-generated tsunamis depends on the knowledge of the number, size, and frequency of large submarine landslides

  17. Tracking control for an ellipsoidal submarine driven by Kirchhoff's Thomas Chambrion and Mario Sigalotti

    E-print Network

    Paris-Sud XI, Université de

    Tracking control for an ellipsoidal submarine driven by Kirchhoff's laws Thomas Chambrion and Mario is known about the effective control of standard submarines, which are harder to handle and much quicker. In this paper, we establish the controllability of such a submarine driven by two directional controls (turn

  18. Occurrence and origin of submarine plunge pools at the base of the US continental slope

    E-print Network

    Hogg, Andrew

    Occurrence and origin of submarine plunge pools at the base of the US continental slope Simon E to reduced bed shear stress downstream of hydraulic jumps in submarine sediment-laden density flows £ows; continental slope; morphology; hydraulic jump 1. Introduction Submarine sediment-laden density

  19. 33 CFR 165.1328 - Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. 165.1328 Section...Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. (a) Location...Washington whenever any U.S. Navy submarine is operating in the Hood Canal and is being...

  20. submarine_case2.doc 1 GIS Professional Ethics Project gisprofessionalethics.org

    E-print Network

    Wright, Dawn Jeannine

    submarine_case2.doc 1 GIS Professional Ethics Project gisprofessionalethics.org Case study transit back to Guam. #12;submarine_case2.doc 2 Fig. 1. Photograph of the USS San Francisco in dry dock nautical charts in the shallow coastal waters of the Middle East as part of the #12;submarine_case2.doc 3

  1. Submarine Ring of Fire 2004 -Mariana Arc R/V Thomas G. Thompson, Cruise TN167

    E-print Network

    #12;Submarine Ring of Fire 2004 - Mariana Arc R/V Thomas G. Thompson, Cruise TN167 March 27 - April..............................................................................................................................................3 1.0 SUBMARINE RING OF FIRE 2004 CRUISE SUMMARY (Bob Embley..........................................................................................................25 3.0 SUBMARINE RING OF FIRE (SROF) 2004 DISCIPLINE SUMMARIES

  2. Association of submarine cable reliability and network protection for very high availability transoceanic transmission networks

    Microsoft Academic Search

    Steven Desbrulais; Vincent Lemaire; Loic Le Gall; Christophe Mathieu

    1999-01-01

    To match the bandwidth requirements of our fast-growing communication world, submarine networks have to provide ever greater transmission capacity. Thus, almost 2 Tbit\\/s will soon be the capacity available in submarine networks. A high level of availability is achieved owing to a very reliable submarine cable and to powerful network protection mechanisms.

  3. Submarine Communications Cables and Law of the Sea: Problems in Law and Practice

    Microsoft Academic Search

    Tara Davenport

    2012-01-01

    Submarine communications cables laid on the seabed of the ocean are the foundation of the world's international telecommunications network. International law, in particular, the law of the sea, has recognized the freedom to lay submarine cables and perform associated operations and has placed certain obligations on states related to the protection of submarine cables. This article examines the international law

  4. Research on an Optimized Method for Submarine Torpedo Attacking with Incomplete Information

    Microsoft Academic Search

    Sun Zhufeng; Huang Wenbing; Xiao Mingyan; Xue Changyou

    2008-01-01

    The anti-submarine ability of the warship improved quickly as the increasing threat of the submarine. On the other hand, the submarine commander should make tactical decision quickly and accurately under high threat environment. This fact means that not only should be launch torpedo snugly, quickly and accurately, but also make this decision with incomplete target information. This paper takes a

  5. Submarine tracking using multi-sensor fusion and reactive planning for the positioning of passive sonobuoys

    Microsoft Academic Search

    Kristian Johansson; Karsten Jöred; Per Svensson

    This paper describes the development and validation of a simulation model capable of simulat- ing a submarine hunt using multi-sensor fusion of signals from passive sonobuoys and of computing a near-optimal placement for the next buoy to be deployed. Keywords: passive sonobuoys, archipelagic anti-submarine warfare, submarine tracking, reactive planning, Kalman filter

  6. Some Remarks on the US\\/UK Submarine Deception In Swedish Waters in the 1980s

    Microsoft Academic Search

    Ola Tunander

    After a Soviet Whiskey submarine was stranded in 1981 in the Swedish archipelago, massive submarine intrusions took place within Swedish waters - later described as the first Soviet military initiative against a Western European state since the Berlin crisis.1 After a dramatic hunt in 1982, a parliamentary commission stated that six Soviet submarines had 'played their games' in the Stockholm

  7. Preliminary Velocity Measurements in the Wake of a Submarine Model

    NASA Astrophysics Data System (ADS)

    Jimenez, J. M.; Reynolds, R.; Smits, A. J.

    2000-11-01

    Preliminary Particle Image Velocimetry (PIV) over a submarine shape has been conducted in a low speed wind tunnel at Princeton University. The model is a 1/67 replica of the USS Albacore, an experimental submarine designed to achieve maximum underwater performance, and based on "bodies of revolution." The model is tested with a sail, and different tail appendages. Velocity vector fields and flow visualizations in the wake region are presented for Reynolds numbers based on model length up to 10^5. The experiments establish the groundwork for future investigations of submarine models in the new High Reynolds Number Test Facility (http://www.princeton.edu/ gasdyn/HRTF.html). Supported by ONR Grants N00014-97-1-0325, N00014-97-1-0340 and N00014-97-1-0618.

  8. Submarine volcanic features west of Kealakekua Bay, Hawaii

    USGS Publications Warehouse

    Fornari, D.J.; Lockwood, J.P.; Lipman, P.W.; Rawson, M.; Malahoff, A.

    1980-01-01

    Visual observations of submarine volcanic vents were made from the submersible vehicle DSV "Sea Cliff" in water depths between 1310 and 690 m, west of Kealakekua Bay, Hawaii. Glass-rich, shelly submarine lavas surround circular 1- to 3-m-diameter volcanic vents between 1050 and 690 m depth in an area west-northwest of the southernpoint (Keei Pt.) of Kealakekua Bay. Eye-witness accounts indicate that this area was the site of a submarine eruption on February 24, 1877. Chemical analyses of lavas from these possible seafloor vent areas indicate that the eruptive products are very similar in composition to volcanic rocks produced by historic eruptions of Mauna Loa volcano. ?? 1980.

  9. Submarine volcanic features west of Kealakekua Bay, Hawaii

    NASA Astrophysics Data System (ADS)

    Fornari, Daniel J.; Lockwood, John P.; Lipman, Peter W.; Rawson, Michael; Malahoff, Alexander

    1980-05-01

    Visual observations of submarine volcanic vents were made from the submersible vehicle DSV "Sea Cliff" in water depths between 1310 and 690 m, west of Kealakekua Bay, Hawaii. Glass-rich, shelly submarine lavas surround circular 1- to 3-m-diameter volcanic vents between 1050 and 690 m depth in an area west-northwest of the southernpoint (Keei Pt.) of Kealakekua Bay. Eye-witness accounts indicate that this area was the site of a submarine eruption on February 24, 1877. Chemical analyses of lavas from these possible seafloor vent areas indicate that the eruptive products are very similar in composition to volcanic rocks produced by historic eruptions of Mauna Loa volcano.

  10. Computational Simulation of Submarine Oil Spill with Current

    NASA Astrophysics Data System (ADS)

    Li, Wei; Pang, Yongjie; Li, Hongwei

    Nowadays, the oil spill models are usually based on the sea surface and few of them are for submarine oil spill. Therefore, the simulation for submarine pipeline oil spill is discussed by FLUENT in this paper to forecast the trajectory of oil. The coupling of pressure and velocity under unsteady-state condition is solved by pressure implicit with splitting of operators algorithm, and the boundary condition of nonlinear free surface is solved by volume of fluid. The simulation of oil particles motion is carried out. Furthermore, the quantity and trajectory of spilled oil under different operating pressure and current velocity are compared and analyzed. The results show that the submarine diffusion scope of spilled oil is smaller with larger operating pressure or lower current velocity.

  11. Submarine-Fan delta depositional environment of the Pennsylvania Redfork sandstone

    SciTech Connect

    Anderson, E. (LL E, New Orleans, LA (United States))

    1993-09-01

    Active exploration and development drilling for the Upper Pennsylvanian Red Fork sandstone has been going on since 1979 in the western part of the Anadarko basin of Oklahoma. The fine-grained, low-permeability gas and gas condensate reservoir produces at depths ranging from 12,000 to 14,000 ft from stratigraphic traps. Although drilling generally has been continuous through the years, producing the Red Fork play is very sensitive to gas price because of drilling depths and reservoir characteristics. The play is now mature, but because of the complex submarine-fan depositional environment, it is not easy to predict the good-quality reservoir sandstone. Isopach maps, log shapes, lithologic information, and seismic data are all used to define the facies within the fan. In the Red Fork, most of the sand was deposited; in the middle fan with the best reservoirs found in narrow channels of the suprafan lobes. Quality of the reservoir rock in the levee facies deteriorates significantly away from the channel The gross morphology of interpreted suprafan lobes in the Red Fork arc compared to and show a similarity with the modern Mississippi submarine fan and suprafan lobes seen in the outcrop. Using two-dimensional and three dimensional seismic data to map the suprafan lobes and channel systems has proven very challenging the Red Fork; however, careful integration of all well information with the seismic data will yield the best interpretation. Changes in amplitude are used to help define the presence or absence of sandstone and the relative quality of the reservoir.

  12. Historical bathymetric charts and the evolution of Santorini submarine volcano, Greece

    NASA Astrophysics Data System (ADS)

    Watts, A. B.; Nomikou, P.; Parks, M.; Smith, J.

    2013-12-01

    Historical bathymetric charts are a potential resource for better understanding the dynamics of the seafloor and the role of active processes such as those associated with submarine faulting, landsliding, and magmatism. The UK Hydrographic Office, for example, has been involved in lead line measurements of seafloor depth since the early 1790s in a range of geological settings including ocean islands. Here, we report on an analysis of historical bathymetric charts in the region of Santorini volcano, Greece. Repeat lead line surveys in 1848, 1866 and 1928 and multibeam swath bathymetric surveys in 2001 and 2006 have been used to document changes in the depth of the seafloor in Santorini caldera. The data reveal that the flanks of the Kameni islands, a volcanic dome and dacitic lava complex in the caldera centre, have shallowed by up to 215 m and deepened by up to 60 m since 1848. The largest shallowing occurred between the 1866 and 1928 surveys and was accompanied by a significant increase in the surface area of the island of Nea Kameni, especially its southeast flank. Field observations by the French Geologist, F. A. Fouqué, during 1866-1870 suggest the shallowing is associated with the formation of the Giorgos and Aphroessa domes and their associated lava flows. Other shallowing probably occurred during 1925-1928 when lava flows filled the narrow strait between Nea Kameni and Mikra Kameni. The largest deepenings occurred between the 1928 and 2001 and 2006 surveys, on the shelf and slope of Nea Kameni. One possibility is that the deepening is caused by mass wasting due to large-scale slope failure and debris flow. Another is that it reflects a stress-induced viscoelastic relaxation of the crust following dome loading. Irrespective, the rates implied from the volumes and duration of the 19th century submarine magmatic activity are up to 0.11 km3/yr, which is significantly larger than rates inferred from mapping of surface lava flows.

  13. Facies architecture of Spraberry submarine fan reservoirs (Permian), Midland basin, Texas

    SciTech Connect

    Guevara, E.H.; Tyler, N.

    1989-03-01

    Facies of mud-rich submarine fans of the Spraberry formation (Permian, Leonardian) form oil reservoirs in the central part of the Midland basin, west Texas. The principal reservoirs are submarine-channel and associated facies in the upper parts of generally upward-coarsening and upward-thickening sequences of the Jo Mill (lower Spraberry) and Driver and overlying Floyd (upper Spraberry) fans. They are naturally fractured, massive and laminated, very fine-grained, calcareous sandstones and siltstones usually occurring in beds 2 to approximately 12 ft thick. Two main subdivisions, inner and middle to outer fan, are recognized using isoliths, log motifs, and cores of predominantly terrigenous clastic, mostly basin-wide genetic intervals. The boundary between the subdivisions approximately coincides with the location of the subjacent Horseshoe atoll (Pennsylvanian). The narrow range in grain size of the fans results in limited basinward variations in texture and sedimentary structures and paucity of Bouma sequences. Facies architecture strongly influences hydrocarbon distribution and recovery. Wells having the best cumulative productions generally occur in sandstone depositional axes. Most accumulations in inner fan facies are scattered structural traps having relatively high recovery efficiencies (24%, Jo Mill field). The largest accumulations in mid to outer fan facies are stratigraphic traps in meandering to anastomosing channel sandstone belts 1-3 mi wide occurring in a widespread area. Recovery efficiencies range from 5% (Spraberry trend, stratigraphic trap) to 15% (Benedum field, combined stratigraphic-structural trap). Additional reserves can be recovered from partly drained and untapped reservoir compartments, especially in layered and compartmentalized middle to outer fan facies.

  14. Geology and tsunamigenic potential of submarine landslides in Santa Barbara Channel, Southern California

    USGS Publications Warehouse

    Fisher, M.A.; Normark, W.R.; Greene, H. Gary; Lee, H.J.; Sliter, R.W.

    2005-01-01

    A large submarine landslide complex and four small landslides developed under the Santa Barbara Channel, suggesting a potential hazard from landslide-generated tsunamis. We integrate offshore stratigraphy and geologic structure, multibeam bathymetric information, and several kinds of seismic-reflection data to understand how and when the submarine landslides formed. Seismic-reflection data show that mass failure along the slope began at least 200 ka ago. Landslides appear as zones of poor reflectivity having an irregular upper surface, and these zones alternate vertically with strong parallel reflections. The emplacement ages of two of the three main landslide lobes are well established at 8 and 10 ka. The source material for the youngest part of the landslide complex was sediment of probable late Pleistocene and Holocene age that accumulated in a shelf-edge delta. Directly under this delta, growth of faults and anticlines was particularly intense and tended to oversteepen the deltaic deposits. These active structures also formed migration pathways and reservoirs for aqueous and hydrocarbon fluids from the deep basin. Tsunami deposits have been described from a low-lying area near Santa Barbara, and numerical modeling of tsunamis generated by hypothetical landslides in Santa Barbara Channel indicates a moderate to severe threat [Borrero, J.C., Dolan, J.F. and Synolakis, C.E., 2001. Tsunamis within the eastern Santa Barbara Channel. Geophys. Res. Lett., 28(4): 643-646.], involving wave runups of 2-20 m, for a range of assumed landslide volumes. Inundation from these waves, however, is expected to be highly focused so that only narrow (???10-km) sections of the shoreline would be affected. Crown Copyright ?? 2005 Published by Elsevier B.V. All rights reserved.

  15. Morphological and genetic diversity of the wood-boring Xylophaga (Mollusca, Bivalvia): new species and records from deep-sea Iberian canyons.

    PubMed

    Romano, Chiara; Voight, Janet Ruth; Pérez-Portela, Rocío; Martin, Daniel

    2014-01-01

    Deep-sea bivalves of the Xylophagaidae, a poorly known group, are obligate wood-borers. Deployment of wood in three submarine canyons off the Iberian coast, the Blanes and La Fonera Canyons (Mediterranean Sea) and the Avilés Canyon (Cantabric Sea, Bay of Biscay), lead to the discovery of four xylophagaid species in our samples. Xylophaga dorsalis (the dominant species), X. atlantica, X. cf. anselli and the new species X. brava, were identified on the basis of morphological data, and supported by a phylogenetic reconstruction based on the nuclear genes 18S rDNA and 28S rDNA and including several genus of Xylophagaidae. Genetic divergence between species of Xylophaga varied between genes, ranging from 0.5 to 4.0% for the 18SrDNA and from 4.1 to 16.6% for the 28SrDNA. Xylophaga brava sp. nov. appeared to be restricted to the Mediterranean and morphologically resembled the closely related X. cf. anselli from the Cantabrian Sea. However, they clearly diverged in two well-supported clades. Low levels of intraspecific variability and higher interspecific divergence between species also supported the existence of these two different species. Morphologically they differ in the number of cirri at the siphon openings, in the shape of the posterior shell and in the size of prodissoconch II. The new species is characterized by having weak, poorly mineralized mesoplax and siphons united throughout, covered by a periostracal, non-calcified tube; distinct proximal and distal siphons, the former translucent and soft, the latter muscular, with concentric rings. Xylophaga atlantica, previously known only from the western Atlantic, is reported for the first time in the Mediterranean Sea. Whether its presence in the Mediterranean indicates its natural distribution or reflects its recent introduction is unknown. Although xylophagaids have been previously reported to recruit heavily to wood deposited on the seabed, these four species colonized wood suspended 30 m above the seafloor. PMID:25061913

  16. Evolution of depositional and slope instability processes on Bryant Canyon area, Northwest Gulf of Mexico 

    E-print Network

    Tripsanas, Efthymios

    2005-02-17

    . Right after their abandonment, at the beginning of Stage 5, salt diapirs encroached into the canyons, and resulted in their transformation into a network of intraslope basins. The transformation of the canyons resulted in the generation of massive...

  17. 75 FR 10308 - Fire Management Plan, Final Environmental Impact Statement, Record of Decision, Grand Canyon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ...DEPARTMENT OF THE INTERIOR National Park Service Fire Management Plan, Final Environmental Impact...Environmental Impact Statement for the Fire Management Plan, Grand Canyon National...availability of the Record of Decision for the Fire Management Plan, Grand Canyon...

  18. Sediment transport in the Mississippi Canyon: the role of currents and storm events on optical variability

    E-print Network

    Burden, Cheryl A

    1999-01-01

    Two modes of sediment transport were found to exist in the Mississippi Canyon: the offshelf transport of material in intermediate nepheloid layers originating at depths of 50-175 m and the resuspension and transport of material within the canyon...

  19. Software Configuration Management Plan for the B-Plant Canyon Ventilation Control System

    SciTech Connect

    MCDANIEL, K.S.

    1999-08-31

    Project W-059 installed a new B Plant Canyon Ventilation System. Monitoring and control of the system is implemented by the Canyon Ventilation Control System (CVCS). This Software Configuration Management Plan provides instructions for change control of the CVCS.

  20. 76 FR 42654 - Endangered and Threatened Wildlife and Plants; Petition To List Grand Canyon Cave Pseudoscorpion

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ...ceilings, and floors for animals and invertebrates. He identified 12 invertebrates from the 8 caves. The Grand Canyon cave...unpublished literature on cave-dwelling invertebrates within Grand Canyon National Park, as...