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Sample records for blanes submarine canyon

  1. Are deep-sea organisms dwelling within a submarine canyon more at risk from anthropogenic contamination than those from the adjacent open slope? A case study of Blanes canyon (NW Mediterranean)

    Science.gov (United States)

    Koenig, Samuel; Fernández, Pilar; Company, Joan B.; Huertas, David; Solé, Montserrat

    2013-11-01

    Due to their geomorphological structure and proximity to the coastline, submarine canyons may act as natural conduit routes for anthropogenic contaminants that are transported from surface waters to the deep-sea. Organisms dwelling in these canyon environments might thus be at risk of experiencing adverse health effects due to higher pollution exposure. To address this question, chemical and biochemical analyses were conducted on two of the most abundant deep-sea fish species in the study area, namely Alepocephalus rostratus and Lepidion lepidion, and the most abundant deep-sea commercial decapod crustacean Aristeus antennatus sampled inside Blanes canyon (BC) and on the adjacent open slope (OS). Persistent organic pollutants (POPs) levels, including polychlorinated biphenyl (PCB), dichlorodiphenyltrichloroethane (DDT) and derivatives, hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were determined in muscle tissue of selected samples from 900 m and 1500 m depth. Potential effects resulting from contaminant exposure were determined using hepatic biomarkers such as ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-O-deethylase (PROD), catalase (CAT), carboxylesterase (CbE), glutathione-S-transferase (GST), total glutathione peroxidase (GPX), glutathione reductase (GR) and superoxide-dismutase (SOD) enzyme activities and lipid peroxidation levels (LP). L. lepidion and A. antennatus tissues exhibited higher POP levels inside BC compared to the OS at 900 m depth. These findings were consistent with biomarker data (i.e. enzymatic response to presence of contaminant agents). Elevated xenobiotic-metabolizing (EROD and PROD) and antioxidant enzymes (CAT and GPX) indicated higher contaminant exposure in both species caught within BC. No difference in POP accumulation between sites was observed in L. lepidion at 1500 m depth, nor in biomarker data, suggesting that the pollution gradient was less pronounced at greater depths. This trend was further corroborated

  2. Flow dynamics around downwelling submarine canyons

    Directory of Open Access Journals (Sweden)

    J. M. Spurgin

    2014-05-01

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

  3. Flow dynamics around downwelling submarine canyons

    Directory of Open Access Journals (Sweden)

    J. M. Spurgin

    2014-10-01

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

  4. Flow dynamics around downwelling submarine canyons

    Science.gov (United States)

    Spurgin, J. M.; Allen, S. E.

    2014-10-01

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

  5. Bioavailability of sinking organic matter in the Blanes canyon and the adjacent open slope (NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    P. Lopez-Fernandez

    2013-05-01

    Full Text Available Submarine canyons are sites of intense energy and material exchange between the shelf and the deep adjacent basins. To test the hypothesis that active submarine canyons represent preferential conduits of available food for the deep-sea benthos, two mooring lines were deployed at 1200 m depth from November 2008 to November 2009 inside the Blanes canyon and on the adjacent open slope (Catalan Margin, NW Mediterranean Sea. We investigated the fluxes, biochemical composition and food quality of sinking organic carbon (OC. OC fluxes in the canyon and the open slope varied among sampling periods, though not consistently in the two sites. In particular, while in the open slope the highest OC fluxes were observed in August 2009, in the canyon the highest OC fluxes occurred in April–May 2009. For almost the entire study period, the OC fluxes in the canyon were significantly higher than those in the open slope, whereas OC contents of sinking particles collected in the open slope were consistently higher than those in the canyon. This result confirms that submarine canyons are effective conveyors of OC to the deep sea. Particles transferred to the deep sea floor through the canyons are predominantly of inorganic origin, significantly higher than that reaching the open slope at a similar water depth. Using multivariate statistical tests, two major clusters of sampling periods were identified: one in the canyon that grouped trap samples collected in December 2008, concurrently with the occurrence of a major storm at the sea surface, and associated with increased fluxes of nutritionally available particles from the upper shelf. Another cluster grouped samples from both the canyon and the open slope collected in March 2009, concurrently with the occurrence of the seasonal phytoplankton bloom at the sea surface, and associated with increased fluxes of total phytopigments. Our results confirm the key ecological role of submarine canyons for the functioning of

  6. Bioavailability of sinking organic matter in the Blanes canyon and the adjacent open slope (NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    P. Lopez-Fernandez

    2012-12-01

    Full Text Available Submarine canyons are sites of intense energy and material exchange between the shelf and the deep adjacent basins. To test the hypothesis that active submarine canyons represent preferential conduits of available food for the deep-sea benthos, two mooring lines were deployed at 1200 m depth from November 2008 to November 2009 inside the Blanes canyon and on the adjacent open slope (Catalan Margin, NW Mediterranean Sea. We investigated the fluxes, biochemical composition and food quality of sinking organic carbon (OC. OC fluxes in the canyon and the open slope varied among sampling periods, though not consistently in the two sites. In particular, while in the open slope the highest OC fluxes were observed in August 2009, in the canyon the highest OC fluxes occurred in April–May 2009. For almost the entire study period, the OC fluxes in the canyon were significantly higher than those in the open slope, whereas OC contents of sinking particles collected in the open slope were consistently higher than those in the canyon. This result confirms that submarine canyons are effective conveyors of OC to the deep sea, particles transferred are predominantly of inorganic origin, significantly higher than that reaching the open slope at a similar water depth. Using multivariate statistical tests, two major clusters of sampling periods were identified: one in the canyon that grouped trap samples collected in December 2008, concurrently with the occurrence of a major storm at the sea surface, and associated with increased fluxes of nutritionally available particles from the upper shelf. Another cluster grouped samples from both the canyon and the open slope collected in March 2009, concurrently with the occurrence of the seasonal phytoplankton bloom at the sea surface, and associated with increased fluxes of total phytopigments. Our results confirm the key ecological role of submarine canyons for the functioning of deep-sea ecosystems, and highlight the

  7. High spatiotemporal variability in meiofaunal assemblages in Blanes Canyon (NW Mediterranean) subject to anthropogenic and natural disturbances

    Science.gov (United States)

    Román, Sara; Vanreusel, Ann; Romano, Chiara; Ingels, Jeroen; Puig, Pere; Company, Joan B.; Martin, Daniel

    2016-11-01

    We investigated the natural and anthropogenic drivers controlling the spatiotemporal distribution of the meiofauna in the submarine Blanes Canyon, and its adjacent western slope (NW Mediterranean margin of the Iberian Peninsula). We analyzed the relationships between the main sedimentary environmental variables (i.e. grain size, Chl-a, Chl-a: phaeopigments, CPE, organic carbon and total nitrogen) and the density and structure of the meiofaunal assemblages along a bathymetric gradient (from 500 to 2000 m depth) in spring and autumn of 2012 and 2013. Twenty-one and 16 major taxa were identified for respectively the canyon and slope, where the assemblages were always dominated by nematodes. The gradual decreasing meiofaunal densities with increasing depth at the slope showed little variability among stations and corresponded with a uniform pattern of food availability. The canyon was environmentally much more variable and sediments contained greater amounts of food resources (Chl-a and CPE) throughout, leading not only to increased meiofaunal densities compared to the slope, but also different assemblages in terms of composition and structure. This variability in the canyon is only partly explained by seasonal food inputs. The high densities found at 900 m and 1200 m depth coincided with significant increases in food availability compared to shallower and deeper stations in the canyon. Our results suggest that the disruption in expected bathymetric decrease in densities at 900-1200 m water depth coincided with noticeable changes in the environmental variables typical for disturbance and deposition events (e.g., higher sand content and CPE), evoking the hypothesis of an anthropogenic effect at these depths in the canyon. The increased downward particle fluxes at 900-1200 m depth caused by bottom trawling along canyon flanks, as reported in previous studies, support our hypothesis and allude to a substantial anthropogenic factor influencing benthic assemblages at these

  8. Submarine canyons off Madras Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

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

  9. Primary Initiation of Submarine Canyons

    CERN Document Server

    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.

  10. Geomorphic process fingerprints in submarine canyons

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    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.

  11. Submarine canyons as the preferred habitat for wood-boring species of Xylophaga (Mollusca, Bivalvia)

    Science.gov (United States)

    Romano, C.; Voight, J. R.; Company, J. B.; Plyuscheva, M.; Martin, D.

    2013-11-01

    Submarine canyons are often viewed as natural “debris concentrators” on the seafloor. Organic substrates may be more abundant inside than outside canyon walls. To determine the effects of the presence these substrates in the Blanes submarine canyon (NW Mediterranean) and its adjacent western open slope, we deployed wood to study colonizing organisms. Three replicate pine and oak cubes (i.e. most common trees inland) were moored at 900, 1200, 1500 and 1800 m depth and collected after 3, 9 and 12 months. Wood from inside the canyon was significantly more heavily colonized by the five morphotypes of wood-boring bivalves than was wood on the adjacent open slope. Xylophaga sp. A dominated all wood types and locations, with peak abundance at 900 and 1200 m depth. Its growth rate was highest (0.070 mm d-1) during the first three months and was faster (or it recruits earlier) in pine than in oak. Size distribution showed that several recruitment events may have occurred from summer to winter. Xylophaga sp. B, appeared first after 9 months and clearly preferred pine over oak. As the immersion time was the same, this strongly supported a specific association between recruiters and type of substrate. Three morphotypes, pooled as Xylophaga spp. C, were rare and seemed to colonize preferentially oak inside the canyon and pine in the adjacent open slope. Individuals of Xylophaga were more abundant inside the canyon than in nearby off-canyon locations. Blanes Canyon may serve as a long-term concentrator of land-derived vegetal fragments and as a consequence sustain more animals. Are the species richness and abundance of wood-boring bivalves higher inside the canyon than on the adjacent open slope? Do the composition and density of the wood-boring bivalves change with deployment time and depth, as well as on the type of the sunken wood? What is the growth rate of the dominant wood-boring species?

  12. An experimental approach to submarine canyon evolution

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    Lai, Steven Y. J.; Gerber, Thomas P.; Amblas, David

    2016-03-01

    We present results from a sandbox experiment designed to investigate how sediment gravity flows form and shape submarine canyons. In the experiment, unconfined saline gravity flows were released onto an inclined sand bed bounded on the downstream end by a movable floor that was used to increase relief during the experiment. In areas unaffected by the flows, we observed featureless, angle-of-repose submarine slopes formed by retrogressive breaching processes. In contrast, areas influenced by gravity flows cascading across the shelf break were deeply incised by submarine canyons with well-developed channel networks. Normalized canyon long profiles extracted from successive high-resolution digital elevation models collapse to a single profile when referenced to the migrating shelf-slope break, indicating self-similar growth in the relief defined by the canyon and intercanyon profiles. Although our experimental approach is simple, the resulting canyon morphology and behavior appear similar in several important respects to that observed in the field.

  13. The Whittard Canyon - A case study of submarine canyon processes

    Science.gov (United States)

    Amaro, T.; Huvenne, V. A. I.; Allcock, A. L.; Aslam, T.; Davies, J. S.; Danovaro, R.; De Stigter, H. C.; Duineveld, G. C. A.; Gambi, C.; Gooday, A. J.; Gunton, L. M.; Hall, R.; Howell, K. L.; Ingels, J.; Kiriakoulakis, K.; Kershaw, C. E.; Lavaleye, M. S. S.; Robert, K.; Stewart, H.; Van Rooij, D.; White, M.; Wilson, A. M.

    2016-08-01

    Submarine canyons are large geomorphological features that incise continental shelves and slopes around the world. They are often suggested to be biodiversity and biomass hotspots, although there is no consensus about this in the literature. Nevertheless, many canyons do host diverse faunal communities but owing to our lack of understanding of the processes shaping and driving this diversity, appropriate management strategies have yet to be developed. Here, we integrate all the current knowledge of one single system, the Whittard Canyon (Celtic Margin, NE Atlantic), including the latest research on its geology, sedimentology, geomorphology, oceanography, ecology, and biodiversity in order to address this issue. The Whittard Canyon is an active system in terms of sediment transport. The net suspended sediment transport is mainly up-canyon causing sedimentary overflow in some upper canyon areas. Occasionally sediment gravity flow events do occur, some possibly the result of anthropogenic activity. However, the role of these intermittent gravity flows in transferring labile organic matter to the deeper regions of the canyon appears to be limited. More likely, any labile organic matter flushed downslope in this way becomes strongly diluted with bulk material and is therefore of little food value for benthic fauna. Instead, the fresh organic matter found in the Whittard Channel mainly arrives through vertical deposition and lateral transport of phytoplankton blooms that occur in the area during spring and summer. The response of the Whittard Canyon fauna to these processes is different in different groups. Foraminiferal abundances are higher in the upper parts of the canyon and on the slope than in the lower canyon. Meiofaunal abundances in the upper and middle part of the canyon are higher than on adjacent slopes, but lower in the deepest part. Mega- and macrofauna abundances are higher in the canyon compared with the adjacent slope and are higher in the eastern than

  14. Contemporary sediment-transport processes in submarine canyons.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. Lonely populations in the deep: genetic structure of red gorgonians at the heads of submarine canyons in the north-western Mediterranean Sea

    Science.gov (United States)

    Pérez-Portela, Rocío; Cerro-Gálvez, Elena; Taboada, Sergi; Tidu, Carlo; Campillo-Campbell, Carolina; Mora, Joan; Riesgo, Ana

    2016-09-01

    The red gorgonian Paramuricea clavata plays a central role in coralligenous ecosystems of the Mediterranean Sea, being relatively abundant in shallow habitats (5-35 m depth). Recently, deeper populations have been discovered at the heads of submarine canyons in the north-western Mediterranean Sea, between 50 and 70 m deep. Colonies from some of these deeper populations were exceptionally large (>1 m high), contrasting with the general prevalence of smaller size classes in shallower populations. Importantly, the high pressure of trawling activities on the nearby continental shelf could threaten these populations of large and old colonies. Although the genetic diversity and structure of populations in shallow habitats is relatively well known, very little is known about deeper populations. We aimed to assess the genetic structure, connectivity and potential demographic decline of six deep populations of P. clavata located at the heads of La Fonera, Blanes and Arenys de Mar submarine canyons, as well as potential gene flow between those and the two nearest shallow populations. A total of 188 individuals were genotyped using nine microsatellite loci. Results showed strong genetic differentiation among populations in different submarine canyons, among populations within one of the canyons and between shallow and deep populations. Gene flow among populations was very limited, estimates of effective population size in some populations were small, and evidence of recent population reductions (bottlenecks) was detected in several populations. The large genetic differentiation in populations of P. clavata among canyons is related to limited effective dispersal.

  17. The Whittard Canyon – a case study of submarine canyon processes

    NARCIS (Netherlands)

    Amaro, T.; Huvenne, V.A.I.; Allcock, A.L.; Aslam, T.; Davies, J.S.; Danovaro, R.; de Stigter, H.C.; Duineveld, G.C.A.; Gambi, C.; Gooday, A.J.; Gunton, L.M.; Hall, R.; Howell, K.L.; Ingels, J.; Kiriakoulakis, K.; Kershaw, C.E.; Lavaleye, M.; Robert, K.; Stewart, H.; Van Rooij, D.; White, M.; Wilson, A.M.

    2016-01-01

    Submarine canyons are large geomorphological features that incise continental shelves and slopes around the world. They are often suggested to be biodiversity and biomass hotspots, although there is no consensus about this in the literature. Nevertheless, many canyons do host diverse faunal communit

  18. Biodiversity of suprabenthic peracarid assemblages from the Blanes Canyon region (NW Mediterranean Sea) in relation to natural disturbance and trawling pressure

    Science.gov (United States)

    Almeida, Mariana; Frutos, Inmaculada; Company, Joan B.; Martin, Daniel; Romano, Chiara; Cunha, Marina R.

    2017-03-01

    Blanes Canyon and its adjacent margin are important fishery areas (mainly by bottom trawling) located in a highly energetic oceanographic setting in the NW Mediterranean Sea. Here we assess the spatial and temporal variability in abundance, diversity and community structure of the suprabenthic peracarid assemblages in this region and examine this variability in relation to the natural and anthropogenic (trawling fisheries) disturbance regimes. The sampling was conducted between March 2003 and May 2004 in three main fishing grounds, the canyon head (average depth: 490 m), the canyon wall (average depth: 550 m) and the eastern adjacent slope (average depth: 820 m), as well as in two non-exploited areas in the western (at 900 m depth) and eastern (at 1500 m depth) slope near the canyon mouth. A total of 138 species were identified, with amphipods being the most speciose and abundant group, followed by mysids in terms of abundance. Our results show high spatial and temporal variability in suprabenthic assemblages. Densities were higher in the canyon head and western slope, which appear to be the preferential routes for water masses and particle fluxes in months of flood events, and other energetic processes. In the canyon head, where periodic erosion processes are more active, low diversity, high dominance and higher turnover (β-diversity) were observed, apparently coupled with significant temporal fluctuations in the densities of the highly motile component of suprabenthos (mysids, predatory and scavenging amphipods). In the sedimentary more stable eastern slope, high diversity values were observed, accompanied by a higher relative contribution of the less motile groups (i.e. amphipods, most isopods, cumaceans). These groups have a closer interaction with the sediment where they exploit different food sources and are more susceptible to physical disturbance. Temporal variability in their diversity may be related to changes in food quality rather than quantity. In the

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

    Science.gov (United States)

    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.

  20. Bottom-trawling along submarine canyons impacts deep sedimentary regimes

    Science.gov (United States)

    Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

    2017-01-01

    Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities. PMID:28233856

  1. Tectonic activity and the evolution of submarine canyons: The Cook Strait Canyon system, New Zealand

    Science.gov (United States)

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

    2016-04-01

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

  2. Submarine canyons off the Coromandel coast

    Digital Repository Service at National Institute of Oceanography (India)

    Varadachari, V.V.R.; Nair, R.R.; Murty, P.S.N.

    During the 26th Cruise of I.N.S. `KISTNA', a bathymetric survey was carried out in some detail off the Pondicherry coast. This survey has revealed the existence of three sets of distinctly separate canyons between Cuddalore and Palar River...

  3. Measuring currents in submarine canyons: technological and scientific progress in the past 30 years

    Science.gov (United States)

    Xu, J. P.

    2011-01-01

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

  4. Submarine canyons as important habitat for cetaceans, with special reference to the Gully: A review

    Science.gov (United States)

    Moors-Murphy, Hilary B.

    2014-06-01

    There has been much research interest in the use of submarine canyons by cetaceans, particularly beaked whales (family Ziphiidae), which appear to be especially attracted to canyon habitats in some areas. However, not all submarine canyons are associated with large numbers of cetaceans and the mechanisms through which submarine canyons may attract cetaceans are not clearly understood. This paper reviews some of the cetacean associations with submarine canyons that have been anecdotally described or presented in scientific literature and discusses the physical, oceanographic and biological mechanisms that may lead to enhanced cetacean abundance around these canyons. Particular attention is paid to the Gully, a large submarine canyon and Marine Protected Area off eastern Canada for which there exists some of the strongest evidence available for submarine canyons as important cetacean habitat. Studies demonstrating increased cetacean abundance in the Gully and the processes that are likely to attract cetaceans to this relatively well-studied canyon are discussed. This review provides some limited evidence that cetaceans are more likely to associate with larger canyons; however, further studies are needed to fully understand the relationship between the physical characteristics of canyons and enhanced cetacean abundance. In general, toothed whales (especially beaked whales and sperm whales) appear to exhibit the strongest associations with submarine canyons, occurring in these features throughout the year and likely attracted by concentrating and aggregating processes. By contrast, baleen whales tend to occur in canyons seasonally and are most likely attracted to canyons by enrichment and concentrating processes. Existing evidence thus suggests that at least some submarine canyons are important foraging areas for cetaceans, and should be given special consideration for cetacean conservation and protection.

  5. Quantifying submarine landslide processes driven by active tectonic forcing: Cook Strait submarine canyon, New Zealand.

    Science.gov (United States)

    Mountjoy, J. J.; Barnes, P. M.; Pettinga, J. R.

    2006-12-01

    The Cook Strait submarine canyon system is a multi-branched, deeply incised and highly sinuous feature of New Zealand's active margin, covering some 1500km2 of sea floor between the North and South Islands and spanning water depths of between 50 and 2700m. The canyon occurs at the transition from the westward dipping oblique subduction zone adjacent to the SE North Island and the zone of continental transpression in NE South Island. The recent acquisition of high resolution (5-10m) SIMRAD EM300 bathymetric data allows active tectonic and geomorphic processes to be assessed and quantified at a level of detail previously not possible. While multiple active submarine fault traces have been identified in the Cook Strait by previous studies, quantitative information on their activity has been limited. Cook Strait is structurally characterized by westward dipping thrust faults and E-W trending dextral strike slip faults. The multiple large magnitude high frequency earthquake sources define zones of very high ground shaking expected to contribute to triggering of extensive submarine slope failures. Landslide activity within the canyon system is widespread and represents the dominant mass movement process affecting canyon heads and walls, redistributing material into valley fills. Complexes of large (km3) multi-stepped, deep-seated (100m) translational bedding plane failures represented by gently sloping (<3°) evacuated slide-scar areas with associated blocky valley fill deposits are numerous. Steep catchment heads, channel walls and the leading edges of asymmetric thrust-fault driven anticlines are dominated by gulley and rill systems with associated eroded and/or incipient slump features. Large (107m3+) slide blocks are recognized in discrete failures with quantifiable displacement vectors. Tsunamigenic landslides in this environment are inevitable. This study will provide quantification of landslide models including triggering mechanisms, discrete geometries and

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

    Science.gov (United States)

    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

  7. Geo-hazard by sediment mass movements in submarine canyons

    Science.gov (United States)

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

    2017-04-01

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

  8. Submarine canyons along the upper Sardinian slope (Central Western Mediterranean) as repositories for derelict fishing gears.

    Science.gov (United States)

    Cau, Alessandro; Alvito, Andrea; Moccia, Davide; Canese, Simonepietro; Pusceddu, Antonio; Rita, Cannas; Angiolillo, Michela; Follesa, Maria C

    2017-09-11

    By means of ROV surveys, we assessed the quantity, composition and bathymetric distribution of marine litter in 17 sites along the Sardinian continental margin (Central Western Mediterranean) at depths ranging from 100 to 480m. None of the investigated sites was litter free, but the mean density of litter (0.0175±0.0022itemsm(-2)) was lower than that reported from other Tyrrhenian regions. The difference in the total litter density among sites was negligible, but the density of derelict fishing gear (DFG) items (most of which ascribable to small scale fishery) in submarine canyons was higher in submarine canyons than in other habitats. Our result suggest that submarine canyons (known to be highly vulnerable ecosystems) act as major repositories of DFGs, and, therefore, we anticipate the need of specific measures aimed at minimizing the loss and abandonment of DFGs in submarine canyons. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Sand Wave Migrations Within Monterey Submarine Canyon, California

    Science.gov (United States)

    Xu, J.; Wong, F. L.

    2006-12-01

    Repeated high-resolution multi-beam surveys revealed the existence of a sand wave field along the axis of the Monterey submarine canyon between 20 and 300 m water depth. These sand waves range in wave length from 20 to 70 m and 2 to 5 m in height. Comparison of sequential multi-beam grid data (months apart) indicates that the sand waves apparently migrate upcanyon at some places while the same data clearly show that the sand waves migrate downcanyon at other locations. One hypothesis is that strong internal tidal flows, whose upcanyon component is intensified by the narrow canyon, are responsible for forming the sand wave field and for migrating the sand waves upcanyon. Another hypothesis is that the sand wave field is formed by creeping (analogous to the movement within glaciers), and in general they move in the downcanyon direction. A field experiment was conducted in 2005-06 to measure the driving forces (in hypothesis #1) that form and move the sand waves, and to collect the internal sedimentological structure within the sand waves that could reveal information on hypothesis #2. A mooring designed to measure near-floor velocity profiles, temperature, salinity, and sediment concentration in the water column was deployed for one year (June 2005 -July 2006) at 250 m water depth, slightly downcanyon of the sand wave field. In addition, a mapping survey was conducted in February, 2006 for collecting multi-beam and chirp profiles in the canyon head area of the sand wave field. Preliminary examination of the ADCP (downward looking) showed some very interesting features - the near- floor current dramatically changes with the spring-neap cycle of the surface tide. The time variation of the along-canyon current during neap tides - a sudden jump of upcanyon velocity before gradually tapering down, is typical of internal tides (internal bores). The time variation during spring tides when along canyon velocities reverse directions from upcanyon to downcanyon and gradually

  10. Marine litter on the floor of deep submarine canyons of the Northwestern Mediterranean Sea: The role of hydrodynamic processes

    Science.gov (United States)

    Tubau, Xavier; Canals, Miquel; Lastras, Galderic; Rayo, Xavier; Rivera, Jesus; Amblas, David

    2015-05-01

    Marine litter represents a widespread type of pollution in the World's Oceans. This study is based on direct observation of the seafloor by means of Remotely Operated Vehicle (ROV) dives and reports litter abundance, type and distribution in three large submarine canyons of the NW Mediterranean Sea, namely Cap de Creus, La Fonera and Blanes canyons. Our ultimate objective is establishing the links between active hydrodynamic processes and litter distribution, thus going beyond previous, essentially descriptive studies. Litter was monitored using the Liropus 2000 ROV. Litter items were identified in 24 of the 26 dives carried out in the study area, at depths ranging from 140 to 1731 m. Relative abundance of litter objects by type, size and apparent weight, and distribution of litter in relation to depth and canyon environments (i.e. floor and flanks) were analysed. Plastics are the dominant litter component (72%), followed by lost fishing gear, disregarding their composition (17%), and metal objects (8%). Most of the observed litter seems to be land-sourced. It reaches the ocean through wind transport, river discharge and after direct dumping along the coastline. While coastal towns and industrial areas represent a permanent source of litter, tourism and associated activities relevantly increase litter production during summer months ready to be transported to the deep sea by extreme events. After being lost, fishing gear such as nets and long-lines has the potential of being harmful for marine life (e.g. by ghost fishing), at least for some time, but also provides shelter and a substrate on which some species like cold-water corals are capable to settle and grow. La Fonera and Cap de Creus canyons show the highest mean concentrations of litter ever seen on the deep-sea floor, with 15,057 and 8090 items km-2, respectively, and for a single dive litter observed reached 167,540 items km-2. While most of the largest concentrations were found on the canyon floors at

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

    Science.gov (United States)

    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.

  12. Submarine canyons as coral and sponge habitat on the eastern Bering Sea slope

    Directory of Open Access Journals (Sweden)

    Robert J. Miller

    2015-07-01

    Full Text Available Submarine canyons have been shown to positively influence pelagic and benthic biodiversity and ecosystem function. In the eastern Bering Sea, several immense canyons lie under the highly productive “green belt” along the continental slope. Two of these, Pribilof and Zhemchug canyons, are the focus of current conservation interest. We used a maximum entropy modeling approach to evaluate the importance of these two canyons, as well as canyons in general, as habitat for gorgonian (alcyonacean corals, pennatulacean corals, and sponges, in an area comprising most of the eastern Bering Sea slope and outer shelf. These invertebrates create physical structure that is a preferred habitat for many mobile species, including commercially important fish and invertebrates. We show that Pribilof canyon is a hotspot of structure-forming invertebrate habitat, containing over 50% of estimated high-quality gorgonian habitat and 45% of sponge habitat, despite making up only 1.7% of the total study area. The amount of quality habitat for gorgonians and sponges varied in other canyons, but canyons overall contained more high-quality habitat for structure-forming invertebrates compared to other slope areas. Bottom trawling effort was not well correlated with habitat quality for structure-forming invertebrates, and bottom-contact fishing effort in general, including longlining and trawling, was not particularly concentrated in the canyons examined. These results suggest that if conserving gorgonian coral habitat is a management goal, canyons, particularly Pribilof Canyon, may be a prime location to do this without excessive impact on fisheries.

  13. Morphology, origin and evolution of Pleistocene submarine canyons, New Jersey continental slope

    Science.gov (United States)

    Bhatnagar, T.; Mountain, G. S.

    2015-12-01

    Submarine canyons serve as important conduits for transport of detrital sediments from nearshore and shelf environments to adjacent deep marine basins. However, the processes controlling the formation, maintenance, and fill of these sediment pathways are complex. This study presents an investigation of these systems at the New Jersey continental margin using a grid of high-resolution, 48-channel seismic reflection data collected in 1995 on the R/V Oceanus cruise Oc270 as a part of the STRATAFORM initiative. The aim is to shed new light on the origin and role of submarine canyons in Pleistocene sedimentation beneath the outer shelf and upper continental slope. Preliminary investigation of the Pleistocene interval reveals prominent unconformities tied to and dated with published studies at 7 sites drilled by ODP Legs 150 and 174A. The profiles of the continental slope unveil a series of abandoned and now buried submarine canyons that have influenced the development of modern canyons. Mapping these systems has revealed a range of canyon geometries, including U, V-shaped and flat-bottomed cross sections, each suggesting different histories. At least three types of seismic facies constitute the canyon fills: parallel onlap, interpreted as infilling by alternating coarser turbidites and finer hemipelagic sediments, chaotic infill, signifying structureless, massive debris flow deposition, and lateral accretion infill by both turbidity and bottom currents. Canyon formation and development appear to be strongly influenced by variations in sediment supply, grain size, and currents on the continental slope. One goal of our research is to establish if the canyons were initiated by failures at the base of the slope followed by upslope erosion, or by erosion at the shelf slope transition, and then downslope extension by erosive events. No single model accounts for all canyons. The history of these canyons may elucidate the extent to which the shelf was exposed during sea

  14. Partly standing internal tides in a dendritic submarine canyon observed by an ocean glider

    Science.gov (United States)

    Hall, Rob A.; Aslam, Tahmeena; Huvenne, Veerle A. I.

    2017-08-01

    An autonomous ocean glider is used to make the first direct measurements of internal tides within Whittard Canyon, a large, dendritic submarine canyon system that incises the Celtic Sea continental slope and a site of high benthic biodiversity. This is the first time a glider has been used for targeted observations of internal tides in a submarine canyon. Vertical isopycnal displacement observations at different stations fit a one-dimensional model of partly standing semidiurnal internal tides - comprised of a major, incident wave propagating up the canyon limbs and a minor wave reflected back down-canyon by steep, supercritical bathymetry near the canyon heads. The up-canyon internal tide energy flux in the primary study limb decreases from 9.2 to 2.0 kW m-1 over 28 km (a dissipation rate of 1 - 2.5 ×10-7 Wkg-1), comparable to elevated energy fluxes and internal tide driven mixing measured in other canyon systems. Within Whittard Canyon, enhanced mixing is inferred from collapsed temperature-salinity curves and weakened dissolved oxygen concentration gradients near the canyon heads. It has previously been hypothesised that internal tides impact benthic fauna through elevated near-bottom current velocities and particle resuspension. In support of this, we infer order 20 cm s-1 near-bottom current velocities in the canyon and observe high concentrations of suspended particulate matter. The glider observations are also used to estimate a 1 °C temperature range and 12 μmol kg-1 dissolved oxygen concentration range, experienced twice a day by organisms on the canyon walls, due to the presence of internal tides. This study highlights how a well-designed glider mission, incorporating a series of tide-resolving stations at key locations, can be used to understand internal tide dynamics in a region of complex topography, a sampling strategy that is applicable to continental shelves and slopes worldwide.

  15. Tidal motions and tidally induced fluxes through La Línea submarine canyon, western Alboran Sea

    Science.gov (United States)

    Lafuente, Jesús GarcíA.; Sarhan, Tarek; Vargas, Manuel; Vargas, Juan M.; Plaza, Francisco

    1999-02-01

    Detailed observations from two mooring lines deployed in La Línea submarine canyon, western Alboran Sea, are presented. This is a narrow canyon in the sense that its width is always less than the internal radius of deformation. Tidal currents within the canyon are polarized in the along-canyon direction according to its narrow nature. They have considerable amplitude (values of around 0.5 m/s are often observed) and are forced by the internal pressure gradients associated with the baroclinic tide that is generated in the surroundings. Subsequent amplification of onshore baroclinic currents within the canyon accounts for the large amplitude observed. Cross-shelf exchange through the canyon due to tidal motions is different from zero despite the close to zero mean of tidal currents. The explanation is based on the asymmetry of water properties flowing up-canyon and down-canyon (some sort of tidal rectification). Regarding the energy flux, the canyon seems to be an adequate conduit to carry energy to the shore. Estimations made from our observations indicate that energy input onto the shelf per unit length parallel to the shore at the canyon head is enough to maintain mixing on the shelf at intermediate depths.

  16. The World's Largest Submarine Canyon—Kroenke Canyon in the Western Equatorial Pacific

    Science.gov (United States)

    Coffin, M. F.; Adams, N.; Whittaker, J. M.; Lucieer, V.; Heckman, M.; Ketter, T.; Neale, J. F.; Reyes, A.; Travers, A.

    2015-12-01

    Kroenke Canyon lies on the Ontong Java Plateau (OJP) in the western Equatorial Pacific, between the Solomon Islands and the Federated States of Micronesia. In late 2014 aboard the Schmidt Ocean Institute's RV Falkor, we mapped, albeit incompletely, the Canyon for the first time, revealing that it is both the longest (>700 km) and the most voluminous (>6800 km3) submarine canyon yet discovered on Earth. Kroenke Canyon appears to originate in the vicinity of Ontong Java (Solomon Islands) and Nukumanu (Papua New Guinea) atolls, and presumably began to develop when the atolls were high-standing volcanic islands surmounting the ~120 Ma igneous basement of the OJP. The Canyon is characterised by numerous tributaries and significant mass wasting. Kroenke Canyon incises the layer-cake stratigraphy of OJP sediment and sedimentary rock, mostly carbonate with some interbedded chert, which has provided numerous slip surfaces for submarine landslides. The carbonate compensation depth (CCD) roughly coincides with the depth of the transition between the OJP and the neighbouring Nauru Basin. As a result, despite the large volume of sediment eroded and transported by canyon-forming processes, only a minor fan is evident in the Nauru Basin because most of the carbonate has dissolved.

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

    NARCIS (Netherlands)

    Cunha, M.R.; Paterson, G.L.J.; Amaro, T.; Blackbird, S.; de Stigter, H.C.; Ferreira, C.; Glover, A.; Hilário, A.; Kiriakoulakis, K.; Neal, L.; Ravara, A.; Rodrigues, C.F.; Tiago, A.; Billett, D.S.M.

    2011-01-01

    The macrofaunal assemblages from three Portuguese submarine canyons, Nazare, Cascais and Setubal were studied from samples collected at their upper (900-1000 m), middle (3200-3500 m) and lower sections (4200-4500 m) and at the adjacent open slopes (similar to 1000 m), during the HERMES cruises D297

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

    Science.gov (United States)

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

    2016-12-01

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

  19. Internal tide convergence and mixing in a submarine canyon

    Science.gov (United States)

    Waterhouse, Amy

    2016-11-01

    Observations from Eel Canyon, located on the north coast of California, show that elevated turbulence in the full water column arises from the convergence of remotely-generated internal wave energy. The incoming semidiurnal and bottom-trapped diurnal internal tides generate complex interference patterns. The semidiurnal internal tide sets up a partly standing wave within the canyon due to reflection at the canyon head, dissipating all of its energy within the canyon. Dissipation in the near-bottom is associated with the diurnal trapped tide, while midwater isopycnal shear and strain is associated with the semidiurnal tide. Dissipation is elevated up to 600 m off the bottom, in contrast to observations over flat continental shelf where dissipation occurs closer to the topography. Slope canyons are sinks for internal wave energy and may have important influences on the global distribution of tidally-driven mixing.

  20. Internal tides affect benthic community structure in an energetic submarine canyon off SW Taiwan

    Science.gov (United States)

    Liao, Jian-Xiang; Chen, Guan-Ming; Chiou, Ming-Da; Jan, Sen; Wei, Chih-Lin

    2017-07-01

    Submarine canyons are major conduits of terrestrial and shelf organic matter, potentially benefiting the seafloor communities in the food-deprived deep sea; however, strong bottom currents driven by internal tides and the potentially frequent turbidity currents triggered by storm surges, river flooding, and earthquakes may negatively impact the benthos. In this study, we investigated the upper Gaoping Submarine Canyon (GPSC), a high-sediment-yield canyon connected to a small mountain river (SMR) off southwest (SW) Taiwan. By contrasting the benthic meiofaunal and macrofaunal communities within and outside the GPSC, we examined how food supplies and disturbance influenced the benthic community assemblages. The benthic communities in the upper GPSC were mainly a nested subset of the adjacent slope assemblages. Several meiofaunal (e.g. ostracods) and macrofaunal taxa (e.g. peracarid crustaceans and mollusks) that typically occurred on the slope were lost from the canyon. The polychaete families switched from diverse feeding guilds on the slope to motile subsurface deposit feeders dominant in the canyon. The diminishing of epibenthic peracarids and proliferation of deep burrowing polychaetes in the GPSC resulted in macrofauna occurring largely within deeper sediment horizons in the canyon than on the slope. The densities and numbers of taxa were depressed with distinct and more variable composition in the canyon than on the adjacent slope. Both the densities and numbers of taxa were negatively influenced by internal tide flushing and positively influenced by food availability; however, the internal tides also negatively influenced the food supplies. While the meiofauna and macrofauna densities were both depressed by the extreme physical conditions in the GPSC, only the macrofaunal densities increased with depth in the canyon, presumably related to increased frequency and intensity of disturbance toward the canyon head. The population densities of meiofauna, on the

  1. Anthropogenic impacts on deep submarine canyons of the western Mediterranean Sea

    Science.gov (United States)

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

    2016-02-01

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

  2. Cold-Water Coral Habitats in Submarine Canyons of the Bay of Biscay

    Directory of Open Access Journals (Sweden)

    Inge M. J. van den Beld

    2017-05-01

    Full Text Available The topographical and hydrological complexity of submarine canyons, coupled with high substratum heterogeneity, make them ideal environments for cold-water coral (CWC habitats. These habitats, including reefs, are thought to provide important functions for many organisms. The canyons incising the continental slope of the Bay of Biscay have distinct morphological differences from the north to the south. CWCs have been reported from this basin in the late nineteenth century; however, little is known about their present-day distribution, diversity and environmental drivers in the canyons. In this study, the characteristics and distribution of CWC habitats in the submarine canyons of the Bay of Biscay are investigated. Twenty-four canyons and three locations between adjacent canyons were sampled using a Remotely Operated Vehicle (ROV or a towed camera system. Acquired images were annotated for habitat type (using the CoralFISH classification system, substrate cover and coral identification. Furthermore, the influence of hydrological factors and geomorphology on the CWC distribution was investigated. Eleven coral habitats, formed by 62 morphotypes of scleractinians, gorgonians, antipatharians and seapens, inhabiting hard and/or soft substrate, were observed. The distribution patterns were heterogenous at regional and local scales; the south Bay of Biscay and the southeastern flank favored soft substrate habitats. Biogenic and hard substrate habitats supported higher coral diversities than soft substrate habitats and had similar species compositions. A higher coral species turnover characterized soft substrate habitats. Substrate type was the most important driver of the patterns in both distribution and composition. Observations of coral reefs on steeper areas in the canyons and coral rubble on flatter areas on the interfluve/upper slope support the hypothesis that canyons serve as refuges, being less accessible to trawling, although natural causes

  3. From suspended particles to strata: The fate of terrestrial substances in the Gaoping (Kaoping) submarine canyon

    Science.gov (United States)

    Liu, James T.; Hung, Jia-Jang; Lin, Hui-Ling; Huh, Chih-An; Lee, Chon-Lin; Hsu, Ray T.; Huang, Ya-Wen; Chu, Joel C.

    2009-03-01

    The river-sea system consisting of the Gaoping (new spelling according to the latest government's directive, formerly spelled Kaoping) River (KPR), shelf, and Submarine Canyon (KPRSC) located off southern Taiwan is an ideal natural laboratory to study the source, pathway, transport, and fate of terrestrial substances. In 2004 during the flood season of the KPR, a system-wide comprehensive field experiment was conducted to investigate particle dynamics from a source-to-sink perspective in the KPRSC with the emphasis on the effect of particle size on the transport, settling, and sedimentation along the pathway. This paper reports the findings from (1) two sediment trap moorings each configured with a Technicap PPS 3/3 sediment trap, and an acoustic current meter (Aquadopp); (2) concurrent hydrographic profiling and water sampling was conducted over 8 h next to the sediment trap moorings; and (3) box-coring in the head region of the submarine canyon near the mooring sites. Particle samples from sediment traps were analyzed for mass fluxes, grain-size composition, total organic carbon (TOC) and nitrogen (TN), organic matter (OM), carbonate, biogenic opal, polycyclic aromatic hydrocarbon (PAH), lithogenic silica and aluminum, and foraminiferal abundance. Samples from box cores were analyzed for grain-size distribution, TOC, particulate organic matter (POM), carbonate, biogenic opal, water content, and 210Pb ex. Water samples were filtered through 500, 250, 63, 10 µm sieves and 0.4 µm filter for the suspended sediment concentration of different size-classes. Results show that the river and shelf do not supply all the suspended particles near the canyon floor. The estimated mass flux near the canyon floor exceeds 800 g/m 2/day, whose values are 2-7 times higher than those at the upper rim of the canyon. Most of the suspended particles in the canyon are fine-grained (finer than medium silt) lithogenic sediments whose percentages are 90.2% at the upper rim and 93.6% in

  4. The timing of sediment transport down Monterey Submarine Canyon, offshore California

    Science.gov (United States)

    Stevens, Thomas; Paull, Charles K.; Ussler, William III; McGann, Mary; Buylaert, Jan-Pieter; Lundsten, Eve M

    2013-01-01

    While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages measured on benthic foraminifera to examine the timing of sediment transport through the axial channel of Monterey Submarine Canyon and Fan, offshore California. The OSL ages date the timing of sediment entry into the canyon head while the 14C ages of benthic foraminifera record the deposition of hemipelagic sediments that bound the sand horizons. We use both single-grain and small (∼2 mm area) single-aliquot regeneration approaches on vibracore samples from fining-upward sequences at various water depths to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand (from 14C ages of benthic foraminifera in bracketing hemipelagic sediments) are interpreted as indicating that the sand does not pass through the entire canyon instantly in large individual events, but rather moves multiple times before emerging onto the fan. The increased spread in single-grain OSL dates with water depth provides evidence of mixing and temporary storage of sediment as it moves through the canyon system. The ages also indicate that the frequency of sediment transport events decreases with distance down the canyon channel system. The amalgamated sands near the canyon head yield OSL ages that are consistent with a sub-decadal recurrence frequency while the fining-upward sand sequences on the fan indicate that the channel is still experiencing events with a 150

  5. Mixing and phytoplankton dynamics in a submarine canyon in the West Antarctic Peninsula

    Science.gov (United States)

    Carvalho, Filipa; Kohut, Josh; Oliver, Matthew J.; Sherrell, Robert M.; Schofield, Oscar

    2016-07-01

    Bathymetric depressions (canyons) exist along the West Antarctic Peninsula shelf and have been linked with increased phytoplankton biomass and sustained penguin colonies. However, the physical mechanisms driving this enhanced biomass are not well understood. Using a Slocum glider data set with over 25,000 water column profiles, we evaluate the relationship between mixed layer depth (MLD, estimated using the depth of maximum buoyancy frequency) and phytoplankton vertical distribution. We use the glider deployments in the Palmer Deep region to examine seasonal and across canyon variability. Throughout the season, the ML becomes warmer and saltier, as a result of vertical mixing and advection. Shallow ML and increased stratification due to sea ice melt are linked to higher chlorophyll concentrations. Deeper mixed layers, resulting from increased wind forcing, show decreased chlorophyll, suggesting the importance of light in regulating phytoplankton productivity. Spatial variations were found in the canyon head region where local physical water column properties were associated with different biological responses, reinforcing the importance of local canyon circulation in regulating phytoplankton distribution in the region. While the mechanism initially hypothesized to produce the observed increases in phytoplankton over the canyons was the intrusion of warm, nutrient enriched modified Upper Circumpolar Deep Water (mUCDW), our analysis suggests that ML dynamics are key to increased primary production over submarine canyons in the WAP.

  6. Chemically traced blobs in the vicinity of a submarine canyon

    Science.gov (United States)

    Brogueira, M. J.; Cabeçadas, G.; Gonçalves, C.; Cabeçadas, P.

    2003-04-01

    A hydrographic cruise was carried out in May 2001 off southern Portugal, in the vicinity of Portimão canyon. This major topographic irregularity across the path of the Mediterranean undercurrent is known to induce water masses instability and to be a site of dipole formation. Two blobs of distinct water masses were revealed mainly through chemical tracers, namely dissolved oxygen and nutrients. One low-salinity blob, centred at ˜800 m depth, displayed high values of AOU (above 100 μmol/kg) and nutrients (NO_3 up to 14 μmol/kg, PO_4 up to 0.9 and Si(OH)_4 up to 11 μmol/kg), which are features of the Antarctic Intermediate Water (AAIW) present in the area. The deeper salty warm blob, extending from the MW outflow, corresponded to the relatively more oxygenated (AOU 77 μmol/kg) and nutrient-impoverished (NO_3 9 μmol/kg, PO_4 0.6 μmol/kg and Si(OH)_4 6 μmol/kg) saline Mediterranean Water. Further, the influence of this deeper blob expanding down (till 1800--2000 m) into the well-ventilated and nutrient-enriched North Atlantic Deep Water (NADW) was visible through nutrient patterns. The chemical data enabled the identification of the described blobs structure associated with this particular canyon located on the westward flow of MW into the North Atlantic.

  7. Submarine canyons on the north of Chiwei Island:influenced by recent extension of the southern Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yuexia; LIU Baohua; LI Xishuang; LIU Chenguang; WU Jinlong; WANG Kuiyang

    2008-01-01

    Based on new multibeam bathymetric data and about 300 km long single seismic profiles,three topographic units were identified:the canyons,fractural valley and submarine terrace on the north of Chiwei Island where is a structural transition zone between the southern trough and the middle trough.The Chiwei Canyon and the North Chiwei Canyon are two of the largest canyons in the East China Sea (ECS) slope.Topographic features and architectures of them are described.The study shows that both of them are originated along faults.The evolution and spatial distribution of topographic units in the study area are controlled mainly by three groups of faults which were formed and reactive in the recent extensional phase of Okinawa Trough.The Chiwei Canyon was initia-ted during the middle Pleistocene and guided by F4 that is a N-S trending fault on the slope and F1,a large NW-SE trending fault on the trough.The pathway migration from the remnant channel to the present one of Chiwei Canyon is the result of uplift of tilted fault block that is coupled to the recent extension movements of the southern trough.The submarine terrace is detached from the ECS slope by the NEE-trending fault.The North Chiwei Canyon,developing during the late Pleistocene,is guided by F5,a N-S trending fault,diverted and blocked by the submarine terrace.

  8. Downward and suspended sediment fluxes in the Palamós submarine canyon (North-Western Mediterranean)

    Science.gov (United States)

    Palanques, A.; Martín, J.; Puig, P.; Guillén, J.

    2003-04-01

    The Palamós canyon is deeply incised in the Northern Catatonia continental shelf (North-western Mediterranean) which favour an active shelf-slope sediment transfer. To study particle dynamics in this canyon, seven moorings arrays equipped with current meters, turbidimeters and sediment traps were deployed near the bottom along the main canyon axis (400, 1200 and 1700 m depth), on both canyon walls (1200 m depth) and on the adjacent slope (1200 m depth). One set of these instruments was also deployed at intermediate waters (400 m water depth) in the canyon axis. At surface and mid-depths, suspended sediment fluxes were oriented along the mean flow direction (NE-SW), whereas near-bottom sediment fluxes were more constrained by the local bathymetry. The higher near-bottom downward and suspended particle fluxes were not recorded in the canyon head but in the mid-canyon axis, suggesting additional sediment supplies through or over the canyon walls and/or sediment resuspension in the mid canyon region. Several events of sharp sediment flux increases took place in the mid-canyon axis site during the water stratification season. These events could be related to the action of internal waves and even to fishing activities. In the canyon walls, downward and suspended particle fluxes were higher in the southern wall, where currents were lower than in the northern wall, evidencing an asymmetrical pattern. In the adjacent slope sediment fluxes were significantly lower than in the canyon. An important increase of downward particle fluxes in the canyon axis and both walls occurred by mid-November when a severe storm took place. The pattern of the sediment fluxes in the Palamós Canyon has some differences in relation to those observed in other Mediterranean submarine canyons and has downward particle fluxes from 2 to10 times higher than other studied canyons of this region.

  9. Seasonal pathways of organic matter within the Avilés submarine canyon: Food web implications

    Science.gov (United States)

    Romero-Romero, Sonia; Molina-Ramírez, Axayacatl; Höfer, Juan; Duineveld, Gerard; Rumín-Caparrós, Aitor; Sanchez-Vidal, Anna; Canals, Miquel; Acuña, José Luis

    2016-11-01

    The transport and fate of organic matter (OM) sources within the Avilés submarine canyon (Cantabrian Sea, Southern Bay of Biscay) were studied using carbon and nitrogen stable isotope ratios. The isotopic composition of settling particles and deep bottom sediments closely resembled that of surface particulate OM, and there were no marked differences in the isotopic composition of settling particles inside and outside of the AC. This indicates that the Avilés Canyon (AC) receives inputs of sinking OM mostly from the upper water column and less through advective near-bottom down-canyon transport. Sinking OM fluxes are of marine and terrestrial origin in proportions which vary seasonally. Analysis of δ13C in the canyon fauna indicates a dependence on OM mainly produced by marine phytoplankton. A tight coupling of isotopic signatures between pelagic organisms and benthic suspension feeders reflects an active biological vertical transport of OM from the surface to the deep-sea. The food web presented seasonal variations in the trophic niche width and the amplitude of the primary carbon sources, reflecting seasonality in the availability of fresh particulate OM. Those seasonal changes are larger for benthic organisms of lower trophic levels.

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

    Science.gov (United States)

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

    2011-12-01

    The macrofaunal assemblages from three Portuguese submarine canyons, Nazaré, Cascais and Setúbal were studied from samples collected at their upper (900-1000 m), middle (3200-3500 m) and lower sections (4200-4500 m) and at the adjacent open slopes (˜1000 m), 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 and community structure of the benthic macrofauna were described. Annelida (42.1% of total abundance; 137 species) and Arthropoda (20.6%; 162 species) were, respectively, the most abundant and the most species-rich Phyla among the 342 taxa identified during this study. Multivariate analyses showed significant differences between and within canyons and between canyons and open slope assemblages. At their upper section, canyons supported higher macrofauna abundance but slightly lower biodiversity than the adjacent slopes at similar depth. In all canyons abundance reached the highest value in the middle section and the lowest in the upper section, with marked fluctuations in Nazaré (474-4599 ind. m -2) and lower variability in Cascais (583-1125 ind. m -2). The high abundance and dominance of the assemblages in the middle section of Nazaré and Setúbal was accompanied by depressed biodiversity, while in Cascais, Hurlbert's expected species richness showed increasing values from the upper to the middle canyon, and maintained the high values at the lower section. Overall, the Nazaré Canyon showed the lowest expected species richness (ES (100): 16-39) and the Cascais Canyon the highest (39-54). There was a significant negative Kendall's correlation between total organic carbon concentrations in the superficial sediments and ES (100) and a significant positive correlation between total nitrogen and macrofauna density. The influences of organic enrichment, sediment heterogeneity and hydrodynamic regime on the abundance

  11. A new model for turbidity current behavior based on integration of flow monitoring and precision coring in a submarine canyon

    Science.gov (United States)

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

    2017-01-01

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

  12. Deep macrobenthic communities from Nazaré Submarine Canyon (NW Portugal

    Directory of Open Access Journals (Sweden)

    J. Cúrdia

    2004-04-01

    Full Text Available Macrofauna community structure within Nazaré Submarine Canyon is analysed and used to assess the potential effects of natural enrichment in this area subjected to accumulation of coastal sediments. A transect including three stations (2894, 3514 and 4141 m was carried out in the Nazaré Submarine Canyon (NW Portugal during a cruise of OMEX II programme (Ocean Margin Exchange, in the winter season of 1999. Although data was not collected in order to calculate sedimentation rates, sampling station at 2894 m is located in an area characterised by high levels of sedimentation, thus a high amount of organic matter is expected to be available for the local communities. Faunistic data are discussed in the context of the different features of the stations sampled. Multivariate analysis clearly separates the shallowest station from the other ones, which otherwise appear to be very similar. It also revealed a perceptible gradient along sediment depth at all stations, from shallow to deeper layers. Exceptionally depressed species richness and low evenness values were observed at the 2894 m station. The high number of individuals of a single species, Cossura sp. A, and the atypical diversity, dominance and evenness values obtained for this station support the hypothesis of community disturbance due to organic enrichment.

  13. Influence of San Gabriel submarine canyon on narrow-shelf sediment dynamics, southern California

    Science.gov (United States)

    Karl, Herman A.

    1980-01-01

    Variations in the concentration of total suspended particulate matter (TSM) collected 1 m above bottom, changes in vertical profiles of light transmission, and substrate textural patterns reveal a corridor for preferential sediment transport on San Pedro continental shelf, California. During the winter, this corridor, designated the preferential transport corridor (PTC), is defined by higher concentrations of TSM relative to the rest of the shelf and extends for 10-15 km from the inner shelf to the head of San Gabriel Submarine Canyon. Vertical profiles of light transmission within the PTC suggest density stratification throughout the water column and apparent mixing in the upper 15-20 m of water column on either side of the PTC. The PTC is not as fully developed during the summer. Excursions in isopleths of substrate textural variables perpendicular to isobaths in the PTC suggest that although the PTC is seasonally episodic, it recurs regularly over a longer period.

  14. Large wave-shaped bedforms in the axial channel of Monterey Submarine Canyon: Monterey Bay, California

    Science.gov (United States)

    Paull, C. K.; Normark, W. R.; Ussler, W.; Caress, D. W.; Keaten, R.; Barry, J.; Xu, J.; Smith, D.; Covault, J. A.; Maier, K. L.

    2007-12-01

    Multibeam bathymetric data show that large wave-shaped bedforms exist on the seafloor within the axial channel of Monterey Submarine Canyon offshore northern California (Smith et al., 2006). These features have wavelengths up to 70 m, amplitudes up to 2 m, and distinct asymmetrical crests that are roughly perpendicular to the channel. Comparisons of repetitive multibeam surveys since 2004 shows that the bedforms are active features because their positions change between surveys. Three complementary studies are underway to understand the origin of these features: (1) Vibracoring - In June 2007, the ROV Ventana collected 18 vibracores up to 2 m in length along a 130-m transect in ~285 m water depth that spanned the crests of two and the flanks of three waves. Sediment in these cores is composed of one or more sequences of coarse gravel or multicolored clay-clasts that fine upward into sand. Sometimes individual gravel-clasts or clay-chips occur within sand. The internal stratigraphy of these waves shows they resemble classic gravity-flow deposits. (2) Sediment Movement - A pilot study was conducted to assess whether sediment within the canyon floor moves by traction from currents or mass transport. On February 8, 2007, three acoustic beacons were deployed in ~290 m water depth within the canyon axis using Ventana. The beacons were placed within recesses in 50-cm-high ~45 kg poured-concrete monuments. These boulder-sized monuments were buried leaving only the top of the beacon standing ~6 cm above the sediment surface. Thus, the monuments were largely entombed within the seafloor. We also placed 3 acoustic beacons mounted on trapezoidal frames at the edge of a terrace on the canyon's lower flank. On February 12th, we returned to the area and determined that all three monuments had moved ~150 m down canyon. Two trapezoidal frames were found on their sides entwined with each other 50 and 75 m down canyon from their deployment site. The third frame was never located. A

  15. Submarine canyon development in the Izu-Bonin forearc: A SeaMARC II and seismic survey of Aoga Shima Canyon

    Science.gov (United States)

    Klaus, Adam; Taylor, Brian

    1991-05-01

    SeaMARC II sidescan (imagery and bathymetry) and seismic data reveal the morphology, sedimentary processes, and structural controls on submarine canyon development in the central Izu-Bonin forearc, south of Japan. Canyons extend up to 150 km across the forearc from the trench-slope break to the active volcanic arc. The canyons are most deeply incised (1200 1700 m) into the gentle gradients (1 2°) upslope on the outer arc high (OAH) and lose bathymetric expression on the steep (6 18°) inner trench-slope. The drainage patterns indicate that canyons are formed by both headward erosion and downcutting. Headward erosion proceeds on two scales. Initially, pervasive small-scale mass wasting creates curvilinear channels and pinnate drainage patterns. Large-scale slumping, evidenced by abundant crescent-shaped scarps along the walls and tributaries of Aoga Shima Canyon, occurs only after a channel is present, and provides a mechanism for canyon branching. The largest slump has removed >16 km3 of sediment from an ˜85 km2 area of seafloor bounded by scarps more than 200 m high and may be in the initial stages of forming a new canyon branch. The northern branch of Aoga Shima Canyon has eroded upslope to the flanks of the arc volcanoes allowing direct tapping of this volcaniclastic sediment source. Headward erosion of the southern branch is not as advanced but the canyon may capture sediments supplied by unconfined (non-channelized) mass flows. Oligocene forearc sedimentary processes were dominated by unconfined mass flows that created sub-parallel and continuous sedimentary sequences. Pervasive channel cut-and-fill is limited to the Neogene forearc sedimentary sequences which are characterized by migrating and unconformable seismic sequences. Extensive canyon formation permitting sediment bypassing of the forearc by canyon-confined mass flows began in the early Miocene after the basin was filled to the spill points of the OAH. Structural lows in the OAH determined the

  16. Morphology of submarine canyon system and geotechnical properties of surficial sediments across the Peru-Chile forearc

    Energy Technology Data Exchange (ETDEWEB)

    Bergersen, D.D.; Coulbourn, W.T.; Moberly, R.

    1989-03-01

    During August 1987, a SeaMARC II side-scan and sampling survey was conducted across the Peru-Chile forearc from 17/degrees/30'S to 19/degrees/30'S. Side-scan images reveal a complex submarine canyon system. Incised canyons meander across the Arequipa basin; their sinuosity results from erosion and cutbank slumping of the basin sediments. Lenticular packets of strata visible in reprocessed digital single-channel seismic profiles are interpreted to be buried channels. Tributary canyons coalesce into a single canyon at the structural high that deviates from its north-south course to a northeast-southwest course as a result of stream piracy. A dendritic drainage basin forming on the midslope may be the rejuvenation of an abandoned channel. Sediment properties were measured on 42 free-fall cores and 7 piston cores recovered both in and around the submarine canyon. Olive-gray (5Y 3/2) hemipelagic mud is the predominant sediment across the forearc. Most cores exhibit a small degree of bioturbation and thin laminae of sand; the number of sand laminae increases as the distance away from the canyon decreases. Shear strengths, averaged over a 1-m core length, decrease slightly with water depth. Carbonate content in all samples from this area is negligible with the exception of one piston core recovered from the upper reaches of the canyon, the bottom of which is composed of gravel- and sand-size shell fragments. Bulk mineralogy, determined from semiquantitative analysis of x-ray diffraction patterns, shows a decrease in relative feldspar percent and an increase in total clay content with increasing water depth. Preliminary analysis of core tops shows a mean grain size in the medium to very fine silt class, with increasing grain size toward the canyon. Smear slide counts generally show a surprisingly low abundance of volcanic glass and biogenic material, particularly diatoms.

  17. Macro- and megafauna recorded in the submarine Bari Canyon (southern Adriatic, Mediterranean Sea using different tools

    Directory of Open Access Journals (Sweden)

    G. D'ONGHIA

    2015-01-01

    Full Text Available Macro- and megafauna were recorded in the submarine Bari Canyon (southern Adriatic Sea, Mediterranean Sea during an oceanographic cruise carried out in May-June 2012 and an experimental fishing survey conducted in November 2013. During the former, a total of 20 benthic samples were taken using a Van Veen grab at depths between 268 and 770 m and 4 deployments of a baited lander, for about 43 hours of video records, were carried out at depths between 443 and 788 m. During the latter, 8 longline fishing operations were conducted from 338 down to 612 m. Eighty-five living benthic and benthopelagic species were recorded: 29 Porifera, 1 Cnidaria, 2 Mollusca, 11 Annelida, 1 Arthropoda, 19 Bryozoa, 3 Echinodermata and 19 Chordata. A total of 51 species are new records for the Bari Canyon, 29 new records for the Adriatic Sea. Among the Porifera Cerbaris curvispiculifer is a new addition for the Italian Sponge Fauna. The first certain record of living specimens for the bryozoan Crisia tenella longinodata is reported. A total of 6 Mediterranean endemic species have been identified: 4 Porifera and 2 Annelida. The bathymetric range of some species has been extended. New information acquired for deep sea species confirms their importance in the structure of cold-water coral communities. This study has updated the knowledge on the biodiversity of the Adriatic Sea, as well as of the Bari Canyon in particular, one of the sites designated as “jewels of the Mediterranean” for which urgent conservation measures are needed.

  18. Macro- and megafauna recorded in the submarine Bari Canyon (southern Adriatic, Mediterranean Sea using different tools

    Directory of Open Access Journals (Sweden)

    G. D'ONGHIA

    2015-01-01

    Full Text Available Macro- and megafauna were recorded in the submarine Bari Canyon (southern Adriatic Sea, Mediterranean Sea during an oceanographic cruise carried out in May-June 2012 and an experimental fishing survey conducted in November 2013. During the former, a total of 20 benthic samples were taken using a Van Veen grab at depths between 268 and 770 m and 4 deployments of a baited lander, for about 43 hours of video records, were carried out at depths between 443 and 788 m. During the latter, 8 longline fishing operations were conducted from 338 down to 612 m. Eighty-five living benthic and benthopelagic species were recorded: 29 Porifera, 1 Cnidaria, 2 Mollusca, 11 Annelida, 1 Arthropoda, 19 Bryozoa, 3 Echinodermata and 19 Chordata. A total of 51 species are new records for the Bari Canyon, 29 new records for the Adriatic Sea. Among the Porifera Cerbaris curvispiculifer is a new addition for the Italian Sponge Fauna. The first certain record of living specimens for the bryozoan Crisia tenella longinodata is reported. A total of 6 Mediterranean endemic species have been identified: 4 Porifera and 2 Annelida. The bathymetric range of some species has been extended. New information acquired for deep sea species confirms their importance in the structure of cold-water coral communities. This study has updated the knowledge on the biodiversity of the Adriatic Sea, as well as of the Bari Canyon in particular, one of the sites designated as “jewels of the Mediterranean” for which urgent conservation measures are needed.

  19. AUV Mapping and ROV Exploration of Los Frailes Submarine Canyon, Cabo Pulmo National Marine Park, Baja California Sur, Mexico

    Science.gov (United States)

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

    2015-12-01

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

  20. Tidal Signatures of the Benthic Nepheloid Layer (BNL) in the Gaoping/Kaoping Submarine Canyon off Southwestern Taiwan

    Science.gov (United States)

    Liu, J. T.; Lee, I.; Wang, Y.

    2008-12-01

    Temporal and spatial variations of benthic nepheloid layer (BNL) have been observed in the head region of the Gaoping/Kaoping Submarine Canyon (KPSC) along the canyon thalweg in different seasons between 1999 and 2000. The top of the BNL could be as high as 100 m above the canyon floor whose suspended sediment concentration (SSC) could be as high as 30 mg/l. In the BNL, silt comprises the largest size-class in the suspended sediment population. In 2000, 2002, and 2004 three taut-line moorings were deployed at different locations in the head region of the KPSC for one month. Time series measurements of along- canyon flow velocity, water temperature, and the volume concentration (VC) of clay, very-fine-to-medium silt, coarse silt and sand size-classes were obtained near the canyon floor from each mooring. Results show that the BNL is strongly modulated by the tides in the descending order at semidiurnal, diurnal, and spring-neap frequencies. In the course of a semidiurnal tidal cycle, the flood (up-canyon) current brings colder water from seaward part of the canyon and the SSC and thickness of the BNL increases. The SSC near the canyon floor also increases in response to the peaks of flood and ebb currents of the semidiurnal tide. The tidal-to-total energy ratio (ER) for the along-canon flow is between 70-80%, and between 50-80% among the suspended sediment of clay, very-fine-to-medium silt, coarse silt and sand size-classes. M2 is the most important constituent in the along-canyon flow, water temperature, and the VC of the four size-classes. The local phase difference between the forcing (velocity), and the responses (temperature and VC) at the M2 frequency suggest the a mixture of progressive and standing waves and that topographic effect caused the phase varied along the canyon. The VC tidal amplitude ratio between M4 and M2 constituents of the four size-classes indicates that the temporal fluctuations of the suspended sediment concentration in the BNL are highly

  1. Composition and provenance of terrigenous organic matter transported along submarine canyons in the Gulf of Lion (NW Mediterranean Sea)

    Science.gov (United States)

    Pasqual, Catalina; Goñi, Miguel A.; Tesi, Tommaso; Sanchez-Vidal, Anna; Calafat, Antoni; Canals, Miquel

    2013-11-01

    Previous projects in the Gulf of Lion have investigated the path of terrigenous material in the Rhone deltaic system, the continental shelf and the nearby canyon heads. This study focuses on the slope region of the Gulf of Lion to further describe particulate exchanges with ocean’s interior through submarine canyons and atmospheric inputs. Nine sediment traps were deployed from the heads to the mouths of Lacaze-Duthiers and Cap de Creus submarine canyons and on the southern open slope from October 2005 to October 2006. Sediment trap samples were analyzed by CuO oxidation to investigate spatial and temporal variability in the yields and compositional characteristics of terrigenous biomarkers such as lignin-derived phenols and cutin acids. Sediment trap data show that the Dense Shelf Water Cascading event that took place in the months of winter 2006 (January, February and March) had a profound impact on particle fluxes in both canyons. This event was responsible for the majority of lignin phenol (55.4%) and cutin acid (42.8%) inputs to submarine canyons, with lignin compositions similar to those measured along the mid- and outer-continental shelf, which is consistent with the resuspension and lateral transfer of unconsolidated shelf sediment to the canyons. The highest lithogenic-normalized lignin derived phenols contents in sediment trap samples were found during late spring and summer at all stations (i.e., 193.46 μg VP g-1 lithogenic at deep slope station), when river flow, wave energy and total particle fluxes were relatively low. During this period, lignin compositions were characterized by elevated cinnamyl to vanillyl phenol ratios (>3) at almost all stations, high p-coumaric to ferulic acid ratios (>3) and high yields of cutin acids relative to vanillyl phenols (>1), all trends that are consistent with high pollen inputs. Our results suggest marked differences in the sources and transport processes responsible for terrigenous material export along

  2. Export of terrigenous organic carbon along submarine canyons driven by dense shelf water cascading

    Science.gov (United States)

    Tesi, T.; Puig, P.; Goni, M.; Canals, M.; Langone, L.; Palanques, A.; Miserocchi, S.; Heussner, S.; Trincardi, F.; Calafat, A.; Turchetto, M.; Fabres, J.; Durrieu de Madron, X.; Boldrin, A.

    2008-12-01

    At current highstand in sea level, shelves are considered major sites of terrigenous organic carbon (OCterr) accumulation with relatively little connectivity to the ocean interior. In recent years, the process of dense water cascading from the continental shelf, which occurs in numerous places around the world, has been suggested as carrier for OCterr to the deep ocean. The land-locked Mediterranean Sea is characterized by intense and recurrent cascades of dense shelf water. In winter, cold and dry winds cause the formation of dense water over the shelf that may overflow it and travel down to the outer margin and basin. Moored instruments were deployed in the canyons of the Gulf of Lion (France-Spain) and the Adriatic Sea (Italy) to intercept particulate material escaping the shelf and to investigate hydrodynamic and physical properties of the water column. Surface sediments along the shelves were also sampled to evaluate their contribution to the particle fluxes. The relative fractions of autochthonous and advected OC in sediment trap samples were investigated using biogeochemical proxies including alkaline CuO oxidation products (lignin phenols, dicarboxylic acids, and fatty acids), radiocarbon measurements (Ä14C), and elemental and carbon stable isotope (ä13C) compositions. Lignin-derived CuO products were a powerful biogeochemical tool that allowed us to identify the provenance of the material from the continental margin and to assess the amount of OCterr transferred across the slope in both Mediterranean regions. The results indicate that the composition of OC escaping the shelf through submarine canyons depends on the geomorphological setting. At the present sea level stage, cascading on a broad shelf limits the transport of OCterr, promoting instead the down-slope export of material accumulated in the mid- and outer-shelf. In contrast, cascade events on narrow shelves lead to the efficient export of OCterr from shallower regions of the margin along with

  3. Linking Planktonic Larval Abundance to Internal Bores at the Head of the Monterey Submarine Canyon.

    Science.gov (United States)

    Phelan, J.; Walter, R. K.; Steinbeck, J. R.

    2015-12-01

    Variability in the physical coastal environment can play an important role in determining the spatio-temporal variation in abundance of planktonic organisms. Combining planktonic larval abundance estimates over the course of a year with concurrent temperature and current data, this study provides empirical data linking a locally predominant internal tidal feature to patterns of biological abundance in the very nearshore environment at the head of Monterey Submarine Canyon. The physical observations indicate the presence of seasonally-variable semidiurnal internal bores that result in the pumping of cold (subthermocline) waters onto the adjacent shelf. Analysis of the larval abundance data indicates an assemblage shift from a relatively abundant shelf assemblage of larval fishes to a reduced abundance assemblage that is concurrent with the semidiurnal cold water intrusions driven by the tidal pumping. Results suggest that the tidal period pumping of subthermocline waters by internal bores dilutes or displaces shelf waters and their associated planktonic larval community. This could have important ecological implications at these scales and may also be of interest when siting industrial facilities that require seawater for cooling or desalination, as it would potentially reduce their impact on regional planktonic communities by diluting their rates of entrainment.

  4. Epibiotic relationships on Zygochlamys patagonica (Mollusca, Bivalvia, Pectinidae) increase biodiversity in a submarine canyon in Argentina

    Science.gov (United States)

    Schejter, Laura; López Gappa, Juan; Bremec, Claudia Silvia

    2014-06-01

    The continental slope of the southern SW Atlantic Ocean has many distinguishable deep submarine canyons, varying in depth and extension. The benthic fauna within one of them, detected in April 2005 by means of a multibeam SIMRAD EM1002 sonar, and located at 43°35‧S to 59°33‧W, 325 m depth, was studied to discuss faunal affinities with the neighbouring Patagonian scallop fishing grounds located at upper slope depths. In order to add faunal information to the previous general study, we studied the epibiotic species settled on Patagonian scallops (the dominant species in the area) collected in the reference sampling site using a 2.5-m mouth-opening dredge, 10 mm mesh size. We sampled 103 scallops with shell heights between 22 and 69 mm; epibionts were recorded on both valves. We found 53 epibiotic taxa, which were most conspicuous on the upper valve. Bryozoa was the most diverse group (34 species) while Polychaeta was the most abundant group, recorded on 94% of the scallops. Stylasteridae (2 species) and Clavulariidae (Cnidaria) conform newly recorded epibionts on Z. patagonica and the sponge Tedania (Tedaniopsis) infundibuliformis also represents a new record for the SW Atlantic Ocean.

  5. Food-web dynamics and isotopic niches in deep-sea communities residing in a submarine canyon and on the adjacent open slopes

    Science.gov (United States)

    Demopoulos, Amanda; McClain-Counts, Jennifer; Ross, Steve W.; Brooke, Sandra; Mienis, Furu

    2017-01-01

    Examination of food webs and trophic niches provide insights into organisms' functional ecology, yet few studies have examined trophodynamics within submarine canyons, where the interaction of canyon morphology and oceanography influences habitat provision and food deposition. Using stable isotope analysis and Bayesian ellipses, we documented deep-sea food-web structure and trophic niches in Baltimore Canyon and the adjacent open slopes in the US Mid-Atlantic Region. Results revealed isotopically diverse feeding groups, comprising approximately 5 trophic levels. Regression analysis indicated that consumer isotope data are structured by habitat (canyon vs. slope), feeding group, and depth. Benthic feeders were enriched in 13C and 15N relative to suspension feeders, consistent with consuming older, more refractory organic matter. In contrast, canyon suspension feeders had the largest and more distinct isotopic niche, indicating they consume an isotopically discrete food source, possibly fresher organic material. The wider isotopic niche observed for canyon consumers indicated the presence of feeding specialists and generalists. High dispersion in δ13C values for canyon consumers suggests that the isotopic composition of particulate organic matter changes, which is linked to depositional dynamics, resulting in discrete zones of organic matter accumulation or resuspension. Heterogeneity in habitat and food availability likely enhances trophic diversity in canyons. Given their abundance in the world's oceans, our results from Baltimore Canyon suggest that submarine canyons may represent important havens for trophic diversity.

  6. Increasing sediment accumulation rates in La Fonera (Palamós) submarine canyon axis and their relationship with bottom trawling activities

    Science.gov (United States)

    Puig, P.; Martín, J.; Masqué, P.; Palanques, A.

    2015-10-01

    Previous studies conducted in La Fonera (Palamós) submarine canyon (NW Mediterranean) found that trawling activities along the canyon flanks cause resuspension and transport of sediments toward the canyon axis. 210Pb chronology supported by 137Cs dating applied to a sediment core collected at 1750 m in 2002 suggested a doubling of the sediment accumulation rate since the 1970s, coincident with the rapid industrialization of the local trawling fleet. The same canyon area has been revisited a decade later, and new data are consistent with a sedimentary regime shift during the 1970s and also suggest that the accumulation rate during the last decade could be greater than expected, approaching ~2.4 cm yr-1 (compared to ~0.25 cm yr-1 pre-1970s). These results support the hypothesis that commercial bottom trawling can substantially affect sediment dynamics and budgets on continental margins, eventually initiating the formation of anthropogenic depocenters in submarine canyon environments.

  7. Vertical stratification in the distribution of demersal fishes along the walls of the La Jolla and Scripps submarine canyons, California, USA

    Science.gov (United States)

    Smith, Joshua G.; Lindholm, James

    2016-08-01

    The geographic distributions of many coastal marine fish assemblages are strongly driven by habitat features, particularly among demersal fishes that live along the seafloor. Ecologists have long recognized the importance of characterizing fish habitat associations, especially where spatial management is under consideration. However, little is known about fish distributions and habitat suitability in unique demersal habitats such as submarine canyons. The active continental margin of the California coast is cut by eight submarine canyons, several of which extend from the shore to the deep abyssal plain. We sampled the demersal fish assemblages in two of those canyons: (1) the Scripps submarine canyon in the San-Diego-Scripps State Marine Conservation Area (SMCA) and (2) the La Jolla canyon in the Matlahuayl State Marine Reserve (SMR) to gain insight into both the distributions and habitat associations of demersal fishes in canyons. A remotely operated vehicle was used to conduct 21 vertically oriented transects along the canyon walls in depths ranging from 20 to 300 m. Species composition was assessed in three depth-stratified zones (100 m per zone) along the canyon walls. Species richness, abundance, and attributes of the surrounding canyon habitat structure (slope and benthic terrain ruggedness) were quantified. Three distinct assemblage groupings were identified, which comprised 35 species of demersal fishes from 17 families. Among all factors analyzed in this study, depth, slope, and ruggedness were strong explanatory variables of patterns of species richness and abundance; however, the relationship between depth and assemblage structure was non-linear. The greatest number of species was observed in the mid depth-stratified zone. These trends suggest that variation in canyon dynamics across depth strata may facilitate distinct assemblage groupings of demersal fishes, which can in turn be used to better manage these unique habitats.

  8. Occurrence of submarine canyons, sediment waves and mass movements along the northern continental slope of the South China Sea

    Science.gov (United States)

    Chen, Hongjun; Zhan, Wenhuan; Li, Liqing; Wen, Ming-ming

    2017-07-01

    In this study, we reveal a series of newly discovered submarine canyons, sediment waves, and mass movements on a flat and smooth seafloor using high-resolution, multi-beam bathymetry and shallow seismic surveys along the northern slope of the South China Sea. We also describe their geomorphology and seismic stratigraphy characteristics in detail. These canyons display U-shaped cross sections and are roughly elongated in the NNW-SSE direction; they are typically 8-25 km long, 1.2-7 km wide, and form incisions up to 175 m into Pliocene-Quaternary slope deposits at water depths of 400-1000 m. Slide complexes and the sediment wave field are oriented in the NE-SW direction and cover areas of approximately 1790 and 926 km2, respectively. Debris/turbidity flows are present within these canyons and along their lower slopes. Detailed analysis of seismic facies indicates the presence of six seismic facies, in which Cenozoic strata located above the acoustic basement in the study area can be roughly subdivided into three sequences (1-3), which are separated by regional unconformities (Tg, T4, and T3). By combining these data with the regional geological setting and the results of previous studies, we are able to determine the genetic mechanisms used to create these canyons, sediment wave field, and mass movements. For example, frontally confined slide complexes could have been influenced by high sedimentation rates and high pore pressures. A series of very large subaqueous sediment waves, which record wavelengths of 1.4-2 km and wave heights of 30-50 m, were likely produced by interactions between internal solitary waves and along-slope bottom (contour) currents. Canyons were likely initially created by landslides and then widened laterally by the processes of downcutting, headward erosion, and active bottom currents and debris/turbidity flows on canyon floors. We therefore propose a three-dimensional model to describe the development of these mass movements, the sediment

  9. Occurrence of submarine canyons, sediment waves and mass movements along the northern continental slope of the South China Sea

    Indian Academy of Sciences (India)

    Hongjun Chen; Wenhuan Zhan; Liqing Li; Ming-ming Wen

    2017-07-01

    In this study, we reveal a series of newly discovered submarine canyons, sediment waves, and mass movements on a flat and smooth seafloor using high-resolution, multi-beam bathymetry and shallow seismic surveys along the northern slope of the South China Sea. We also describe their geomorphology and seismic stratigraphy characteristics in detail. These canyons display U-shaped cross sections and are roughly elongated in the NNW–SSE direction; they are typically 8–25 km long, 1.2–7 km wide, and form incisions up to 175 m into Pliocene–Quaternary slope deposits at water depths of 400–1000 m. Slide complexes and the sediment wave field are oriented in the NE–SW direction and cover areas of approximately 1790 and 926 km2, respectively. Debris/turbidity flows are present within these canyons and along their lower slopes. Detailed analysis of seismic facies indicates the presence of six seismic facies, in which Cenozoic strata located above the acoustic basement in the study area can be roughly subdivided into three sequences (1–3), which are separated by regional unconformities (Tg, T4, and T3). By combining these data with the regional geological setting and the results of previous studies, we are able to determine the genetic mechanisms used to create these canyons, sediment wave field, and mass movements. For example, frontally confined slide complexes could have been influenced by high sedimentation rates and high pore pressures. A series of very large subaqueous sediment waves, which record wavelengths of 1.4–2 km and wave heights of 30–50 m, were likely produced by interactions between internal solitary waves and along-slope bottom (contour) currents. Canyons were likely initially created by landslides and then widened laterally by the processes of downcutting, headward erosion, and active bottom currents and debris/turbidity flows on canyon floors. We therefore propose a three-dimensional model to describe the development of these mass movements

  10. Shelf erosion and submarine river canyons: implications for deep-sea oxygenation and ocean productivity during glaciation

    Directory of Open Access Journals (Sweden)

    I. Tsandev

    2010-06-01

    Full Text Available The areal exposure of continental shelves during glacial sea level lowering enhanced the transfer of erodible reactive organic matter to the open ocean. Sea level fall also activated submarine canyons thereby allowing large rivers to deposit their particulate load, via gravity flows, directly in the deep-sea. Here, we analyze the effects of shelf erosion and particulate matter re-routing to the open ocean during interglacial to glacial transitions, using a coupled model of the marine phosphorus, organic carbon and oxygen cycles. The results indicate that shelf erosion and submarine canyon formation may significantly lower deep-sea oxygen levels, by up to 25%, during sea level low stands, mainly due to the supply of new material from the shelves, and to a lesser extent due to particulate organic matter bypassing the coastal zone. Our simulations imply that deep-sea oxygen levels can drop significantly if eroded shelf material is deposited to the seafloor. Thus the glacial ocean's oxygen content could have been significantly lower than during interglacial stages. Primary production, organic carbon burial and dissolved phosphorus inventories are all affected by the erosion and rerouting mechanisms. However, re-routing of the continental and eroded shelf material to the deep-sea has the effect of decoupling deep-sea oxygen demand from primary productivity in the open ocean. P burial is also not affected showing a disconnection between the biogeochemical cycles in the water column and the P burial record.

  11. Gravity instabilities in the Dohrn Canyon (Bay of Naples, Southern Tyrrhenian Sea): potential wave and run-up (tsunami) reconstruction from a fossil submarine landslide

    Science.gov (United States)

    di Fiore, Vincenzo; Aiello, Gemma; D'Argenio, Bruno

    2011-02-01

    We discuss a mathematical model for wave and run-up generated submarine landslides in the canyons of the Bay of Naples (Magnaghi-Dohrn canyon system). The morpho-bathymetry and submarine gravity instabilities of such incisions have been investigated through the interpretation of a high resolution DEM. The canyons are located in a sector of the bay where there is a variable interaction of volcanic activity (Phlegrean Fields and Ischia and Procida Islands) with sedimentary processes due to the Sarno-Sebeto rivers. At present the Naples canyon-system is inactive, as is shown by the Holocene sedimentary drapes deposited during the present sea-level highstand, but gravity instabilities occurred in the recent past at the canyons' heads. In particular the Dohrn Canyon is characterized by a double regressive head, while the Magnaghi Canyon shows a trilobate head, formed by the junction of three main tributary channels and coincident with the retreat of the shelf break around the 140 m isobath. The results of a simulation of failures in the above source areas show that the amplitude of wave run-up, expressed in terms of the sea floor depth percentage, may range up to 2.5 % of the water depth at the sea bottom.

  12. On vertical advection truncation errors in terrain-following numerical models: Comparison to a laboratory model for upwelling over submarine canyons

    Science.gov (United States)

    Allen, S. E.; Dinniman, M. S.; Klinck, J. M.; Gorby, D. D.; Hewett, A. J.; Hickey, B. M.

    2003-01-01

    Submarine canyons which indent the continental shelf are frequently regions of steep (up to 45°), three-dimensional topography. Recent observations have delineated the flow over several submarine canyons during 2-4 day long upwelling episodes. Thus upwelling episodes over submarine canyons provide an excellent flow regime for evaluating numerical and physical models. Here we compare a physical and numerical model simulation of an upwelling event over a simplified submarine canyon. The numerical model being evaluated is a version of the S-Coordinate Rutgers University Model (SCRUM). Careful matching between the models is necessary for a stringent comparison. Results show a poor comparison for the homogeneous case due to nonhydrostatic effects in the laboratory model. Results for the stratified case are better but show a systematic difference between the numerical results and laboratory results. This difference is shown not to be due to nonhydrostatic effects. Rather, the difference is due to truncation errors in the calculation of the vertical advection of density in the numerical model. The calculation is inaccurate due to the terrain-following coordinates combined with a strong vertical gradient in density, vertical shear in the horizontal velocity and topography with strong curvature.

  13. Megafauna of vulnerable marine ecosystems in French mediterranean submarine canyons: Spatial distribution and anthropogenic impacts

    Science.gov (United States)

    Fabri, M.-C.; Pedel, L.; Beuck, L.; Galgani, F.; Hebbeln, D.; Freiwald, A.

    2014-06-01

    Vulnerable Marine Ecosystems (VME) in the deep Mediterranean Sea have been identified by the General Fisheries Commission for the Mediterranean as consisting of communities of Scleractinia (Lophelia pertusa and Madrepora oculata), Pennatulacea (Funiculina quadrangularis) and Alcyonacea (Isidella elongata). This paper deals with video data recorded in the heads of French Mediterranean canyons. Quantitative observations were extracted from 101 video films recorded during the MEDSEACAN cruise in 2009 (Aamp/Comex). Qualitative information was extracted from four other cruises (two Marum/Comex cruises in 2009 and 2011 and two Ifremer cruises in 1995 and 2010) to support the previous observations in the Cassidaigne and Lacaze-Duthiers canyons. All the species, fishing impacts and litter recognized in the video films recorded from 180 to 700 m depth were mapped using GIS. The abundances and distributions of benthic fishing resources (marketable fishes, Aristeidae, Octopodidae), Vulnerable Marine Species, trawling scars and litter of 17 canyons were calculated and compared, as was the open slope between the Stoechades and Toulon canyons. Funiculina quadrangularis was rarely observed, being confined for the most part to the Marti canyon and, I. elongata was abundant in three canyons (Bourcart, Marti, Petit-Rhône). These two cnidarians were encountered in relatively low abundances, and it may be that they have been swept away by repeated trawling. The Lacaze-Duthiers and Cassidaigne canyons comprised the highest densities and largest colony sizes of scleractinian cold-water corals, whose distribution was mapped in detail. These colonies were often seen to be entangled in fishing lines. The alcyonacean Callogorgia verticillata was observed to be highly abundant in the Bourcart canyon and less abundant in several other canyons. This alcyonacean was also severely affected by bottom fishing gears and is proposed as a Vulnerable Marine Species. Our studies on anthropogenic

  14. Macrofaunal Patterns in and around du Couedic and Bonney Submarine Canyons, South Australia.

    Directory of Open Access Journals (Sweden)

    Kathleen E Conlan

    Full Text Available Two South Australian canyons, one shelf-incising (du Couedic and one slope-limited (Bonney were compared for macrofaunal patterns on the shelf and slope that spanned three water masses. It was hypothesized that community structure would (H1 significantly differ by water mass, (H2 show significant regional differences and (H3 differ significantly between interior and exterior of each canyon. Five hundred and thirty-one species of macrofauna ≥ 1 mm were captured at 27 stations situated in depth stratified transects inside and outside the canyons from 100 to 1500 m depth. The macrofauna showed a positive relationship to depth in abundance, biomass, species richness and community composition while taxonomic distinctness and evenness remained high at all depths. Biotic variation on the shelf was best defined by variation in bottom water primary production while sediment characteristics and bottom water oxygen, temperature and nutrients defined biotic variation at greater depth. Community structure differed significantly (p<0.01 among the three water masses (shelf-flowing South Australian current, upper slope Flinders current and lower slope Antarctic Intermediate Water (H1. Although community differences between the du Couedic and Bonney regions were marginally above significance at p = 0.05 (H2, over half of the species captured were unique to each region. This supports the evidence from fish and megafaunal distributions that the du Couedic and Bonney areas are in different bioregions. Overall, the canyon interiors were not significantly different in community composition from the exterior (H3. However, both canyons had higher abundance and/or biomass, increased species dominance, different species composition and coarser sediments near the canyon heads compared to outside the canyons at the same depth (500 m, suggestive of heightened currents within the canyons that influence community composition there. At 1000-1500 m, the canyon interiors were

  15. Temperature, salinity, oxygen, silicate, and phosphate data collected in Pacific Ocean from Monterey Submarine Canyon Station by Stanford University from 1951-01-02 to 1955-12-31 (NODC Accession 0093160)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, oxygen, silicate, and phosphate data collected in Pacific Ocean from Montery Submarine Canyon Station by Stanford University from 1951-01-02...

  16. Cold-Water Corals and Anthropogenic Impacts in La Fonera Submarine Canyon Head, Northwestern Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Galderic Lastras

    Full Text Available We assess the occurrence and extent of cold-water coral (CWC species Madrepora oculata and Dendrophyllia cornigera, as well as gorgonian red coral Corallium rubrum, in La Fonera canyon head (Northwestern Mediterranean Sea, as well as human impacts taking place in their habitats. Occurrence is assessed based on Remotely Operated Vehicle (ROV video imaging. Terrain classification techniques are applied to high-resolution swath bathymetric data to obtain semi-automatic interpretative maps to identify the relationship between coral distribution patterns and canyon environments. A total of 21 ROV immersions were carried out in different canyon environments at depths ranging between 79 and 401 m. Large, healthy colonies of M. oculata occur on abrupt, protected, often overhanging, rocky sections of the canyon walls, especially in Illa Negra branch. D. cornigera is sparser and evenly distributed at depth, on relatively low sloping areas, in rocky but also partially sedimented areas. C. rubrum is most frequent between 100 and 160 m on highly sloping rocky areas. The probable extent of CWC habitats is quantified by applying a maximum entropy model to predict habitat suitability: 0.36 km2 yield M. oculata occurrence probabilities over 70%. Similar predictive models have been produced for D. cornigera and C. rubrum. All ROV transects document either the presence of litter on the seafloor or pervasive trawling marks. Nets and longlines are imaged entangled on coral colonies. Coral rubble is observed at the foot of impacted colonies. Some colonies are partially covered by sediment that could be the result of the resuspension generated by bottom trawling on neighbouring fishing grounds, which has been demonstrated to be responsible of daily increases in sediment fluxes within the canyon. The characteristics of the CWC community in La Fonera canyon are indicative that it withstands high environmental stress of both natural and human origin.

  17. The timing of sediment transport down Monterey Submarine Canyon, offshore California

    DEFF Research Database (Denmark)

    Stevens, Thomas; Paull, C.K.; Ussler, W., III

    2014-01-01

    to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand...

  18. Marine geophysical investigations across the submarine canyon (Swatch-of-No-Ground), northern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, V.; Krishna, K.S.; Ramana, M.V.; Murthy, K.S.R.

    depression with step-like micro-terraces running in NNE–SSW direction. The depth to the seafloor topography varies from 900 to 1459 m with 100-150 m thick levee sediments deposited on both the edges of the canyon as seafloor swells spreading over a distance...

  19. Deposition rates, mixing intensity and organic content in two contrasting submarine canyons

    NARCIS (Netherlands)

    García, R.; Van Oevelen, D.; Soetaert, K.E.R.; Thomsen, L.; De Stigter, H.C.; Epping, E.

    2008-01-01

    The hydrographically different conditions characterising the Western Iberian Margin (NE Atlantic) and the Gulf of Lions (Mediterranean) may play an important role in determining the biogeochemical characteristics of the sediments. To investigate this, we compared the Nazaré and Cap de Creus canyons,

  20. Megafauna of vulnerable marine ecosystems in French mediterranean submarine canyons: Spatial distribution and anthropogenic impacts

    OpenAIRE

    Fabri, Marie-Claire; Pedel, Laura; Beuck, L.; Galgani, Francois; Hebbeln, D.; A. Freiwald

    2014-01-01

    Vulnerable Marine Ecosystems (VME) in the deep Mediterranean Sea have been identified by the General Fisheries Commission for the Mediterranean as consisting of communities of Scleractinia (Lophelia pertusa and Madrepora oculata), Pennatulacea (Funiculina quadrangularis) and Alcyonacea (Isidella elongata). This paper deals with video data recorded in the heads of French Mediterranean canyons. Quantitative observations were extracted from 101 video films recorded during the MEDSEACAN cruise in...

  1. A picture on the wall: innovative mapping reveals cold-water coral refuge in submarine canyon.

    Directory of Open Access Journals (Sweden)

    Veerle A I Huvenne

    Full Text Available 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.

  2. Impact of bottom trawling on deep-sea sediment properties along the flanks of a submarine canyon.

    Directory of Open Access Journals (Sweden)

    Jacobo Martín

    Full Text Available 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.

  3. Deep Submarine Tailings Disposal (DSTP) the Proposed Use of Submarine Canyons and Artificial Turbidity Currents for the Disposal of Mine Waste: Current Practice, Future Plans, and Cumulative Impacts.

    Science.gov (United States)

    Young, R.; Moran, R.

    2015-12-01

    The wastes from mining operations ( tailings) have been disposed of in the fluvial environment (riverine disposal) and in nearshore marine environments for much of the last century. The scale of modern mining operations has led to increasing use of steep slopes and submarine canyons for deposition of these wastes at depths of 2000m - 4000m. Current mine disposal operations in Indonesia and Papua New Guinea which use Deep Sea Tailings Placement (DSTP) release volumes between 5000 tpd and 160,000 tpd. Planning is underway by the"Consortium," an industry and government group in Chile which would deposit mine waste of 1M tpd into the Humbolt Current Large Marine Ecosystem (HCLME) which provides nearly 20% of the fish biomass harvested on a sustainable basis worldwide. Underwater pipelines discharge tailings as a slurry to create a continuous artificial turbidity current with particle size distribtions (PSD's) ranging from sand to clay sized fractions. Potential problems arise from benthic smothering, angular particulate uptake by benthic organisms, and from the bioaccumulation of a complex of heavy metals by both benthic and pelagic species. While much is known about the binding of copper and other toxic heavy metals in a reducing environment, little has been done to consider the implications of ocean dumping where 1% of tailings discharged may consist of unrecovered heavy metals. Synergistic cumulative impacts to just the HCLME from the dumping of the more than 3M tpy of reactive metals in these tailings sediments remains unknown and poses substantial risks. DSTP assumes a stable deep sea depositional environment but upwelling currents and plume shear may make this hard to accomplish.

  4. Swept away by a turbidity current in Mendocino submarine canyon, California

    Science.gov (United States)

    Sumner, E. J.; Paull, C. K.

    2014-11-01

    We present unique observations and measurements of a dilute turbidity current made with a remotely operated vehicle in 400 m water depth near the head of Mendocino Canyon, California. The flow had a two-layer structure with a thin (0.5 to 30 m), relatively dense (<0.04 vol %) and fast (up to ~1.7 m/s) wedge-shaped lower layer overlain by a thicker (up to 89 m) more dilute and slower current. The fast moving lower layer lagged the slow moving, dilute flow front by 14 min, which we infer resulted from the interaction of two initial pulses. The two layers were strongly coupled, and the sharp interface between the layers was characterized by a wave-like instability. This is the first field-scale data from a turbidity current to show (i) the complex dynamics of the head of a turbidity current and (ii) the presence of multiple layers within the same event.

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

    Science.gov (United States)

    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.

  6. Demography and movement patterns of leopard sharks (Triakis semifasciata) aggregating near the head of a submarine canyon along the open coast of southern California, USA

    Science.gov (United States)

    Nosal, D.C.; Cartamil, D.C.; Long, J.W.; Luhrmann, M.; Wegner, N.C.; Graham, J.B.

    2013-01-01

    The demography, spatial distribution, and movement patterns of leopard sharks (Triakis semifasciata) aggregating near the head of a submarine canyon in La Jolla, California, USA, were investigated to resolve the causal explanations for this and similar shark aggregations. All sharks sampled from the aggregation site (n=140) were sexually mature and 97.1 % were female. Aerial photographs taken during tethered balloon surveys revealed high densities of milling sharks of up to 5470 sharks ha-1. Eight sharks were each tagged with a continuous acoustic transmitter and manually tracked without interruption for up to 48 h. Sharks exhibited strong site-fidelity and were generally confined to a divergence (shadow) zone of low wave energy, which results from wave refraction over the steep bathymetric contours of the submarine canyon. Within this divergence zone, the movements of sharks were strongly localized over the seismically active Rose Canyon Fault. Tracked sharks spent most of their time in shallow water (≤2 m for 71.0 % and ≤10 m for 95.9 % of time), with some dispersing to deeper (max: 53.9 m) and cooler (min: 12.7 °C) water after sunset, subsequently returning by sunrise. These findings suggest multiple functions of this aggregation and that the mechanism controlling its formation, maintenance, and dissolution is complex and rooted in the sharks' variable response to numerous confounding environmental factors.

  7. Tectono-climatic signals in linear, confined, point-sourced, deep-marine siliciclastic systems as analog for submarine-canyon fills, Eocene, Spanish Pyrenees

    Science.gov (United States)

    Pickering, K.

    2008-12-01

    The linear, confined geometry, and point-sourced nature, of the deep-marine siliciclastic systems in the Eocene Ainsa-Jaca basin, Spanish Pyrenees, provides a useful ancient spatial-temporal comparison and partial analog for the architecture and controls on the sedimentary infill of large submarine canyons / multiple canyons at continental margins with active tectonics, including salt and shale diapirism. The cumulative ~4 km of stratigraphy contains 8 sandy systems with a total of ~25 discrete channelized sandbodies that accumulated over ~10 Myr in water depths of ~400 to 800 m, that were controlled by the ~400-kyr Milkankovitch frequency with modes, at ~100 kyr and ~41 kyr (possibly stacked ~23-kyr) influencing bottom- water conditions, causing periodic stratification in the water column across a submarine sill within the western part of the more proximal depositional systems. Local tectonics defined and controlled the position and stacking patterns of the 8 sandy systems and their constituent channelized sandbodies, in a process of "seesaw tectonics" by: (i) Westward lateral offset-stacking of channelized sandbodies due to growth of the eastern side of the basin, and (ii) Eastward (orogenwards) "back-stepping" of the depositional axis of each sandy system, due to phases of relative uplift of the opposing lateral margin. Thus, the first-order control on accommodation for deep-marine sedimentation was tectonic, with the pacing of the supply of coarse siliciclastics being driven by global climatic processes, particularly Milankovitch-type frequencies. The dominance of eccentricity and obliquity is similar to results from the continental lacustrine, Eocene Green River Formation. The age model for the Ainsa basin yields an average sediment accumulation rate of ~40 cm kyr-1, that is consistent with that inferred from the spectral analysis on bioturbation intensity for fine-grained sedimentation (~30 cm kyr-1). This paper compares and contrasts depositional patterns

  8. Particulate Scavenging and Lateral Transport Processes in the Gaoping Submarine Canyon Deduced From Pb-210 and Po-210 Observations

    Science.gov (United States)

    Hung, G.; Wang, P.; Shen, Y.

    2009-05-01

    Pb-210 and Po-210 were measured on the suspended particulate matter(SPM) and filtered water samples collected in profile from five stations in the Gaoping Submarine Canyon (GPSC) during a cruise aboard R/V Ocean Researcher III in late November, 2006. These stations were selected along the axis of the GPSC, and denoted as CW1 through CW5 sequentially from the shallow part near the mouth of the Gaoping River to the deep-water region of the canyon. Except for CW4, the SPM profiles generally show a rapid increase to a maximum near bottom, the value of which is an order of magnitude higher than that observed above, suggesting a significant particulate resuspension or lateral input in the bottom layer. The SPM concentrations obtained at canyon head stations(CW1 to CW3) vary between 0.36 and 19.17 mg/kg. These values are generally higher than those obtained farther outward(CW4 and CW5), which range from 0.01 to 2.13 mg/kg, indicating a decrease away from the shore. The dissolved Pb-210 and Po-210 profiles observed from CW1 and CW2 are fairly uniform for the entire water column, with a mean of about 14 and 12 dpm/100kg, respectively. The other stations show a large variation in dissolved Pb-210 and Po-210 with a mean of about 23 and 14 dpm/100kg, respectively. At stations CW1, CW2 and CW3, the particulate Pb-210 and Po-210 profiles generally display a maximum around 28-38 and 27-48 dpm/100kg, respectively, in the bottom layer, suggesting significant particulate resuspension and scavenging. Variable Pb-210 and Po-210 activities in the particulates at CW4 and CW5 are observed in the surface layer. Both the dissolved and the total (dissolved + particulate) Po-210 to Pb-210 activity ratios vary between 0.1 and 1.7, mostly less than 1.0, with a mean of 0.7 and 0.8, indicating a variable deficiency of Po-210 relative to Pb- 210 in this study area. Total activities of Pb-210 are generally higher than those of Po-210. The Ra-226 profiles show much lower activities than those of

  9. Assessment of canyon wall failure process from multibeam bathymetry and Remotely Operated Vehicle (ROV) observations, U.S. Atlantic continental margin: Chapter 10 in Submarine mass movements and their consequences: 7th international symposium part II

    Science.gov (United States)

    Chaytor, Jason D.; Demopoulos, Amanda W. J.; Ten Brink, Uri; Baxter, Christopher D. P.; Quattrini, Andrea M.; Brothers, Daniel S.; Lamarche, Geoffroy; Mountjoy, Joshu; Bull, Suzanne; Hubble, Tom; Krastel, Sebastian; Lane, Emily; Micallef, Aaron; Moscardelli, Lorena; Mueller, Christof; Pecher, Ingo; Woelz, Susanne

    2016-01-01

    Over the last few years, canyons along the northern U.S. Atlantic continental margin have been the focus of intensive research examining canyon evolution, submarine geohazards, benthic ecology and deep-sea coral habitat. New high-resolution multibeam bathymetry and Remotely Operated Vehicle (ROV) dives in the major shelf-breaching and minor slope canyons, provided the opportunity to investigate the size of, and processes responsible for, canyon wall failures. The canyons cut through thick Late Cretaceous to Recent mixed siliciclastic and carbonate-rich lithologies which impart a primary control on the style of failures observed. Broad-scale canyon morphology across much of the margin can be correlated to the exposed lithology. Near vertical walls, sedimented benches, talus slopes, and canyon floor debris aprons were present in most canyons. The extent of these features depends on canyon wall cohesion and level of internal fracturing, and resistance to biological and chemical erosion. Evidence of brittle failure over different spatial and temporal scales, physical abrasion by downslope moving flows, and bioerosion, in the form of burrows and surficial scrape marks provide insight into the modification processes active in these canyons. The presence of sessile fauna, including long-lived, slow growing corals and sponges, on canyon walls, especially those affected by failure provide a critical, but as yet, poorly understood chronological record of geologic processes within these systems.

  10. Particle fluxes and their drivers in the Avilés submarine canyon and adjacent slope, central Cantabrian margin, Bay of Biscay

    Science.gov (United States)

    Rumín-Caparrós, A.; Sanchez-Vidal, A.; González-Pola, C.; Lastras, G.; Calafat, A.; Canals, M.

    2016-05-01

    The Avilés Canyon in the central Cantabrian margin is one of the largest submarine canyons in Europe, extending from the shelf edge at 130 m depth to 4765 m depth in the Biscay abyssal plain. In this paper we present the results of a year-round (March 2012 to April 2013) study of particle fluxes in this canyon and the adjacent continental slope. Three mooring lines equipped with automated sequential sediment traps, high-accuracy conductivity-temperature recorders and current meters allowed measuring total mass fluxes and their major components (lithogenics, calcium carbonate, opal and organic matter) in the settling material jointly with a set of environmental parameters. The integrated analysis of the data obtained from the moorings together with remote sensing images and meteorological and hydrographical data has shed light on the sources of particles and the across- and along margin mechanisms involved in their transfer to the deep. Our results allow interpreting the dynamics of the sedimentary particles in the study area. Two factors play a critical role: (i) direct delivery of river-sourced material to the narrow continental shelf, and (ii) major resuspension events caused by large waves and near bottom currents developing at the occasion of the rather frequent severe storms that are typical of the Cantabrian Sea. Wind direction and subsequent wind-driven currents largely determine the way sedimentary particles reach the canyon. While westerly winds favour the injection of sediments into the Avilés Canyon mainly by building an offshore transport in the bottom Ekman layer, easterly winds ease the offshore advection of particulate matter towards the Avilés Canyon and its adjacent western slope principally through the surface Ekman layer. Furthermore, repeated cycles of semidiurnal tides add an extra amount of energy to the prevailing bottom currents and actively contribute to keep a permanent background of suspended particles in near-bottom waters. High

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

    Science.gov (United States)

    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

  12. 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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    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 as well as birds and marine mammals. We show that in some areas the floor of these canyons harbors high densities of gorgonian and pennatulacean corals and sponges, likely due to enhanced surface productivity, benthic currents and seafloor topography. Rockfishes, including the commercially important Pacific ocean perch, Sebastes alutus, were associated with corals and sponges as well as with isolated boulders. Sculpins, poachers and pleuronectid flounders were also associated with corals in Pribilof Canyon, where corals were most abundant. Fishes likely use corals and sponges as sources of vertical relief, which may harbor prey as well as provide shelter from predators. Boulders may be equivalent habitat in this regard, but are sparse in the canyons, strongly suggesting that biogenic structure is important fish habitat. Evidence of disturbance to the benthos from fishing activities was observed in these remote canyons. Bottom trawling and other benthic fishing gear has been shown to damage corals and sponges that may be very slow to recover from such disturbance. Regulation of these destructive practices is key to conservation of benthic habitats in these canyons and the ecosystem services they provide. PMID:22470486

  14. Structure-forming corals and sponges and their use as fish habitat in Bering Sea submarine canyons.

    Directory of Open Access Journals (Sweden)

    Robert J Miller

    Full Text Available 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 as well as birds and marine mammals. We show that in some areas the floor of these canyons harbors high densities of gorgonian and pennatulacean corals and sponges, likely due to enhanced surface productivity, benthic currents and seafloor topography. Rockfishes, including the commercially important Pacific ocean perch, Sebastes alutus, were associated with corals and sponges as well as with isolated boulders. Sculpins, poachers and pleuronectid flounders were also associated with corals in Pribilof Canyon, where corals were most abundant. Fishes likely use corals and sponges as sources of vertical relief, which may harbor prey as well as provide shelter from predators. Boulders may be equivalent habitat in this regard, but are sparse in the canyons, strongly suggesting that biogenic structure is important fish habitat. Evidence of disturbance to the benthos from fishing activities was observed in these remote canyons. Bottom trawling and other benthic fishing gear has been shown to damage corals and sponges that may be very slow to recover from such disturbance. Regulation of these destructive practices is key to conservation of benthic habitats in these canyons and the ecosystem services they provide.

  15. Effect of submarine canyons on tsunami heights, currents and run-up off the southeast coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    JayaKumar, S.; ManiMurali, R.; Baldock, T.E.

    , travel time and time of arrival7–12, coastal inundation or run-up height measure- ments and modelling. Although a few studies along the Indian coast hint at the amplification of the tsunami and therefore increase in run-up heights13, not many studies... was affected by diffraction and refraction process and then divided into different parts. These different parts of the tsunami waves travel perpendicular to both the sides of the canyon as well as propagating along the canyon, thereby travelling...

  16. Marine litter in the upper São Vicente submarine canyon (SW Portugal): Abundance, distribution, composition and fauna interactions.

    Science.gov (United States)

    Oliveira, Frederico; Monteiro, Pedro; Bentes, Luis; Henriques, Nuno Sales; Aguilar, Ricardo; Gonçalves, Jorge M S

    2015-08-15

    Marine litter has become a worldwide environmental problem, tainting all ocean habitats. The abundance, distribution and composition of litter and its interactions with fauna were evaluated in the upper S. Vicente canyon using video images from 3 remote operated vehicle exploratory dives. Litter was present in all dives and the abundance was as high as 3.31 items100m(-1). Mean abundance of litter over rock bottom was higher than on soft substrate. Mean litter abundance was slightly higher than reported for other canyons on the Portuguese margin, but lower in comparison to more urbanized coastal areas of the world. Lost fishing gear was the prevalent type of litter, indicating that the majority of litter originates from maritime sources, mainly fishing activity. Physical contact with sessile fauna and entanglement of specimens were the major impacts of lost fishing gear. Based on the importance of this region for the local fishermen, litter abundance is expected to increase.

  17. Pharmacological Potential of Phylogenetically Diverse Actinobacteria Isolated from Deep-Sea Coral Ecosystems of the Submarine Avilés Canyon in the Cantabrian Sea.

    Science.gov (United States)

    Sarmiento-Vizcaíno, Aida; González, Verónica; Braña, Alfredo F; Palacios, Juan J; Otero, Luis; Fernández, Jonathan; Molina, Axayacatl; Kulik, Andreas; Vázquez, Fernando; Acuña, José L; García, Luis A; Blanco, Gloria

    2017-02-01

    Marine Actinobacteria are emerging as an unexplored source for natural product discovery. Eighty-seven deep-sea coral reef invertebrates were collected during an oceanographic expedition at the submarine Avilés Canyon (Asturias, Spain) in a range of 1500 to 4700 m depth. From these, 18 cultivable bioactive Actinobacteria were isolated, mainly from corals, phylum Cnidaria, and some specimens of phyla Echinodermata, Porifera, Annelida, Arthropoda, Mollusca and Sipuncula. As determined by 16S rRNA sequencing and phylogenetic analyses, all isolates belong to the phylum Actinobacteria, mainly to the Streptomyces genus and also to Micromonospora, Pseudonocardia and Myceligenerans. Production of bioactive compounds of pharmacological interest was investigated by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) techniques and subsequent database comparison. Results reveal that deep-sea isolated Actinobacteria display a wide repertoire of secondary metabolite production with a high chemical diversity. Most identified products (both diffusible and volatiles) are known by their contrasted antibiotic or antitumor activities. Bioassays with ethyl acetate extracts from isolates displayed strong antibiotic activities against a panel of important resistant clinical pathogens, including Gram-positive and Gram-negative bacteria, as well as fungi, all of them isolated at two main hospitals (HUCA and Cabueñes) from the same geographical region. The identity of the active extracts components of these producing Actinobacteria is currently being investigated, given its potential for the discovery of pharmaceuticals and other products of biotechnological interest.

  18. Heavy mineral sorting as a tool to distinguish depositional characteristics of “in situ” sands from their related injected sands in a Palaeogene submarine Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Moatari Kazerouni, Afsoon; Friis, Henrik; Svendsen, Johan. B

    in the Paleocene Siri Canyon near the Danish Central Graben of the North Sea hydrocarbon province from borehole data. The emplacement of large-scale injection complexes has been commonly attributed in the geological literature to seismic activity and consequent sand liquefaction. However, due to very small...... and has been interpreted to represent the depositional sorting. This study demonstrates the detailed sorting pattern of heavy minerals in thin, injected sands and relates it to the flow patterns during injection. The sorting pattern is used to explain the large scale sorting pattern of the reservoir sands...... and to suggest a tool for petrographic/geochemical distinction between "in situ" sands and their related injected sands within a submarine canyon setting....

  19. Distributions of Different Submarine Canyons on the East China Sea Slope and Their Tectonic Response%东海陆坡不同类型海底峡谷的分布构造响应

    Institute of Scientific and Technical Information of China (English)

    赵月霞; 刘保华; 李西双; 刘晨光; 裴彦良; 吴金龙; 郑彦鹏

    2009-01-01

    利用1997-2001年在东海海域获得的多波束全覆盖测深数据和收集的部分高分辨率单道地震剖面,对东海陆坡海底峡谷的地形要素,如长度、弯曲度、平均坡度、剖面特征、头部和末端的水深等进行了详细的分析和统计.根据平面形态将海底峡谷划分为3种类型:直线型、蛇曲型和树枝型.海底峡谷主要分布于中段和南段的东海陆坡之上,平面形态特征总体上自北向南趋于复杂(直线型→蛇曲型→树枝型),规模逐渐增大,不同平面类型代表了峡谷不同的演化阶段.峡谷的分布格局和变化趋势主要受控于冲绳海槽扩张背景下的构造活动.%Topographical features such as the length, the bending level, the mean slope, the profile character and the water depth at the head and the tail of the submarine canyons on the East China Sea Slope were studied based on the multibeam bathymetric data acquired in the East China Sea from 1997 to 2001 and the collection of single-channel seismic profiles with high resolution. In morphology, three types of submarine canyons were recognized, which are linear, meandering and dendritic. They are mainly distributed on the middle and the southern segments of the slope. Their morphology tends generally to become complicated (linear→rneadering→dendritic) and their scale increases graduallyfrom north to south. Different types of canyons represent different evolutionary stages. The distribution pattern and the changing tendency of the canyons are mainly controlled by the tectonic activities related to the spreading of the Okinawa Trough.

  20. Development of submarine canyons after the Mid-Pleistocene Transition on the Ebro margin, NW Mediterranean: The role of fluvial connections

    Science.gov (United States)

    Mauffrey, Marie-Aline; Urgeles, Roger; Berné, Serge; Canning, Jason

    2017-02-01

    After the Messinian Salinity Crisis (MSC), the Ebro Margin, like other Mediterranean deltaic margins, rebuilt through progradation and increasingly significant aggradation. The Plio-Quaternary transition from a ramp-like system to a ;new; margin with large clinoforms is an opportunity to understand the processes that govern canyon initiation and evolution. We used a 3D seismic data set located at the outer shelf - upper slope of the Ebro margin. We tied major bounding surfaces to chrono-stratigraphic constraints from borehole data or, for the most recent interval, from averaged accumulation rates derived from borehole stratigraphy. The major shelfal erosion surfaces are interpreted as sequence boundaries, tied to major glacial maxima. Along these surfaces, seismic attributes characterize the fluvial/canyon connection, viewed as one of the key factors in canyon development. The first appearance of ;proto-canyons; (dense networks of channels and gullies 50-100 m deep and 1-2 km wide) occurs in the late Zanclean. Their size increased progressively throughout the Pliocene and early Quaternary, in relation to the increase in clinoform heights. ;True canyons; (with distinct interfluves, more than 200 m deep and 3-4 km wide) appeared during the Mid-Pleistocene Transition (MPT, 1250-700 ka BP). The first evidence of direct connection between canyon heads and fluvial systems is observed during Marine Isotope Stage 22, one of the most pronounced glacial stages of the Quaternary. Similar connections also existed, at least, during MIS 16 and MIS 12, which are also stages of pronounced low sea level. The topography of fluvial channels in the outer shelf is not imaged in detail in the picked horizons at the resolution of our seismic data, but sinuous fluvial systems are very well imaged through amplitude and coherency attributes. Direct connection of fluvial systems during and after MIS 22 also favored headward erosion and the formation of shelf-indenting canyons, probably

  1. Morphological and genetic diversity of the wood-boring Xylophaga (Mollusca, Bivalvia): new species and records from deep-sea Iberian canyons.

    Science.gov (United States)

    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.

  2. Morphological and genetic diversity of the wood-boring Xylophaga (Mollusca, Bivalvia: new species and records from deep-sea Iberian canyons.

    Directory of Open Access Journals (Sweden)

    Chiara Romano

    Full Text Available 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

  3. Data from Oceanographer, Lydonia, and Gilbert Canyons acquired in 1965 (SCHWARTZ65 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine canyons occur at the edge of the continental shelf and cut across the slope and rise along the U.S. east coast. Three of these canyons (Oceanographer,...

  4. Data from Oceanographer, Lydonia, and Gilbert Canyons acquired in 1965 (SCHWARTZ65 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine canyons occur at the edge of the continental shelf and cut across the slope and rise along the U.S. east coast. Three of these canyons (Oceanographer,...

  5. Samples from the Georges Bank Canyons acquired in 1936 (STETSON36 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine canyons cut into the edge of the continental shelf and the continental slope along much of the U.S. Atlantic coast. Three canyons along the southern edge...

  6. Canyon conditions impact carbon flows in food webs of three sections of the Nazare canyon

    NARCIS (Netherlands)

    van Oevelen, D.; Soetaert, K.; Garcia, R.; de Stigter, H.C.; Cunha, M.R.; Pusceddu, A.; Danovaro, R.; Garcia, R.

    2011-01-01

    Submarine canyons transport large amounts of sediment and organic matter (OM) from the continental shelf to the abyssal plain. Three carbon-based food web models were constructed for the upper (300-750 m water depth), middle (2700-3500 m) and lower section (4000-5000 m) of the Nazare canyon (eastern

  7. Reurbanització de la Plaça Blanes al municipi del Prat de Llobregat

    OpenAIRE

    Moreno Amorós, Gustavo

    2012-01-01

    El present projecte correspon a l’execució de les obres d’urbanització de la Plaça de Blanes comprés entre els carrers de Lleida, de Catalunya, de Cáceres i la carretera de la Bunyola. Dins de l’àmbit del projecte s’inclou l’actual plaça de Blanes, el carrer d’Enric Morera, comprés entre els carrers de Lleida i de Catalunya, el Jardí de Garrovillas, la plaça del Mercat i el tram del carrer de Cadaqués comprés entre els carrers d’Enric Morera i de Cáceres, i la vorera sud-oes...

  8. The trophic biology of the holothurian Molpadia musculus: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon

    Directory of Open Access Journals (Sweden)

    A. Pusceddu

    2010-08-01

    Full Text Available Megafaunal organisms play a key role in ecosystem functioning in the deep-sea through bioturbation, bioirrigation and organic matter cycling. At 3500 m water depth in the Nazaré Canyon, NE Atlantic, very high abundances of the infaunal holothurian Molpadia musculus were observed. To quantify the role of M. musculus in sediment cycling, sediment samples and holothurians were collected using an ROV and in situ experiments were conducted with incubation chambers. The biochemical composition of the sediment (in terms of proteins, carbohydrates and lipids, the holothurians' gut contents and holothurians' faecal material were analysed. In the sediments, proteins were the dominant organic compound, followed by carbohydrates and lipids. In the holothurian's gut contents, protein concentrations were higher than the other compounds, decreasing significantly as the material passed through the digestive tract. Approximately 33±1% of the proteins were digested by the time sediment reached the mid gut, with a total digestion rate equal to 67±1%. Carbohydrates and lipids were ingested in smaller amounts and digested with lower efficiencies (23±11% and 50±11%, respectively. As a result, the biopolymeric C digestion rate was on average 62±3%. We estimated that the population of M. musculus could remove approximately 0.49±0.13 g biopolymeric C and 0.13±0.03 g N m−2 d−1 from the sediments. These results suggest that M. musculus plays a key role in the benthic tropho-dynamics and biogeochemical processes in the Nazaré Canyon.

  9. Canyon conditions impact carbon flows in food webs of three sections of the Nazaré canyon

    NARCIS (Netherlands)

    Van Oevelen, D.; Soetaert, K.E.R.; Garcia, R.; De Stigter, H.; Cunha, M.R.; Pusceddu, A.; Danovaro, R.

    2011-01-01

    Submarine canyons transport large amounts of sediment and organic matter (OM) from the continental shelf to the abyssal plain. Three carbon-based food web models were constructed for the upper (300–750 m water depth), middle (2700–3500 m) and lower section (4000–5000 m) of the Nazaré canyon (eastern

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

    Science.gov (United States)

    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

  11. Submarines against Submarines (Selected Articles),

    Science.gov (United States)

    1979-07-05

    vowels , and after b, b; t 1lse Whre. . ."r. w itten as ! in Russian, transliterate as yL cr . RUSSIAN AND ENGLISH TRIGONOMETRIC FUNCTIONS . 1-1 English...submarines. The assimilation of postwar scientific and technological achieve- ments into submarine construction has greatly enlarged the role and

  12. Mass movements in small canyons in the northeast of Baiyun deepwater area, north of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LI Xishuang; LIU Lejun; LI Jiagang; GAO Shan; ZHOU Qingjie; SU Tianyun

    2015-01-01

    The process of mass movements and their consequent turbidity currents in large submarine canyons has been widely reported, however, little attention was paid to that in small canyons. In this paper, we document mass movements in small submarine canyons in the northeast of Baiyun deepwater area, north of the South China Sea (SCS), and their strong effects on the evolution of the canyons based on geophysical data. Submarine canyons in the study area arrange closely below the shelf break zone which was at the depth of –500 m. Within submarine canyons, seabed surface was covered with amounts of failure scars resulted from past small-sized landslides. A complex process of mass transportation in the canyons is indicated by three directions of mass movements. Recent mass movement deposits in the canyons exhibit translucent reflections or parallel reflections which represent the brittle deformation and the plastic deformation, respectively. The area of most landslides in the canyons is less than 3 km2. The trigger mechanisms for mass movements in the study area are gravitational overloading, slope angle and weak properties of soil. Geophysical data indicate that the genesis of submarine canyons is the erosion of mass movements and consequent turbidity currents. The significant effects of mass movements on canyon are incision and sediment transportation at the erosion phases and fillings supply at the fill phases. This research will be helpful for the geological risk assessments and understanding the sediment transportation in the northern margin of the SCS.

  13. Currents, temperature, attenuation, and conductivity data collected during the Monterey Canyon Experiment from moorings deployed from platforms ROBERT GORDON SPROUL and NOAA Ship McARTHUR from 1993-08-03 to 1995-05-15 (NCEI Accession 0067570)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Monterey Canyon experiment studied the mechanisms that govern the circulation within and the transport of sediment and water through Monterey Submarine Canyon....

  14. Origin and transport of trace metals deposited in the canyons off Lisboa and adjacent slopes (Portuguese Margin) in the last century

    NARCIS (Netherlands)

    Costa, A.M.; Mil-Homens, M.; Lebreiro, S.M.; Richter, T.O.; de Stigter, H.; Boer, W.; Trancoso, M.A.; Melo, Z.; Mouro, F.; Mateus, M.; Canário, J.; Branco, V.; Caetano, M.

    2011-01-01

    Submarine canyons play an important role in the transfer of contaminated sediments from shelf areas to the deeper ocean. To evaluate the importance of submarine canyons adjacent to the Tagus and Sado estuaries (Portuguese Margin) as sediment pathway major and trace elements, (210)Pb radionuclides,

  15. Regarding several points of doubt of the structure of the olfactory bulb: as described by T. Blanes.

    Science.gov (United States)

    Levine, Catherine; Marcillo, Alexander

    2008-07-01

    In order to complement the studies on the fila olfactoria completed by Dr. Santiago Ramón y Cajal, we have included a translation of "Sobre Algunos Puntos Dudosos de la Estructura del Bulbo Olfatorio" by T. Blanes, a student of Dr. Cajal. This work describes in stunning detail additional morphological aspects of the olfactory pathway, including what was at the time the modestly studied neuroglia. The neuroglia of the olfactory system has been revisited in the last several decades for its importance in the field of regenerative neuroscience. Olfactory ensheathing glia has the unique quality of providing ensheathment to neurons which traverse from the central to the peripheral nervous system and are being used as a candidate in present-day transplantation studies to mimic this phenomenon at the dorsal root entry zone after a central nervous system injury. Although this fine work has passed its centennial anniversary since initial publication, it has been widely cited throughout the years, and of recent when Pressler and Stowbridge reported Blanes cell electrophysiological recordings (Neuron V 49, 6; p 889-904, 2006). An English translation the details of what Blanes initially documented with unduplicated precision can now be made available to a wider audience in the field of neuroscience, and is especially important now that more and more present-day studies require a precise and complete understanding of the anatomical structures contained within the olfactory system. (c) 2008 Wiley-Liss, Inc.

  16. Source and sink characteristics of the continental slope-parallel Central Canyon in the Qiongdongnan Basin on the northern margin of the South China Sea

    Science.gov (United States)

    Li, Chao; Lv, Chengfu; Chen, Guojun; Zhang, Gongcheng; Ma, Ming; Shen, Huailei; Zhao, Zhao; Guo, Shuai

    2017-02-01

    The "source-conduit-sink" model is crucial for studying deep-water sedimentary systems along a continental margin. Using seismic data, bulk rare earth element compositions of sediments and zircon U-Pb age data, we examined the supply and deposition (i.e., the source and sink) of the sediments in the Central Canyon of the South China Sea. Five phases of secondary canyon fill are present in the Central Canyon. The natural levees developed at the head of phase 1 of the secondary canyon deposits indicate that the Central Canyon initially developed at 10.5 Ma. The sediments in the Central Canyon were supplied by the Ledong submarine fan, and the provenance of the material in the Ledong submarine fan and Central Canyon was eastern Vietnam. Large amounts of sediments were transported through the Central Canyon to the Shuangfeng Basin and deposited during four phases of submarine fan development. Phases 1-3 of the Shuangfeng submarine fans are composed of deep-water branching channel and inter-channel sediments. Phase 4 of the Shuangfeng submarine fan consists of deep-water channel and lobe sediments. Tectonic events, including the broad uplift of the Tibetan Plateau and central-southern Vietnam during the late Miocene, reversal of the strike-slip Red River Fault, and rapid subsidence in the Qiongdongnan Basin at approximately 5.5 Ma, provided favourable conditions for the growth of the Ledong submarine fan, Central Canyon and Shuangfeng submarine fan system.

  17. Submarine hydrodynamics

    CERN Document Server

    Renilson, Martin

    2015-01-01

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

  18. Submarine Communications .

    Directory of Open Access Journals (Sweden)

    H.B. Singh

    1993-01-01

    Full Text Available Submarines operating in deep water are virtually cut off from the outer world. It becomes very important and essential to convey survivable and critical information to the submarine during the time it operates under water. Conventional means of radio communication do not serve any useful purpose as the higher frequencies get attenuated very sharply in sea water. At VLF band, which is presently being used by most of the world Navies, signal can penetrate only upto 8-10 m of depth. This depth is not sufficient under hostile environment. ELF is another band where listening depth is around 100 m but data rate is very low. This paper summarizes the various means of communication used to send messages to submarine while cruising at various depths. It seems that in the near future blue-green laser is going to be the vital means of sending large information to a submarine operating much deeper (500-700 m with unrestricted speed.

  19. Quantitative analysis of the geometry of submarine channels: Implications for the classification of submarine fans

    Science.gov (United States)

    Clark, J. D.; Kenyon, N. H.; Pickering, K. T.

    1992-07-01

    Certain attributes of submarine channels measured from GLORIA sidescan sonar data from 16 different submarine fans indicate similarities with fluviatile systems. Channel width, depth, meander radius and wavelength, sinuosity, and gradient were measured. This approach makes it possible to identify high- sinuosity, low-gradient (e.g., Indus Fan channels) and low-sinuosity, high- gradient (e.g., Porcupine Seabight channels) channel systems as end members. Current classifications of submarine fans relate fan shape to grain size or sediment caliber and therefore are inadequate, principally because the shape of the fan is strongly controlled by the shape of the receiving basin, which in turn is dependent upon parameters such as tectonics and diapirism. Overall fan shape is almost invariably independent of the physics of sediment transport. Rather than fan shape, the geometry and other characteristics of submarine channels and canyons provide a more promising means of differentiating deep- marine turbidite systems.

  20. Submarine Atmospheres

    Science.gov (United States)

    1990-07-01

    antimutagenesis. Obviously, as a lot of you know, extracts of many, many vegetables , especially cruciferous vegetables , contain a lot of antimutagenic...accidents, suicides, and hcmocldes) and cancer . The accidental deaths of enlisted veterans were higher among those with history of demotlons or duty...aboard fast-attack submarines. There was clustering of cancer deaths in the year immediately following discharge from the Navy for medical disability

  1. Heavy mineral sorting as a tool to distinguish depositional characteristics of “in situ” sands from their related injected sands in a Palaeogene submarine Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Moatari Kazerouni, Afsoon; Friis, Henrik; Svendsen, Johan. B

    Postdepositional remoblization and injection of sand are important processes in deep-water clastic systems. Subsurface mobilisation and injection of sand has been recently recognised as a significant control of deep-water sandstone geometry. Kilometre-scale injection complexes have been interpreted...... in the Paleocene Siri Canyon near the Danish Central Graben of the North Sea hydrocarbon province from borehole data. The emplacement of large-scale injection complexes has been commonly attributed in the geological literature to seismic activity and consequent sand liquefaction. However, due to very small...... differences in textural and compositional properties, and the lack of depositional structures of reservoir sands in the Siri Canyon, the distinction between "in situ" and injected or remobilised sands is difficult. Large scale heavy mineral sorting (in 10 m thick units) is observed in several reservoir units...

  2. Application of a Lagrangian transport model to organo-mineral aggregates within the Nazaré canyon

    OpenAIRE

    S. Pando; Juliano, M.; Garcia, R.; P. A. de Jesus Mendes; Thomsen, L.

    2013-01-01

    In this study, a hydrodynamic model was applied to the Nazaré submarine canyon with boundary forcing provided by an operational forecast model for the West Iberian coast. After validation, a Lagrangian transport model was coupled to the hydrodynamic model to study the transport patterns of the organo-mineral aggregates along the Nazaré canyon comparing three different classes of organo-mineral aggregates. The results showed that the transport in the canyon is neither constant, nor unid...

  3. Application of a Lagrangian transport model to organo-mineral aggregates within the Nazaré canyon

    OpenAIRE

    Pando, S.; Juliano, M.; Garcia, R.; P. A. de Jesus Mendes; Thomsen, L.

    2013-01-01

    In this study, a hydrodynamic model was applied to the Nazaré submarine canyon with boundary forcing provided by an operational forecast model for the West Iberian coast. After validation, a Lagrangian transport model was coupled to the hydrodynamic model to study the transport patterns of the organo-mineral aggregates along the Nazaré canyon comparing three different classes of organo-mineral aggregates. The results showed that the transport in the canyon is neither constant, nor unid...

  4. Submarine Medicine Team

    Data.gov (United States)

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

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

    Science.gov (United States)

    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.

  6. Subinertial canyon resonance

    Science.gov (United States)

    Clarke, Allan J.; Van Gorder, Stephen

    2016-04-01

    Near the bottom of a narrow canyon currents that oscillate back and forth along the bottom slope hx in a stratified ocean of buoyancy frequency N do so with a natural internal gravitational frequency Nhx. From May 2012 to May 2013 Acoustic Doppler Current Profiler measurements were made at 715 m depth in the deep narrow part of the DeSoto Canyon south of Pensacola, Florida, in water with 2π/Nhx ≈ 2.5 days. Above the canyon the flow follows the large-scale isobaths, but beneath the canyon rim the current oscillates along the canyon axis with 2-3 day periodicity, and is much stronger than and uncorrelated with the overlying flow. A simple theoretical model explains the resonant response. Published observations from the Hudson and Gully canyons suggest that the strong subinertial current oscillations observed in these canyons occur close to the relevant local frequency Nhx, consistent with the proposed simple model physics.

  7. Oceanographic data collected during the Atlantic Deep-Water Canyons: Pathways to the Abyss 2011 on NOAA Ship Nancy Foster in the North Atlantic Ocean from 2011-06-04 to 2011-06-17 (NCEI Accession 0082240)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Submarine canyons are dominant features of the outer continental shelf and slope of the US East coast from Cape Hatteras to the Gulf of Maine. They are important...

  8. The marine soundscape of the Perth Canyon

    Science.gov (United States)

    Erbe, Christine; Verma, Arti; McCauley, Robert; Gavrilov, Alexander; Parnum, Iain

    2015-09-01

    The Perth Canyon is a submarine canyon off Rottnest Island in Western Australia. It is rich in biodiversity in general, and important as a feeding and resting ground for great whales on migration. Australia's Integrated Marine Observing System (IMOS) has moorings in the Perth Canyon monitoring its acoustical, physical and biological oceanography. Data from these moorings, as well as weather data from a near-by Bureau of Meteorology weather station on Rottnest Island and ship traffic data from the Australian Maritime Safety Authority were correlated to characterise and quantify the marine soundscape between 5 and 3000 Hz, consisting of its geophony, biophony and anthrophony. Overall, biological sources are a strong contributor to the soundscape at the IMOS site, with whales dominating seasonally at low (15-100 Hz) and mid frequencies (200-400 Hz), and fish or invertebrate choruses dominating at high frequencies (1800-2500 Hz) at night time throughout the year. Ships contribute significantly to the 8-100 Hz band at all times of the day, all year round, albeit for a few hours at a time only. Wind-dependent noise is significant at 200-3000 Hz; winter rains are audible underwater at 2000-3000 Hz. We discuss how passive acoustic data can be used as a proxy for ocean weather. Passive acoustics is an efficient way of monitoring animal visitation times and relative densities, and potential anthropogenic influences.

  9. Jaume Ferrer de Blanes i Les sentències catòliques del diví poeta Dant. Una mostra de la presència de Dant al renaixement català

    Directory of Open Access Journals (Sweden)

    Josep Llorenç i Blat

    2014-12-01

    Full Text Available Procurador reial i nobiliari, cosmògraf, joier, lapidari, mercader i escriptor, i al capdavall, un ciutadà català honrat, Ferrer (Vidreres, ~1445 – Blanes, 1529 va marxar de ben jove a la cort de Nàpols, al servei del rei Ferran i. Acabada aquesta peripècia italiana va tornar a Blanes al servei del vescomte de Cabrera i de Bas fins que va morir a la mateixa vila al 1529. Un seu criat, disset anys més tard, va editar uns papers esparsos que havia trobat a can Ferrer, les Sentèncias cathòlicas del diví poeta Dant florentí, compilades per lo prudentíssim mossèn Jaume Ferrer de Blanes, que constiueixen un exemple de la presència de Dant al renaixement català. Lord Ferrer (Vidreres,~1445 – Blanes,1529, royal and aristocratic attorney, cosmographer, jewelrer, lapidary, merchant and writer, after all, an honorable Catalan citizen, left early age, at the court of Naples at King Ferdinand’s i service. After this eventful Italian journey he went back to Blanes at the Viscount of Cabrera and Bas’ service, until he died in the same town in 1529. One of his servants, seventeen years later, published some of the documents which were found scattered in Ferrer’s House, Catholic sentences from the divine poet Dante Florentine, compiled by most respectable lord Jaume Ferrer de Blanes, an exemple of the presence of Dante in Catalan Renaissance.

  10. Application of a Lagrangian transport model to organo-mineral aggregates within the Nazaré canyon

    Directory of Open Access Journals (Sweden)

    S. Pando

    2013-01-01

    Full Text Available In this study, a hydrodynamic model was applied to the Nazaré submarine canyon with boundary forcing provided by an operational forecast model for the West Iberian coast. After validation, a Lagrangian transport model was coupled to the hydrodynamic model to study the transport patterns of the organo-mineral aggregates along the Nazaré canyon comparing three different classes of organo-mineral aggregates. The results showed that the transport in the canyon is neither constant, nor unidirectional and that there are preferential areas where suspended matter is resuspended, transported and deposited. The results showed that the transport of the larger size classes of organo-mineral aggregates is less pronounced, and that there is a decrease in the phytodetrital carbon flux along the canyon. The Nazaré canyon acts as depocenter of sedimentary organic matter and the canyon is not a conduit of organo-mineral aggregates to the deep sea.

  11. Environment in Submarine Compartments

    Directory of Open Access Journals (Sweden)

    Anil K. Shrivastava

    1987-04-01

    Full Text Available The crew operating in the confined environment of a submarine are subjected to discomfort as a result of physiological stress caused by toxic substances which are generated due to engineering, operational and other human activities. The physioiogical problems of men under prolonged confinement in a submarine have been reviewed. Data on air pollutants monitored during 'cruise' and 'at rest' conditions inside a submarine are given. Threshold limit value (TLV of trace substances in the confined environment has been discussed. The merits of air purification and air revitalization systems currently employed for control of air pollution have been brought out.

  12. Submarine neutrino communication

    CERN Document Server

    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.

  13. Submarine neutrino communication

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Patrick, E-mail: pahuber@vt.ed [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States)

    2010-09-06

    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.

  14. Submarine neutrino communication

    Science.gov (United States)

    Huber, Patrick

    2010-09-01

    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.

  15. Submarine neutrino communication

    OpenAIRE

    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...

  16. The Probable Whole of Slope Submarine Landslides of Southeast Queensland, Australia.

    Science.gov (United States)

    Hubble, T.

    2015-12-01

    A research cruise aboard the RV Southern Surveyor (SS2013-V01) conducted in January 2013 offshore east Australia collected regional bathymetric data for the seabed of the continental margin of southern Queensland for the seabed bounded by Noosa Heads in the south and Indian Head, Fraser Island in the north. This newly mapped area presents a particularly steep portion of continental slope (5o to 10 o) that presents numerous submarine landslides, including two 'whole-of-slope' features (The Wide Bay Canyon, and Inskip Slides. The slope is also dissected by three large submarine canyons offshore northern Fraser Island, Wide Bay and Noosa Heads (i.e. the Fraser Canyons, the Wide Bay Canyon and the Noosa Canyon). Dredge and core samples were collected from slide scars in the northern, central and southern areas of the bathymetric survey area. The initial examination of the area's bathymetry, the core and dredge sample sedimentology, and determination of biostratigraphic ages for these sediment samples indicates that the larger, submarine slides present in this study area have probably been shed from the slope since the late Pliocene and that canyon incision is currently active on this portion of the slope. In one case, canyon incision is partly responsible for generating slides due to undercutting and removal of the toe of the slope. Slope sediments are dominantly comprised of hemipelagic muds but the presence of massive coarse sands and graded sands in some cores above erosion surfaces that cut into slope mud units is interpreted to indicate that areas of the southern Queensland continental slope are probably subjected to abrasion by grain-flows and turbidites comprised of shelf-derived sands and upper slope sediment. The results from this voyage confirms and extends previous work on the southeastern Australian continental margin that indicates that sediment transport from the shelf to deep water on this margin is dominated by gravity mass transport and that the margin

  17. Circulation in Vilkitsky Canyon in the eastern Arctic Ocean

    Science.gov (United States)

    Janout, Markus; Hölemann, Jens

    2016-04-01

    The eastern Arctic Ocean is characterized by steep continental slopes and vast shallow shelf seas that receive a large amount of riverine freshwater from some of the largest rivers on earth. The northwestern Laptev Sea is of particular interest, as it is a freshwater transport pathway for a swift surface-intensified current from the Kara Sea toward the Arctic Basin, as was recently highlighted by high-resolution model studies. The region features complex bathymetry including a narrow strait and a large submarine canyon, strong tides, polynyas and severe sea ice conditions throughout much of the year. A year-long mooring record as well as detailed hydrographic shipboard measurements resulted from summer expeditions to the area in 2013 and 2014, and now provide a detailed picture of the region's water properties and circulation. The hydrography is characterized by riverine Kara Sea freshwater near the surface in the southern part of the canyon, while warmer (~0°C) saline Atlantic-derived waters dominate throughout the canyon at depths >150m. Cold shelf-modified waters near the freezing point are found along the canyon edges. The mean flow at the 300 m-deep mooring location near the southern edge of the canyon is swift (30 cm/s) and oriented eastward near the surface as suggested by numerical models, while the deeper flow follows the canyon topography towards the north-east. Wind-driven deviations from the mean flow coincide with sudden changes in temperature and salinity. This study characterizes the general circulation in Vilkitsky Canyon and investigates its potential as a conduit for upwelling of Atlantic-derived waters from the Arctic Basin to the Laptev Sea shelf.

  18. Flow in bedrock canyons.

    Science.gov (United States)

    Venditti, Jeremy G; Rennie, Colin D; Bomhof, James; Bradley, Ryan W; Little, Malcolm; Church, Michael

    2014-09-25

    Bedrock erosion in rivers sets the pace of landscape evolution, influences the evolution of orogens and determines the size, shape and relief of mountains. A variety of models link fluid flow and sediment transport processes to bedrock incision in canyons. The model components that represent sediment transport processes are increasingly well developed. In contrast, the model components being used to represent fluid flow are largely untested because there are no observations of the flow structure in bedrock canyons. Here we present a 524-kilometre, continuous centreline, acoustic Doppler current profiler survey of the Fraser Canyon in western Canada, which includes 42 individual bedrock canyons. Our observations of three-dimensional flow structure reveal that, as water enters the canyons, a high-velocity core follows the bed surface, causing a velocity inversion (high velocities near the bed and low velocities at the surface). The plunging water then upwells along the canyon walls, resulting in counter-rotating, along-stream coherent flow structures that diverge near the bed. The resulting flow structure promotes deep scour in the bedrock channel floor and undercutting of the canyon walls. This provides a mechanism for channel widening and ensures that the base of the walls is swept clear of the debris that is often deposited there, keeping the walls nearly vertical. These observations reveal that the flow structure in bedrock canyons is more complex than assumed in the models presently used. Fluid flow models that capture the essence of the three-dimensional flow field, using simple phenomenological rules that are computationally tractable, are required to capture the dynamic coupling between flow, bedrock erosion and solid-Earth dynamics.

  19. Canyon and channel networks of Peru-Chile fore arc at Arica Bight

    Energy Technology Data Exchange (ETDEWEB)

    Coulbourn, W.T. (Hawaii Institute of Geophysics, Honolulu (USA))

    1990-05-01

    Canyons and channels of the Peru-Chile fore arc between 17{degree}30'S to 19{degree}30'S form a complex, integrated network revealed in SeaMARC II side-scan mosaics. The largest canyon, incised 200-600 m, is bordered by a series of sidewall slumps, producing a sinuosity that mimics subaerial meanders. The canyon courses across the Arequipa fore-arc basin floor, across a structural high and onto the middle trench slope to about 4,000 m where it disappears into a background of complex small-scale structures, From 500-2,500 m depth the canyon strikes north-south oblique to the regional slope. At 2,500 m, it abruptly turns to the southwest toward the trench axis. At this elbow, a second canyon heads on the midslope and also trends north-south until 3,500 m, where it too abruptly changes to a southwest course. A history of stream piracy analogous to subaerial systems is implied in this geometry. Tributaries join this main canyon from the landward side, forming a dendritic pattern. These channels have levees which are linked by submarine crevasse splays to sediment waves on the Arequipa basin floor. The orientation of the waves is reminiscent of bow waves from a passing ship, oblique to channel and pointing downslope, and may provide an indication of the vertical extent of passing turbidity currents. Sediments are dominantly olive gray, hemipelagic silts with sands present only immediately adjacent to the canyons. Boulders of mudstone line portions of the canyon floor. Sands are absent from the lowermost slope and trench axis, as are any indications of submarine fans. Sands may be rare in this system, with those that are present kneaded into the active margin system along the lower trench slope.

  20. Evaluation of Ancient and Future Submarine Landslides Along the Central California Coast and Their Potential to Generate Tsunamis

    Science.gov (United States)

    Greene, H. G.; Paull, C. K.; Ward, S.; Ussler, W.; Maher, N. M.

    2001-12-01

    Submarine landslides have been located along the central California continental margin with the use of multibeam bathymetric and sub-bottom profiling data. These features are primarily concentrated on the lower continental slope and in submarine canyons. Recent evaluation of these landslides indicates that they are of various ages and types and formed in different ways. For example, the extensive slope failure morphology on the lower Point Sur slope range from subtle to very sharp geomorphic shapes that suggest these landslides have occurred over a long period of time. These landslides are large features (up to 215 km2) and form primarily from bottom-up processes in a retrogressive fashion. In contrast, some of the landslide scars located on flanks of submarine canyons appear youthful indicating recent activity. Several landslide scars and blocks are also located in the headward parts of Ascension and Monterey canyons. If these scars were generated by catastrophic slope failure, they are of the size (greater than 2 km2) and depth (lie at water depths less than 400 m) to have produced a tsunamis. Based on the presence of possible incipient crown scarps, we have also identified areas within the Ascension-Monterey submarine canyons system where wall failures may occur in the future. We are in the process of using computer simulations to assess the size and extent of tsunamis that these landslides might induce. On the horizon, we hope to develop a full probabilistic hazard estimate for landslide tsunamis run-up around Monterey Bay.

  1. Facies and depositional model of Almada Canyon, Almada Basin, Bahia, Brazil; Facies e modelo deposicional do Canyon de Almada, Bacia de Almada, Bahia

    Energy Technology Data Exchange (ETDEWEB)

    D' Avila, Roberto Salvador Francisco; Souza Cruz, Carlos Emanoel de; Oliveira Filho, Jose Souto; Jesus, Candida Menezes de; Cesero, Pedro de; Dias Filho, Dorval Carvalho; Lima, Claudio Coelho de; Queiroz, Claudia Lima de; Santos, Saulo Ferreira; Ferreira, Eduardo Araripe [PETROBRAS, Santos, SP (Brazil). Unidade de Negocio de Exploracao]. E-mail: rdavila@petrobras.com.br

    2004-11-01

    In the continental portion of the Almada Basin outcrops of canyon filling deposits are represented by turbidite channels and associated facies from Urucutuca Formation. The canyon - semi-exhumated - eroded basement and pre-Cenomanian sedimentary rocks. The field study of the outcrops and cores obtained in adjacent perforations lead to the understanding of the facies and processes that controlled the deposition of these channeled turbidite that can be compared to the reservoirs of many oil fields in Brazil. The Almada canyon is a submarine conduct of tectonic origin that was enlarged by the repeated passing of turbidity currents. During the rift phase and the Albian period, compressive events reactivated old N E and N W faults in the basement as trans current fault systems. The continuation of these stresses, from the Cenomanian to the Maastrichtian, developed normal faults that controlled a submarine canyon that connected the continent, where an estuary was formed between the mountains, to the deep marine region of the basin. The canyon has received sediments brought by catastrophic fluvial floods coming from the surrounding mountains, which formed hyperpicnal flows that have evolved as turbidity currents, thus causing erosion of the substrate and carrying a huge volume of sediments to the basin. A part of that load was deposited in the canyon and formed turbidite channels filled by conglomerates, sandstones and shales. These moderately to highly efficient turbidite are intercalated to pro delta pelites and low density turbid plumes deposits, which have mostly been re mobilized as slump and debris flows (chaotic deposits). Pelites were accumulated mainly in the normal fluvial sedimentation phases, when the sandy sediment was retained next to the canyon head and were reworked by the tides on the upper part of the estuary. (author)

  2. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-09-01

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

  3. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-01-01

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

  4. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

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

  5. Contact Lenses on Submarines

    Science.gov (United States)

    2014-09-26

    Kinney, J.A.S., Luria , S.M., McKay, C.L., and Ryan, A.P. Vision of submariners. Undersea Biomed. Res. Sub. Suppl.: S163-S173, 1979. 3’. Kinney, J.A.S... Luria , S.M., Ryan, A. P., Schlichting, C.L., and Paulson, H.M. The vision of submariners and National Guardsmen: a longitudinal study. NSMRL...Rep. No. 918, 1980. 4. Socks, J.F. and Luria , S.M. Improvement of vision through the periscope, background and proposed solutions. NSMRL Rep. No

  6. Submarine-fan facies associations of the Eocene Butano Sandstone, Santa Cruz mountains, California

    Science.gov (United States)

    Nilsen, Tor H.

    1984-06-01

    The Eocene Butano Sandstone was deposited as a submarine fan in a relatively small, partly restricted basin in a borderland setting. It is possibly as thick as 3000 m and was derived from erosion of nearly Mesozoic granitic and older metamorphic rocks located to the south. Deposition was at lower bathyal to abyssal water depths. The original fan may have been 120-to 160-km long and 80-km wide. Outcrops of submarine-canyon, innerfan, middle-fan, and outer-fan facies associations indicate that the depositional model of Mutti and Ricci Lucchi can be used to describe the Butano Sandstone.

  7. Bathymetry and Canyons of the western Solomon Sea

    Science.gov (United States)

    Davies, H. L.; Keene, J. B.; Hashimoto, K.; Joshima, M.; Stuart, J. E.; Tiffin, D. L.

    1986-12-01

    The floor of the western Solomon Sea (for new bathymetric map see inside back cover of this issue) is dominated by the arched and ridged basement of the Solomon Sea Basin, the partly-sediment-filled New Britain Trench, and a more completely filled trench, the Trobriand Trough. There is a deep basin where the trenches join (149° Embayment), and a silled basin west of the New Britain Trench (Finsch Deep). Submarine canyons descend from the west and south to the 149° Embayment. Abyssal fans and plains are structurally defined and locally disturbed by young faults. Probable submerged pinnacle reefs stand in water depths as great as 1,200 m.

  8. On subsurface cooling associated with the Biobio River Canyon (Chile)

    Science.gov (United States)

    Sobarzo, Marcus; Saldías, Gonzalo S.; Tapia, Fabian J.; Bravo, Luis; Moffat, Carlos; Largier, John L.

    2016-07-01

    Submarine canyons cutting across the continental shelf can modulate the cross-shelf circulation being effective pathways to bring water from the deep ocean onto the shelf. Here, we use 69 days of moored array observations of temperature and ocean currents collected during the spring of 2013 and winter-spring 2014, as well as shipboard hydrographic surveys and sea-level observations to characterize cold, oxygen poor, and nutrient-rich upwelling events along the Biobio Submarine Canyon (BbC). The BbC is located within the Gulf of Arauco at 36° 50'S in the Central Chilean Coast. The majority of subtidal temperature at 150 m depth is explained by subtidal variability in alongshore currents on the canyon with a lag of less than a day (r2 = 0.65). Using the vertical displacement of the 10° and 10.5°C isotherms, we identified nine upwelling events, lasting between 20 h to 4.5 days, that resulted in vertical isothermal displacements ranging from 29 to 137 m. The upwelled water likely originated below 200 m. Majority of the cooling events were related with strong northward (opposite Kelvin wave propagation) flow and low pressure at the coast. Most of these low pressure events occur during relatively weak local wind forcing conditions, and were instead related with Coastal Trapped Waves (CTWs) propagating southwards from lower latitudes. These cold, high-nutrient, low-oxygen waters may be further upwelled and advected into the Gulf of Arauco by wind forcing. Thus, canyon upwelling may be a key driver of biological productivity and oxygen conditions in this Gulf.

  9. Canyon conditions impact carbon flows in food webs of three sections of the Nazaré canyon

    Science.gov (United States)

    van Oevelen, Dick; Soetaert, Karline; Garcia, R.; de Stigter, Henko C.; Cunha, Marina R.; Pusceddu, Antonio; Danovaro, Roberto

    2011-12-01

    Submarine canyons transport large amounts of sediment and organic matter (OM) from the continental shelf to the abyssal plain. Three carbon-based food web models were constructed for the upper (300-750 m water depth), middle (2700-3500 m) and lower section (4000-5000 m) of the Nazaré canyon (eastern Atlantic Ocean) using linear inverse modeling to examine how the food web is influenced by the characteristics of the respective canyon section. The models were based on an empirical dataset consisting of biomass and carbon processing data, and general physiological data constraints from the literature. Environmental conditions, most notably organic matter (OM) input and hydrodynamic activity, differed between the canyon sections and strongly affected the benthic food web structure. Despite the large difference in depth, the OM inputs into the food webs of the upper and middle sections were of similar magnitude (7.98±0.84 and 9.30±0.71 mmol C m -2 d -1, respectively). OM input to the lower section was however almost 6-7 times lower (1.26±0.03 mmol C m -2 d -1). Carbon processing in the upper section was dominated by prokaryotes (70% of total respiration), though there was a significant meiofaunal (21%) and smaller macrofaunal (9%) contribution. The high total faunal contribution to carbon processing resembles that found in shallower continental shelves and upper slopes, although the meiofaunal contribution is surprisingly high and suggest that high current speeds and sediment resuspension in the upper canyon favor the role of the meiofauna. The high OM input and conditions in the accreting sediments of the middle canyon section were more beneficial for megafauna (holothurians), than for the other food web compartments. The high megafaunal biomass (516 mmol C m -2), their large contribution to respiration (56% of total respiration) and secondary production (0.08 mmol C m -2 d -1) shows that these accreting sediments in canyons are megafaunal hotspots in the deep

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

    Science.gov (United States)

    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.

  11. Application of a lagrangian transport model to organo-mineral aggregates within the Nazaré canyon

    Directory of Open Access Journals (Sweden)

    S. Pando

    2013-06-01

    Full Text Available In this study, a hydrodynamic model was applied to the Nazaré submarine canyon with boundary forcing provided by an operational forecast model for the west Iberian coast for the spring of 2009. After validation, a lagrangian transport model was coupled to the hydrodynamic model to study and compare the transport patterns of three different classes of organo-mineral aggregates along the Nazaré canyon. The results show that the transport in the canyon is neither constant, nor unidirectional and that there are preferential areas where deposited matter is resuspended and redistributed. The transport of the larger class size of organo-mineral aggregates (2000 μm and 4000 μm is less pronounced, and a decrease in the phytodetrital carbon flux along the canyon is observed. During the modelled period, the Nazaré canyon acts as a depocentre of sedimentary organic matter rather than a conduit of organo-mineral aggregates to the deep sea, as has been reported by other authors. The results of this study are crucial for the understanding of the oceanic carbon sequestration at the continental margin, and therefore important for evaluating the role of submarine canyons within the global carbon cycle.

  12. Application of a lagrangian transport model to organo-mineral aggregates within the Nazaré canyon

    Science.gov (United States)

    Pando, S.; Juliano, M. F.; García, R.; Mendes, P. A. de Jesus; Thomsen, L.

    2013-06-01

    In this study, a hydrodynamic model was applied to the Nazaré submarine canyon with boundary forcing provided by an operational forecast model for the west Iberian coast for the spring of 2009. After validation, a lagrangian transport model was coupled to the hydrodynamic model to study and compare the transport patterns of three different classes of organo-mineral aggregates along the Nazaré canyon. The results show that the transport in the canyon is neither constant, nor unidirectional and that there are preferential areas where deposited matter is resuspended and redistributed. The transport of the larger class size of organo-mineral aggregates (2000 μm and 4000 μm) is less pronounced, and a decrease in the phytodetrital carbon flux along the canyon is observed. During the modelled period, the Nazaré canyon acts as a depocentre of sedimentary organic matter rather than a conduit of organo-mineral aggregates to the deep sea, as has been reported by other authors. The results of this study are crucial for the understanding of the oceanic carbon sequestration at the continental margin, and therefore important for evaluating the role of submarine canyons within the global carbon cycle.

  13. Cold-water coral ecosystems in Cassidaigne Canyon: An assessment of their environmental living conditions

    Science.gov (United States)

    Fabri, M.-C.; Bargain, A.; Pairaud, I.; Pedel, L.; Taupier-Letage, I.

    2017-03-01

    where the substratum shows irregularities, slopes and topographic highs. Concerning environmental variables resulting from the hydrodynamic model, temperature and high current velocities were identified as explanatory factors of the distribution of M. oculata. Suitable areas for M. oculata habitat settlement were mapped at the scale of the canyon. This study gathers multiple disciplines combined to consider a submarine canyon as a global functioning system and is an approach intended to promote the management of sensitive ecosystems in complex topographic features such as canyons.

  14. ANS Based Submarine Simulation

    Science.gov (United States)

    1994-08-01

    computer based simulation proraon supplied by Dr. John Ware at Computer Sceinces Corporation (CSC). Thee am two reasons to use simulated data instead...ANS (Artificial Neural System) capable of modeling submarine perfomncie based on full scale data generated using a computer based simulabon program...The Optimized Entropy algorilth enables the solutions to diffcu problems on a desktop computer within an acceptable time frame. Ob6ectve for w

  15. Braiding of submarine channels controlled by aspect ratio similar to rivers

    Science.gov (United States)

    Foreman, Brady Z.; Lai, Steven Y. J.; Komatsu, Yuhei; Paola, Chris

    2015-09-01

    The great majority of submarine channels formed by turbidity and density currents are meandering in planform; they consist of a single, sinuous channel that transports a turbid, dense flow of sediment from submarine canyons to ocean floor environments. Braided turbidite systems consisting of multiple, interconnected channel threads are conspicuously rare. Furthermore, such systems may not represent the spontaneous planform instability of true braiding, but instead result from erosive processes or bathymetric variability. In marked contrast to submarine environments, both meandering and braided planforms are common in fluvial systems. Here we present experiments of subaqueous channel formation conducted at two laboratory facilities. We find that density currents readily produce a braided planform for flow aspect ratios of depth to width that are similar to those that produce river braiding. Moreover, we find that stability model theory for river planform morphology successfully describes submarine channels in both experiments and the field. On the basis of these observations, we propose that the rarity of braided submarine channels is explained by the generally greater flow depths in submarine systems, which necessitate commensurately greater widths to achieve the required aspect ratio, along with feedbacks among flow thickness, suspended sediment concentration and channel relief that induce greater levee deposition rates and limit channel widening.

  16. Process sedimentology of submarine fan deposits - new perspectives

    Science.gov (United States)

    Postma, George

    2017-04-01

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

  17. Mapping the True 3D Morphology of Deep-Sea Canyons

    Science.gov (United States)

    Huvenne, V. A.; Masson, D.; Tyler, P. A.; Huehnerbach, V.

    2010-12-01

    The importance of submarine canyons as ecosystem hotspots and sediment transport pathways has been recognised for decades (e.g. Heezen et al., 1955; Vetter & Dayton, 1998). However, studying canyon systems in detail is a challenge, because of the complexity and steepness of the terrain. Acoustic surveys are hampered by side-echoes, while the high slope angles cause most types of sampling equipment, deployed from surface vessels, to fail. Ship-borne bathymetric surveys tend to represent the canyon topography in an overly smoothed way as a result of their limited resolution in deep water compared to the scale of the terrain variability. Moreover, it is clear that overhanging cliffs cannot be mapped correctly with traditional, downward looking multibeam echosounders. The increasing availability of underwater vehicles, however, opens new opportunities. During summer 2009, we mapped several submarine canyon habitats in detail, using the UK deep-water Remotely Operated Vehicle (ROV) ISIS. In particular, we developed a new methodology to map vertical cliffs and overhangs by placing the high-resolution Simrad SM2000 multibeam system of the ROV in a forward-looking position rather than in the traditional downward-looking configuration. The cliff morphology was then mapped by moving the ROV laterally in parallel passes at different depths. Repeating this approach at different distances from the cliff face, we obtained maps of varying resolution and extent. The low resolution maps provide an overview of the general geological framework, while individual strata and faunal colonies can be recognised on the highest resolution maps. Using point-cloud models, we combined the ship-borne bathymetry with the ROV-based data, in order to obtain a true 3D seabed morphology of the canyon study site, which can be used for fly-throughs, geomorphological analysis or habitat mapping. With this approach, we could visualise the spatial structure and density distribution of a unique and

  18. Seismic depth conversion problems associated with the Mississippi Canyon in the vicinity of Ewing Bank Block 305 field, offshore Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    Leveille, G.P. (Conoco Inc., New Orleans, LA (USA)); Sahai, K.S.; McDaniel, P.G.

    1990-05-01

    Ewing Bank Block 305 field is located on the outermost edge of the continental shelf, approximately 145 km south of New Orleans, Louisiana. The geology of the field is fairly typical of other fields found offshore of Louisiana, except there is a huge, partly filled, Pleistocene submarine canyon that overlies the field. This canyon, which is commonly referred to as the Mississippi Canyon, causes a large seismic depth conversion problem that makes it virtually impossible to correctly map the structure of the field using normally processed marine seismic data The Mississippi Canyon is a large erosional feature that was formed at the mouth of the ancestral Mississippi River during the last glacial sea level lowstand. In the vicinity of the field, the canyon is about 10 km wide and 1 km deep, which is approximately two-thirds the size of the Grand Canyon of the Colorado River, and is filled mostly with Holocene sediments. Because the sediments that fill the canyon are very young, their interval velocities are much lower than the interval velocities of the sediments that form the canyon walls. This creates abrupt near surface lateral velocity variations that distort the geometry of seismic reflectors such that the time geometries seen on seismic lines are not at all indicative of the structure of the subsurface. Using a model-based processing technique and available well control, the authors have been able to solve this difficult depth conversion problem and have gained a better understanding of the geology of this field.

  19. Physical linkages between an offshore canyon and surf zone morphologic change

    Science.gov (United States)

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

    2017-04-01

    The causes of surf zone morphologic changes observed along a sandy beach onshore of a submarine canyon were investigated using field observations and a numerical model (Delft3D/SWAN). Numerically simulated morphologic changes using four different sediment transport formulae reproduce the temporal and spatial patterns of net cross-shore integrated (between 0 and 6.5 m water depths) accretion and erosion observed in a ˜300 m alongshore region, a few hundred meters from the canyon head. The observations and simulations indicate that the accretion or erosion results from converging or diverging alongshore currents driven primarily by breaking waves and alongshore pressure gradients. The location of convergence or divergence depends on the direction of the offshore waves that refract over the canyon, suggesting that bathymetric features on the inner shelf can have first-order effects on short-term nearshore morphologic change.

  20. Anti Submarine Warfare Search Models

    Science.gov (United States)

    2016-09-01

    DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) Stealth and high endurance make submarines ideally suited to a variety of missions, and finding...INTENTIONALLY LEFT BLANK v ABSTRACT Stealth and high endurance make submarines ideally suited to a variety of missions, and finding ways to detect, track...II. UNIFORM DIRECTION ......................................................................................5 A. NOTATION AND DEFINITIONS

  1. Submarine Landslides: A Multidisciplinary Crossroad

    Science.gov (United States)

    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.

  2. Submarine Escape Set Test Facilities

    Directory of Open Access Journals (Sweden)

    G.S.N. Murthy

    2009-07-01

    Full Text Available Submarine Escape Set (SES is used by submariners to escape from a sunken submarine. This set caters for breathing needs of the submariner under water, until he reaches the surface. Evaluation of such life-saving equipment is of paramount importance. This paper describes the submarine escape set and various constructional features and schedules of operation of test facilities designed indegenously and which can evaluate the SES. The test facility is divided into two parts: the reducer test facility, and the breathing bag test facility. The equipment has been rigorously tested and accepted by Indian Navy. Two such test facilities have been developed, one of which is installed at INS Satavahana, Visakhapatnam, and are working satisfactorily.

  3. Current submarine atmosphere control technology.

    Science.gov (United States)

    Mazurek, W

    1998-01-01

    Air purification in submarines was introduced towards the end of World War II and was limited to the use of soda lime for the removal of carbon dioxide and oxygen candles for the regeneration of oxygen. The next major advances came with the advent of nuclear-powered submarines. These included the development of regenerative and, sometimes, energy-intensive processes for comprehensive atmosphere revitalization. With the present development of conventional submarines using air-independent propulsion there is a requirement for air purification similar to that of the nuclear-powered submarines but it is constrained by limited power and space. Some progress has been made in the development of new technology and the adoption of air purification equipment used in the nuclear-powered submarines for this application.

  4. New York Canyon Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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

  6. SCICEX: Submarine Arctic Science Program

    Data.gov (United States)

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

  7. Carbohydrate Metabolism in Submariner Personnel

    Science.gov (United States)

    1983-06-01

    metabolism the Wilkerson Point System, for glucose values, used in conjunction with patterns of insulin response described by Kraft(4) serves as the means...amount of exercise and carbohydrate metabolism characteristics occurred in both submariners and non-submariners. An inverse relationship also seems to...individuals(7). In the present study a significant negative correlation was also found between exercise vs one and two hour postprandial glucose and two hour

  8. Giant landslides and turbidity currents in the Agadir Canyon Region, NW-Africa

    Science.gov (United States)

    Krastel, Sebastian; Wynn, Russell B.; Stevenson, Christopher; Feldens, Peter; Mehringer, Lisa; Schürer, Anke

    2017-04-01

    Coring and drilling of the Moroccan Turbidite System off NW-Africa revealed a long sequence of turbidites, mostly sourced from the Moroccan continental margin and the volcanic Canary Islands. The largest individual flow deposits in the Moroccan Turbidite System contain sediment volumes >100 km3, although these large-scale events are relatively infrequent with a recurrence interval of 10,000 years (over the last 200,000 years). The largest siliciclastic flow in the last 200,000 years was the 'Bed 5 event', which transported 160 km3 of sediment up to 2000 km from the Agadir Canyon region to the southwest Madeira Abyssal Plain. 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 RV Maria S. Merian Cruise MSM32 in late 2013. A major landslide area was identified 200 km south of the Agadir Canyon. A landslide was traced from this failure area to the Agadir Canyon. This landslide entered the canyon in about 2500 m water depth. Despite a significant increase in slope angle, the landslide did not disintegrate into a turbidity current when entering the canyon but moved on as landslide for at least another 200 km down the canyon. The age of the landslide ( 145 ka) does not correspond to any major turbidte deposit in the Moroccan Turbidite System, further supporting the fact that the landslide did not disintegrate into a major turbidity current. A core taken about 350 m above the thalweg in the head region of Agadir Canyon shows a single coarse-grained turbidite, which resembles the composition of the Bed 5 event in the Madeira Abyssal Plain. Hence, the Bed 5 turbidite originated as a failure in the

  9. 2010 Pacific Gas and Electric Diablo Canyon Power Plant (DCPP): Diablo Canyon, CA Central Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Diablo Canyon Power Plant (DCPP) LiDAR and Imagery datasets are comprised of three separate LiDAR surveys: Diablo Canyon (2010), Diablo Canyon (2010), and San...

  10. Comparative naval architecture analysis of diesel submarines

    OpenAIRE

    Torkelson, Kai Oscar

    2005-01-01

    CIVINS 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 on submarines, no exclusively diesel submarine comparative naval architecture analyses have been published. One possible reason for few submarine studies may be the lack of complete and accurate information regarding the naval architecture of foreign diesel subma...

  11. Runout prediction and dynamic characteristic analysis of a potential submarine landslide in Liwan 3-1 gas field

    Institute of Scientific and Technical Information of China (English)

    XIU Zongxiang; LIU Lejun; XIE Qiuhong; LI Jiagang; HU Guanghai; YANG Jianghui

    2015-01-01

    A large number of submarine landslides with different scales have been identified in the canyon area of the submarine pipeline route of Liwan 3-1 gas field. There is still much chance that submarine slope failures would happen, and the following mass movement would present great risk to the submarine pipeline. In view of this, a numerical prediction method based on Eulerian-Eulerian two-phase flow model is introduced to simulate the mass movement of potential submarine landslides. The sliding soil and ambient water are respectively simulated by Herschel-Bulkley rheology model and Newtonian fluid model. The turbulence is simulated using thek-e model. Compared with both the experiment data and Bing result, the two-phase flow model shows a good accuracy, and its result is more close to the actual situation; the dynamic coupling between soil and ambient water can be effectively simulated and the phenomena of hydroplaning and head detachment can be obtained. Finally, the soil movement of a potential submarine landslide is simulated as an example, according to the seismic profile in the canyon area. The result shows that the hydroplaning occurs during the movement process. The runout distance calculated by the two-phase flow model is 877 m, which is 27.1% larger than the Bing result. However, the peak front velocity of soil is relative small, with a maximum value of 8.32 m/s. The Bing program with a simple and rapid process can be used for a preliminary evaluation, while the two-phase flow model is more appropriate for an accurate assessment.

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

    Directory of Open Access Journals (Sweden)

    A. Gori

    2012-12-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    A. Gori

    2013-03-01

    Full Text Available 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.

  14. Role of sediment supply and relative sea-level on sediment delivery to submarine deltas and fans of the Laurentian Channel (Lower St. Lawrence Estuary, Eastern Canada)

    Science.gov (United States)

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

    2016-04-01

    Series of submarine canyons and channels observed in the Lower St. Lawrence Estuary (LSLE; Eastern Canada) provide an opportunity to analyze in great detail their morphology, spatial distribution and Holocene activity in a relatively shallow (≤300 m) semi-enclosed basin. Four categories of canyons and channels were identified according to their feeding sources: glacially-fed, river-fed, longshore drift-fed and sediment-starved systems. This presentation will focus on the interaction between glacially-fed, river-fed (deltas) and longshore drift-fed systems. Three main types of deposits were identified in sediment core samples and seismic stratigraphy: turbidites, debrites and hyperpycnites. The analysis of high-resolution multibeam data, seismic profiles and sediment cores reveals the differences in timing of these gravity flow deposits related to submarine fan deposition. Submarine fans related to glacial meltwaters were formed during deglaciation, near 11 ka cal BP. Following the retreat of the Laurentide Ice Sheet margin in the LSLE, delta progradation allowed the formation of submarine channels by debris and hyperpycnal flows. A reduction of sediment supply from the rivers and a relative sea-level stabilization by 7 ka cal BP then limited the occurrence of these debris and hyperpycnal flows and favoured erosion of the delta fronts. During delta progradation, longshore drift-fed submarine fans were also formed due to high sediment supply, but continued transferring terrigenous material throughout the Holocene. This continued activity was possible because delta fronts eroded and longshore drift transported sediments to the canyons located at the end of a littoral cell. This study highlights that the variability and timing of sediment deposition in submarine deltas and fans is controlled primarily by variations in sediment supply in a formerly glaciated environment.

  15. Hawaiian submarine manganese-iron oxide crusts - A dating tool?

    Science.gov (United States)

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

    2004-01-01

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

  16. Deepwater Canyons 2013: Pathways to the Abyss

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Leg I focused on biological objectives in Norfolk Canyon, with some sampling in Baltimore Canyon. Leg II focused on archaeological targets in and around the Norfolk...

  17. North American Submarine Cable Association (NASCA) Submarine Cables

    Data.gov (United States)

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

  18. Obstacle avoidance sonar for submarines

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  20. California State Waters Map Series—Monterey Canyon and vicinity, California

    Science.gov (United States)

    Dartnell, Peter; Maier, Katherine L.; Erdey, Mercedes D.; Dieter, Bryan E.; Golden, Nadine E.; Johnson, Samuel Y.; Hartwell, Stephen R.; Cochrane, Guy R.; Ritchie, Andrew C.; Finlayson, David P.; Kvitek, Rikk G.; Sliter, Ray W.; Greene, H. Gary; Davenport, Clifton W.; Endris, Charles A.; Krigsman, Lisa M.; Dartnell, Peter; Cochran, Susan A.

    2016-06-10

    IntroductionIn 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 bathymetry 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 subsurface geology.The Monterey Canyon and Vicinity map area lies within Monterey Bay in central California. Monterey Bay is one of the largest embayments along the west coast of the United States, spanning 36 km from its northern to southern tips (in Santa Cruz and Monterey, respectively) and 20 km along its central axis. Not only does it contain one of the broadest sections of continental shelf along California’s coast, it also contains Monterey Canyon, one of the largest and deepest submarine canyons in the world. Note that the California’s State Waters limit extends farther offshore between Santa Cruz and Monterey so that it encompasses all of Monterey Bay.The coastal area within the map area is lightly populated. The community of Moss Landing (population, 204) hosts the largest commercial fishing fleet in Monterey Bay in its harbor. The map area also includes parts of the cities of Marina (population, about 20,000) and Castroville (population, about 6,500). Fertile lowlands of the Salinas River and Pajaro River valleys largely occupy the inland part of the map area, and land use is primarily agricultural.The offshore part of the map area lies completely within the Monterey Bay National Marine Sanctuary. The

  1. Comparative Naval Architecture Analysis of Diesel Submarines

    Science.gov (United States)

    2005-06-01

    space required to enclose all of the requirements, this volume must be able to support the weight of the submarine. In other words, Archimedes ’ principle ...accurate information regarding the naval architecture of foreign diesel submarines. However, with some fundamental submarine design principles , drawings of...cycling and hiking, I thank you for pushing me to relieve stress through my favorite sports. Last but not least of all, I want to pay tribute to the

  2. SYCAMORE CANYON PRIMITIVE AREA, ARIZONA.

    Science.gov (United States)

    Huff, Lyman C.; Raabe, R.C.

    1984-01-01

    The Sycamore Canyon Primitive Area, which occupies about 74 sq mi, lies about 24 mi southwest of Flagstaff, Arizona. To help evaluate the area for mineral resources, sediment samples were collected along Sycamore Creek and its tributaries. These were analyzed for traces of the ore metals without finding any local concentrations. In addition, a scintillometer was used to test rocks in the area without finding any abnormal radioactivity.

  3. Submarines, spacecraft and exhaled breath.

    Science.gov (United States)

    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

  4. Local scour at submarine pipelines

    Institute of Scientific and Technical Information of China (English)

    Yee-Meng Chiew

    2010-01-01

    The rapid development of offshore oil_fields has increased the number of submarine pipelines being constructed for the transport of crude oil to onshore refineries.Interactions between the pipeline and an erodible bed under the influence of current and waves often lead to local scouring around the structure.When this occurs, the pipeline may be suspended on the seabed resulting in the formation of a span.If the free span is long enough, the pipe may experience resonant flow-induced oscillations,leading to structural failure.This study examines the complex flow-structure-sediment interaction leading to the development of local scour holes around submarine pipelines.It reviews published literature in this area,which primarily is confined to the development of 2-dimensional scour holes.Despite the abundance of such research studies,pipeline-scour in the field essentially is 3-dimensional in nature.Hence, most of these studies have overlooked the importance of the transverse dimension of the scour hole,while emphasizing on its vertical dimension.This dearly is an issue that must be re-examined in light of the potential hazard and environmental disaster that one faces in the event of a pipeline failure.Recent studies have begun to recognize this shortcoming,and attempts have been made to overcome the deficiency.The study presents the state-of-the-art knowledge on local scour at submarine pipelines,both from a 2-dimensional as well as the 3-dimensional perspective.

  5. Hudson Canyon benthic habitats characterization and mapping by integrated analysis of multidisciplinary data

    Science.gov (United States)

    Pierdomenico, Martina; Guida, Vincent G.; Rona, Peter A.; Macelloni, Leonardo; Scranton, Mary I.; Asper, Vernon; Diercks, Arne

    2013-04-01

    Hudson Canyon, about 180 km SE of New York City, is the largest eastern U.S. submarine canyon and is under consideration for HAPC (Habitat Area of Particular Concern) status, representing a fisheries and biodiversity hot spot. Interest in the area, within the perspective of ecosystem based management, marine spatial planning, habitat and species conservation, led to a joint project between NOAA Northeast Fisheries, U.S. Geological Survey (USGS), Mississippi Mineral Research Institute (MMRI), National Institute for Undersea Science and Technology (NIUST), Stony Brook and Rutgers Universities for the study of benthic habitats, that includes the assembly of existing data with newly collected ones: acoustic mapping, visual ground-truthing, hydrographic, sedimentological, and trawl data collections. Acoustic mapping, performed using AUV-mounted multibeam sonar, provided ultra-high resolution bathymetric and backscatter imagery (3m and 1m respectively) at all water depths for identification of geomorphological features and for the characterization of surficial sediments along the two thirds of the shelf portion of the canyon. Identification of benthic and demersal communities was accomplished by visual ground thruthing with underwater vehicle video and still cameras, and from trawl catch data. A CTD-rosette sampler provided water column salinity-temperature profiles and water samples for dissolved methane analysis in the vicinity of suspected bottom sources. Analysis of data revealed a complex of topographic structures and hydrological patterns that provide a wide range of physical habitats in a relatively small area. A mosaic of sandy and muddy substrates, gravel beds, rock outcrops, and semilithified clay outcrops host rich and varied faunal assemblages, including deepwater corals and sponge communities. Pockmark fields, occurring below 300 m depth, suggest that methane-based chemosynthetic carbonate deposition contributes to creation of specific hard bottom habitats

  6. 47 CFR 32.2424 - Submarine & deep sea cable.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  7. 32 CFR 700.1058 - Command of a submarine.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine... submarines....

  8. Sediment transport to the deep canyons and open-slope of the western Gulf of Lions during the 2006 intense cascading and open-sea convection period

    Science.gov (United States)

    Palanques, A.; Puig, P.; Durrieu de Madron, X.; Sanchez-Vidal, A.; Pasqual, C.; Martín, J.; Calafat, A.; Heussner, S.; Canals, M.

    2012-11-01

    An array of mooring lines deployed between 300 and 1900 m depth along the Lacaze-Duthiers and Cap de Creus canyons and in the adjacent southern open slope was used to study the water and sediment transport on the western Gulf of Lions margin during the 2006 intense cascading period. Deep-reaching cascading pulses occurred in early January, in late January and from early March to mid-April. Dense water and sediment transport to the deep environments occurred not only through submarine canyons, but also along the southern open slope. During the deep cascading pulses, temporary upper and mid-canyon and open slope deposits were an important source of sediment to the deep margin. Significant sediment transport events at the canyon head only occurred in early January because of higher sediment availability on the shelf after the stratified and calm season, and in late February because of the interaction of dense shelf water cascading with a strong E-SE storm. During the January deep cascading pulses, increases in suspended sediment concentration within the canyon were greater and earlier at 1000 m depth than at 300 m depth, whereas during the March-April deep cascading pulses sediment concentration only increased below 300 m depth, indicating resuspension and redistribution of sediments previously deposited at upper and mid-canyon depths. Deeper than 1000 m depth, net fluxes show that most of the suspended sediment left the canyon and flowed along the southern open slope towards the Catalan margin, whereas a small part flowed down-canyon and was exported basinward. Additionally, on the mid- and lower-continental slope there was an increase in the near-bottom currents induced by deep open-sea convection processes and the propagation of eddies. This, combined with the arrival of deep cascading pulses, also generated moderate suspended sediment transport events in the deeper slope regions.

  9. Environmental assessment: Davis Canyon site, Utah

    Energy Technology Data Exchange (ETDEWEB)

    none,

    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.

  10. Environmental assessment: Davis Canyon site, Utah

    Energy Technology Data Exchange (ETDEWEB)

    none,

    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.

  11. H-Canyon Recovery Crawler

    Energy Technology Data Exchange (ETDEWEB)

    Kriikku, E. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hera, K. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Marzolf, A. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Phillips, M. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-01

    The Nuclear Material Disposition Project group asked the Savannah River National Lab (SRNL) Research and Development Engineering (R&DE) department to help procure, test, and deploy a remote crawler to recover the 2014 Inspection Crawler (IC) that tipped over in the H-Canyon Air Exhaust Tunnel. R&DE wrote a Procurement Specification for a Recovery Crawler (RC) and SRNS Procurement Department awarded the contract to Power Equipment Manufacturing Inc. (PEM). The PEM RC was based on their standard sewer inspection crawler with custom arms and forks added to the front. The arms and forks would be used to upright the 2014 Inspection Crawler. PEM delivered the RC and associated cable reel, 2014 Inspection Crawler mockup, and manuals in late April 2015. R&DE and the team tested the crawler in May of 2015 and made modifications based on test results and Savannah River Site (SRS) requirements. R&DE delivered the RC to H-Area at the end of May. The team deployed the RC on June 9, 10, and 11, 2015 in the H-Canyon Air Exhaust Tunnel. The RC struggled with some obstacles in the tunnel, but eventually made it to the IC. The team spent approximately five hours working to upright the IC and eventually got it on its wheels. The IC travelled approximately 20 feet and struggled to drive over debris on the air tunnel floor. Unfortunately the IC tripped over trying to pass this obstacle. The team decided to leave the IC in this location and inspect the tunnel with the RC. The RC passed the IC and inspected the tunnel as it travelled toward H-Canyon. The team turned the RC around when it was about 20 feet from the H-Canyon crossover tunnel. From that point, the team drove the RC past the manway towards the new sand filter and stopped approximately 20 feet from the new sand filter. The team removed the RC from the tunnel, decontaminated the RC, and stored it the manway building, 294-2H. The RC deployment confirmed the IC was not in a condition to perform useful tunnel inspections and

  12. Late Quaternary climatic events and sea-level changes recorded by turbidite activity, Dakar Canyon, NW Africa

    Science.gov (United States)

    Pierau, Roberto; Hanebuth, Till J. J.; Krastel, Sebastian; Henrich, Rüdiger

    2010-03-01

    The relationship of sea-level changes and short-term climatic changes with turbidite deposition is poorly documented, although the mechanisms of gravity-driven sediment transport in submarine canyons during sea-level changes have been reported from many regions. This study focuses on the activity of the Dakar Canyon off southern Senegal in response to major glacial/interglacial sea-level shifts and variability in the NW-African continental climate. The sedimentary record from the canyon allows us to determine the timing of turbidite events and, on the basis of XRF-scanning element data, we have identified the climate signal at a sub-millennial time scale from the surrounding hemipelagic sediments. Over the late Quaternary the highest frequency in turbidite activity in the Dakar Canyon is confined to major climatic terminations when remobilisation of sediments from the shelf was triggered by the eustatic sea-level rise. However, episodic turbidite events coincide with the timing of Heinrich events in the North Atlantic. During these times continental climate has changed rapidly, with evidence for higher dust supply over NW Africa which has fed turbidity currents. Increased aridity and enhanced wind strength in the southern Saharan-Sahelian zone may have provided a source for this dust.

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

    Science.gov (United States)

    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.

  14. Structure and history of submarine slope failures at the Cape Fear submarine landslide, U.S. Atlantic margin

    Science.gov (United States)

    Miller, N. C.; Chaytor, J. D.; Hutchinson, D. R.; Ten Brink, U. S.; Flores, C. H.

    2015-12-01

    New multi-channel seismic (MCS), chirp sub-bottom, and multibeam bathymetry and backscatter data image the Late Pleistocene-Holocene age Cape Fear submarine landslide (CFS) along its complete ~375 km length, from the multiple headwalls at ~2500 m water depth on the slope to the lobate, low-relief toe at ~5400 m water depth. A surficial chaotic mass transport deposit (MTD) filling the failure scar exceeds 100 m in thickness over large sections of the deposit, thinning towards the margins of the slide. Below 5000 m, the CFS truncates the surficial MTD of the Cape Lookout Landslide in several places, indicating that it post-dates the Cape Lookout Landslide. At depth, the MCS data image the edge of the Cape Fear salt diapir and a seismically transparent region that may be associated with fluid flow focused along the edge of the diapir. This potential fluid pathway sits directly beneath the headwalls of the CFS, supporting the hypothesis that the salt diapir is responsible for the failure, either through deformation of sediments during salt emplacement or by focusing of fluids, or both. The MCS data also image several earlier MTDs. These deposits are confined to sediments younger than the early Cenozoic, consistent with interpretations of major canyon cutting in the Eocene and initiation of intense deep and erosive currents in the Late Paleogene. These processes can over-steepen and redistribute slope sediments, enhancing conditions for slope failures and salt diapirism.

  15. Prehistoric deforestation at Chaco Canyon?

    Science.gov (United States)

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

    2014-08-12

    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.

  16. The submarine river of Port Miou (France), A karstic system inherited from the Messinian deep stage

    Science.gov (United States)

    Cavalera, T.; Gilli, E.

    2009-04-01

    The Port Miou system (Cassis, France) is a two kilometers long submarine gallery that extends in the limestone series of Calanques (Marseille, France). The average discharge is between 2 to 5 m3/s but the water is brackish and cannot be used for water supply. In the 1970s, a dam was built to prevent saltwater intrusion in the cave but these experimental attempts did not succeed in getting rid of the residual salinity which remained near 3 g l-1 upstream the dam. The use of helium and later rebreathers by cave divers made possible the exploration of a vertical pit down to 179 m below the sea level. At that depth, the water is still brackish. The cave extends further and deeper but the exploration is limited by the present diving technology. The canyon of Cassidaigne is located a few kilometers south from Port Miou. It cuts the continental shelf where bathymetric studies have shown the presence of dolines. Caves and speleothems have been observed during submarine explorations on the walls of the canyon. This canyon is not connected to a continental valley and it is assumed that it is a pocket valley. Its presence is related to the several lowering stages of the Mediterranean Sea during the Messinian Salinity Crisis. We suggest that during the important drop of sea level of the Mediterranean, the underground river of Port-Miou, flowed several hundreds meters below its current position, and excavated the canyon. At the end of the Messinian crisis, the system was flooded by seawater. The karst water now flows through an upper gallery but the presence of a paleo-drain filled by seawater makes possible a deep marine intrusion into the karst system. Several geomorphologic clues (bathymetry, submarine valley network…) reinforce the fact that the continental shelf near Marseilles is an important karstic network drowned below the sea level. This model is supported by the observation in Port Miou of an important quantity of titanium at the upper surface of the cave sediment

  17. Deep-Sea, Deep-Sequencing: Metabarcoding Extracellular DNA from Sediments of Marine Canyons.

    Directory of Open Access Journals (Sweden)

    Magdalena Guardiola

    Full Text Available Marine sediments are home to one of the richest species pools on Earth, but logistics and a dearth of taxonomic work-force hinders the knowledge of their biodiversity. We characterized α- and β-diversity of deep-sea assemblages from submarine canyons in the western Mediterranean using an environmental DNA metabarcoding. We used a new primer set targeting a short eukaryotic 18S sequence (ca. 110 bp. We applied a protocol designed to obtain extractions enriched in extracellular DNA from replicated sediment corers. With this strategy we captured information from DNA (local or deposited from the water column that persists adsorbed to inorganic particles and buffered short-term spatial and temporal heterogeneity. We analysed replicated samples from 20 localities including 2 deep-sea canyons, 1 shallower canal, and two open slopes (depth range 100-2,250 m. We identified 1,629 MOTUs, among which the dominant groups were Metazoa (with representatives of 19 phyla, Alveolata, Stramenopiles, and Rhizaria. There was a marked small-scale heterogeneity as shown by differences in replicates within corers and within localities. The spatial variability between canyons was significant, as was the depth component in one of the canyons where it was tested. Likewise, the composition of the first layer (1 cm of sediment was significantly different from deeper layers. We found that qualitative (presence-absence and quantitative (relative number of reads data showed consistent trends of differentiation between samples and geographic areas. The subset of exclusively benthic MOTUs showed similar patterns of β-diversity and community structure as the whole dataset. Separate analyses of the main metazoan phyla (in number of MOTUs showed some differences in distribution attributable to different lifestyles. Our results highlight the differentiation that can be found even between geographically close assemblages, and sets the ground for future monitoring and conservation

  18. Stratigraphic evolution of a long-lived submarine channel system in the Late Cretaceous Nanaimo Group, British Columbia, Canada

    Science.gov (United States)

    Bain, Heather A.; Hubbard, Stephen M.

    2016-05-01

    Submarine canyons and slope channel systems are important conveyers of sediment from uplifted catchments to oceanic sedimentary sinks. Long-lived conduits can be established through deep incision of submarine canyons, with bathymetric relief of hundreds of meters to greater than a kilometer in many instances. Alternatively, a combination of erosion of the continental slope and aggradation of levees can yield a broadly comparable stratigraphic product through evolution of channels with more subdued bathymetric relief. Despite differences in formative geomorphic elements on the paleo-seafloor, differentiating the stratigraphic architecture amongst these systems is challenging, particularly in outcrop datasets. Accurate stratigraphic interpretation has significant implications for understanding the frequency and magnitude of controlling processes such as mountain building and denudation or eustatic sea-level fluctuations. In this study, deep-water channel strata of the Late Cretaceous Nanaimo Group are examined at Hornby and Denman islands, British Columbia, Canada. Evidence for a long-lived submarine conduit records the history of sediment transfer at multiple temporal and spatial scales. The composite submarine channel system deposit is 19.5 km wide and 1500 m thick, which formed and filled over ~ 15 Ma. Facies scale analyses highlight conglomeratic channel fill juxtaposed against thin-bedded out-of-channel deposits. Erosional surfaces are commonly mantled by mass-transport deposits, which provide evidence for conduit wall reworking and maintenance. At a larger scale, a series of composite, conglomerate-prone channelform bodies are observed to stratigraphically stack in two distinct phases: (1) early persistence of laterally offset (migrated) channels; and (2) later vertically aligned and aggraded channels. This stratigraphic trend is comparable to composite, multi-phase degradational-aggradational submarine channel complexes observed globally. As such, we consider

  19. Flow Over a Model Submarine

    Science.gov (United States)

    Jiménez, Juan; Smits, Alexander

    2003-11-01

    Experimental investigation over a DARPA SUBOFF submarine model (SUBOFF Model) was performed using flow visualization and Digital Particle Image Velocimetry (DPIV). The model has an axisymmetric body with sail and fins, and it was supported by a streamlined strut that was formed by the extension of the sail appendage. The range of flow conditions studied correspond to a Reynolds numbers based on model length, Re_L, of about 10^5. Velocity vector fields, turbulence intensities, vorticity fields, and flow visualization in the vicinity of the junction flows are presented. In the vicinity of the control surface and sail hull junctions, the presence of streamwise vortices in the form of horseshoe or necklace vortices locally dominates the flow. The effects of unsteady motions about an axis passing through the sail are also investigated to understand the evolution of the unsteady wake.

  20. Personality and coping strategies during submarine missions.

    Science.gov (United States)

    Sandal, Gro M; Endresen, Inger M; Vaernes, Ragnar; Ursin, Holger

    2003-01-01

    Relations between personality profiles, measured by the Personality Characteristics Inventory (PCI), and habitual coping strategies, measured by the Utrecht Coping List (UCL), were investigated in a sample of submarine personnel and office employees. The predictive validity of these instruments were examined for reported stress, health complaints, and salivary cortisone measures during 3 submarine missions. PCI and UCL were completed before the missions, and questionnaires and saliva were collected weekly. The results showed no significant relations between PCI profiles and coping strategies. Interpersonal orientation, achievement motivation, and habitual coping strategies were predictors for coping during the submarine missions. Problem-directed strategies and interpersonal sensitivity combined with strong achievement motivation were related to low indicated stress from social factors (lack of privacy, interpersonal tension, and crowding) and homesickness. The findings suggest that interpersonal characteristics need to be considered in the selection of submariners and personnel for other military settings in which units are exposed to prolonged stress and isolation.

  1. Aspects of Propeller Developements for a Submarine

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  2. CHALLENGES POSED BY RETIRED RUSSIAN NUCLEAR SUBMARINES

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Dieter; Kroken, Ingjerd; Latyshev, Eduard; Griffith, Andrew

    2003-02-27

    The purpose of this paper is to provide an overview of the challenges posed by retired Russian nuclear submarines, review current U.S. and International efforts and provide an assessment of the success of these efforts.

  3. Seasonal variability in particulate matter source and composition to the depositional zone of Baltimore Canyon, U.S. Mid-Atlantic Bight

    Science.gov (United States)

    Prouty, Nancy G.; Mienis, Furu; Campbell, P.; Roark, E. Brendan; Davies, Andrew; Robertson, Craig M.; Duineveld, Gerard; Ross, Steve W.; Rhodes, M.; Demopoulos, Amanda W.J.

    2017-01-01

    Submarine canyons are often hotspots of biomass and productivity in the deep sea. However, the majority of deep-sea canyons remain poorly sampled. Using a multi-tracer approach, results from a detailed geochemical investigation from a year-long sediment trap deployment reveals details concerning the source, transport, and fate of particulate matter to the depositional zone (1318 m) of Baltimore Canyon on the US Mid-Atlantic Bight (MAB). Both organic biomarker composition (sterol and n-alkanes) and bulk characteristics (δ13C, Δ14C, Chl-a) suggest that on an annual basis particulate matter from marine and terrestrially-derived organic matter are equally important. However, elevated Chlorophyll-a and sterol concentrations during the spring sampling period highlight the seasonal influx of relatively fresh phytodetritus. In addition, the contemporaneous increase in the particle reactive elements cadmium (Cd) and molybdenum (Mo) in the spring suggest increased scavenging, aggregation, and sinking of biomass during seasonal blooms in response to enhanced surface production within the nutricline. While internal waves within the canyon resuspend sediment between 200 and 600 m, creating a nepheloid layer rich in lithogenic material, near-bed sediment remobilization in the canyon depositional zone is minimal. Instead, vertical transport and lateral transport across the continental margin are the dominant processes driving seasonal input of particulate matter. In turn, seasonal variability in deposited particulate organic matter may be linked to benthic faunal composition and ecosystem scale carbon cycling.

  4. Personality and Coping Strategies During Submarine Missions

    OpenAIRE

    Sandal, Gro M.; Endresen, Inger M.; Vaernes, Ragnar; Ursin, Holger

    2003-01-01

    Relations between personality profiles, measured by the Personality Characteristics Inventory (PCI), and habitual coping strategies, measured by the Utrecht Coping List (UCL), were investigated in a sample of submarine personnel and office employees. The predictive validity of these instruments were examined for reported stress, health complaings, and salivary cortisone measures during 3 submarine missions. PCI and UCL were completed before the missions, and questionnaires and saliva were col...

  5. China's First Robot Submarine Archeologist

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    China recently announced successful experimentation with the first bionic robot “fish” in submarine archeology. This fish-like robot was put to work off the Fujian coast last year by archeologists conducting a submarine survey of an ancient battleship that was part of Ming general Zheng Chenggong's fleet The robot is capable of working continuously for 2-3 hours at a maximum speed of 1.5 m per second. Its performance was reported as “excellent”

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

    Science.gov (United States)

    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.

  7. Contours--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  8. Street canyon ventilation and atmospheric turbulence

    Science.gov (United States)

    Salizzoni, P.; Soulhac, L.; Mejean, P.

    Operational models for pollutant dispersion in urban areas require an estimate of the turbulent transfer between the street canyons and the overlying atmospheric flow. To date, the mechanisms that govern this process remain poorly understood. We have studied the mass exchange between a street canyon and the atmospheric flow above it by means of wind tunnel experiments. Fluid velocities were measured with a Particle Image Velocimetry system and passive scalar concentrations were measured using a Flame Ionisation Detector. The mass-transfer velocity between the canyon and the external flow has been estimated by measuring the cavity wash-out time. A two-box model, used to estimate the transfer velocity for varying dynamical conditions of the external flow, has been used to interpret the experimental data. This study sheds new light on the mechanisms which drive the ventilation of a street canyon and illustrates the influence of the external turbulence on the transfer process.

  9. Modelling Aerosol Dispersion in Urban Street Canyons

    Science.gov (United States)

    Tay, B. K.; Jones, D. P.; Gallagher, M. W.; McFiggans, G. B.; Watkins, A. P.

    2009-04-01

    Flow patterns within an urban street canyon are influenced by various micrometeorological factors. It also represents an environment where pollutants such as aerosols accumulate to high levels due to high volumes of traffic. As adverse health effects are being attributed to exposure to aerosols, an investigation of the dispersion of aerosols within such environments is of growing importance. In particular, one is concerned with the vertical structure of the aerosol concentration, the ventilation characteristics of the street canyon and the influence of aerosol microphysical processes. Due to the inherent heterogeneity of the aerosol concentrations within the street canyon and the lack of spatial resolution of measurement campaigns, these issues are an on-going debate. Therefore, a modelling tool is required to represent aerosol dispersion patterns to provide insights to results of past measurement campaigns. Computational Fluid Dynamics (CFD) models are able to predict detailed airflow patterns within urban geometries. This capability may be further extended to include aerosol dispersion, by an Euler-Euler multiphase approach. To facilitate the investigation, a two-dimensional, multiphase CFD tool coupled with the k-epsilon turbulence model and with the capability of modelling mixed convection flow regimes arising from both wind driven flows and buoyancy effects from heated walls was developed. Assuming wind blowing perpendicularly to the canyon axis and treating aerosols as a passive scalar, an attempt will be made to assess the sensitivities of aerosol vertical structure and ventilation characteristics to the various flow conditions. Numerical studies were performed using an idealized 10m by 10m canyon to represent a regular canyon and 10m by 5m to represent a deep one. An aerosol emission source was assigned on the centerline of the canyon to represent exhaust emissions. The vertical structure of the aerosols would inform future directives regarding the

  10. Habitat--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Monterey Canyon and Vicinity map area, California. The vector data file is included in...

  11. Habitat--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Monterey Canyon and Vicinity map area, California. The vector data file is included in...

  12. Contours--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  13. Influence of submarine morphology on bottom water flow across the western Ross Sea continental margin

    Science.gov (United States)

    Davey, F.J.; Jacobs, S.S.

    2007-01-01

    Multibeam sonar bathymetry documents a lack of significant channels crossing outer continental shelf and slope of the western Ross Sea. This indicates that movement of bottom water across the shelf break into the deep ocean in this area is mainly by laminar or sheet flow. Subtle, ~20 m deep and up to 1000 m wide channels extend down the continental slope, into tributary drainage patterns on the upper rise, and then major erosional submarine canyons. These down-slope channels may have been formed by episodic pulses of rapid down slope water flow, some recorded on bottom current meters, or by sub-ice melt water erosion from an icesheet grounded at the margin. Narrow, mostly linear furrows on the continental shelf thought to be caused by iceberg scouring are randomly oriented, have widths generally less than 400 m and depths less than 30m, and extend to water depths in excess of 600 m.

  14. Flow Structure in a Bedrock Canyon (Invited)

    Science.gov (United States)

    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

  15. Structure of Flow in a Bedrock Canyon

    Science.gov (United States)

    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

  16. Environmental assessment: Davis Canyon site, Utah

    Energy Technology Data Exchange (ETDEWEB)

    none,

    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.

  17. Different Views of the Grand Canyon

    Science.gov (United States)

    Elders, Wilfred A.

    Each year the spectacular scenery of the Grand Canyon of Arizona awes its more than 4,000,000 visitors. Just as its enormous scale dwarfs our human sense of space, its geology also dwarfs our human sense of time. Perhaps here, more than anywhere else on the planet, we can experience a sense of ``Deep Time.'' The colorful rocks exposed in the vertical walls of the canyon display a span of 1.8 billion years of Earth's history [Beus and Morales, 2003]. But wait! There is a different view! According to Vail [2003], this time span is only 6,000 years and the Grand Canyon and its rocks are a record of the Biblical 6 days of creation and Noah's flood. During a visit to Grand Canyon, in August 2003, I learned that Vail's book, Grand Canyon: A Different View, is being sold within the National Park. The author and compiler of Grand Canyon: A Different View is a Colorado River guide who is well acquainted with the Grand Canyon at river level. He has produced a book with an attractive layout and beautiful photographs. The book is remarkable because it has 23 co-authors, all male, who comprise a veritable ``Who's Who'' in creationism. For example, Henry Morris and John Whitcomb, the authors of the seminal young Earth creationist text, The Genesis Flood [Whitcomb and Morris, 1961], each contribute a brief introduction. Each chapter of Grand Canyon: A Different View begins with an overview by Vail, followed by brief comments by several contributors that ``have been peer reviewed to ensure a consistent and Biblical perspective.'' This perspective is strict Biblical literalism.

  18. Hydroplaning and submarine debris flows

    Science.gov (United States)

    de Blasio, Fabio V.; Engvik, Lars; Harbitz, Carl B.; ElverhøI, Anders

    2004-01-01

    Examination of submarine clastic deposits along the continental margins reveals the remnants of holocenic or older debris flows with run-out distances up to hundreds of kilometers. Laboratory experiments on subaqueous debris flows, where typically one tenth of a cubic meter of material is dropped down a flume, also show high velocities and long run-out distances compared to subaerial debris flows. Moreover, they show the tendency of the head of the flow to run out ahead of the rest of the body. The experiments reveal the possible clue to the mechanism of long run-out. This mechanism, called hydroplaning, begins as the dynamic pressure at the front of the debris flow becomes of the order of the pressure exerted by the weight of the sediment. In such conditions a layer of water can intrude under the sediment with a lubrication effect and a decrease in the resistance forces between the sediment and the seabed. A physical-mathematical model of hydroplaning is presented and investigated numerically. The model is applied to both laboratory- and field-scale debris flows. Agreement with laboratory experiments makes us confident in the extrapolation of our model to natural flows and shows that long run-out distances can be naturally attained.

  19. GRIM FATE OF UNLUCKY STRANDED SUBMARINE E13

    DEFF Research Database (Denmark)

    Nørby, Søren

    2015-01-01

    THE STORY OF A BRITISH SUBMARINE THAT SUFFERED AT THE HANDS OF THE GERMANS AFTER RUNNING AGROUND IN AUGUST 1915.......THE STORY OF A BRITISH SUBMARINE THAT SUFFERED AT THE HANDS OF THE GERMANS AFTER RUNNING AGROUND IN AUGUST 1915....

  20. Was the 1531 Lisbon tsunami generated by a landslide along the Cascais Canyon? Geologic inferences and tsunami simulation

    Science.gov (United States)

    Lo Iacono, C.; Masson, D. G.; Glimsdal, S.; Huvenne, V. A. I.; Wynn, R. B.; Harbitz, C. B.

    2015-12-01

    In 1531, a 6.5 magnitude earthquake with an epicentre inland of Lisbon caused severe damage to the city, rendering a third of its buildings uninhabitable, with its intensity comparable or even greater than the 1755 Lisbon earthquake. This event was followed by a destructive tsunami of slightly smaller size than the 1755 and, in contrast to the latter, it was only observed locally along the entire Tagus estuary and in coastal belt surroundings the mouth of the Tagus River. For the 1531 tsunami, a satisfactory mechanism for its generation has yet to be found, but the inland earthquake epicentre and the absence of large submarine scarps tend to rule out fault-related seabed displacement in and out of the Tagus estuary. An alternative possibility is that the 1531 tsunami was caused by a submarine landslide triggered by the earthquake. Here we describe a submarine landslide along the Cascais Canyon, whose head faces the Tagus estuary, which may have caused the 1531 tsunami. At a depth of around 2000 m, up to 150 m across and 45 m high bocks, erosional furrows and possible gravel waves have been imaged over an area of at least 15 km2 using 30 kHz deep-towed sidescan sonar, suggesting a geologically recent large-scale flow event. High-resolution bathymetry and seafloor photographs acquired at around 4000 m using a remotely operated vehicle (ROV) in the blocky landslide area show boulders at the seafloor, mantled with a thin sediment cover, again suggestive of a recent landslide. Radiocarbon dates from collected cores show that this landslide is likely to have been generated during the 16th century, suggesting a cause-effect relationship with the 1531 earthquake. Preliminary tsunami models suggest that a landslide potentially fitting the characteristics of the Cascais landslide is able to generate a near-field tsunami wave reaching the Lisbon coast but not crossing the whole Tagus estuary. Recognising that the 1531 Lisbon tsunami may have been generated by a submarine

  1. TRAFFIC EMISSION TRANSPORTATION IN STREET CANYONS

    Institute of Scientific and Technical Information of China (English)

    XIE Xiao-min; WANG Jia-song; HUANG Zhen

    2009-01-01

    Spatial distributions of traffic-related pollutants in street canyons were investigated by field measurements and Computational Fluid Dynamics(CFD).Two typical street canyons were selected for field monitoring,and a three-dimensional numerical model was built based on Reynolds-averaged Navier-Stokes equations equipped with the standard k-ε turbulence models for CFD simulations.The study shows that the pollutant concentrations of vehicle emission correlate well with the traffic volume variation,wind direction and wind speed.The wind direction and speed at the roof level determine overwhellmingly the flow field and the distributions of pollutant concentrations in the street canyon.When the wind speed is equal to zero,the pollutant concentrations on the breath height of the both sides of the street canyon are almost the same.When the wind direction is perpendicular to the street,one main vortex is formed with a shape depending on the building structure on both sides of the street,the pollutant is accumulated on the leeward side,and the pollutant concentrations at the breath height on the leeward side are 2 to 3 times as those at the breath height on the windward side.If the wind direction makes some angles with the street canyon,the pollutant concentration will be higher on the leeward side because one main vortex will also be formed in the vertical section of the canyon by the perpendicular component of the wind.But pollutant concentrations decrease in the canyon because pollutants are dispersed along the axis of the street.Pollutants at different heights of the vertical section decrease with height,i.e.there are concentration gradients in the vertical section,and the pollutant concentrations on the leeward side of the upstream building are much higher than those on the windward side of the downstream building.

  2. Reducing Unsteady Loads on a Piggyback Miniature Submarine

    Science.gov (United States)

    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.

  3. A simple and efficient GIS tool for volume calculations of submarine landslides

    Science.gov (United States)

    Völker, David Julius

    2010-10-01

    A numeric tool is presented for calculating volumes of topographic voids such as slump scars of landslides, canyons or craters (negative/concave morphology), or alternatively, bumps and hills (positive/convex morphology) by means of digital elevation models embedded within a geographical information system (GIS). In this study, it has been used to calculate landslide volumes. The basic idea is that a (singular) event (landslide, meteorite impact, volcanic eruption) has disturbed an intact surface such that it is still possible to distinguish between the former (undisturbed) landscape and the disturbance (crater, slide scar, debris avalanche). In such cases, it is possible to reconstruct the paleo-surface and to calculate the volume difference between both surfaces, thereby approximating the volume gain or loss caused by the event. I tested the approach using synthetically generated land surfaces that were created on the basis of Shuttle Radar Topography Mission data. Also, I show the application to two real cases, (1) the calculation of the volume of the Masaya Slide, a submarine landslide on the Pacific continental slope of Nicaragua, and (2) the calculation of the void of a segment of the Fish River Canyon, Namibia. The tool is provided as a script file for the free GIS GRASS. It performs with little effort, and offers a range of interpolation parameters. Testing with different sets of interpolation parameters results in a small range of uncertainty. This tool should prove useful in surface studies not exclusively on earth.

  4. Submarine Pipeline Routing Risk Quantitative Analysis

    Institute of Scientific and Technical Information of China (English)

    徐慧; 于莉; 胡云昌; 王金英

    2004-01-01

    A new method for submarine pipeline routing risk quantitative analysis was provided, and the study was developed from qualitative analysis to quantitative analysis.The characteristics of the potential risk of the submarine pipeline system were considered, and grey-mode identification theory was used. The study process was composed of three parts: establishing the indexes system of routing risk quantitative analysis, establishing the model of grey-mode identification for routing risk quantitative analysis, and establishing the standard of mode identification result. It is shown that this model can directly and concisely reflect the hazard degree of the routing through computing example, and prepares the routing selection for the future.

  5. Grand Canyon Humpback Chub Population Improving

    Science.gov (United States)

    Andersen, Matthew E.

    2007-01-01

    The humpback chub (Gila cypha) is a long-lived, freshwater fish found only in the Colorado River Basin. Physical adaptations-large adult body size, large predorsal hump, and small eyes-appear to have helped humpback chub evolve in the historically turbulent Colorado River. A variety of factors, including habitat alterations and the introduction of nonnative fishes, likely prompted the decline of native Colorado River fishes. Declining numbers propelled the humpback chub onto the Federal list of endangered species in 1967, and the species is today protected under the Endangered Species Act of 1973. Only six populations of humpback chub are currently known to exist, five in the Colorado River Basin above Lees Ferry, Ariz., and one in Grand Canyon, Ariz. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center oversees monitoring and research activities for the Grand Canyon population under the auspices of the Glen Canyon Dam Adaptive Management Program (GCDAMP). Analysis of data collected through 2006 suggests that the number of adult (age 4+ years) humpback chub in Grand Canyon increased to approximately 6,000 fish in 2006, following an approximate 40-50 percent decline between 1989 and 2001. Increasing numbers of adult fish appear to be the result of steadily increasing numbers of juvenile fish reaching adulthood beginning in the mid- to late-1990s and continuing through at least 2002.

  6. Deciphering Outburst Flood Discharges from the Morphology of Hesperian Canyons

    Science.gov (United States)

    Lapotre, M. G. A.; Lamb, M. P.; Williams, R. M.

    2014-07-01

    We model the hydraulics of outburst floods over canyon escarpments. We show that canyons only maintain a constant width under a certain hydraulic regime. We combine the hydraulic model to an erosion law to constrain paleodischarges at Echus Chasma.

  7. Addressing submarine geohazards through scientific drilling

    Science.gov (United States)

    Camerlenghi, A.

    2009-04-01

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

  8. California State Waters Map Series—Monterey Canyon and vicinity, California

    Science.gov (United States)

    Dartnell, Peter; Maier, Katherine L.; Erdey, Mercedes D.; Dieter, Bryan E.; Golden, Nadine E.; Johnson, Samuel Y.; Hartwell, Stephen R.; Cochrane, Guy R.; Ritchie, Andrew C.; Finlayson, David P.; Kvitek, Rikk G.; Sliter, Ray W.; Greene, H. Gary; Davenport, Clifton W.; Endris, Charles A.; Krigsman, Lisa M.; Dartnell, Peter; Cochran, Susan A.

    2016-06-10

    IntroductionIn 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 bathymetry 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 subsurface geology.The Monterey Canyon and Vicinity map area lies within Monterey Bay in central California. Monterey Bay is one of the largest embayments along the west coast of the United States, spanning 36 km from its northern to southern tips (in Santa Cruz and Monterey, respectively) and 20 km along its central axis. Not only does it contain one of the broadest sections of continental shelf along California’s coast, it also contains Monterey Canyon, one of the largest and deepest submarine canyons in the world. Note that the California’s State Waters limit extends farther offshore between Santa Cruz and Monterey so that it encompasses all of Monterey Bay.The coastal area within the map area is lightly populated. The community of Moss Landing (population, 204) hosts the largest commercial fishing fleet in Monterey Bay in its harbor. The map area also includes parts of the cities of Marina (population, about 20,000) and Castroville (population, about 6,500). Fertile lowlands of the Salinas River and Pajaro River valleys largely occupy the inland part of the map area, and land use is primarily agricultural.The offshore part of the map area lies completely within the Monterey Bay National Marine Sanctuary. The

  9. The Role of Antecedent Geology in Submarine Slope Failure: Insights from the Currituck Slide Complex along the Central U.S. Atlantic Margin

    Science.gov (United States)

    Hill, J. C.; Brothers, D. S.; Ten Brink, U. S.; Craig, B.; Chaytor, J. D.; Flores, C. H.

    2015-12-01

    To investigate the influence of antecedent geology on the distribution of submarine landslides along the central U.S. Atlantic margin, we examined a suite of multichannel seismic data, including vintage airgun data from Norfolk Canyon to Cape Hatteras and new high-resolution sparker data across the Currituck Slide, as well as regional multibeam bathymetry. Areas north and south of the Currituck Slide are characterized by oblique margin morphology, defined by angular, convex deltaic clinoforms deposited during the Mid-Miocene, which generated an abrupt shelf-break with relatively steep downslope gradients (>8°). As a result, upper slope sediment bypass, closely spaced submarine canyons, and small landslides confined to canyon headwalls and sidewalls characterize these areas. In contrast, the Currituck region is defined by a sigmoidal geometry, with a smooth shelf-edge rollover and more gentle slope gradient (800m of Plio-Pleistocene sediment accumulation across the continental slope prior to failure. Regionally continuous seismic reflectors show little or no evidence of canyonization beneath the Currituck Slide. A significant volume of intact strata on the lower slope suggests the Currituck region was a primary depocenter for fluvial inputs during multiple sea level lowstands. Failure along bedding planes is evident in outcropping strata along the upper and lower headwalls. Buried scarps beneath these headwalls imply repeated cycles of failure. Folds and faults suggest differential compaction across these scarps may have contributed to the most recent failure. These results suggest high sedimentation and subsequent compaction along a sigmoidal margin were critical components in preconditioning the Currituck Slide for failure. Examination of the regional geological framework illustrates the importance of sediment supply and antecedent slope morphology in the development of large, potentially unstable depocenters along passive margins.

  10. 27 CFR 9.152 - Malibu-Newton Canyon.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Malibu-Newton Canyon. 9... Malibu-Newton Canyon. (a) Name. The name of the viticultural area described in this petition is “Malibu-Newton Canyon.” (b) Approved maps. The appropriate map for determining the boundary of the...

  11. 78 FR 21415 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-04-10

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group..., the AMWG, a technical work group, a Grand Canyon Monitoring and Research Center, and...

  12. 77 FR 43117 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-07-23

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group... Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon Monitoring and...

  13. 77 FR 22801 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-04-17

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation... Management Work Group (AMWG) makes recommendations to the Secretary of the Interior concerning Glen Canyon... AMP includes a Federal advisory committee, the AMWG, a technical work group, a Grand Canyon...

  14. 77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2012-02-16

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group... Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon Monitoring and...

  15. Seatbelt submarining injury and its prevention countermeasures: How a cantilever seat pan structure exacerbate submarining.

    Science.gov (United States)

    Thorbole, Chandrashekhar K

    2015-01-01

    The purpose of this study and a case report was to demonstrate seat belt webbing induced injury due to seatbelt submarining during the frontal motor vehicle crash. Submarining is an undesired phenomenon during a frontal crash scenario and is dependent on design features of the seat pan and seatbelt system. The lack of adequate anti-submarining features at any seating position with three-point restraint can cause abdominal solid and hollow organ injuries. This paper reports a case of submarining and factors that exacerbated this phenomenon leading to critical occupant abdominal injury. This case report and the following injury causation analysis demonstrate the shortcomings of a cantilever seat pan design in context to the occupant safety. The inadequate seat pan anti-submarining feature in association with lack of seatbelt load-limiter and Pretensioner reduces the level of occupant protection offered by the seat belt system in the rear seat. This case report shows the dangers of cantilever seat pan design and its association with increased risk of submarining causing severe abdominal injuries.

  16. Seatbelt submarining injury and its prevention countermeasures: How a cantilever seat pan structure exacerbate submarining

    Directory of Open Access Journals (Sweden)

    Chandrashekhar K Thorbole

    2015-01-01

    Full Text Available The purpose of this study and a case report was to demonstrate seat belt webbing induced injury due to seatbelt submarining during the frontal motor vehicle crash. Submarining is an undesired phenomenon during a frontal crash scenario and is dependent on design features of the seat pan and seatbelt system. The lack of adequate anti-submarining features at any seating position with three-point restraint can cause abdominal solid and hollow organ injuries. This paper reports a case of submarining and factors that exacerbated this phenomenon leading to critical occupant abdominal injury. This case report and the following injury causation analysis demonstrate the shortcomings of a cantilever seat pan design in context to the occupant safety. The inadequate seat pan anti-submarining feature in association with lack of seatbelt load-limiter and Pretensioner reduces the level of occupant protection offered by the seat belt system in the rear seat. This case report shows the dangers of cantilever seat pan design and its association with increased risk of submarining causing severe abdominal injuries.

  17. German Submarine Offensives and South African Countermeasures ...

    African Journals Online (AJOL)

    Evert

    The first German submarine offensive in South African waters during 1942, Operation ... The German occupation of France in May 1940 provided the BdU with an ...... trawlers had to protect an average of 38 convoys which operated in South ...

  18. Phase 1 Final Report: Titan Submarine

    Science.gov (United States)

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

    2015-01-01

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

  19. Monitoring of the nuclear submarine Komsomolets

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

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

    Science.gov (United States)

    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.

  1. Miocene Current-Modified Submarine Fans

    Science.gov (United States)

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

    2016-12-01

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

  2. Seasonal monitoring of deep-sea megabenthos in Barkley Canyon cold seep by internet operated vehicle (IOV).

    Science.gov (United States)

    Doya, Carolina; Chatzievangelou, Damianos; Bahamon, Nixon; Purser, Autun; De Leo, Fabio C; Juniper, S Kim; Thomsen, Laurenz; Aguzzi, Jacopo

    2017-01-01

    Knowledge of the processes shaping deep-sea benthic communities at seasonal scales in cold-seep environments is incomplete. Cold seeps within highly dynamic regions, such as submarine canyons, where variable current regimes may occur, are particularly understudied. Novel Internet Operated Vehicles (IOVs), such as tracked crawlers, provide new techniques for investigating these ecosystems over prolonged periods. In this study a benthic crawler connected to the NEPTUNE cabled infrastructure operated by Ocean Networks Canada was used to monitor community changes across 60 m2 of a cold-seep area of the Barkley Canyon, North East Pacific, at ~890 m depth within an Oxygen Minimum Zone (OMZ). Short video-transects were run at 4-h intervals during the first week of successive calendar months, over a 14 month period (February 14th 2013 to April 14th 2014). Within each recorded transect video megafauna abundances were computed and changes in environmental conditions concurrently measured. The responses of fauna to environmental conditions as a proxy of seasonality were assessed through analysis of abundances in a total of 438 video-transects (over 92 h of total footage). 7698 fauna individuals from 6 phyla (Cnidaria, Ctenophora, Arthropoda, Echinodermata, Mollusca, and Chordata) were logged and patterns in abundances of the 7 most abundant taxa (i.e. rockfish Sebastidae, sablefish Anoplopoma fimbria, hagfish Eptatretus stoutii, buccinids (Buccinoidea), undefined small crabs, ctenophores Bolinopsis infundibulum, and Scyphomedusa Poralia rufescens) were identified. Patterns in the reproductive behaviour of the grooved tanner crab (Chionnecetes tanneri) were also indicated. Temporal variations in biodiversity and abundance in megabenthic fauna was significantly influenced by variabilities in flow velocity flow direction (up or down canyon), dissolved oxygen concentration and month of study. Also reported here for the first time are transient mass aggregations of grooved tanner

  3. 78 FR 7775 - Boulder Canyon Project

    Science.gov (United States)

    2013-02-04

    .... \\1\\ 75 FR 57912 (September 23, 2010). \\2\\ 133 FERC ] 62,229. The proposed BCP electric service base... in power rate adjustments (10 CFR part 903) were published on September 18, 1985 (50 FR 87835... Area Power Administration Boulder Canyon Project AGENCY: Western Area Power Administration, DOE....

  4. ACUMEN 2012: Atlantic Canyons Undersea Mapping Expeditions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Between February and August 2012, a team of NOAA and external partners will conduct a mapping ‘blitz’ focused on deepwater canyons off the northeastern...

  5. Creationism in the Grand Canyon, Texas Textbooks

    Science.gov (United States)

    Folger, Peter

    2004-01-01

    AGU President Bob Dickinson, together with presidents of six other scientific societies, have written to Joseph Alston, Superintendent of Grand Canyon National Park, pointing out that a creationist book, The Grand Canyon: A Different View, is being sold in bookstores within the borders of the park as a scientific explanation about Grand Canyon geologic history. President Dickinson's 16 December letter urges that Alston clearly separate The Grand Canyon: A Different View from books and materials that discuss the legitimate scientific understanding of the origin of the Grand Canyon. The letter warns the Park Service against giving the impression that it approves of the anti-science movement known as young-Earth creationism, or that it endorses the advancement of religious tenets disguised as science. The text of the letter is on AGU's Web site http://www.agu.org/sci_soc/policy/sci_pol.html. Also, this fall, AGU sent an alert to Texas members about efforts by intelligent design creationists aimed at weakening the teaching of biological evolution in textbooks used in Texas schools. The alert pointed scientists to a letter, drafted by AGU, together with the American Institute of Physics, the American Physical Society, the Optical Society of America, and the American Astronomical Society, that urged the Texas State Board of Education to adopt textbooks that presented only accepted, peer-reviewed science and pedagogical expertise. Over 550 scientists in Texas added their names to the letter (http://www.agu.org/sci_soc/policy/texas_textbooks.pdf ), sent to the Board of Education on 1 November prior to their vote to adopt a slate of new science textbooks. The Board voted 11-5 in favor of keeping the textbooks free of changes advocated by groups supporting intelligent design creationism.

  6. Response analysis of a submarine cable under fault movement

    Institute of Scientific and Technical Information of China (English)

    Liu Aiwen

    2009-01-01

    Based on the performance of submarine cables in past earthquakes, an analytical method to determine cable performance under seabed fault movement is proposed in this paper. First, common types of earthquake damage to submarine cables are summarized, which include seabed displacement induced by fault movement, submarine landslides and seabed soil liquefaction, etc. The damage is similar to damage observed to buried pipelines following land earthquakes. The Hengchun earthquake of Dec. 26, 2006 is used as a case study. The M7.2 earthquake occurred in the South China Sea at 20:26 Beijing Time, and caused 14 international submarine cables to sever and break. The results show that the proposed method predicts damage similar to that observed in the Hengchun earthquake. Based on parametric studies of the influence of the water depth and the magnitude of the submarine earthquake, countermeasures to prevent damage to submarine cables are proposed.

  7. Submarine Magnetic Field Extrapolation Based on Boundary Element Method

    Institute of Scientific and Technical Information of China (English)

    GAO Jun-ji; LIU Da-ming; YAO Qiong-hui; ZHOU Guo-hua; YAN Hui

    2007-01-01

    In order to master the magnetic field distribution of submarines in the air completely and exactly and study the magnetic stealthy performance of submarine, a mathematic model of submarine magnetic field extrapolation is built based on the boundary element method (BEM). An experiment is designed to measure three components of magnetic field on the envelope surface surrounding a model submarine. The data in differentheights above the model submarine are obtained by use of tri-axial magnetometers. The results show that this extrapolation model has good stabilities and high accuracies compared the measured data with the extrapolated data. Moreover, the model can reflect the submarine magnetic field distribution in the air exactly, and is valuable in practical engineering.

  8. Big Canyon Creek Ecological Restoration Strategy.

    Energy Technology Data Exchange (ETDEWEB)

    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

  9. Hybrid Intelligent Control for Submarine Stabilization

    Directory of Open Access Journals (Sweden)

    Minghui Wang

    2013-05-01

    Full Text Available While sailing near the sea surface, submarines will often undergo rolling motion caused by wave disturbance. Fierce rolling motion seriously affects their normal operation and even threatens their security. We propose a new control method for roll stabilization. This paper studies hybrid intelligent control combining a fuzzy control, a neural network and extension control technology. Every control strategy can achieve the ideal control effect within the scope of its effective control. The neuro‐fuzzy control strategy is used to improve the robustness of the controller. The speed control strategy and the course control strategy are conducted to extend the control range. The paper also proposes the design of the controller and carries out the simulation experiment in different sea conditions. The simulation results show that the control method proposed can indeed effectively improve the control performance of submarine stabilization.

  10. Voluminous submarine lava flows from Hawaiian volcanoes

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, R.T.; Moore, J.G.; Lipman, P.W.; Belderson, R.H.

    1988-05-01

    The GLORIA long-range sonar imaging system has revealed fields of large lava flows in the Hawaiian Trough east and south of Hawaii in water as deep as 5.5 km. Flows in the most extensive field (110 km long) have erupted from the deep submarine segment of Kilauea's east rift zone. Other flows have been erupted from Loihi and Mauna Loa. This discovery confirms a suspicion, long held from subaerial studies, that voluminous submarine flows are erupted from Hawaiian volcanoes, and it supports an inference that summit calderas repeatedly collapse and fill at intervals of centuries to millenia owing to voluminous eruptions. These extensive flows differ greatly in form from pillow lavas found previously along shallower segments of the rift zones; therefore, revision of concepts of volcano stratigraphy and structure may be required.

  11. Hybrid Intelligent Control for Submarine Stabilization

    Directory of Open Access Journals (Sweden)

    Minghui Wang

    2013-05-01

    Full Text Available Abstract While sailing near the sea surface, submarines will often undergo rolling motion caused by wave disturbance. Fierce rolling motion seriously affects their normal operation and even threatens their security. We propose a new control method for roll stabilization. This paper studies hybrid intelligent control combining a fuzzy control, a neural network and extension control technology. Every control strategy can achieve the ideal control effect within the scope of its effective control. The neuro-fuzzy control strategy is used to improve the robustness of the controller. The speed control strategy and the course control strategy are conducted to extend the control range. The paper also proposes the design of the controller and carries out the simulation experiment in different sea conditions. The simulation results show that the control method proposed can indeed effectively improve the control performance of submarine stabilization.

  12. Influence of Anchoring on Burial Depth of Submarine Pipelines

    OpenAIRE

    Yuan Zhuang; Yang Li; Wei Su

    2016-01-01

    Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emerge...

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

    OpenAIRE

    Eagle, James N.

    1987-01-01

    A Lanchester model is developed for a battlegroup ASW engagement. Two variations are included. In the first, long-range missile firing submarines, short-range missile or torpedo firing submarines, and submarines firing only torpedoes distribute their attack uniformly over battlegroup escort ships and carriers. In the second variation, the attack is concentrated on the carriers. supported by the Naval War College http://archive.org/details/lanchestermodelo00eagl NA

  14. Submarine Landslides: What we Know and Where we are Going!

    Science.gov (United States)

    Moscardelli, L. G.; Mountjoy, J. J.; Micallef, A.; Strasser, M.; Vanneste, M.; Chaytor, J. D.; Mosher, D.; Krastel, S.; Lo Iacono, C.; Yamada, Y.

    2015-12-01

    Submarine landslides and other gravity-induced movements can disrupt very large areas of continental margins resulting in long-term seafloor morphologic change and multi-scale mass transport deposits (MTDs). Potential consequences of submarine landslides include damage to seabed infrastructure, offshore facilities, as well as generation or enhancement of tsunamis. MTDs are common on the modern seafloor and within the stratigraphic record. Slides, slumps and debris flows can be constituents of MTDs and can co-occur in the same event or depositional unit. Recent research indicates that relationships exist between MTD geological setting, causal mechanisms, and geometries. Quantitative data analysis suggests that MTD morphometric parameters can be used to link these three parameters. Despite many advances in this field, it still remains unclear how to definitively identify pre-conditioning factors and triggers of submarine landslides in modern slopes, and how submarine landslides evolve after initiation. In addition, new questions regarding the interaction between submarine landslides and active marine processes, such as bottom currents and fluid flow, have emerged.One of the mandates of the S4SLIDE (IGCP-640) project, a joint endeavor of UNESCO and IGCP that represents the broad field of submarine landslide research, is to facilitate interactions at an international level among scientists, industry and government representatives to advance our knowledge on a number of outstanding science questions: (i) What is the nature of the interaction between current-controlled sedimentation and submarine landslides? (ii) What role do transient turbulent-laminar flows play in the formation of submarine landslides? (iii) Do climatic variations control the occurrence of submarine landslides? (iv) What is the economic significance of submarine landslides? (v) Do we understand the hazards that submarine landslides pose to the environment and to humans? This presentation will cover

  15. LINEAR AND NONLINEAR BUCKLING ANALYSIS OF STIFFENED CYLINDRICAL SUBMARINE HULL

    OpenAIRE

    SREELATHA P.R; ALICE MATHAI

    2012-01-01

    Submarine is a watercraft capable of independent operation under water. Use of submarines includes marine science, offshore industry underwater exploration etc. The pressure hull of submarine is constructed as combination of cylinders and domes. The shell is subjected to very high hydrostatic pressure, which creates large compressive stress resultants. Due to this the structure is susceptible to buckling. The introduction of stiffeners in both directions considerably increases the buckling st...

  16. SSN 774 Virginia Class Submarine (SSN 774)

    Science.gov (United States)

    2015-12-01

    increasing performance capabilities more than eleven years after lead ship delivery in October 2004. With the delivery to the Navy of USS JOHN WARNER (SSN...of VIRGINIA Class Submarines are highlighted by the Commissioning of USS JOHN WARNER (SSN 785) at Norfolk Naval Shipyard on August 1, 2015 and the...significant production milestone with the completion of her pressure hull on August 29, 2015. Other near term VIRGINIA Class program events include Pre

  17. Using Ice Predictions to Guide Submarines

    Science.gov (United States)

    2016-01-01

    prevented the use of several airfields used for transporting personnel and equipment to the ice camp. The rapidly changing conditions of the ice ...of the ice cover. The age of the sea ice serves as an indicator of its physical properties including surface roughness, melt pond coverage, and...Sailors and members of the Applied Physics Laboratory Ice Station clear ice from the hatch of the submarine USS Connecticut (SSN 22) during Ice

  18. Westernmost Grand Canyon incision: Testing thermochronometric resolution

    Science.gov (United States)

    Fox, M.; Tripathy-Lang, A.; Shuster, D. L.; Winn, C.; Karlstrom, K.; Kelley, S.

    2017-09-01

    The timing of carving of Grand Canyon has been debated for over 100 years with competing endmember hypotheses advocating for either a 70 Ma (;old;) or history and corresponding estimates of landscape evolution have been in debate. In particular, 4He/3He thermochronometric data record the distribution of radiogenic 4He (from the 238U, 235U and 232Th decay series) within an individual apatite crystal and thus are highly sensitive to the thermal history corresponding to landscape evolution. However, there are several complicating factors that make interpreting such data challenging in geologic scenarios involving reheating. Here, we analyze new data that provide measures of the cooling of basement rocks at the base of westernmost Grand Canyon, and use these data as a testbed for exploring the resolving power and limitations of 4He/3He data in general. We explore a range of thermal histories and find that these data are most consistent with a ;young; Grand Canyon. A problem with the recovered thermal history, however, is that burial temperatures are under predicted based on sedimentological evidence. A solution to this problem is to increase the resistance of alpha recoil damage to annealing, thus modifying He diffusion kinetics, allowing for higher temperatures throughout the thermal history. This limitation in quantifying radiation damage (and hence crystal retentivity) introduces non-uniqueness to interpreting time-temperature paths in rocks that resided in the apatite helium partial retention zone for long durations. Another source of non-uniqueness, is due to unknown U and Th distributions within crystals. We show that for highly zoned with a decrease in effective U of 20 ppm over the outer 80% of the radius of the crystal, the 4He/3He data could be consistent with an ;old; canyon model. To reduce this non-uniqueness, we obtain U and Th zonation information for separate crystals from the same rock sample through LA-ICP-MS analysis. The observed U and Th

  19. 3D View of Grand Canyon, Arizona

    Science.gov (United States)

    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

  20. Decontamination and Decommissioned Small Nuclear AIP Hybrid Systems Submarines

    Directory of Open Access Journals (Sweden)

    Guangya Liu

    2013-11-01

    Full Text Available Being equipped with small reactor AIP is the trend of conventional submarine power in 21st century as well as a real power revolution in conventional submarine. Thus, the quantity of small reactor AIP Submarines is on the increase, and its decommissioning and decontamination will also become a significant international issue. However, decommissioning the small reactor AIP submarines is not only a problem that appears beyond the lifetime of the small reactor nuclear devices, but the problem involving the entire process of design, construction, running and closure. In the paper, the problem is explored based on the conception and the feasible decommissioning and decontamination means are supplied to choose from.

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

    Science.gov (United States)

    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.

  2. Surprise and Opportunity for Learning in Grand Canyon: the Glen Canyon Dam Adaptive Management Program

    Directory of Open Access Journals (Sweden)

    Theodore S. Melis

    2015-09-01

    Full Text Available With a focus on resources of the Colorado River ecosystem below Glen Canyon Dam, the Glen Canyon Dam Adaptive Management Program has included a variety of experimental policy tests, ranging from manipulation of water releases from the dam to removal of non-native fish within Grand Canyon National Park. None of these field-scale experiments has yet produced unambiguous results in terms of management prescriptions. But there has been adaptive learning, mostly from unanticipated or surprising resource responses relative to predictions from ecosystem modeling. Surprise learning opportunities may often be viewed with dismay by some stakeholders who might not be clear about the purpose of science and modeling in adaptive management. However, the experimental results from the Glen Canyon Dam program actually represent scientific successes in terms of revealing new opportunities for developing better river management policies. A new long-term experimental management planning process for Glen Canyon Dam operations, started in 2011 by the U.S. Department of the Interior, provides an opportunity to refocus management objectives, identify and evaluate key uncertainties about the influence of dam releases, and refine monitoring for learning over the next several decades. Adaptive learning since 1995 is critical input to this long-term planning effort. Embracing uncertainty and surprise outcomes revealed by monitoring and ecosystem modeling will likely continue the advancement of resource objectives below the dam, and may also promote efficient learning in other complex programs.

  3. Turbulent ventilation of a street canyon

    DEFF Research Database (Denmark)

    Nielsen, Morten

    2000-01-01

    A selection of turbulence data corresponding to 185 days of field measurements has een analysed. The non-ideal building geometry influenced the circulation patterns in the street canyon and the largest average vertical velocities were observed in the wake of an unbroken line of buildings. The sta......A selection of turbulence data corresponding to 185 days of field measurements has een analysed. The non-ideal building geometry influenced the circulation patterns in the street canyon and the largest average vertical velocities were observed in the wake of an unbroken line of buildings...... small, and this suggests that most of the velocity fluctuations were fairly local and not caused by unsteady street vortices. The observed velocities scaled with the ambient wind speed except under low-wind conditions....

  4. “SHANGRI-LA” IN NUJIANG CANYON

    Institute of Scientific and Technical Information of China (English)

    李晓勤

    2004-01-01

    A few hours' drive took me to a place called Bingzhongluo,the largest piece of flatland in the canyon,where the Nujiang River takes two abrupt turns, forming the first bend on the Nujiang River,which is a best known scenic spot in China. At the side of the river there is a tablet of pure white marble inscribed with words painted in bright red,reading:“Bingzhongluo,the Shangri-La.”

  5. Horseshoe Canyon and Mannville case studies

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, T. [Trident Exploration Corp., Calgary, AB (Canada)

    2005-07-01

    This presentation outlined the coalbed methane (CBM) activities underway at Trident Exploration Corp. with particular reference to the results achieved in the Horseshoe Canyon and Mannville formations. In order to be commercially successful, companies drilling for unconventional gas must spend millions of dollars testing and evaluating different drilling, completion and production methods. Early regional exploration programs are also important to gain an understanding of the economics of each particular play. The Horseshoe Canyon play extends for more than 250 miles and is 100 miles wide. Most of the wells drilled to date have been drilled by a few large operators, including Trident. Most of the Horseshoe Canyon is greatly underpressured and there may not be enough gas in place in some areas to justify drilling for the coals alone. The coal properties within the Horseshoe Canyon vary widely from well to well. The total coal thickness ranges from less than 5 to more than 30 metres. The number of seams per well varies from 8 to 25 and the average seam thickness is 1 metre. The well depths range from 150 metres in the east to more than 900 metres in the west. The Mannville is among the largest CBM resources in western Canada, with estimates of up to several hundred trillion cubic feet of recoverable reserves. Trident operates the largest and longest running Mannville pilot at Corbett, northwest of Edmonton. The pilot wells have shown the area has good quality coal, excellent gas content and good permeability. As of February 2005, there are 47 active producers, 2 disposal wells and 3 observation wells. Average production per well is 1.5 E{sup 3}m{sup 3} gas per day and 17 m{sup 3} water per day. Declining water production on individual wells along with limited gas production and high reservoir pressure suggests that the wells are progressively damaged. Initial experience with horizontal wells at Corbett has proved to be encouraging. figs.

  6. Assessing GPS Constellation Resiliency in an Urban Canyon Environment

    Science.gov (United States)

    2015-03-26

    Assessing GPS Constellation Resiliency in an Urban Canyon Environment THESIS MARCH 2015 Aaron J. Burns, Second Lieutenant, USAF AFIT-ENS-MS-15-M-138...URBAN CANYON ENVIRONMENT THESIS Presented to the Faculty Department of Operational Sciences Graduate School of Engineering and Management Air Force...UNLIMITED. AFIT-ENS-MS-15-M-138 ASSESSING GPS CONSTELLATION RESILIENCY IN AN URBAN CANYON ENVIRONMENT Aaron J. Burns, B.S. Second Lieutenant, USAF Committee

  7. 32 CFR 707.7 - Submarine identification light.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all...

  8. Three dimensional boundary layers on submarine conning towers and rudders

    Science.gov (United States)

    Gleyzes, C.

    1988-01-01

    Solutions for the definition of grids adapted to the calculation of three-dimensional boundary layers on submarine conning towers and on submarine rudders and fins are described. The particular geometry of such bodies (oblique shaped hull, curved fins) required special adaptations. The grids were verified on examples from a test basin.

  9. Monitoring of radioactivity at the Russian nuclear submarine Kursk

    Energy Technology Data Exchange (ETDEWEB)

    Amundsen, I. [Norwegian Radiation Protection Authority, Oesteraes (Norway); Lind, B. [Norwegian Radiation Protection Authority, Enviromental Protection Unit, Polar Environmental Centre, Tromsoe (Norway)

    2002-04-01

    In the morning of August 12th 2000, a Russian submarine accident occurred in international waters east of Rybatschi Peninsula in the Barents Sea about 250 km from Norway. The submarine, a Russian Oscar class II attack submarine, sunk to 116 meters depth at the position 69 deg. 36,99N, 37 deg. 34,50E. The submarine 'Kursk' is 154 meters long, equipped with two pressurised water reactors and the submerged displacement is 24000 tons. Each reactor has a thermal effect or 190 megawatt, or less than 10% of a typical nuclear power plant reactor. The submarines in Oscar-II class is one of the largest and most capable in the Russian Northern Fleet. No indications of leakage from the submarine have so far been observed during the monitoring expeditions. Elevated levels of radioactivity have note been detected in any dose-rate readings or at any of the measurements of environmental samples taken close to Kursk. Furthermore, no increased levels were measured on bits and pieces from the submarine or from water sampled inside the submarine. A more comprehensive report covering experience and monitoring results from the two expeditions term and impact assessments of possible future releases from Kursk. (LN)

  10. NUMERICAL PREDICTION OF SUBMARINE HYDRODYNAMIC COEFFICIENTS USING CFD SIMULATION

    Institute of Scientific and Technical Information of China (English)

    PAN Yu-cun; ZHANG Huai-xin; ZHOU Qi-dou

    2012-01-01

    The submarine Hydrodynamic coefficients are predicted by numerical simulations.Steady and unsteady Reynolds Averaged Navier-Stokes (RANS) simulations are carried out to numerically simulate the oblique towing experiment and the Planar Motion Mechanism (PMM) experiment performed on the SUBOFF submarine model.The dynamic mesh method is adopted to simulate the maneuvering motions of pure heaving,pure swaying,pure pitching and pure yawing.The hydrodynamic forces and moments acting on the maneuvering submarine are obtained.Consequently,by analyzing these results,the hydrodynamic coefficients of the submarine maneuvering motions can be determined.The computational results are verified by comparison with experimental data,which show that this method can be used to estimate the hydrodynamic derivatives of a fully appended submarine.

  11. Experimental Study on Free Spanning Submarine Pipeline Under Dynamic Excitation

    Institute of Scientific and Technical Information of China (English)

    李昕; 刘亚坤; 周晶; 马恒春; 朱彤

    2002-01-01

    Seismic load has a significant effect on the response of a free spanning submarine pipeline when the pipeline is constructed in a seismically active region. The model experiment is performed on an underwater shaking table to simulate the response of submarine pipelines under dynamic input. In consideration of the effects of the terrestrial and submarine pipeline, water depth, support condition, distance from seabed, empty and full pipeline, and span on dynamic response, 120 groups of experiments are conducted. Affecting factors are analyzed and conclnsions are drawn for reference. For the control of dynamic response, the span of a submarine pipeline is by far more important than the other factors. Meanwhile, the rosponse difference between a submarine pipeline under sine excitation and that under random excitation exists in experiments.

  12. The 1929 Grand Banks submarine landslide revisited

    Science.gov (United States)

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

    2017-04-01

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

  13. Submarine harbor navigation using image data

    Science.gov (United States)

    Stubberud, Stephen C.; Kramer, Kathleen A.

    2017-01-01

    The process of ingress and egress of a United States Navy submarine is a human-intensive process that takes numerous individuals to monitor locations and for hazards. Sailors pass vocal information to bridge where it is processed manually. There is interest in using video imaging of the periscope view to more automatically provide navigation within harbors and other points of ingress and egress. In this paper, video-based navigation is examined as a target-tracking problem. While some image-processing methods claim to provide range information, the moving platform problem and weather concerns, such as fog, reduce the effectiveness of these range estimates. The video-navigation problem then becomes an angle-only tracking problem. Angle-only tracking is known to be fraught with difficulties, due to the fact that the unobservable space is not the null space. When using a Kalman filter estimator to perform the tracking, significant errors arise which could endanger the submarine. This work analyzes the performance of the Kalman filter when angle-only measurements are used to provide the target tracks. This paper addresses estimation unobservability and the minimal set of requirements that are needed to address it in this complex but real-world problem. Three major issues are addressed: the knowledge of navigation beacons/landmarks' locations, the minimal number of these beacons needed to maintain the course, and update rates of the angles of the landmarks as the periscope rotates and landmarks become obscured due to blockage and weather. The goal is to address the problem of navigation to and from the docks, while maintaining the traversing of the harbor channel based on maritime rules relying solely on the image-based data. The minimal number of beacons will be considered. For this effort, the image correlation from frame to frame is assumed to be achieved perfectly. Variation in the update rates and the dropping of data due to rotation and obscuration is considered

  14. Demersal fish distribution and habitat use within and near Baltimore and Norfolk Canyons, U.S. Middle Atlantic Slope

    Science.gov (United States)

    Ross, Steve W.; Rhode, Mike; Quattrini, Andrea M.

    2015-01-01

    Numerous submarine canyons along the United States middle Atlantic continental margin support enhanced productivity, diverse and unique habitats, active fisheries, and are vulnerable to various anthropogenic disturbances. During two cruises (15 Aug–2 Oct 2012 and 30 Apr–27 May 2013), Baltimore and Norfolk canyons and nearby areas (including two cold seeps) were intensively surveyed to determine demersal fish distributions and habitat associations. Overall, 34 ROV dives (234–1612 m) resulted in 295 h of bottom video observations and numerous collections. These data were supplemented by 40, 30-min bottom trawl samples. Fish observations were assigned to five general habitat designations: 1) sand-mud (flat), 2) sloping sand-mud with burrows, 3) low profile gravel, rock, boulder, 4) high profile, canyon walls, rocks or ridges, and 5) seep-mixed hard and soft substrata, the later subdivided into seven habitats based on amounts of dead mussel and rock cover. The influence of corals, sponges and live mussels (seeps only) on fish distributions was also investigated. Both canyon areas supported abundant and diverse fish communities and exhibited a wide range of habitats, including extensive areas of deep-sea corals and sponges and two nearby methane seeps (380–430 m, 1455–1610 m). All methods combined yielded a total of 123 species of fishes, 12 of which are either new records for this region or have new range data. Depth was a major factor that separated the fish faunas into two zones with a boundary around 1400 m. Fishes defining the deeper zone included Lycodes sp.,Dicrolene introniger, Gaidropsaurus ensis, Hydrolagus affinis, Antimora rostrata, andAldrovandia sp. Fishes in the deep zone did not exhibit strong habitat affinities, despite the presence of a quite rugged, extensive methane seep. We propose that habitat specificity decreases with increasing depth. Fishes in the shallower zone, characterized by Laemonema sp., Phycis chesteri, Nezumia bairdii, Brosme

  15. 36 CFR 7.4 - Grand Canyon National Park.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Grand Canyon National Park. 7.4 Section 7.4 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.4 Grand Canyon National Park. (a)...

  16. Modeling the Effect of Wider Canyons on Urban Heating

    Directory of Open Access Journals (Sweden)

    Rizwan Ahmed Memon

    2011-04-01

    Full Text Available The k-? turbulence model is adopted in this study to simulate the impact of street canyon AR (Aspect Ratios on heating within street canyon. The two-dimensional model was validated for RANS (Reynolds Averaged Navier Stokes and energy transport equations. The validation process confirms that the results of the model for airtemperature and wind speed could be trusted. The application of the said model is carried out to ideal street canyons of ARs (ratio of building-height-to-street-width from 0.4 to 2 with the same boundary conditions. Notably, street canyon aspect ratio was calculated by varying the street width while keeping the building height constant. Results show that the weighted-average-air-temperature within AR 0.4 was around 0.8% (i.e. 2.4K higher than that within AR 2.0. Conversely, there was strong correlation (i.e., R2>0.9 between air temperature within the street canyon and street canyon AR. Results demonstrate stronger influence of vertical velocity on heating within street canyon. Evidently, increased vertical velocity decreased the temperatures. Conversely, temperatures were higher along the leeward side of the canyon in lower ARs.

  17. Wave run up in Zones of Underwater Canyons

    Directory of Open Access Journals (Sweden)

    Katline Koblev A. Julio

    2013-01-01

    Full Text Available The wave run up on coast and shore protection constructions in zones of underwater canyons is considered. The mathematical model of wave run up on the coast, considering distinctions in biases of underwater and surface parts of the coastal slope, allowing to receive setup parameters in zones of the underwater canyons, corresponding to data of supervision is offered.

  18. 78 FR 7810 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-02-04

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Glen Canyon Dam Adaptive Management Work Group.... L. 102-575) of 1992. The AMP includes a Federal advisory committee, the AMWG, a technical work...

  19. 75 FR 34476 - Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2010-06-17

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of Reclamation... Interior (Secretary) is renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose of the Adaptive Management Work Group is to advise and to provide recommendations to the...

  20. Gas hydrate dissociation structures in submarine slopes

    Energy Technology Data Exchange (ETDEWEB)

    Gidley, I.; Grozic, J.L.H. [Calgary Univ., AB (Canada). Dept. of Civil Engineering

    2008-07-01

    Studies have suggested that gas hydrates may play a role in submarine slope failures. However, the mechanics surrounding such failures are poorly understood. This paper discussed experimental tests conducted on a small-scale physical model of submarine soils with hydrate inclusions. The laboratory tests investigated the effects of slope angle and depth of burial of the hydrate on gas escape structures and slope stability. Laponite was used to model the soils due to its ability to swell and produce a clear, colorless thixotropic gel when dispersed in water. An R-11 refrigerant was used to form hydrate layers and nodules. The aim of the experiment was to investigate the path of the fluid escape structures and the development of a subsequent slip plane caused by the dissociation of the R-11 hydrates. Slope angles of 5, 10, and 15 degrees were examined. Slopes were examined using high-resolution, high-speed imaging techniques. Hydrate placement and slope inclinations were varied in order to obtain stability data. Results of the study showed that slope angle influenced the direction of travel of the escaping gas, and that the depth of burial affected sensitivity to slope angle. Theoretical models developed from the experimental data have accurately mapped deformations and stress states during testing. Further research is being conducted to investigate the influence of the size, shape, and placement of the hydrates. 30 refs., 15 figs.

  1. Submarine landslides and tsunami potential Off SE Australian Margin: results from the voyage SS2008/12

    Science.gov (United States)

    Rahman Talukder, Asrarur; Boyd, Ron; Keene, Jock; Hubble, Tom; Clarke, Samantha; Kinsela, Michael; Exon, Neville; Gardner, Jim; Felzenberg, Janice

    2010-05-01

    Although the continental margins around Australia are themselves passive, they are surrounded by the Pacific Ring of Fire characterized by a great many earthquakes, tsunamis and submarine landslides. The Earthquake Catalogue of Geo-science Australia shows that in Australia earthquakes with a magnitude 5.5+ occur on average every two years with the potential of a disastrous earthquake of magnitude 6 or more every six years. Historical records also show that there were 47 tsunami hits in Australian Coasts during the last 150 years. The main objective of Voyage SS2008/12 onboard RV Southern Surveyor in 2008, was to map out the submarine landslides in the region off northern New South Wales and southern Queensland in order to investigate its tsunami-genic potential that could impact their densely populated coastal cities. During the survey ca. 13,000 square km of multi-beam swath bathymetry data (MBES) along with TOPAS high resolution seismic and different types of ground truth samples were collected in the continental slope. This study presents the preliminary morpho-tectonic analysis of the collected acoustic images of the seabeds and near surfaces. In the survey area, the continental slopes extend from the shelf break to the abyssal plain between ~150m to ~4500m water depth. The survey area can be divided into northern and southern areas separated by relatively stable seabed of the Nerang Plateau. The average slopes range from a minimum of 2.8° on plateau to a maximum of 8.5° in steeper segments. Submarine slides of all sizes from 0.5 to 20 cubic km were encountered, there having different morphologies. They can be characterized as slab slides, debris flows and carbonate platform slides. The gravity cores takes from selected slide planes suggest that they have different ages (between ca. 6 to 25 ka) and the northern slides are older than the southern ones. Other bathymetric features are box canyons, linear canyons, volcanic cones, carbonate mounds and pockmarks

  2. Big Canyon Creek Ecological Restoration Strategy.

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. Transfer processes in a simulated urban street canyon

    Science.gov (United States)

    Solazzo, E.; Britter, R. E.

    2007-07-01

    The transfer processes within and above a simulated urban street canyon were investigated in a generic manner. Computational fluid dynamics (CFD) was used to aid understanding and to produce some simple operational parameterisations. In this study we addressed specifically the commonly met situation where buoyancy effects arising from elevated surface temperatures are not important, i.e. when mechanical forces outweigh buoyancy forces. In a geophysical context this requires that some suitably defined Richardson number is small. From an engineering perspective this is interpreted as the important case when heat transfer within and above urban street canyons is by forced convection. Surprisingly, this particular scenario (for which the heat transfer coefficient between buildings and the flow is largest), has been less well studied than the situation where buoyancy effects are important. The CFD technique was compared against wind-tunnel experiments to provide model evaluation. The height-to-width ratio of the canyon was varied through the range 0.5 5 and the flow was normal to the canyon axis. By setting the canyon’s facets to have the same or different temperatures or to have a partial temperature distribution, simulations were carried out to investigate: (a) the influence of geometry on the flow and mixing within the canyon and (b) the exchange processes within the canyon and across the canyon top interface. Results showed that the vortex-type circulation and turbulence developed within the canyon produced a temperature distribution that was, essentially, spatially uniform (apart from a relatively thin near-wall thermal boundary layer) This allowed the temperatures within the street canyon to be specified by just one value T can , the canyon temperature. The variation of T can with wind speed, surface temperatures and geometry was extensively studied. Finally, the exchange velocity u E across the interface between the canyon and the flow above was calculated

  4. What threat do turbidity currents and submarine landslides pose to submarine telecommunications cable infrastructure?

    Science.gov (United States)

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

    2016-04-01

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

  5. The Black Canyon of the Gunnison: Today and Yesterday

    Science.gov (United States)

    Hansen, Wallace R.

    1965-01-01

    Since the early visit of Captain John William Gunnison in the middle of the last century, the Black Canyon of the Gunnison has stirred mixed apprehension and wonder in the hearts of its viewers. It ranks high among the more awesome gorges of North America. Many great western canyons are as well remembered for their brightly colored walls as for their airy depths. Not so the Black Canyon. Though it is assuredly not black, the dark-gray tones of its walls and the hazy shadows of its gloomy depths join together to make its name well deserved. Its name conveys an impression, not a picture. After the first emotional impact of the canyon, the same questions come to the minds of most reflective viewers and in about the following order: How deep is the Black Canyon, how wide, how does it compare with other canyons, what are the rocks, how did it form, and how long did it take? Several western canyons exceed the Black Canyon in overall size. Some are longer; some are deeper; some are narrower; and a few have walls as steep. But no other canyon in North American combines the depth, narrowness, sheerness, and somber countenance of the Black Canyon. In many places the Black Canyon is as deep as it is wide. Between The Narrows and Chasm View in the Black Canyon of the Gunnison National Monument (fig. 15) it is much deeper than wide. Average depth in the monument is about 2,000 feet, ranging from a maximum of about 2,700 feet, north of Warner Point (which also is the greatest depth anywhere in the canyon), to a minimum of about 1,750 feet at The Narrows. The stretch of canyon between Pulpit Rock and Chasm View, including The Narrows, though the shallowest in the monument, is also the narrowest, has some of the steepest walls, and is, therefore, among the most impressive segments of the canyon (fig. 3). Profiles of several well-known western canyons are shown in figure 1. Deepest of these by far is Hells Canyon of the Snake, on the Idaho-Oregon border. Clearly, it dwarfs the

  6. A potential submarine landslide tsunami in South China Sea

    Science.gov (United States)

    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. Sound effects as a genre-defining factor in submarine films

    Directory of Open Access Journals (Sweden)

    Linda Maria Koldau

    2009-09-01

    Full Text Available Submarine films can be regarded as a genre with a specific semantic and syntactical structure that heavily depends on the acoustemological nature of submarine warfare. The sound design in submarine films therefore has decisive dramatic and emotive functions. The article presents the sound effects most specific to submarine films and discusses the creative potential they offer both as diegetic sounds bound to submarine existence and as emotive cues with an immediate effect on the audience.

  8. Differentiation of Palaeogene sand by glauconitic and geochemical fingerprinting, Siri Canyon, Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Olivarius, M.; Knudsen, Christian; Svendsen, Johan B.

    2011-07-01

    The submarine Siri Canyon is NE-SW-oriented and located in the Danish North Sea. It contains a number of oil reservoirs with glauconite-rich sand. The reservoirs of interest in the Nini oil field are the Late Paleocene Tyr Member of the Lista Formation and the Kolga Member of the Sele Formation, presumably of Early Eocene age. These members have previously been known as the Ty and Hermod members. The sand shows signs of injection, both in cores and in seismic data. The aim of this work is to chemically characterise and fingerprint the sand in order to reveal the origin of the sand found in three horizontal wells, which could have been injected from one or both of the Tyr and Kolga members. Core samples were collected from two vertical wells of known stratigraphy to make a basis of comparison, whereas samples of the cuttings were collected from the three horizontal wells with ages primarily corresponding to the Kolga Member. The purpose was moreover to evaluate whether cuttings samples can be used for fingerprinting as an alternative to core samples. The interest in discriminating between the ages of the injected sand is the fact that the reservoir properties (porosity and permeability) are largely controlled by the original composition of the sand. Consequently, results from this study could affect the property modelling of the field. (LN)

  9. The fluorescent tracer experiment on Holiday Beach near Mugu Canyon, Southern California

    Science.gov (United States)

    Kinsman, Nicole; Xu, J. P.

    2012-01-01

    After revisiting sand tracer techniques originally developed in the 1960s, a range of fluorescent coating formulations were tested in the laboratory. Explicit steps are presented for the preparation of the formulation evaluated to have superior attributes, a thermoplastic pigment/dye in a colloidal mixture with a vinyl chloride/vinyl acetate copolymer. In September 2010, 0.59 cubic meters of fluorescent tracer material was injected into the littoral zone about 4 kilometers upcoast of Mugu submarine canyon in California. The movement of tracer was monitored in three dimensions over the course of 4 days using manual and automated techniques. Detailed observations of the tracer's behavior in the coastal zone indicate that this tracer successfully mimicked the native beach sand and similar methods could be used to validate models of tracer movement in this type of environment. Recommendations including how to time successful tracer studies and how to scale the field of view of automated camera systems are presented along with the advantages and disadvantages of the described tracer methodology.

  10. Australia’s Submarine Design Capabilities and Capacities: Challenges and Options for the Future Submarine

    Science.gov (United States)

    2011-01-01

    Tool Examples Number of Tools Naval architecture   40 Submarine arrangements Software: AutoCAD, CATIA, Siemens NX , Solidworks, SolidEdge 36 Applied...Software), ROH2 10 Mechanical systems Software: AutoCAD, CATIA, Siemens NX , Solidworks, SolidEdge 24 Propulsion systems   2 Acoustic analysis   3...companies, including MSC Software, NEi Software (NEi NASTRAN), and Siemens PLM Software ( NX NASTRAN). DDAM, in conjunction with NASTRAN and Finite

  11. 75 FR 76650 - Proposed Modification of Class E Airspace; Bryce Canyon, UT

    Science.gov (United States)

    2010-12-09

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Modification of Class E Airspace; Bryce Canyon, UT...: This action proposes to modify Class E airspace at Bryce Canyon, UT to accommodate Area Navigation... airspace extending upward from 700 feet above the surface at Bryce Canyon Airport, Bryce Canyon,...

  12. Coastal and submarine instabilities distribution in the tectonically active SW margin of the Corinth Rift (Psathopyrgos, Achaia, Greece)

    Science.gov (United States)

    Simou, Eirini; Papanikolaou, Dimitrios; Lykousis, Vasilios; Nomikou, Paraskevi; Vassilakis, Emmanuel

    2014-05-01

    The Corinth Rift, one of the most active rifts in the world as local extension trending NE-SW reaches the amount of 14±2 mm/yr, corresponds to one of the largest zones of seismically active normal faulting. The formation, growth and migration southwards of the prevailing fault systems, which evolve simultaneously with the intense morphogenetic processes, are overprinted in the age, facies and thickness of the Plio-Pleistocene sequences constructing the south margin of the western Gulf of Corinth. The dominant fault blocks, defined by east-west trending, north dipping normal faults, are accompanied by several morphological features and anomalies, noticed in both the terrestrial and the marine environment. Our main aim has been to examine how the tectonic evolution, in combination with the attendant fierce erosional and sedimentary processes, has affected the morphology through geodynamic processes expressed as failures in the wider coastal area. High resolution multibeam bathymetry in combination with the available land surface data have contributed to submarine and subaerial morphological mapping. These have been used as a basis for the detection of all those geomorphic features that indicate instabilities probably triggered, directly or indirectly, by the ongoing active tectonic deformation. The interpretation of the combined datasets shows that the southwestern margin of the Corinth Rift towards Psathopyrgos fault zone is characterized by intense coastal relief and a narrow, almost absent, continental shelf, which passes abruptly to steep submarine slopes. These steep slope values denote the effects of the most recent brittle deformation and are related to coastal and submarine instabilities and failures. High uplift rates and rapid sedimentation, indicative of the regional high-energy terrestrial and submarine environment, are subsequently balanced by the transportation of the seafloor currents, especially where slope gradients decrease, disintegrating the

  13. A Karst Connection model for Grand Canyon, Arizona, USA

    Science.gov (United States)

    Hill, C. A.; Eberz, N.; Buecher, R. H.

    2008-03-01

    A new model for the connection of the eastern and western Grand Canyon is proposed that involves westward flow of Redwall karst aquifer water under the Kaibab arch along the steepest hydraulic gradient to discharge at a structural low in a headward-eroding protowestern Grand Canyon. A karst-aquifer hydrological connection was first established between the eastern and western Grand Canyon, then collapse, incision, and headward erosion of the canyon followed this subterranean route. This proposed model is based on what is happening today on the northern Marble Platform where the Redwall-Muav aquifer is still intact. The three sinkhole/caves Ah Hol Sah, Indian Pit, and Black Abyss provide vertical flow routes down to the Redwall karst aquifer, joining water discharging from the Kaiparowits hydrologic basin to the Colorado River along the Fence Springs system. Projecting this process back in time and spatially southward, we propose that at around 6 Ma a sinkhole or sinkholes existed at the confluence of the Colorado River with the Little Colorado River. Little Colorado River water, then flowing northward to an interior lake basin ("Glen Lake") in southern Utah, became pirated down this sinkhole(s), thus causing a reversal of drainage (barbed tributaries) in Marble Canyon. Headward erosion then proceeded up Marble and Little Colorado Canyons from the collapsing sinkhole, with Marble Canyon incision breaching Glen Lake at around 5.5 Ma. This effected the "final connection" and total integration of the Colorado River from Colorado to the Gulf of California.

  14. Recent progress in submarine geosciences in China

    Institute of Scientific and Technical Information of China (English)

    JIN Xianglong

    2013-01-01

    In China submarine geosciences represents a newly established discipline of oceanography, focusing on the oceanic lithosphere, and its interface with the hydrosphere and biosphere. Recently, supported by the National High Technology Research and Development Program and other high-tech development projects, significant progress has been made in the development of advanced technologies and equipment. This en-ables the scientists in China to carry out explorations of the international seabed area in the Pacific Ocean and on the Southwest Indian Ridge. In addition, they have been active in the research activities associated the mid-ocean ridges and western Pacific marginal seas. It is anticipated that this research field will continue to be highly fruitful in the near future.

  15. Effect of Submarine Groundwater Discharge on Relict Arctic Submarine Permafrost and Gas Hydrate

    Science.gov (United States)

    Frederick, J. M.; Buffett, B. A.

    2014-12-01

    Permafrost-associated gas hydrate deposits exist at shallow depths within the sediments of the circum-Arctic continental shelves. Degradation of this shallow water reservoir has the potential to release large quantities of methane gas directly to the atmosphere. Gas hydrate stability and the permeability of the shelf sediments to gas migration is closely linked with submarine permafrost. Submarine permafrost extent depends on several factors, such as the lithology, sea level variations, mean annual air temperature, ocean bottom water temperature, geothermal heat flux, and the salinity of the pore water. The salinity of the pore water is especially relevant because it partially controls the freezing point for both ice and gas hydrate. Measurements of deep pore water salinity are few and far between, but show that deep off-shore sediments are fresh. Deep freshening has been attributed to large-scale topographically-driven submarine groundwater discharge, which introduces fresh terrestrial groundwater into deep marine sediments. We investigate the role of submarine ground water discharge on the salinity field and its effects on the seaward extent of relict submarine permafrost and gas hydrate stability on the Arctic shelf with a 2D shelf-scale model based on the finite volume method. The model tracks the evolution of the temperature, salinity, and pressure fields given imposed boundary conditions, with latent heat of water ice and hydrate formation included. The permeability structure of the sediments is coupled to changes in permafrost. Results show that pore fluid is strongly influenced by the permeability variations imposed by the overlying permafrost layer. Groundwater discharge tends to travel horizontally off-shore beneath the permafrost layer and the freshwater-saltwater interface location displays long timescale transient behavior that is dependent on the groundwater discharge strength. The seaward permafrost extent is in turn strongly influenced by the

  16. Submarine volcanoes along the Aegean volcanic arc

    Science.gov (United States)

    Nomikou, Paraskevi; Papanikolaou, Dimitrios; Alexandri, Matina; Sakellariou, Dimitris; Rousakis, Grigoris

    2013-06-01

    The Aegean volcanic arc has been investigated along its offshore areas and several submarine volcanic outcrops have been discovered in the last 25 years of research. The basic data including swath bathymetric maps, air-gun profiles, underwater photos and samples analysis have been presented along the four main volcanic groups of the arc. The description concerns: (i) Paphsanias submarine volcano in the Methana group, (ii) three volcanic domes to the east of Antimilos Volcano and hydrothermal activity in southeast Milos in the Milos group, (iii) three volcanic domes east of Christiana and a chain of about twenty volcanic domes and craters in the Kolumbo zone northeast of Santorini in the Santorini group and (iv) several volcanic domes and a volcanic caldera together with very deep slopes of several volcanic islands in the Nisyros group. The tectonic structure of the volcanic centers is described and related to the geometry of the arc and the neotectonic graben structures that usually host them. The NE-SW direction is dominant in the Santorini and Nisyros volcanic groups, located at the eastern part of the arc, where strike-slip is also present, whereas NW-SE direction dominates in Milos and Methana at the western part, where co-existence of E-W disrupting normal faults is observed. The volcanic relief reaches 1100-1200 m in most cases. This is produced from the outcrops of the volcanic centers emerging usually at 400-600 m depth and ending either below sea level or at high altitudes of 600-700 m on the islands. Hydrothermal activity at relatively high temperatures observed in Kolumbo is remarkable whereas low temperature phenomena have been detected in the Santorini caldera around Kameni islands and in the area southeast of Milos. In Methana and Nisyros, hydrothermal activity seems to be limited in the coastal areas without other offshore manifestations.

  17. Alternative OTEC Scheme for a Submarine Robot

    Science.gov (United States)

    Jones, Jack; Chao, Yi

    2009-01-01

    A proposed system for exploiting the ocean thermal gradient to generate power would be based on the thawing-expansion/ freezing-contraction behavior of a wax or perhaps another suitable phase-change material. The power generated by this system would be used to recharge the batteries in a battery-powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and various depths, measuring temperature and salinity. This proposed system would be an alternative to another proposed ocean thermal energy conversion (OTEC) system that would serve the same purpose but would utilize a thermodynamic cycle in which CO2 would be the working fluid. That system is described in Utilizing Ocean Thermal Energy in a Submarine Robot (NPO-43304), immediately following this brief. The main advantage of this proposed system over the one using CO2 is that it could derive a useful amount of energy from a significantly smaller temperature difference. At one phase of its operational cycle, the system now proposed would utilize the surface ocean temperature (which lies between 15 and 20 C over most of the Earth) to melt a wax (e.g., pentadecane) that has a melting/freezing temperature of about 10 C. At the opposite phase of its operational cycle, the system would utilize the lower ocean temperature at depth (e.g., between 4 and 7 C at a depth of 300 m) to freeze the wax. The melting or freezing causes the wax to expand or contract, respectively, by about 8 volume percent.

  18. Improved OTEC System for a Submarine Robot

    Science.gov (United States)

    Chao, Yi; Jones, Jack; Valdez, Thomas

    2010-01-01

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

  19. Three-dimensional grid generation about a submarine

    Science.gov (United States)

    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.

  20. Exploration of submarine wake and powering performance using CFD method

    Energy Technology Data Exchange (ETDEWEB)

    Huizhi, Y.; Hongcui, S.; Nan, Z.; Renyou, Y.; Liangmei, Y. [China Ship Scientific Research Center, Wuxi, Jiangsu (China)]. E-mail: Yaohuizhi@Yahoo.com

    2005-07-01

    In response to the needs of better design and less time, Computational Fluid Dynamic(CFD) methods have become an impartible part in the ship design, especially in the earlier design phases. In this paper FLUENT software was used to predict the wake character and powering performance of submarine at model scale. By an effective combination of the block topology, grid, turbulence model and validation, the simulation scheme was developed and applied to the predictions of multiple designs and optimizations of the earlier submarine design iterations. The incompressible RANS equations with different turbulence models were solved. To handle the block interface between the propeller and submarine stern, sliding girds in multiple blocks were employed, unstructural grids were used in the block around the propeller. Submarine with/without stator and/or propeller were studied. The flow feature, forces and powering performance at various conditions were calculated. The results were compared with experimental data, and a good agreement was obtained. (author)

  1. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics

    Data.gov (United States)

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

  2. Compounding the Losses of Convoyed Ships Attacked by Tactical Submarines

    Directory of Open Access Journals (Sweden)

    Kåre M. Mjelde

    1982-10-01

    Full Text Available It is demonstrated that a time dependent stochastic model for the losses of convoyed ships attacked by submarines can be applied in the determination of the losses in terms of the results of two submodels:

  3. Application of SAR Imagery in Submarine Topography Surveys

    Institute of Scientific and Technical Information of China (English)

    张宁川; 梁开龙; 桂力民

    2004-01-01

    An important research area in oceanographic surveying and mapping is to obtain submarine topography by remote sensing technique, especially by SAR imagery. In this article, problems related to SAR imagery are analyzed to provide references for the further research.

  4. At Periscope Depth: Exploring Submarine Proliferation In Southeast Asia

    Science.gov (United States)

    2015-09-01

    that Malaysia would sell more than €230 million worth of palm oil to France and accept more than €130 million in French investment.83 In total, the...deterrence, enforcement, prestige, or a combination of the three? This thesis compared the case studies of Indonesia , Malaysia, Singapore, and...rationales for purchasing submarines. Indonesia , Malaysia, and Singapore likely purchased submarines for deterrence and enforcement, and Vietnam for

  5. Littoral Combat Ship Open Ocean Anti-Submarine Warfare

    Science.gov (United States)

    2014-06-01

    COVERED Capstone 4. TITLE AND SUBTITLE LITTORAL COMBAT SHIP OPEN OCEAN ANTI-SUBMARINE WARFARE 5. FUNDING NUMBERS 6. AUTHOR(S) 311-124O/Team LCS...Life cycle cost LCCE Life cycle cost estimate LCS Littoral combat ship LHA Landing ship, helicopter assault LHD Landing ship, helicopter...is unlimited LITTORAL COMBAT SHIP OPEN OCEAN ANTI- SUBMARINE WARFARE by Team LCS 311-124O June 2014 Capstone Advisors: John Green Dan

  6. Topology Model of the Flow around a Submarine Hull Form

    Science.gov (United States)

    2015-12-01

    measured from the body (x) axis hf height of the fin measured from the casing L length of the submarine Lc /4 distance from the submarine nose to the...very fine alternating local positive- and negative- bifurcation lines. These structures scale with the thickness of the boundary layer and they resemble...flow bifurcations. In Fig. 23(a), the smoke filaments (illuminated by a 2mm thick laser-light sheet) capture the instantaneous roll-up. In the simplest

  7. An Analysis on Limit Load for Corroded Submarine Pipelines

    Institute of Scientific and Technical Information of China (English)

    TAN Kai-ren; XIAO Xi

    2006-01-01

    By means of elastic-plastic finite element analysis, a systematic nonlinear analysis of material and geometry has been carried out for submarine pipelines. A criterion for deriving limit load is studied. Based on this criterion, the limit load for corroded submarine pipelines is calculated. The corrosion length, corrosion depth and corrosion width affect the limit load. A solution to limit load is proposed and proved valid through comparison of the solution with burst test results and ASME B31G solutions.

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

    CERN Document Server

    Vieira, R S

    2016-01-01

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

  9. The development of permafrost bacterial communities under submarine conditions

    Science.gov (United States)

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

    2017-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Heath G. Gasier

    2016-02-01

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

  11. Liquid-filled canyons on Titan

    Science.gov (United States)

    Poggiali, V.; Mastrogiuseppe, M.; Hayes, A. G.; Seu, R.; Birch, S. P. D.; Lorenz, R.; Grima, C.; Hofgartner, J. D.

    2016-08-01

    In May 2013 the Cassini RADAR altimeter observed channels in Vid Flumina, a drainage network connected to Titan's second largest hydrocarbon sea, Ligeia Mare. Analysis of these altimeter echoes shows that the channels are located in deep (up to 570 m), steep-sided, canyons and have strong specular surface reflections that indicate they are currently liquid filled. Elevations of the liquid in these channels are at the same level as Ligeia Mare to within a vertical precision of about 0.7 m, consistent with the interpretation of drowned river valleys. Specular reflections are also observed in lower order tributaries elevated above the level of Ligeia Mare, consistent with drainage feeding into the main channel system.

  12. New hexactinellid sponges from deep Mediterranean canyons.

    Science.gov (United States)

    Boury-Esnault, Nicole; Vacelet, Jean; Dubois, Maude; Goujard, Adrien; Fourt, Maïa; Pérez, Thierry; Chevaldonné, Pierre

    2017-02-21

    During the exploration of the NW Mediterranean deep-sea canyons (MedSeaCan and CorSeaCan cruises), several hexactinellid sponges were observed and collected by ROV and manned submersible. Two of them appeared to be new species of Farrea and Tretodictyum. The genus Farrea had so far been reported with doubt from the Mediterranean and was listed as "taxa inquirenda" for two undescribed species. We here provide a proper description for the specimens encountered and sampled. The genus Tretodictyum had been recorded several times in the Mediterranean and in the near Atlantic as T. tubulosum Schulze, 1866, again with doubt, since the type locality is the Japan Sea. We here confirm that the Mediterranean specimens are a distinct new species which we describe. We also provide18S rDNA sequences of the two new species and include them in a phylogenetic tree of related hexactinellids.

  13. The 3D visualization technology research of submarine pipeline based Horde3D GameEngine

    Science.gov (United States)

    Yao, Guanghui; Ma, Xiushui; Chen, Genlang; Ye, Lingjian

    2013-10-01

    With the development of 3D display and virtual reality technology, its application gets more and more widespread. This paper applies 3D display technology to the monitoring of submarine pipeline. We reconstruct the submarine pipeline and its surrounding submarine terrain in computer using Horde3D graphics rendering engine on the foundation database "submarine pipeline and relative landforms landscape synthesis database" so as to display the virtual scene of submarine pipeline based virtual reality and show the relevant data collected from the monitoring of submarine pipeline.

  14. Habitat Mapping Cruise - Hudson Canyon (HB0904, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives are to: 1) perform multibeam mapping of transitional and deepwater habitats in Hudson Canyon (off New Jersey) with the National Institute of Undersea...

  15. Faults--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the faults for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in...

  16. Faults--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the faults for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in...

  17. Folds--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the folds for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in...

  18. The Trail Inventory of Leslie Canyon NWR [Cycle 2

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this report is to create a baseline inventory of all non-motorized trails on Leslie Canyon National Wildlife Refuge. Trails in this inventory are...

  19. Paleoshorelines--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the paleoshorelines for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is...

  20. Investigations of Carbon Phases in Canyon Diablo Meteorite

    Science.gov (United States)

    Karczemska, A.; Jakubowski, T.; Ouzillou, M.; Batory, D.; Abramczyk, H.; Brozek-Pluska, B.; Kopec, M.; Kozanecki, M.; Wiosna-Salyga, G.

    2016-08-01

    X-ray diffraction, Raman mapping and micro-spectrofluorimetric studies have been used in investigations of carbon in Canyon Diablo meteorite. Results show the presence of defected diamond and not well recognized carbon phases (unclear Raman peaks).

  1. BackscatterC [7125]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  2. Paleoshorelines--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the paleoshorelines for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is...

  3. BackscatterB [EM300]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  4. Faults--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the faults for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included...

  5. Folds--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the folds for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in...

  6. Ecological-geochemical assessment of soil of the Dniester canyon.

    Directory of Open Access Journals (Sweden)

    Zorin D.O.

    2008-05-01

    Full Text Available An method of calculation of background and anomalous heavy metals, petroleum products and pesticides in soil of the Dniester canyon area for the environmental assessment of the future national park.

  7. BackscatterC [7125]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  8. BackscatterB [EM300]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  9. Controls on plan-form evolution of submarine channels

    Science.gov (United States)

    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

  10. H CANYON PROCESSING IN CORRELATION WITH FH ANALYTICAL LABS

    Energy Technology Data Exchange (ETDEWEB)

    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

  11. Safety Evaluation for Packaging (onsite) T Plant Canyon Items

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Diablo Canyon plant information management system and integrated communication system

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, J.W.; Groff, C.

    1990-06-01

    The implementation of a comprehensive maintenance system called the plant information management system (PIMS) at the Diablo Canyon plant, together with its associated integrated communication system (ICS), is widely regarded as the most comprehensive undertaking of its kind in the nuclear industry. This paper provides an overview of the program at Diablo Canyon, an evaluation of system benefits, and highlights the future course of PIMS.

  13. Submarine Landslides at Santa Catalina Island, California

    Science.gov (United States)

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

    2011-12-01

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

  14. Submarine Volcanic Morphology of Santorini Caldera, Greece

    Science.gov (United States)

    Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.

    2012-04-01

    Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at

  15. A sedimentologic and 14C dating study of five eastern Australian upper continental slope submarine landslides

    Science.gov (United States)

    Clarke, S. L.; Hubble, T.; Webster, J.; Airey, D.; De Carli, E.; Ferraz, C.; Reimer, P. J.; Boyd, R.; Keene, J.

    2013-12-01

    Sedimentologic and AMS 14C age data are reported for calcareous hemipelagic mud samples taken from gravity cores collected at sites within, or adjacent to five submarine landslides identified with multibeam bathymetry data on the Nerrang Plateau segment and surrounding canyons of eastern Australia's continental slope (Bribie Bowl, Coolangatta-2, Coolangatta-1, Cudgen and Byron). Sediments are comprised of mixtures of calcareous and terrigenous clay (10-20%), silt (50-65%) and sand (15-40%) and are generally uniform in appearance. Their carbonate contents vary between and 17% and 22% by weight while organic carbon contents are less than 10% by weight. Dating of conformably deposited material identified in ten of the twelve cores indicates a range of sediment accumulation rates between 0.017mka-1 and 0.2 mka-1 which are consistent with previous estimates reported for this area. One slide-adjacent core, and four within-landslide cores present depositional hiatus surfaces located at depths of 0.8 to 2.2 meters below the present-day seafloor and identified by a sharp, colour-change boundary; discernable but small increases in sediment stiffness; and a slight increase in sediment bulk density of 0.1 gcm-3. Distinct gaps in AMS 14C age of at least 20ka are recorded across these boundary surfaces. Examination of sub-bottom profiler records of transects through three of the within-slide core-sites and their nearby landslide scarps available for the Coolangatta-1 and Cudgen slides indicate that: 1) the youngest identifiable sediment layer reflectors upslope of these slides, terminate on and are truncated by slide rupture surfaces; and 2) there is no obvious evidence in the sub-bottom profiles for a post-slide sediment layer draped over or otherwise burying slide ruptures or exposed slide detachment surfaces. This suggests that both these submarine landslides are geologically recent and suggests that the hiatus surfaces identified in Coolangatta-1's and Cudgen's within

  16. Design and analysis of submarine radome

    Science.gov (United States)

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

    2017-07-01

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

  17. From submarine to lacustrine groundwater discharge

    Science.gov (United States)

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

    2017-01-01

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

  18. Submarine Landslides in Arctic Sedimentation: Canada Basin

    Science.gov (United States)

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

    2016-01-01

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

  19. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K.

    1995-12-31

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

  20. Submarine landslides of the Southern California Borderland

    Science.gov (United States)

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

    2009-01-01

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

  1. NOAA Charted Submarine cables in the United States as of December 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data depict the occurrence of submarine cables in and around U.S. navigable waters. The geographic extent of these data is greater than the "NASCA Submarine...

  2. Tsunami run-up and inundation along the coast of Sabah and Sarawak, Malaysia due to a potential Brunei submarine mass failure.

    Science.gov (United States)

    Tan, Wai Kiat; Teh, Su Yean; Koh, Hock Lye

    2017-03-25

    Submarine landslides, also known as submarine mass failures (SMFs), are major natural marine disasters that could critically damage coastal facilities such as nuclear power plants and oil and gas platforms. It is therefore essential to investigate submarine landslides for potential tsunami hazard assessment. Three-dimensional seismic data from offshore Brunei have revealed a giant seabed mass deposited by a previous SMF. The submarine mass extends over 120 km from the continental slope of the Baram Canyon at 200 m water depth to the deep basin floor of the Northwest Borneo Trough. A suite of in-house two-dimensional depth-averaged tsunami simulation model TUNA (Tsunami-tracking Utilities and Application) is developed to assess the vulnerability of coastal communities in Sabah and Sarawak subject to potential SMF tsunami. The submarine slide is modeled as a rigid body moving along a planar slope with the center of mass motion parallel to the planar slope and subject to external forces due to added mass, gravity, and dissipation. The nonlinear shallow water equations are utilized to simulate tsunami propagation from deepwater up to the shallow offshore areas. A wetting-drying algorithm is used when a tsunami wave reaches the shoreline to compute run up of tsunami along the shoreline. Run-up wave height and inundation maps are provided for seven densely populated locations in Sabah and Sarawak to highlight potential risks at each location, subject to two scenarios of slide slopes: 2° and 4°. The first wave may arrive at Kudat as early as 0.4 h after the SMF, giving local communities little time to evacuate. Over a small area, maximum inundated depths reaching 20.3 m at Kudat, 26.1 m at Kota Kinabalu, and 15.5 m at Miri are projected, while the maximum inundation distance of 4.86 km is expected at Miri due to its low-lying coast. In view of the vulnerability of some locations to the SMF tsunami, it is important to develop and implement community resilience

  3. Sediment and organic carbon transport in Cap de Creus canyon, Gulf of Lions (France)

    Science.gov (United States)

    Tesi, T.; Puig, P.; Palanques, A.; Goni, M. A.; Miserocchi, S.; Langone, L.

    2009-04-01

    The off-shelf transport of particles in continental margins is responsible for much of the flux of organic matter (OM)and nutrients towards deep-sea ecosystems, playing a key role in the global oceanic biogeochemical cycles. Off-shelf sediment transport mechanism have been well described for many continental margins being triggered by a series of physical forcings such as tides, storms, internal waves, floods, earthquakes, as well as the combination of some of these processes, while topographic structures such as submarine canyons act as preferential sedimentary conduits toward deep ocean. However, the composition of the material supplied to the deep ocean during these events is still poorly understood since most studies have only investigated the magnitude of the down-slope fluxes or limited their analysis to the major bulk components. A special opportunity to characterize the biogeochemical composition of the off-shelf export in the Gulf of Lions (GoL) margin was provided during the winter 2004-2005, when an exceptional dense water cascading event occurred. Dense water overflowing off the shelf in the GoL has been recently recognized as one of the main process affecting particulate shelf-to-slope exchange in northwestern Mediterranean Sea. During the 2004-2005 cascading event, moored instruments were deployed at the Cap de Creus (CdC) canyon head to monitor the physical parameters and to characterize the temporal variability of the exported material. Post-cascading sediment cores were collected along the sediment dispersal system to trace the sediment transport pathway. In this study we developed a source tracing method using elemental compositions, alkaline CuO reaction products (lignin, cutin, lipids, hydroxy benzenes, proteins, lipids, and polysaccharides products), biogenic silica, carbon stable isotope composition, radiocarbon measurements, and grain size as a fingerprint for each sample. The aforementioned analyses were carried out on both sediment trap and

  4. High-resolution Geophysical Mapping of Submarine Glacial Landforms

    Science.gov (United States)

    Jakobsson, M.; Dowdeswell, J. A.; Canals, M.; Todd, B. J.; Dowdeswell, E. K.; Hogan, K. A.; Mayer, L. A.

    2014-12-01

    Glacial landforms are generated from the activity of glaciers and display spatial dimensions ranging from below one meter up to tens of kilometers. Glacial landforms are used as diagnostic features of past activity of ice sheets and glaciers; they are specifically important in the field of palaeoglaciology. Mapping of submarine glacial landforms is largely dependent on geophysical survey methods capable of imaging the seafloor and sub-bottom through the water column. Full "global" seafloor mapping coverage, equivalent to what exists for land elevation, is to-date only achieved by the powerful method of deriving bathymetry from altimeters on satellites like GEOSAT and ERS-1. The lateral resolution of satellite derived bathymetry is, however, limited by the footprint of the satellite and the need to average out local wave and wind effects resulting in values of around 15 km. Consequently, mapping submarine glacial landforms requires for the most part higher resolution than is achievable by satellite derived bathymetry. The most widely-used methods for mapping submarine glacial landforms are based on echo-sounding principles. This presentation shows how the evolution of marine geophysical mapping techniques, in particular the advent of side-scan and multibeam bathymetric sonars, has made it possible to study submarine glacial landforms in unprecedented detail. Examples are shown from the Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient, which will be published in late 2015 in the Memoir Series of the Geological Society of London.

  5. Effects of canyon geometry on the distribution of traffic-related air pollution in a large urban area: Implications of a multi-canyon air pollution dispersion model

    Science.gov (United States)

    Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu

    2017-09-01

    Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.

  6. Geology of the Hamm Canyon quadrangle, Colorado

    Science.gov (United States)

    Cater, Fred W.

    1953-01-01

    The Hamm Canyon quadrangle is on eof eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

  7. 75 FR 1706 - Regulated Navigation Area; U.S. Navy Submarines, Hood Canal, WA

    Science.gov (United States)

    2010-01-13

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA11 Regulated Navigation Area; U.S. Navy Submarines, Hood... be in effect whenever any U.S. Navy submarine is operating in the Hood Canal and being escorted by the Coast Guard. The RNA is necessary to help ensure the safety and security of the submarines,...

  8. 77 FR 59749 - Safety Zone; Submarine Cable Installation Project; Chicago River, Chicago, IL

    Science.gov (United States)

    2012-10-01

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Submarine Cable Installation Project... intended to restrict vessels from a portion of the Chicago River due to the installation of submarine... the installation of submarine cables in the vicinity of both the West Adams Street and West...

  9. 75 FR 27638 - Regulated Navigation Area; U.S. Navy Submarines, Hood Canal, WA

    Science.gov (United States)

    2010-05-18

    ... No. USCG-2009-1058] RIN 1625-AA11 Regulated Navigation Area; U.S. Navy Submarines, Hood Canal, WA... whenever any U.S. Navy submarine is operating in that area and is being escorted by the Coast Guard. The RNA is necessary to help ensure the safety and security of the submarines, their Coast Guard...

  10. 47 CFR 32.6424 - Submarine and deep sea cable expense.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Submarine and deep sea cable expense. 32.6424 Section 32.6424 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Submarine and deep sea cable expense. (a) This account shall include expenses associated with submarine...

  11. 76 FR 78159 - Safety Zone; Submarine Cable Installation Project; Chicago River South Branch, Chicago, IL

    Science.gov (United States)

    2011-12-16

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Submarine Cable Installation Project... the installation of submarine cables in the vicinity of the Madison Street Bridge. This temporary... the installation of submarine cables in the vicinity of the Madison Street Bridge. Entry into...

  12. 33 CFR 165.1328 - Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA.

    Science.gov (United States)

    2010-07-01

    .... Navy submarines, Hood Canal, WA. 165.1328 Section 165.1328 Navigation and Navigable Waters COAST GUARD... § 165.1328 Regulated Navigation Area; U.S. Navy submarines, Hood Canal, WA. (a) Location. The following... whenever any U.S. Navy submarine is operating in the Hood Canal and is being escorted by the Coast...

  13. 78 FR 67086 - Safety Zone, Submarine Cable Replacement Operations, Kent Island Narrows; Queen Anne's County, MD

    Science.gov (United States)

    2013-11-08

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Submarine Cable Replacement Operations... safety of mariners and their vessels on navigable waters during submarine cable replacement operations at... installation of a submarine cable within a federal navigation channel requiring divers, a barge, and...

  14. High-Resolution Chirp and Mini-Sparker Seismic-Reflection Data From the Southern California Continental Shelf - Gaviota to Mugu Canyon

    Science.gov (United States)

    Sliter, Ray W.; Triezenberg, Peter J.; Hart, Patrick E.; Draut, Amy E.; Normark, William R.; Conrad, James E.

    2008-01-01

    The U.S. Geological Survey (USGS) collected high-resolution shallow seismic-reflection data in September, 2007, and June-July, 2008, from the continental shelf offshore of southern California between Gaviota and Mugu Canyon, in support of the California's State Waters Mapping Program. Data were acquired using SIG 2mille mini-sparker and Edgetech chirp 512 instruments aboard the R/V Zephyr (Sept. 2007) and R/V Parke Snavely (June-July 2008). The survey area spanned approximately 120 km of coastline, and included shore-perpendicular transects spaced 1.0-1.5 km apart that extended offshore to at least the 3-mile limit of State waters, in water depths ranging from 10 m near shore to 300 m near the offshore extent of Mugu and Hueneme submarine canyons. Subbottom acoustic penetration spanned tens to several hundred meters, variable by location. This report includes maps of the surveyed transects, linked to Google Earth software, as well as digital data files showing images of each transect in SEG-Y, JPEG, and TIFF formats. The images of sediment deposits, tectonic structure, and natural-gas seeps collected during this study provide geologic information that is essential to coastal zone and resource management at Federal, State and local levels, as well as to future research on the sedimentary, tectonic, and climatic record of southern California.

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

    Science.gov (United States)

    Vieira, R. S.

    2016-12-01

    In 1989 Supplee described an apparent relativistic paradox on which a submarine seems to sink to observers at rest within the ocean, but it rather seems to float in the submarine proper frame. In this letter, we show that the paradox arises from a misuse of the Archimedes principle in the relativistic case. Considering first the special relativity, we show that any relativistic force field can be written in the Lorentz form, so that it can always be decomposed into a static (electric-like) and a dynamic (magnetic-like) part. These gravitomagnetic effects provide a relativistic formulation of Archimedes principle, from which the paradox is explained. Besides, if the curved spacetime on the vicinity of the Earth is taken into account, we show that the gravitational force exerted by the Earth on a moving body must increase with the speed of the body. The submarine paradox is then analyzed again with this speed-dependent gravitational force.

  16. Understanding losses in three core armoured submarine cables

    DEFF Research Database (Denmark)

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

    2016-01-01

    . For practical an economical reasons the preferred choice of cable for both the array and the transmission cables are three-core armoured submarine cables. Therefore, it has becoming increasingly important to be able to calculate the ampacity of such cables accurately. At present time, the ampacity of three......-core armoured submarine cables is calculated according to IEC 60287-1-1 [1]. Various measurements conducted both by cable manufacturers and transmission system operators (TSO) have shown that using the cable rating method stated in IEC 60287-1-1 underestimates the cable ampacity [2]-[6]. Furthermore....... However, research performed in this paper shows that while the armour is responsible for the extra losses, the main calculation error for typical HVAC submarine cables may be in the screen’s loss factor (λ1). Overestimation of the cable losses may result in core cross-sections too large with more material...

  17. Attitudes to smoking on submarines: results of a questionnaire study.

    Science.gov (United States)

    Norris, William D; Brims, Fraser J H

    2002-07-01

    An anonymous survey to assess the attitudes to smoking of men serving on two Trident Nuclear submarines was conducted by questionnaire. A total of 244 questionnaires were completed, representing 87% of the two crews. Thirty-two percent of respondents declared themselves to be smokers, 69% were nonsmokers, and of these, 31% were ex-smokers. Attitudes of all respondents to an enforced ban of smoking on submarines indicated that 55% felt that it would be justifiable, 46% felt that it would be unfair, 42% felt that it was uncalled for, 46% thought that it would be illegal, and 47% thought that a ban was about time. The separate opinions of smokers and nonsmokers were polarized, whereas the overall results indicate indifferent attitudes of crew members. Further research into the atmospheric effects of environmental tobacco smoke on a submarine is required.

  18. A heuristic solution for the stability problem in conventional submarines

    Directory of Open Access Journals (Sweden)

    M. Sinclair

    2003-12-01

    Full Text Available Seafaring vessels must meet a few very obvious conditions in order to be of any use. The one condition is that they should stay afloat when loaded. The other condition is that they should float upright and with a level keel. The technical terms for these conditions are gravitational stability and trim. In practice some very precise numerical values are calculated for certain parameters in order to describe these conditions. After each refit of a submarine, the numerical values for the parameters referred to above must be recalculated. In the conventional submarines used by the South African Navy these new values must then be translated into the physical redistribution of weights housed in bays in the keel of the submarine. This paper discusses the problem of how this redistribution must be done in order to minimise the amount of work necessary. A heuristic algorithm is proposed by means of which a satisfactory redistribution may economically be computed.

  19. A Havelock Source Panel Method for Near-surface Submarines

    Institute of Scientific and Technical Information of China (English)

    Tim Gourlay; Edward Dawson

    2015-01-01

    A panel method is described for calculating potential flow around near-surface submarines. The method uses Havelock sources which automatically satisfy the linearized free-surface boundary condition. Outputs from the method include pressure field, pressure drag, wave resistance, vertical force, trim moment and wave pattern. Comparisons are made with model tests for wave resistance of Series 58 and DARPA SUBOFF hulls, as well as with wave resistance, lift force and trim moment of three length-to-diameter variants of the DSTO Joubert submarine hull. It is found that the Havelock source panel method is capable of determining with reasonable accuracy wave resistance, vertical force and trim moment for submarine hulls. Further experimental data are required in order to assess the accuracy of the method for pressure field and wave pattern prediction. The method is implemented in the computer code“HullWave”and offers potential advantages over RANS-CFD codes in terms of speed, simplicity and robustness.

  20. Active control of radiated pressure of a submarine hull

    Science.gov (United States)

    Pan, Xia; Tso, Yan; Juniper, Ross

    2008-03-01

    A theoretical analysis of the active control of low-frequency radiated pressure from submarine hulls is presented. Two typical hull models are examined in this paper. Each model consists of a water-loaded cylindrical shell with a hemispherical shell at one end and conical shell at the other end, which forms a simple model of a submarine hull. The conical end is excited by an axial force to simulate propeller excitations while the other end is free. The control action is implemented through a Tee-sectioned circumferential stiffener driven by pairs of PZT stack actuators. These actuators are located under the flange of the stiffener and driven out of phase to produce a control moment. A number of cost functions for minimizing the radiated pressure are examined. In general, it was found that the control system was capable of reducing more than half of the total radiated pressure from each of the submarine hull for the first three axial modes.

  1. Origin of Hot Creek Canyon, Long Valley caldera, California

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, N.J. (California State Univ., Fullerton, CA (United States). Dept. of Geological Sciences)

    1993-04-01

    Hot Creek has eroded a canyon some thirty meters deep across the Hot Creek rhyolite flows located in the southeastern moat of Long Valley Caldera. Maloney (1987) showed that the canyon formed by headward erosion resulting from spring sapping along hydrothermally altered fractures in the rhyolite, and the capture of Mammoth Creek. This analysis ignored the continuing uplift of the central resurgent dome. Reid (1992) concluded that the downward erosion of the canyon must have kept pace with the uplift. Long Valley Lake occupied the caldera until 100,000 to 50,000 years before present. The elevation of the shoreline, determined by trigonometric leveling, is 2,166 m where the creek enters the canyon and 2,148 m on the downstream side of the rhyolite. The slope of the strand line is about equal to the stream gradient. The hill was lower and the stream gradient less at the time of stream capture. Rotational uplift increased the stream gradient which increased the rate of downward erosion and formed the V-shaped canyon

  2. Software Configuration Management Plan for the B-Plant Canyon Ventilation Control System

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Spatial Vegetation Data for Canyon De Chelly National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The Canyon de Chelly National Monument Vegetation Map Database was developed as a primary product in the Canyon de Chelly National Monument Vegetation...

  4. 2013 Pacific Gas and Electric Diablo Canyon Power Plant (DCPP): San Simeon, CA Central Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Diablo Canyon Power Plant (DCPP) LiDAR and Imagery datasets are comprised of three separate LiDAR surveys: Diablo Canyon (2010), Los Osos (2011), and San Simeon...

  5. Water classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data area classified maps of water in the Colorado River at a discharge of approximately 227 meters squared/second in Grand Canyon from Glen Canyon Dam to...

  6. Riparian vegetation classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are classification maps of total riparian vegetation along the Colorado River in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data...

  7. 2011 Pacific Gas and Electric Diablo Canyon Power Plant (DCPP): Los Osos, CA Central Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Diablo Canyon Power Plant (DCPP) LiDAR and Imagery datasets are comprised of three separate LiDAR surveys: Diablo Canyon (2010), Los Osos (2011), and San Simeon...

  8. Constructive measures for handling submarine desalination plants. Konstruktive Massnahmen zur Handhabung submariner Entsalzungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Drude, B.C.; Klapp, E.; Peters, T.

    1978-11-23

    The erection and the periodical repair works of a submarine desalination plant are made easier by the separate construction of the main components, as such a membrane body for the desalination and the fresh water conveying device, both in pressure-proof vessels and by the light-weight construction method. Considerable membrane surfaces for the desalination by reverse osmosis are wound spirally around a collecting vessel of fresh water. The vessel is made of glass-fiber reinforced plastics or another light material. The main components are connected by sufficiently long and flexible pipes by which the handling of the parts is simplified during erection. This is particularly advantageous if several desalination aggregates are fed by one conveyor system.

  9. Directed urban canyons in megacities and its applications in meteorological modeling

    Science.gov (United States)

    Samsonov, Timofey; Konstantinov, Pavel; Varentsov, Mikhail

    2015-04-01

    Directed urban canyons study applies object-oriented analysis to extraction of urban canyons and introduces the concept of directed urban canyon which is then experimentally applied in urban meteorological modeling. Observation of current approach to description of urban canyon geometry is provided. Then a new theoretical approach to canyon delineation is presented that allows chaining the spaces between buildings into directed canyons that comprise three-level hierarchy. An original methodology based on triangular irregular network (TIN) is presented that allows extraction of regular and directed urban canyons from cartographic data, estimation of their geometric characteristics, including local and averaged height-width ratio, primary and secondary canyon directions. Obtained geometric properties of canyons are then applied in micro-scale temperature and wind modeling using URB-MOS model and estimation of possible wind accelerations along canyons. Extraction and analysis of directed canyons highly depends on the presence of linear street network. Thus, in the absence of this GIS layer, it should be reconstructed from another data sources. The future studies should give us an answer to the question, where the limits of directed canyons are and how they can be classified further in terms of the street longitudinal shape. For now all computations are performed in separate scripts and programs. We plan to develop comprehensive automation of described methods of urban canyon description in specialized software. The most perspective extension of proposed methodology seemes to be canyon -based analysis which is truely object-oriented. Various geometric properties of micro-, meso- and macro-scale canyons should be investigated and their applicability in urban climate modeling should be assesed. Object-oriented canyon analysis can also be applied in architectural studies, urban morphology, planning and various physical and social aspects that are concerned with human in

  10. Standardized methods for Grand Canyon fisheries research 2015

    Science.gov (United States)

    Persons, William R.; Ward, David L.; Avery, Luke A.

    2013-01-01

    This document presents protocols and guidelines to persons sampling fishes in the Grand Canyon, to help ensure consistency in fish handling, fish tagging, and data collection among different projects and organizations. Most such research and monitoring projects are conducted under the general umbrella of the Glen Canyon Dam Adaptive Management Program and include studies by the U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service (FWS), National Park Service (NPS), the Arizona Game and Fish Department (AGFD), various universities, and private contractors. This document is intended to provide guidance to fieldworkers regarding protocols that may vary from year to year depending on specific projects and objectives. We also provide herein documentation of standard methods used in the Grand Canyon that can be cited in scientific publications, as well as a summary of changes in protocols since the document was first created in 2002.

  11. Tectonic control and mass-wasting processes along S. Vicente Canyon (SW Iberia): evidences from multibeam bathymetry and seismic reflection data

    Science.gov (United States)

    Valadares, V.; Roque, C.; Terrinha, P.

    2009-04-01

    The S. Vicente Canyon is located in the Gulf of Cadiz (GoC), in the Northwest Atlantic Ocean, offshore SW Iberia. The GoC is located between the Straits of Gibraltar (5°W) and the Gorringe Bank (12°W) and 34°N and 38°N. It is situated in a complex geodynamic setting at the Eastern tip of the Azores-Gibraltar fracture zone, part of the convergent plate boundary between Northwest Africa and Southwest Eurasia. There are several evidences for active tectonics, moderate seismic activity and some events of high magnitude for earthquakes and tsunamis (like the 1755 and 1969 events). The canyon lies between two of the most prominent faults in the GoC: the Marquês de Pombal and the Horseshoe thrust faults. Since the 1990's nineteen multibeam swath bathymetry surveys were carried out in the Gulf of Cadiz and a compilation of the data was produced adding up to more than 180.000km2. This 100m cellsize compilation allowed a detailed analysis of the seafloor of the GoC including the South and Western Portuguese margins and is in the junction point between these two margins that the S. Vicente Canyon (SVC) is located. The bathymetry data here presented is derived from the MATESPRO survey from 2004, the first large multibeam swath bathymetry survey in the area. The canyon has a general staircase-like shape with the upper and lower parts trending NE-SW and the middle sector with an NNE-SSW direction. The SVC head lies very close to the shore, at depths shallower than 70m and runs towards the Horseshoe Abyssal Plain (HAP) at around 4900m depth. It extends for more than 120km (larger than any other submarine canyon on the GoC) and can reach up to 20 km in width. The walls are steep and frequently affected by mass wasting scars and also strongly incised by minor contributories valleys. A major kink is present where the canyon diverts about 60° from its upper course, as well as several minor ones and some knickpoints are also identifiable across its entire track. Across its

  12. 75 FR 41232 - Deer Flat National Wildlife Refuge, Canyon, Owyhee, Payette, and Washington Counties, ID; Malheur...

    Science.gov (United States)

    2010-07-15

    ... Fish and Wildlife Service Deer Flat National Wildlife Refuge, Canyon, Owyhee, Payette, and Washington...). The Refuge has units located in Canyon, Owyhee, Payette, and Washington Counties, ID, and Malheur... the Snake River located in Canyon, Payette, Owyhee, and Washington Counties in ID; and Malheur...

  13. 76 FR 54487 - Charter Renewal, Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2011-09-01

    ... Bureau of Reclamation Charter Renewal, Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of... the Glen Canyon Dam Adaptive Management Work Group. The purpose of the Adaptive Management Work Group... of the Glen Canyon Dam Adaptive Management Work Group is in the public interest in connection...

  14. 78 FR 54482 - Charter Renewal, Glen Canyon Dam Adaptive Management Work Group

    Science.gov (United States)

    2013-09-04

    ... Bureau of Reclamation Charter Renewal, Glen Canyon Dam Adaptive Management Work Group AGENCY: Bureau of... the Glen Canyon Dam Adaptive Management Work Group. The purpose of the Adaptive Management Work Group... Canyon Dam Adaptive Management Work Group is in the public interest in connection with the performance...

  15. 75 FR 39147 - Establishment of Class E Airspace; Bryce Canyon, UT

    Science.gov (United States)

    2010-07-08

    ... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Bryce Canyon, UT AGENCY... E airspace at Bryce Canyon, UT, to accommodate aircraft using a new Area Navigation (RNAV) Global... Bryce Canyon, UT (74 FR 59492). The comments received prompted the FAA on April 26, 2010, to publish...

  16. 75 FR 21532 - Proposed Establishment of Class E Airspace; Bryce Canyon, UT

    Science.gov (United States)

    2010-04-26

    ..., UT AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Supplemental notice of proposed... surface airspace at Bryce Canyon Airport, Bryce Canyon, UT. In a NPRM published in the Federal Register... Airport, Bryce Canyon, UT (74 FR 59492). The comment period closed January 4, 2010. Two comments...

  17. 76 FR 14802 - Modification of Class E Airspace; Bryce Canyon, UT

    Science.gov (United States)

    2011-03-18

    ... Federal Aviation Administration 14 CFR Part 71 Modification of Class E Airspace; Bryce Canyon, UT AGENCY... airspace at Bryce Canyon, UT. Additional controlled airspace is necessary to accommodate aircraft using... a notice of proposed rulemaking to establish additional controlled airspace at Bryce Canyon, UT...

  18. Regional economic impacts of Grand Canyon river runners.

    Science.gov (United States)

    Hjerpe, Evan E; Kim, Yeon-Su

    2007-10-01

    Economic impact analysis (EIA) of outdoor recreation can provide critical social information concerning the utilization of natural resources. Outdoor recreation and other non-consumptive uses of resources are viewed as environmentally friendly alternatives to extractive-type industries. While outdoor recreation can be an appropriate use of resources, it generates both beneficial and adverse socioeconomic impacts on rural communities. The authors used EIA to assess the regional economic impacts of rafting in Grand Canyon National Park. The Grand Canyon region of northern Arizona represents a rural US economy that is highly dependent upon tourism and recreational expenditures. The purpose of this research is twofold. The first is to ascertain the previously unknown regional economic impacts of Grand Canyon river runners. The second purpose is to examine attributes of these economic impacts in terms of regional multipliers, leakage, and types of employment created. Most of the literature on economic impacts of outdoor recreation has focused strictly on the positive economic impacts, failing to illuminate the coinciding adverse and constraining economic impacts. Examining the attributes of economic impacts can highlight deficiencies and constraints that limit the economic benefits of recreation and tourism. Regional expenditure information was obtained by surveying non-commercial boaters and commercial outfitters. The authors used IMPLAN input-output modeling to assess direct, indirect, and induced effects of Grand Canyon river runners. Multipliers were calculated for output, employment, and income. Over 22,000 people rafted on the Colorado River through Grand Canyon National Park in 2001, resulting in an estimated $21,100,000 of regional expenditures to the greater Grand Canyon economy. However, over 50% of all rafting-related expenditures were not captured by the regional economy and many of the jobs created by the rafting industry are lower-wage and seasonal. Policy

  19. Review of the Diablo Canyon probabilistic risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bozoki, G.E.; Fitzpatrick, R.G.; Bohn, M.P. [Sandia National Lab., Albuquerque, NM (United States); Sabek, M.G. [Atomic Energy Authority, Nuclear Regulatory and Safety Center, Cairo (Egypt); Ravindra, M.K.; Johnson, J.J. [EQE Engineering, San Francisco, CA (United States)

    1994-08-01

    This report details the review of the Diablo Canyon Probabilistic Risk Assessment (DCPRA). The study was performed under contract from the Probabilistic Risk Analysis Branch, Office of Nuclear Reactor Research, USNRC by Brookhaven National Laboratory. The DCPRA is a full scope Level I effort and although the review touched on all aspects of the PRA, the internal events and seismic events received the vast majority of the review effort. The report includes a number of independent systems analyses sensitivity studies, importance analyses as well as conclusions on the adequacy of the DCPRA for use in the Diablo Canyon Long Term Seismic Program.

  20. Operating Below Crush Depth: The Formation, Evolution, and Collapse of the Imperial Japanese Navy Submarine Force in World War II

    Science.gov (United States)

    2011-06-10

    Subamrine, Medium) LCDR Lieutenant Commander LT Lieutenant NM Nautical Mile RADM Rear Admiral ST Sen- Taka (Submarine, High Speed) STo Sen-Toku...Special Submarine) STS Sen- Taka -Sho (Submarine, High Speed(Victory)) USS United States Ship VADM Vice Admiral 1 CHAPTER 1 INTRODUCTION On...Kirai-Sen meaning Mine-Layer, KT for Kai-Toku-Chu meaning Medium, Special Submarine, ST for Sen- Taka meaning Submarine, High speed, STo for Sen Toku

  1. Surprise and Opportunity for Learning in Grand Canyon: the Glen Canyon Dam Adaptive Management Program

    Science.gov (United States)

    Melis, T. S.; Walters, C. J.; Korman, J.

    2013-12-01

    With a focus on resources of the Colorado River ecosystem downstream of Glen Canyon Dam in Glen Canyon National Recreation Area (GCNRA) and Grand Canyon National Park (GCNP) of northern Arizona, the Glen Canyon Dam Adaptive Management Program has evaluated experimental flow and nonflow policy tests since 1990. Flow experiments have consisted of a variety of water releases from the dam within pre-existing annual downstream delivery agreements. The daily experimental dam operation, termed the Modified Low Fluctuating Flow (MLFF), implemented in 1996 to increase daily low flows and decrease daily peaks were intended to limit daily flow range to conserve tributary sand inputs and improve navigation among other objectives, including hydropower energy. Other flow tests have included controlled floods with some larger releases bypassing the dam's hydropower plant to rebuild and maintain eroded sandbars in GCNP. Experimental daily hydropeaking tests beyond MLFF have also been evaluated for managing the exotic recreational rainbow trout fishery in the dam's GCNRA tailwater. Experimental nonflow policies, such as physical removal of exotic fish below the tailwater, and experimental translocation of endangered native humpback chub from spawning habitats in the Little Colorado River (the largest natal origin site for chub in the basin) to other tributaries within GCNP have also been monitored. None of these large-scale field experiments has yet produced unambiguous results in terms of management prescriptions, owing to inadequate monitoring programs and confounding of treatment effects with effects of ongoing natural changes; most notably, a persistent warming of the river resulting from reduced storage in the dam's reservoir after 2003. But there have been several surprising results relative to predictions from models developed to identify monitoring needs and evaluate experimental design options at the start of the adaptive ecosystem assessment and management program in 1997

  2. Anti-submarine warfare with continuously active sonar

    NARCIS (Netherlands)

    Vossen, R. van; Beerens, S.P.; Spek, E. van der

    2011-01-01

    Existing surveillance sonar systems for anti-submarine warfare (ASW) use a pulsed sonar deployed at a low duty cycle. Continuously active sonar (CAS) is of special interest since the technique could provide better detection performance than conventional pulsed sonar, and it will provide the operator

  3. Investigating Outfitting Density as a Cost Driver in Submarine Construction

    Science.gov (United States)

    2015-09-01

    35 b. Compensated Gross Tonnage .................................................36 c. Acoustic Requirements and the Effect on Procurement...hours inside the hull. Previously, submarines were assembled piece by piece on location, typically on the shipbuilding ways or inclined railway . The...ultimate capability for ASW, ISR and polar missions, and was fast, acoustically superior and could navigate in deeper waters than any other fast

  4. Losses in armoured three-phase submarine cables

    DEFF Research Database (Denmark)

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

    2014-01-01

    The number of offshore wind farms will keep increasing in the future as a part of the shift towards a CO2 free energy production. The energy harvested from the wind farm must be brought to shore, which is often done by using a three-phase armoured submarine power cable. The use of an armour...

  5. Cold-water coral banks and submarine landslides: a review

    Science.gov (United States)

    de Mol, Ben; Huvenne, Veerle; Canals, Miquel

    2009-06-01

    This paper aims to review the relation between cold-water coral bank development and submarine landslides. Both are common features on continental margins, but so far it has not been reviewed which effect—if at all—they may have upon each other. Indirect and direct relations between coral banks and landslides are evaluated here, based on four case studies: the Magellan Mound Province in the Porcupine Seabight, where fossil coral banks appear partly on top of a buried slide deposit; the Sula Ridge Reef Complex and the Storegga landslide both off mid-Norway; and the Mauritania coral bank province, associated with the Mauritanian Slide Complex. For each of these locations, positive and negative relationships between both features are discussed, based on available datasets. Locally submarine landslides might directly favour coral bank development by creating substratum where corals can settle on, enhancing turbulence due to abrupt seabed morphological variations and, in some cases, causing fluid seepage. In turn, some of these processes may contribute to increased food availability and lower sedimentation rates. Landslides can also affect coral bank development by direct erosion of the coral banks, and by the instantaneous increase of turbidity, which may smother the corals. On the other hand, coral banks might have a stabilising function and delay or stop the headwall retrogradation of submarine landslides. Although local relationships can be deduced from these case studies, no general and direct relationship exists between submarine landslides and cold-water coral banks.

  6. New fuel cell plants and power sources for submarines

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, B.; Sokolov, V. [CDB ME ' ' Rubin' ' (Russian Federation)

    2000-07-01

    The existing storage batteries for submarines have been analyzed, the quality of their design has been estimated and a power plant with electrochemical generators (fuel cells) has been suggested as an electric energy source. The history and the status of power plant design in Russia have been reflected. (authors)

  7. TNMG to Make a Profit on Submarine Mine

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>TNMG released a notice indicating that it and Nautilus Minerals Niugini Limited (hereinafter referred to as "Nautilus Mining Company"), on April 21, signed major clauses of the cooperative agreement concerning submarine ore processing of Bismarck Sea Solwara project in

  8. Submarine barite-opal rocks of hydrothermal origin.

    Science.gov (United States)

    Bertine, K K; Keene, J B

    1975-04-11

    Unusual submarine rocks consisting of barite, opal, and volcanic detritus were recovered from the Lau Basin northeast of Australia. It is proposed that these rocks were formed when hydrothermal solutions emanating from a fracture zone offsetting the active spreading center in the Lau Basin came into contact with cooler ocean waters.

  9. An ongoing large submarine landslide at the Japan trench

    Science.gov (United States)

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

    2013-12-01

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

  10. A submarine perspective of the Honolulu Volcanics, Oahu

    Science.gov (United States)

    Clague, David A.; Paduan, Jennifer B.; McIntosh, William C.; Cousens, Brian L.; Davis, Alicé S.; Reynolds, Jennifer R.

    2006-03-01

    Lavas and volcaniclastic deposits were observed and collected from 4 submarine cones that are part of the Honolulu Volcanics on Oahu, Hawaii. The locations of these and a few additional, but unsampled, vents demonstrate that nearly all the vents are located on or very close to the shoreline of Oahu, with the most distal vent just 12 km offshore. The clastic samples and outcrops range from coarse breccias to cross-bedded ash deposits and show that explosive volcanism at depths between about 350 and 590 m depth played a part in forming these volcanic cones. The eruptive styles appear to be dominantly effusive to strombolian at greater depths, but apparently include violent phreatomagmatic explosive activity at the shallower sites along the submarine southwest extension of the Koko Rift. The compositions of the recovered samples are broadly similar to the strongly alkalic subaerial Honolulu Volcanics lavas, but the submarine lavas, erupted further from the Koolau caldera, have slightly more radiogenic Sr isotopic ratios, and trace element patterns that are distinct from either the subaerial Honolulu Volcanics or the submarine North Arch lavas. These patterns are characterized by moderate to strong positive Sr and P anomalies, and moderate to strong negative Cs, Rb, U, Th, Zr, and Hf anomalies. Most samples have strong negative K and moderate negative Ti anomalies, as do all subaerial Honolulu Volcanics and North Arch samples, but one group of samples from the Koko Rift lack this chemical signature. The data are consistent with more garnet in the source region for the off-shore samples than for either the on-shore Honolulu Volcanics lavas. New Ar-Ar ages show that eruptions at the submarine vents and Diamond Head occurred between about 0.5 Ma and 0.1 Ma, with the youngest ages from the Koko Rift. These ages are in general agreement with most published ages for the formation and suggest that some much younger ages reported previously from the Koko Rift are probably

  11. Titan Submarine: Exploring The Depths of Kraken Mare

    Science.gov (United States)

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

    2015-01-01

    The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase I for 2014. The effort investigated what science a submarine for Titan's liquid hydrocarbon approximately 93 Kelvin (-180 degrees Centigrade) seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (approximately100 kilograms) it was found that a submersible platform can accomplish extensive and exciting science both above and below the surface of the Kraken Mare The submerged science includes mapping using side looking sonar, imaging and spectroscopy of the sea at all depths, as well as sampling of the sea's bottom and shallow shoreline. While surfaced the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 kilometers inland. This imaging requirement pushed the landing date to Titan's next summer period (approximately 2047) to allow for continuous lighted conditions, as well as direct-to-Earth (DTE) communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid/sediment/chemical interactions. An estimated 25 megabits of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system. This paper discusses the results of Phase I as well as the plans for Phase II.

  12. Exploring the submarine Graham Bank in the Sicily Channel

    Directory of Open Access Journals (Sweden)

    Mauro Coltelli

    2016-05-01

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

  13. Grand Canyon Trekkers: School-Based Lunchtime Walking Program

    Science.gov (United States)

    Hawthorne, Alisa; Shaibi, Gabriel; Gance-Cleveland, Bonnie; McFall, Sarah

    2011-01-01

    The incidence of childhood overweight is especially troubling among low income Latino youth. Grand Canyon Trekkers (GCT) was implemented as a quasi-experimental study in 10 Title 1 elementary schools with a large Latino population to examine the effects of a 16-week structured walking program on components of health-related physical fitness: Body…

  14. College of the Canyons Nursing Alumni Surveys, Spring 2001. Report.

    Science.gov (United States)

    Meuschke, Daylene M; Dixon, P. Scott; Gribbons, Barry C.

    In the summer of 2001, College of the Canyons (California) conducted of study of registered nursing (RN) and licensed vocational nursing (LVN) alumni, as well as their employers, to assess satisfaction with the preparation and training they received through the College's nursing programs. Out of the 89 invited nursing alumni, 33 surveys were…

  15. 78 FR 60693 - Establishment of the Ballard Canyon Viticultural Area

    Science.gov (United States)

    2013-10-02

    ... duties in the administration and enforcement of this law. Part 4 of the TTB regulations (27 CFR part 4... adequate information as to the identity and quality of the product. The Alcohol and Tobacco Tax and Trade... professional'' who is familiar with wines produced in the Ballard Canyon area. None of the comments...

  16. Phytophthora ramorum causes cryptic bole cankers in Canyon line Oak

    Science.gov (United States)

    Unusual mortality of large canyon live oaks was observed in natural stands in San Mateo, California starting in 2007. A survey of affected stands showed that symptomatic trees were spatially associated with California bay, the primary source of Phytophthora ramorum spores in this forest type. Trunk ...

  17. Carbonaceous aerosol particles from common vegetation in the Grand Canyon

    Energy Technology Data Exchange (ETDEWEB)

    Hallock, K.A.; Mazurek, M.A. (Brookhaven National Lab., Upton, NY (United States)); Cass, G.R. (California Inst. of Tech., Pasadena, CA (United States). Dept. of Environmental Engineering Science)

    1992-05-01

    The problem of visibility reduction in the Grand Canyon due to fine organic aerosol particles in the atmosphere has become an area of increased environmental concern. Aerosol particles can be derived from many emission sources. In this report, we focus on identifying organic aerosols derived from common vegetation in the Grand Canyon. These aerosols are expected to be significant contributors to the total atmospheric organic aerosol content. Aerosol samples from living vegetation were collected by resuspension of surface wax and resin components liberated from the leaves of vegetation common to areas of the Grand Canyon. The samples were analyzed using high-resolution gas chromatography/mass spectrometry (GC/MS). Probable identification of compounds was made by comparison of sample spectra with National Institute of Standards and Technology (NIST) mass spectral references and positive identification of compounds was made when possible by comparison with authentic standards as well as NIST references. Using these references, we have been able to positively identify the presence of n-alkane and n-alkanoic acid homolog series in the surface waxes of the vegetation sampled. Several monoterpenes, sesquiterpenes, and diterpenes were identified also as possible biogenic aerosols which may contribute to the total organic aerosol abundance leading to visibility reduction in the Grand Canyon.

  18. Effects of electric vehicles on air quality in street canyons

    Directory of Open Access Journals (Sweden)

    Tilmann Schöllnhammer

    2014-09-01

    Full Text Available Road traffic is one of the main causes of poor air quality in European cities. Electric vehicles (EV are often presented as climate friendly and as a solution for air quality problems in cities. The aim of this study is to investigate how much of this claim is true and to find out the necessary shares of electric vehicles of different types needed to solve air quality problems in street canyons. For example, the German government has formulated the ambitious goal of increasing the amount of electric vehicles in Germany to 1 million in 2020 and 6 million in 2030. Will this improve the air quality significantly? The focus of the present study is the air quality in street canyons, with a focus on PM10 and NO2 concentrations. We concentrate our investigation on road traffic, taking the fleet composition into account. A sensitivity study with a dispersion model was carried out for two street canyons in North Rhine-Westphalia, typical for moderately polluted street canyons in European cities. It is shown that the reduction potential is larger for NO2 than for PM10. The necessary share of electric vehicles to comply with the limit values lies at about 40 % for NO2 and 100 % for PM10, respectively. Thus, the share of electric vehicles needed to comply with the limit values is far above the goal of the German government.

  19. Small Mammal Sampling in Mortandad and Los Alamos Canyons, 2005

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Kathy; Sherwood, Sherri; Robinson, Rhonda

    2006-08-15

    As part of an ongoing ecological field investigation at Los Alamos National Laboratory, a study was conducted that compared measured contaminant concentrations in sediment to population parameters for small mammals in the Mortandad Canyon watershed. Mortandad Canyon and its tributary canyons have received contaminants from multiple solid waste management units and areas of concern since establishment of the Laboratory in the 1940s. The study included three reaches within Effluent and Mortandad canyons (E-1W, M-2W, and M-3) that had a spread in the concentrations of metals and radionuclides and included locations where polychlorinated biphenyls and perchlorate had been detected. A reference location, reach LA-BKG in upper Los Alamos Canyon, was also included in the study for comparison purposes. A small mammal study was initiated to assess whether potential adverse effects were evident in Mortandad Canyon due to the presence of contaminants, designated as contaminants of potential ecological concern, in the terrestrial media. Study sites, including the reference site, were sampled in late July/early August. Species diversity and the mean daily capture rate were the highest for E-1W reach and the lowest for the reference site. Species composition among the three reaches in Mortandad was similar with very little overlap with the reference canyon. Differences in species composition and diversity were most likely due to differences in habitat. Sex ratios, body weights, and reproductive status of small mammals were also evaluated. However, small sample sizes of some species within some sites affected the analysis. Ratios of males to females by species of each site (n = 5) were tested using a Chi-square analysis. No differences were detected. Where there was sufficient sample size, body weights of adult small mammals were compared between sites. No differences in body weights were found. Reproductive status of species appears to be similar across sites. However, sample

  20. Monitoring El Hierro submarine volcanic eruption events with a submarine seismic array

    Science.gov (United States)

    Jurado, Maria Jose; Molino, Erik; Lopez, Carmen

    2013-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2012 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. From the beginning of the eruption a geophone string was installed less than 2 km away from the new volcano, next to La Restinga village shore, to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. The analysis of the dataset using spectral techniques allows the characterization of the different phases of the eruption and the study of its dynamics. The correlation of the data analysis results with the observed sea surface activity (ash and lava emission and degassing) and also with the seismic activity recorded by the IGN field seismic monitoring system, allows the identification of different stages suggesting the existence of different signal sources during the volcanic eruption and also the posteruptive record of the degassing activity. The study shows that the high frequency capability of the geophone array allow the study of important features that cannot be registered by the standard seismic stations. The accumulative spectral amplitude show features related to eruptive changes.

  1. [Medical-physiological characteristics of combat training of nuclear-power submarine crews].

    Science.gov (United States)

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

    2009-10-01

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

  2. The clinical implications of a smoking ban on submarines in the U.S. Navy.

    Science.gov (United States)

    Shah, Anil N; Arnold, Michael J

    2011-02-01

    By the end of calendar year 2010, a total smoking ban on submarines is expected to be implemented throughout the submarine force because of the negative health effects of environmental tobacco smoke and the recently demonstrated exposure of nonsmoking submariners to measurable levels of nicotine during submarine deployments. Historically, smoking has been highly prevalent in the military, but new data on the negative health effects of tobacco have led the military to change its policies, restricting its use in certain environments. A number of research studies have examined the effect of smoking on the military, cessation and prevention interventions, effect of environmental tobacco smoke onboard the submarine, and treatment modalities aimed at smokers attempting to quit. With the potential for considerable physical and psychological effects, a mass tobacco cessation program is being implemented to support the prohibition onboard the submarine. Recommendations for a successful implementation program are included.

  3. Numerical simulation and experimental study of the submarine's cold wake temperature character

    Science.gov (United States)

    Chen, Shengtao; Zhong, Jingjun; Sun, Peng

    2014-06-01

    The temperature difference of the submarine's wake on the sea surface is the base for the IR detection. In this paper, the temperature difference on the sea surface caused by the submarine's propellers and the submarine's hull is studied by solving the three dimensional N-S equations. The results show that under the condition of sea temperature surroundings of minus gradient, such as in summer the upper water's temperature is higher than the lower water, it is cold wake on the sea surface and hot wake on the submarine's plane. The temperature difference between the wake and the water around in the wake's initial part becomes more and more obvious as the wake's distance gets longer. Through the IR camera, the submarine's propeller wake is studied under the same temperature status. Obvious IR temperature difference signals can be observed and it is consistent with the numerical simulation for the submarine.

  4. Morphodynamics of submarine channel inception revealed by new experimental approach

    Science.gov (United States)

    de Leeuw, Jan; Eggenhuisen, Joris T.; Cartigny, Matthieu J. B.

    2016-03-01

    Submarine channels are ubiquitous on the seafloor and their inception and evolution is a result of dynamic interaction between turbidity currents and the evolving seafloor. However, the morphodynamic links between channel inception and flow dynamics have not yet been monitored in experiments and only in one instance on the modern seafloor. Previous experimental flows did not show channel inception, because flow conditions were not appropriately scaled to sustain suspended sediment transport. Here we introduce and apply new scaling constraints for similarity between natural and experimental turbidity currents. The scaled currents initiate a leveed channel from an initially featureless slope. Channelization commences with deposition of levees in some slope segments and erosion of a conduit in other segments. Channel relief and flow confinement increase progressively during subsequent flows. This morphodynamic evolution determines the architecture of submarine channel deposits in the stratigraphic record and efficiency of sediment bypass to the basin floor.

  5. Submarine Cables for Ocean/Climate Monitoring and Disaster Warning

    Science.gov (United States)

    Bueti, Cristina; Barnes, Chris; Meldrum, David

    2013-04-01

    A joint initiative between International Telecommunication Union (ITU), the World Meteorological Organization (WMO) and the Intergovernmental Oceanographic Commission (IOC) of UNESCO is examining novel uses for submarine telecommunication cables. The initiative addresses two main issues: the need for sustained climate-quality data from the sparsely observed deep oceans, and the desire to increase the reliability and integrity of the global tsunami warning networks. In the latter case, a significant proportion of the network suffers from failure and vandalism of the sea-surface telemetry buoys that relay the tsunami signals from the sea-bed sensor package: incorporating the sensors within a submarine cable repeater is an obvious way of increasing system reliability. At the present time, plans are well advanced to launch a pilot project with the active involvement of cable industry players.

  6. Optimization of Submarine Hydrodynamic Coefficients Based on Immune Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    HU Kun; XU Yi-fan

    2010-01-01

    Aiming at the demand for optimization of hydrodynamic coefficients in submarine's motion equations, an adaptive weight immune genetic algorithm was proposed to optimize hydrodynamic coefficients in motion equations. Some hydrody-namic coefficients of high sensitivity to control and maneuver were chosen as the optimization objects in the algorithm. By using adaptive weight method to determine the weight and target function, the multi-objective optimization could be transla-ted into single-objective optimization. For a certain kind of submarine, three typical maneuvers were chosen to be the objects of study: overshoot maneuver in horizontal plane, overshoot maneuver in vertical plane and turning circle maneuver in horizontal plane. From the results of computer simulations using primal hydrodynamic coefficient and optimized hydrody-namic coefficient, the efficiency of proposed method is proved.

  7. Armor corrosion monitoring of a submarine AC cable

    Energy Technology Data Exchange (ETDEWEB)

    Genesca, J. [Univ. Nacional Autonoma de Mexico (Mexico). Dept. Ingenieria Metalurgica; Perez, T. [Univ. Autonoma de Campeche (Mexico). Programa Corrosion del Golfo de Mexico; Lara, C. [CFE-LAPEM, Irapuato (Mexico)

    1997-12-01

    After the hurricane Gilberto flattened (devastated) Cancun in September 1988, the submarine cables which supplied electricity to Isla Mjueres Island remained very damaged, and it was decided to install the new ones. In 1989, four new submarine cables were installed from Punta Sam, Cancun to Isla Mujeres. Such cables, of nominal tension 34.5 KV, were manufactures with a galvanized steel armor coated with asphalt, and began operation during 1990. The object of this communication is to present the experimental procedure that gave place to the armor corrosion monitoring procedure carried out in this particular case and to compare the results with those obtained on the field. Results of the cathodic protection system applied are also presented.

  8. The importance of shallow confining units to submarine groundwater flow

    Science.gov (United States)

    Bratton, J.F.

    2007-01-01

    In addition to variable density flow, the lateral and vertical heterogeneity of submarine sediments creates important controls on coastal aquifer systems. Submarine confining units produce semi-confined offshore aquifers that are recharged on shore. These low-permeability deposits are usually either late Pleistocene to Holocene in age, or date to the period of the last interglacial highstand. Extensive confining units consisting of peat form in tropical mangrove swamps, and in salt marshes and freshwater marshes and swamps at mid-latitudes. At higher latitudes, fine-grained glaciomarine sediments are widespread. The net effect of these shallow confining units is that groundwater from land often flows farther offshore before discharging than would normally be expected. In many settings, the presence of such confining units is critical to determining how and where pollutants from land will be discharged into coastal waters. Alternatively, these confining units may also protect fresh groundwater supplies from saltwater intrusion into coastal wells.

  9. ANALYTIC INVESTIGATIONS OF CARBON FIBER REINFORCED POLYMER STIFFENED CYLINDRICAL SUBMARINE HULL

    OpenAIRE

    2013-01-01

    A submarine is any naval vessel that is capable of propelling itself beneath the water as well as on the water surface. Submersibles are capable of operating for extended period of time underwater and are subjected to heavy hydrostatic pressure. The conventional submarines made up of high strength steel and concrete prevents them from going to greater depth owing to its large dead weight. In the present work, the pressure hull of submarine is considered both in isotropic and composite materia...

  10. Submarine and Autonomous Vessel Proliferation: Implications for Future Strategic Stability at Sea

    Science.gov (United States)

    2012-12-01

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

  11. The Study on Fatigue Experiment and Reliability Life of Submarine Pipeline Steel

    OpenAIRE

    Yan Yifei; Shao Bing; Liu Jinkun; Cheng Lufeng

    2013-01-01

    The aim of the fatigue experiment study is to solve the fatigue fracture problem of X70 submarine tubing when it is under the scouring effect of offshore current. The multilevel fatigue experiments are carried out following the internation (GB4337-84) recommended method. The standard round bar fatigue specimen was made by the material of submarine pipeline steel. The fatigue life of submarine pipeline steel in different survival probability and P-S-N curve were achieved. According to reliabil...

  12. Environmental analysis of Lower Pueblo/Lower Los Alamos Canyon, Los Alamos, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ferenbaugh, R.W.; Buhl, T.E.; Stoker, A.K.; Becker, N.M.; Rodgers, J.C.; Hansen, W.R.

    1994-12-01

    The radiological survey of the former radioactive waste treatment plant site (TA-45), Acid Canyon, Pueblo Canyon, and Los Alamos Canyon found residual contamination at the site itself and in the channel and banks of Acid, Pueblo, and lower Los Alamos Canyons all the way to the Rio Grande. The largest reservoir of residual radioactivity is in lower Pueblo Canyon, which is on DOE property. However, residual radioactivity does not exceed proposed cleanup criteria in either lower Pueblo or lower Los Alamos Canyons. The three alternatives proposed are (1) to take no action, (2) to construct a sediment trap in lower Pueblo Canyon to prevent further transport of residual radioactivity onto San Ildefonso Indian Pueblo land, and (3) to clean the residual radioactivity from the canyon system. Alternative 2, to cleanup the canyon system, is rejected as a viable alternative. Thousands of truckloads of sediment would have to be removed and disposed of, and this effort is unwarranted by the low levels of contamination present. Residual radioactivity levels, under either present conditions or projected future conditions, will not result in significant radiation doses to persons exposed. Modeling efforts show that future transport activity will not result in any residual radioactivity concentrations higher than those already existing. Thus, although construction of a sediment trap in lower Pueblo Canyon is a viable alternative, this effort also is unwarranted, and the no-action alternative is the preferred alternative.

  13. Evaluation and comparison of electric propulsion motors for submarines

    OpenAIRE

    Harbour, Joel P.

    2001-01-01

    CIVINS The Navy has announced its conviction to make its warships run on electric power through the decision to make its newest line of destroyers propelled with an electric propulsion system. Several ship construction firms and electric motor manufacturers are thus striving to develop enabling technology, including high power density motors. The purpose of this thesis is to evaluate some of the proposed motor designs for use in a submarine. Permanent magnet, superconducting synchronous an...

  14. The Polar Submarine and Navigation of the Arctic Ocean

    Science.gov (United States)

    1959-05-21

    bottomaide Training troubles Echo sounder for depth SESE 3180 Fwd. torp. rm. Bow-topside Transducer fuied below ice 111-3 Sonic listening JT Fwd...the training siaft keyway of the topside QLA sound head and made it inoperative. Equipments installed on the CARP are listed in Table V and are s;iown...submarine post and between submerged ice stalactites that extend to its depth. The choice of safe cruising depth is determined from oceanographic data of

  15. The evolution of composite materials in submarine structures.

    OpenAIRE

    Lemiere, Y

    1992-01-01

    Since the sixties, the amount of composite structures on submarines has increased continuously. The main reasons are their low apparent weight in water, good behaviour in a marine environment, excellent mechanical properties and acoustic transparency. The new applications required the use of prepreg. Relevant processes had to be adapted to the large dimensions and thickness of the structures. Future applications will be concerned with both structures and internal equipment. A lively debate is...

  16. Scaling for Shock Response of Equipment in Different Submarines

    OpenAIRE

    O’Hara, G.J.; Cunniff, P.F.

    1993-01-01

    This article presents scaling rules developed to predict the response of submarine equipment subjected to underwater chemical explosions. The computer was used as a surrogate for shock tests. A simplified model of a hull section was used to contain frame-mounted single degree of freedom equipment. A general scaling rule has been developed to handle the spread in the shock response attributable to the charge weight, equipment weight, and equipment frequency, where the shock response is the abs...

  17. Canyon formation constraints on the discharge of catastrophic outburst floods of Earth and Mars

    Science.gov (United States)

    Lapotre, Mathieu G. A.; Lamb, Michael P.; Williams, Rebecca M. E.

    2016-07-01

    Catastrophic outburst floods carved amphitheater-headed canyons on Earth and Mars, and the steep headwalls of these canyons suggest that some formed by upstream headwall propagation through waterfall erosion processes. Because topography evolves in concert with water flow during canyon erosion, we suggest that bedrock canyon morphology preserves hydraulic information about canyon-forming floods. In particular, we propose that for a canyon to form with a roughly uniform width by upstream headwall retreat, erosion must occur around the canyon head, but not along the sidewalls, such that canyon width is related to flood discharge. We develop a new theory for bedrock canyon formation by megafloods based on flow convergence of large outburst floods toward a horseshoe-shaped waterfall. The model is developed for waterfall erosion by rock toppling, a candidate erosion mechanism in well fractured rock, like columnar basalt. We apply the model to 14 terrestrial (Channeled Scablands, Washington; Snake River Plain, Idaho; and Ásbyrgi canyon, Iceland) and nine Martian (near Ares Vallis and Echus Chasma) bedrock canyons and show that predicted flood discharges are nearly 3 orders of magnitude less than previously estimated, and predicted flood durations are longer than previously estimated, from less than a day to a few months. Results also show a positive correlation between flood discharge per unit width and canyon width, which supports our hypothesis that canyon width is set in part by flood discharge. Despite lower discharges than previously estimated, the flood volumes remain large enough for individual outburst floods to have perturbed the global hydrology of Mars.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-06-01

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

  19. Estimating the empirical probability of submarine landslide occurrence

    Science.gov (United States)

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

    2010-01-01

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

  20. Long-term eruptive activity at a submarine arc volcano.

    Science.gov (United States)

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

    2006-05-25

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

  1. Flow splitting modifies the helical motion in submarine channels

    Science.gov (United States)

    Islam, M. Ashraful; Imran, Jasim; Pirmez, Carlos; Cantelli, Alessandro

    2008-11-01

    Intricately meandering channels of various scales constitute a major morphological feature of the submarine slope and fan systems. These channels act as conduits of density-driven gravity underflows and in turn are shaped by these underflows. The relationship between channel curvature and the dynamics of sediment-laden underflows commonly known as turbidity current has been an enigma, and recently, a subject of controversy. This contribution unravels the flow field of turbidity current at submarine channel bends captured from large scale laboratory experiments. The experimental results show that a mildly sloping channel bank greatly enhances the tilt of the turbidity current-ambient water interface, so much so that the current completely separates from the convex or the inside bank. We also show that irrespective of the shape of the channel cross section, two cells of helical flow appear in confined submarine bend flow. The near-bed cell has a circulation pattern similar to that observed in fluvial channels; the other cell has an opposite sense of rotation. If, on the other hand, a portion of the flow detaches from the body of the current and spills to the concave or outside overbank area, the upper circulation cell becomes suppressed by the resulting lateral convection.

  2. Structural and acoustic response of a finite stiffened submarine hull

    Science.gov (United States)

    Wang, Xian-zhong; Jiang, Chen-ban; Xu, Rui-yang

    2016-12-01

    After borrowing the idea of precise integration method, a precise integration transfer matrix method (PITMM) is proposed by modifying traditional transfer matrix method. The submarine hull can be modeled as joined conicalcylindrical-spherical shells. By considering the effect of the ring-stiffeners, the field transfer matrixes of shells of revolution are obtained accurately by PITMM. After assembling the field transfer matrixes into an entire matrix, the dynamic model is established to solve the dynamic responses of the joined shell. By describing the sound pressure in fluid by modified wave superposition method (MWSM) and collocating points along the meridian line of the joined shell, finally the structural and acoustic responses of a finite stiffened submarine hull can be predicted by coupled PITMM and MWSM. The effectiveness of the present method has been verified by comparing the structural and acoustic responses of the spherical shell with existing results. Furthermore, the effects of the model truncation, stiffness and thickness on the structural and acoustic responses of the submarine hull are studied.

  3. Submarine navigation based on gravity gradient-terrain matching

    Science.gov (United States)

    Xiong, Ling; Ma, Jie; Zhang, Li; Tian, Jin-Wen; Liu, Jian

    2007-11-01

    Based on the geophysics technology, a gravity gradient-terrain matching submarine navigation approach is proposed in this paper. The submarine's current position obtained by matching the measured gravity gradient data to the prepared gravity gradient reference map is used to correct the inertial navigation system's accumulated error. Although the precision gradiometer is in use, there is no world-wide gravity gradient map. The ocean's gravity gradient data is even scarce. Therefore, a gravity gradient matching navigation system directly utilizing the gravity gradient reference map can't be realized. With the sensitivity of gravity gradient to terrain, the gravity gradient reference map can be computed from the local terrain elevation data and the preparing approach of the gravity gradient map is proposed in detail in the paper. Since the seabed terrain elevation map, especially highly accurate offing terrain elevation map has been pre-surveyed, the location can be actualized through matching the real-time measured gravity gradient data to the prepared gravity gradient reference map. Simulations show that the submarine navigation approach on gravity gradient-terrain matching is feasible and can be put into practice.

  4. Source term analysis for a nuclear submarine accident

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.J.; Hugron, J.J.M.R. [Royal Military College of Canada, Dept. of Chemistry and Chemical Engineering, Kingston, Ontario (Canada)

    1999-07-01

    A source term analysis has been conducted to determine the activity release into the environment as a result of a large-break loss-of-coolant accident aboard a visiting nuclear-powered submarine to a Canadian port. This best-estimate analysis considers the fractional release from the core, and fission product transport in the primary heat transport system, primary containment (i.e. reactor compartment) and submarine hull. Physical removal mechanisms such as vapour and aerosol deposition are treated in the calculation. Since a thermalhydraulic analysis indicated that the integrity of the reactor compartment is maintained, release from the reactor compartment will only occur by leakage; however, it is conservatively assumed that the secondary containment is not isolated for a 24-h period where release occurs through an open hatch in the submarine hull. Consequently, during this period, the activity release into the atmosphere is estimated as 4.6 TBq, leading to a maximum individual dose equivalent of 0.5 mSv at 800 metres from the berthing location. This activity release is comparable to that obtained in the BEREX TSA study (for a similar accident scenario) but is four orders of magnitude less than that reported in the earlier Davis study where, unrealistically, no credit had been taken for the containment system or for any physical removal processes. (author)

  5. Certification of a submarine design using fiber Bragg grating sensors

    Science.gov (United States)

    Kiddy, Jason S.; Baldwin, Chris S.; Salter, Toni J.

    2004-07-01

    Systems Planning and Analysis, Inc. (SPA) has recently planned, installed, and tested a fiber Bragg grating (FBG) strain sensor system to validate FEM predictions of a new submarine design undergoing American Bureau of Shipping (ABS) certification testing. Fiber optic triaxial, biaxial, and uniaxial gage locations were selected based on the FEM analysis. FBGs were placed on six optical fibers with two fibers (33 sensors) mounted internally to the hull and four fibers (64 sensors) mounted externally. Testing was performed by lowering the submarine to the design depth and recording strain measurements. The optical sensor signals were transmitted directly to the water's surface and monitored by top-side interrogation instrumentation through over 2000 feet of optical cable. Measured temperature-compensated strain values were compared to the FEM predicted strain values with excellent results. To the author's knowledge, this successful test represents the first time that FBG sensors have been used to certify a submarine design and to validate FEM analysis on a large-scale structure.

  6. Paulomycin G, a New Natural Product with Cytotoxic Activity against Tumor Cell Lines Produced by Deep-Sea Sediment Derived Micromonospora matsumotoense M-412 from the Avilés Canyon in the Cantabrian Sea.

    Science.gov (United States)

    Sarmiento-Vizcaíno, Aida; Braña, Alfredo F; Pérez-Victoria, Ignacio; Martín, Jesús; de Pedro, Nuria; Cruz, Mercedes de la; Díaz, Caridad; Vicente, Francisca; Acuña, José L; Reyes, Fernando; García, Luis A; Blanco, Gloria

    2017-08-28

    The present article describes a structurally novel natural product of the paulomycin family, designated as paulomycin G (1), obtained from the marine strain Micromonospora matsumotoense M-412, isolated from Cantabrian Sea sediments collected at 2000 m depth during an oceanographic expedition to the submarine Avilés Canyon. Paulomycin G is structurally unique since-to our knowledge-it is the first member of the paulomycin family of antibiotics lacking the paulomycose moiety. It is also the smallest bioactive paulomycin reported. Its structure was determined using HRMS and 1D and 2D NMR spectroscopy. This novel natural product displays strong cytotoxic activities against different human tumour cell lines, such as pancreatic adenocarcinoma (MiaPaca_2), breast adenocarcinoma (MCF-7), and hepatocellular carcinoma (HepG2). The compound did not show any significant bioactivity when tested against a panel of bacterial and fungal pathogens.

  7. Submarine topography and faulting in Bahia de Banderas, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Roman [Instituto de Investigaciones en Matematicas Aplicadas y en Sistemas, Universidad Nacional Autonoma de Mexico, Mexico D.F (Mexico)

    2007-04-15

    A digital elevation model of Bahia de Banderas and its offshore continuation to the Middle America Trench (MAT) is built from a data set of 6872 bathymetric soundings. Two new, offshore basins and several, previously unknown faults within the bay are also identified. The south flank of Banderas canyon is considerably steeper than the north one. This asymmetry and the seismic activity present lead to propose that Banderas Canyon has a half-graben structure of the fault growth type, and reverse drag geometry, which originates in an extensional basin oriented N-S. The canyon is divided in two sections that trend in different directions. The older section of the canyon, trending E-W, is probably Late Miocene; the associated Banderas Fault is suggested to extend westward, down to the MAT along a section that complements that of the half-graben. The section of Banderas Canyon trending NE and continuing into Banderas Valley is identified as a younger portion of the structure. The older and the younger portions of the canyon appear to be active presently. A group of faults also trending NE seem to be associated with the change in direction of the canyon. These results support the hypothesis that the structure of Banderas Canyon is a half-graben, and they strengthen the idea that it is the limit between the region to the north that underwent extension in the Miocene, and the region to the south that did not experienced it. [Spanish] Un modelo digital de elevacion de Bahia de Banderas y su continuacion costa afuera hasta la Trinchera Mesoamericana se construye con 6872 sondeos batimetricos. Se identifi can dos nuevas cuencas costa afuera y tambien varias fallas, hasta ahora no reportadas, dentro de la bahia. El fl anco sur del Canon de Banderas es considerablemente mas empinado que el flanco norte. Esta asimetria, junto con la actividad sismica presente, lleva a proponer que el Canon de Banderas tiene una estructura de semi-graben del tipo de crecimiento de falla, con

  8. Size distributions and failure initiation of submarine and subaerial landslides

    Science.gov (United States)

    ten Brink, U.S.; Barkan, R.; Andrews, B.D.; Chaytor, J.D.

    2009-01-01

    Landslides are often viewed together with other natural hazards, such as earthquakes and fires, as phenomena whose size distribution obeys an inverse power law. Inverse power law distributions are the result of additive avalanche processes, in which the final size cannot be predicted at the onset of the disturbance. Volume and area 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 that show a characteristic size and with few smaller and larger areas, which can be described well by a lognormal distribution. To generate these distributions we assumed that the area of slope failure depends on earthquake magnitude, i.e., that failure occurs simultaneously over the area affected by horizontal ground shaking, and does not cascade from nucleating points. Furthermore, the downslope movement of displaced sediments does not entrain significant amounts of additional material. Our simulations fit well the area distribution of landslide sources along the Atlantic continental margin, if we assume that the slope has been subjected to earthquakes of magnitude ??? 6.3. Regions of submarine landslides, whose area distributions obey inverse power laws, may be controlled by different generation mechanisms, such as the gradual development of fractures in the headwalls of cliffs. The observation of a large number of small subaerial landslides being triggered by a single earthquake is also compatible with the hypothesis that failure occurs simultaneously in many locations within the area affected by ground shaking. Unlike submarine landslides, which are found on large uniformly-dipping slopes, a single large landslide scarp cannot form on land because of the heterogeneous morphology and short slope distances of tectonically-active subaerial regions. However, for a given earthquake magnitude, the total area

  9. Structural evolution of deep-water submarine intraplate volcanoes / Azores

    Science.gov (United States)

    Stakemann, Josefine; Huebscher, Christian; Beier, Christoph; Hildenbrand, Anthony; Nomikou, Paraskevi; Terrinha, Pedro; Weiß, Benedikt

    2017-04-01

    We present multibeam and high-resolution reflection seismic data which elucidate the architecture of three submarine intraplate volcanoes located in the southern Azores Archipelago. Data have been collected during RV Meteor cruise M113 in 2015. Four GI-Guns served as the seismic source. The digital streamer comprised 144 channels distributed over a length of 600 m. The three cones are situated in a depth down to 2300 m with heights varying between 200 m and 243 m, an average diameter of 1360 m and an average slope angle of ca. 22°. All three circular cones are surrounded by a circular channel. These features, previously named "fried eggs" were previously interpreted as impact crater (Dias et al., 2009). A comparison with nearby submarine volcanoes close to São Miguel island (Weiß et al., 2015), however, strongly suggests a volcanic origin. The seismic data indicate that the volcanic cones formed on top of a ca. 100 m thick pelagic succession covering the igneous basement. Magma ascent deformed the volcanic basement, displaced the pelagic sediments and a first eruption phase formed a small, seismically transparent volcanic cone. Further eruptions created a volcanic cone with rather transparent reflections within the inferior region changing to strong reflection amplitudes with a chaotic pattern in the superior area. Compared to the igneous basement internal reflection amplitudes are mainly weak. The seismic transparency and slope angle exclude the presence of effusive rocks, since lavas usually create strong impedance contrasts. A comparison of the seismic characteristics with those from submarine Kolumbo volcano (Hübscher et al., 2015) suggests volcaniclastic lithologies from explosive eruptions. The circular channel around the volcanic cone shows the characteristics of a moat channel created by bottom currents. References: Dias, F.C., Lourenco, N., Lobo, A., Santos de Campos, A., Pinto de Abreu, M., 2009. "Fried Egg": An Oceanic Impact Crater in the Mid

  10. Numerical Study of Urban Canyon Microclimate Related to Geometrical Parameters

    Directory of Open Access Journals (Sweden)

    Andrea de Lieto Vollaro

    2014-11-01

    Full Text Available In this study a microclimate analysis on a particular urban configuration: the—street canyon—has been carried out. The analysis, conducted by performing numerical simulations using the finite volumes commercial code ANSYS-Fluent, shows the flow field in an urban environment, taking into account three different aspect ratios (H/W. This analysis can be helpful in the study on urban microclimate and on the heat exchanges with the buildings. Fluid-dynamic fields on vertical planes within the canyon, have been evaluated. The results show the importance of the geometrical configuration, in relation to the ratio between the height (H of the buildings and the width (W of the road. This is a very important subject from the point of view of “Smart Cities”, considering the urban canyon as a subsystem of a larger one (the city, which is affected by climate changes.

  11. Numerical and Experimental Studies on Flow and Pollutant Dispersion in Urban Street Canyons

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this study numerical simulations and water tank experiments were used to investigate the flow and pollutant dispersion in an urban street canyon. Two types of canyon geometry were tested. The studies indicate that in a step-up notch canyon (higher buildings on the downstream side of the canyon), the height and shape of the upstream lower buildings plays an important role in flow pattern and pollutant dispersion,while in a step-down notch canyon (lower buildings on the downstream side), the downstream lower buildings have little influence. The studies also show that the substitution of tall towers for parallelepiped buildings on one side of the canyon may enhance the street ventilation and decrease the pollutant concentration emitted by motor vehicles.

  12. Apatite 4He/3He and (U-Th)/He evidence for an ancient Grand Canyon.

    Science.gov (United States)

    Flowers, R M; Farley, K A

    2012-12-21

    The Grand Canyon is one of the most dramatic features on Earth, yet when and why it was carved have been controversial topics for more than 150 years. Here, we present apatite (4)He/(3)He thermochronometry data from the Grand Canyon basement that tightly constrain the near-surface cooling history associated with canyon incision. (4)He/(3)He spectra for eastern Grand Canyon apatites of differing He date, radiation damage, and U-Th zonation yield a self-consistent cooling history that substantially validates the He diffusion kinetic model applied here. Similar data for the western Grand Canyon provide evidence that it was excavated to within a few hundred meters of modern depths by ~70 million years ago (Ma), in contrast to the conventional model in which the entire canyon was carved since 5 to 6 Ma.

  13. A review of proposed Glen Canyon Dam interim operating criteria

    Energy Technology Data Exchange (ETDEWEB)

    LaGory, K.; Hlohowskyj, I.; Tomasko, D.; Hayse, J.; Durham, L.

    1992-04-01

    Three sets of interim operating criteria for Glen Canyon Dam on the Colorado River have been proposed for the period of November 1991, to the completion of the record of decision for the Glen Canyon Dam environmental impact statement (about 1993). These criteria set specific limits on dam releases, including maximum and minimum flows, up-ramp and down-ramp rates, and maximum daily fluctuation. Under the proposed interim criteria, all of these parameters would be reduced relative to historical operating criteria to protect downstream natural resources, including sediment deposits, threatened and endangered fishes, trout, the aquatic food base, and riparian plant communities. The scientific bases of the three sets of proposed operating criteria are evaluated in the present report:(1) criteria proposed by the Research/Scientific Group, associated with the Glen Canyon Environmental Studies (GCES); (2) criteria proposed state and federal officials charged with managing downstream resources; and (3) test criteria imposed from July 1991, to November 1991. Data from Phase 1 of the GCES and other sources established that the targeted natural resources are affected by dam operations, but the specific interim criteria chosen were not supported by any existing studies. It is unlikely that irreversible changes to any of the resources would occur over the interim period if historical operating criteria remained in place. It is likely that adoption of any of the sets of proposed interim operating criteria would reduce the levels of sediment transport and erosion below Glen Canyon Dam; however, these interim criteria could result in some adverse effects, including the accumulation of debris at tributary mouths, a shift of new high-water-zone vegetation into more flood-prone areas, and further declines in vegetation in the old high water zone.

  14. Los Alamos Canyon Ice Rink Parking Flood Plain Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hathcock, Charles Dean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States; Keller, David Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States

    2015-02-10

    The project location is in Los Alamos Canyon east of the ice rink facility at the intersection of West and Omega roads (Figure 1). Forty eight parking spaces will be constructed on the north and south side of Omega Road, and a lighted walking path will be constructed to the ice rink. Some trees will be removed during this action. A guardrail of approximately 400 feet will be constructed along the north side of West Road to prevent unsafe parking in that area.

  15. Outbreak of leptospirosis among canyoning participants, Martinique, 2011.

    OpenAIRE

    Hochedez, Patrick; Escher, M.; Decoussy, H.; Pasgrimaud, L.; R. Martinez; Rosine, J.; Théodose, R.; Bourhy,Pascale; Picardeau, Mathieu; Olive, C.; Ledrans, M.; Cabie, André

    2013-01-01

    International audience; Two gendarmes who participated in canyoning activities on 27 June 2011 on the Caribbean island of Martinique were diagnosed with leptospirosis using quantitative real-time polymerase chain reaction (qPCR), 9 and 12 days after the event. Among the 45 participants who were contacted, 41 returned a completed questionnaire, of whom eight met the outbreak case definition. The eight cases sought medical attention and were given antibiotics within the first week after fever o...

  16. Electrical resistance sensors record spring flow timing, Grand Canyon, Arizona

    Science.gov (United States)

    Adams, E.A.; Monroe, S.A.; Springer, A.E.; Blasch, K.W.; Bills, D.J.

    2006-01-01

    Springs along the south rim of the Grand Canyon, Arizona, are important ecological and cultural resources in Grand Canyon National Park and are discharge points for regional and local aquifers of the Coconino Plateau. This study evaluated the applicability of electrical resistance (ER) sensors for measuring diffuse, low-stage (flow in the steep, rocky spring-fed tributaries of the south rim. ER sensors were used to conduct a baseline survey of spring flow timing at eight sites in three spring-fed tributaries in Grand Canyon. Sensors were attached to a nearly vertical rock wall at a spring outlet and were installed in alluvial and bedrock channels. Spring flow timing data inferred by the ER sensors were consistent with observations during site visits, with flow events recorded with collocated streamflow gauging stations and with local precipitation gauges. ER sensors were able to distinguish the presence of flow along nearly vertical rock surfaces with flow depths between 0.3 and 1.0 cm. Laboratory experiments confirmed the ability of the sensors to monitor the timing of diffuse flow on impervious surfaces. A comparison of flow patterns along the stream reaches and at springs identified the timing and location of perennial and intermittent flow, and periods of increased evapotranspiration.

  17. Three-Dimensional Scale-Model Tank Experiment of the Hudson Canyon Region

    Science.gov (United States)

    2014-09-30

    Three-Dimensional Scale-Model Tank Experiment of the Hudson Canyon Region Jason D. Sagers Applied Research Laboratories at The University of...planning for future experiments in ocean environments with slopes and canyons . APPROACH The development of fully 3D numerical acoustic propagation models...Experiment of the Hudson Canyon Region 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER

  18. Late Holocene earthquake history of the Brigham City segment of the Wasatch fault zone at the Hansen Canyon, Kotter Canyon, and Pearsons Canyon trench sites, Box Elder County, Utah

    Science.gov (United States)

    DuRoss, Christopher B.; Personius, Stephen F.; Crone, Anthony J.; McDonald, Greg N.; Briggs, Richard W.

    2012-01-01

    Of the five central segments of the Wasatch fault zone (WFZ) having evidence of recurrent Holocene surface-faulting earthquakes, the Brigham City segment (BCS) has the longest elapsed time since its most recent surface-faulting event (~2.1 kyr) compared to its mean recurrence time between events (~1.3 kyr). Thus, the BCS has the highest time-dependent earthquake probability of the central WFZ. We excavated trenches at three sites––the Kotter Canyon and Hansen Canyon sites on the north-central BCS and Pearsons Canyon site on the southern BCS––to determine whether a surface-faulting earthquake younger than 2.1 ka occurred on the BCS. Paleoseismic data for Hansen Canyon and Kotter Canyon confirm that the youngest earthquake on the north-central BCS occurred before 2 ka, consistent with previous north-central BCS investigations at Bowden Canyon and Box Elder Canyon. At Hansen Canyon, the most recent earthquake is constrained to 2.1–4.2 ka and had 0.6–2.5 m of vertical displacement. At Kotter Canyon, we found evidence for two events at 2.5 ± 0.3 ka and 3.5 ± 0.3 ka, with an average displacement per event of 1.9–2.3 m. Paleoseismic data from Pearsons Canyon, on the previously unstudied southern BCS, indicate that a post-2 ka earthquake ruptured this part of the segment. The Pearsons Canyon earthquake occurred at 1.2 ± 0.04 ka and had 0.1–0.8 m of vertical displacement, consistent with our observation of continuous, youthful scarps on the southern 9 km of the BCS having 1–2 m of late Holocene(?) surface offset. The 1.2-ka earthquake on the southern BCS likely represents rupture across the Weber–Brigham City segment boundary from the penultimate Weber-segment earthquake at about 1.1 ka. The Pearsons Canyon data result in a revised length of the BCS that has not ruptured since 2 ka (with time-dependent probability implications), and provide compelling evidence of at least one segment-boundary failure and multi-segment rupture on the central WFZ. Our

  19. Design of Conventional Submarines with Advanced Air Independent Propulsion Systems and Determination of Corresponding Theater-Level Impacts

    Science.gov (United States)

    2010-01-01

    Response surface method SOA: Speeds of advance TNSW: Thyssen Nordseewerke GmbH tsnorkeling: Time submarine spends snorkeling tquiet: Time submarine spends on...during snorkeling operations. The limiting factor for the power of the diesel engines is the maximum current limitation on charging the batteries...for the AIP endurance of some of the modern submarines are 12–14. Extended AIP endurance reduces the time that the submarine needs to spend snorkeling

  20. UV Radiation in an Urban Canyon in Southeast Queensland

    Science.gov (United States)

    McKinley, A. R.; Moore, M. R.; Kimlin, M. G.

    2006-12-01

    Ultraviolet radiation (UV) has the possibility to both harm and to benefit human beings when unprotected exposure occurs. After receiving small amounts of UV our bodies begin to synthesise vitamin D, which is essential for maintaining healthy bones, however excessive UV exposure can result in a variety of damaging outcomes ranging from sunburn to skin cancer and cataracts. For this reason it is very important to understand the different environments in which people encounter UV so as to better prepare the public to make smart and healthy sun exposure decisions. Each day more and more people are moving into large cities around the world and spending their time inside the urban canyon, however UV measurements are generally taken at scientific stations in open areas or on top of tall buildings, meaning that at times the environmental characteristics measured may not accurately represent those found at street-level in these highly urbanized areas. Urban canyons are home to both very tall buildings and tropospheric air pollution, each of which reduces the amount of UV reaching street-level. This study measured the varying difference between UV measurements taken at street-level and at a standard UV monitoring site on top of a building outside of the urban canyon. Investigation was conducted in the central business district (CBD) of Brisbane, Australia, which models the CBDs of large cities around the world in that it boasts a great number of tall buildings, including many skyscrapers. Data was collected under clear sky conditions at five different street-level sites in the CBD (on either side of two streets running perpendicular to one another (four sites) and in a public square) and then compared to that obtained on the same day at the Queensland University of Technology's Australian Sun and Health Research Laboratory (ASHRL), which is located 2.5 kilometres outside Brisbane's CBD. Minimum erythemal dose (MED) data was collected at each location and it was found that

  1. Compilation of PRF Canyon Floor Pan Sample Analysis Results

    Energy Technology Data Exchange (ETDEWEB)

    Pool, Karl N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Minette, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wahl, Jon H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Greenwood, Lawrence R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Coffey, Deborah S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McNamara, Bruce K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bryan, Samuel A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Scheele, Randall D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Delegard, Calvin H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sinkov, Sergey I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Soderquist, Chuck Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brown, Garrett N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clark, Richard A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-30

    On September 28, 2015, debris collected from the PRF (236-Z) canyon floor, Pan J, was observed to exhibit chemical reaction. The material had been transferred from the floor pan to a collection tray inside the canyon the previous Friday. Work in the canyon was stopped to allow Industrial Hygiene to perform monitoring of the material reaction. Canyon floor debris that had been sealed out was sequestered at the facility, a recovery plan was developed, and drum inspections were initiated to verify no additional reactions had occurred. On October 13, in-process drums containing other Pan J material were inspected and showed some indication of chemical reaction, limited to discoloration and degradation of inner plastic bags. All Pan J material was sealed back into the canyon and returned to collection trays. Based on the high airborne levels in the canyon during physical debris removal, ETGS (Encapsulation Technology Glycerin Solution) was used as a fogging/lock-down agent. On October 15, subject matter experts confirmed a reaction had occurred between nitrates (both Plutonium Nitrate and Aluminum Nitrate Nonahydrate (ANN) are present) in the Pan J material and the ETGS fixative used to lower airborne radioactivity levels during debris removal. Management stopped the use of fogging/lock-down agents containing glycerin on bulk materials, declared a Management Concern, and initiated the Potential Inadequacy in the Safety Analysis determination process. Additional drum inspections and laboratory analysis of both reacted and unreacted material are planned. This report compiles the results of many different sample analyses conducted by the Pacific Northwest National Laboratory on samples collected from the Plutonium Reclamation Facility (PRF) floor pans by the CH2MHill’s Plateau Remediation Company (CHPRC). Revision 1 added Appendix G that reports the results of the Gas Generation Rate and methodology. The scope of analyses requested by CHPRC includes the determination of

  2. 75 FR 1709 - Security Zone; Escorted U.S. Navy Submarines in Sector Seattle Captain of the Port Zone

    Science.gov (United States)

    2010-01-13

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zone; Escorted U.S. Navy Submarines in Sector.... SUMMARY: The Coast Guard is establishing a moving security zone around any U.S. Navy submarine that is... to help ensure the security of the submarines, their Coast Guard security escorts, and the...

  3. 76 FR 56973 - Office of National Marine Sanctuaries Final Policy and Permit Guidance for Submarine Cable Projects

    Science.gov (United States)

    2011-09-15

    ... Policy and Permit Guidance for Submarine Cable Projects AGENCY: Office of National Marine Sanctuaries...) has developed final policy and permitting guidance for submarine cable projects proposed in national... install and maintain submarine cables in sanctuaries are reviewed consistently and in a manner...

  4. 75 FR 28202 - Security Zone; Escorted U.S. Navy Submarines in Sector Seattle Captain of the Port Zone

    Science.gov (United States)

    2010-05-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zone; Escorted U.S. Navy Submarines in Sector... establishing a moving security zone around any U.S. Navy submarine that is operating in the Sector Seattle... of the submarines, their Coast Guard security escorts, and the maritime public in general....

  5. 75 FR 33701 - Security Zone; Escorted U.S. Navy Submarines in Sector Honolulu Captain of the Port Zone

    Science.gov (United States)

    2010-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zone; Escorted U.S. Navy Submarines in Sector.... SUMMARY: The Coast Guard is establishing a moving security zone around all U.S. Navy submarines that are... to help ensure the security of the submarines, their Coast Guard security escorts, and the...

  6. Index of Submarine Medical Officer’s Qualification Theses 1944-1974

    Science.gov (United States)

    1976-04-01

    REPRESENTATIVE IN THE SUB 1961-0002 CLEAR SU TE MEDICAL DEPARTMENT- + rNUALFWTHE NU 1969-0022 N FBM SUBMARINE MEDICAL DEPARTMENT.= + OF A 1969-0023 73 ...PERSONNJEL.- +BETWEEN QUALIFIED AND U 1969-3017 ISONING FROM, -SUBMAR INE PER SONNET .= CARBON TEIRACHLCRIDE, PC 1944-0033 SUBMARINE ENGINE ROOM

  7. ORAL HEALTH OF OPERATING FLEET BALLISTIC MISSILE SUBMARINE CREWS: A CROSS-SECTIONAL SURVEY.

    Science.gov (United States)

    A cross-sectional survey of two fleet ballistic missile submarine crews revealed no remarkable oral health factors. A close relationship was found...effects of FBM submarine service on oral health could be demonstrated; however, in view of the isolated nature of the FBM patrols great stress needs to

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

    Science.gov (United States)

    2010-07-01

    ... cables and pipelines on nautical charts. 209.310 Section 209.310 Navigation and Navigable Waters CORPS OF... of submarine cables and pipelines on nautical charts. (a) The policy of the Corps of Engineers with respect to showing the locations of submarine cables and pipelines on nautical charts published by...

  9. Exploring the Gas Chemistry of Old Submarine Technologies Using Plastic Bottles as Reaction Vessels and Models

    Science.gov (United States)

    Horikoshi, Ryo; Takeiri, Fumitaka; Kobayashi, Yoji; Kageyama, Hiroshi

    2016-01-01

    We describe an activity that is suitable for high school students and makes use of plastic bottles. This activity allows students to familiarize themselves with gas chemistry by introducing technologies that were applied in old submarine systems. Plastic bottles, which are representative of submarines, are used as reaction vessels. Three simple…

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-15

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

  11. Submarine Propulsion Shaft Life: Probabilistic Prediction and Extension through Prevention of Water Ingress

    Science.gov (United States)

    2014-06-01

    Inspection. Reliability Engineering and System Safety , 271-292. 47 Shi, P., & Mahadevan, S. (2001). Damage Tolerance Approach for Probabilistic ...Submarine Propulsion Shaft Life: Probabilistic Prediction and Extension through Prevention of Water Ingress By Douglas E. Jonart M.S. Systems...number. 1. REPORT DATE 01 JUN 2014 2. REPORT TYPE 3. DATES COVERED 4. TITLE AND SUBTITLE Submarine Propulsion Shaft Life: Probabilistic

  12. China’s Future Nuclear Submarine Force. Insights from Chinese Writings

    Science.gov (United States)

    2007-01-01

    Dynamics and Electric Boat], [Naval and Merchant Ships] 1 (2005), pp. 58–61. 31. See, for example, [Yi Fan], “ ” [France’s “ Barracuda ” Class...Attack Submarine], [Militang], no. 3 (2005), p. 17; “ ” [The Demonstration of France’s Barracuda -Class Attack Submarine Nears a Conclusion

  13. The method to control the submarine horseshoe vortex by breaking the vortex core

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-hua; XIONG Ying; TU Cheng-xu

    2014-01-01

    The quality of the inflow across the propeller is closely related with the hydrodynamic performance and the noise characteristics of the propeller. For a submarine, with a horseshoe vortex generated at the junction of the main body and the appendages, the submarine wake is dominated by a kind of highly non-uniform flow field, which has an adverse effect on the performance of the submarine propeller. In order to control the horseshoe vortex and improve the quality of the submarine wake, the flow field around a submarine model is simulated by the detached eddies simulation (DES) method, and the vortex configuration is displayed using the second invariant of the velocity derivative tensor. The state and the transition process of the horseshoe vortex are analyzed, then a modified method to break the vortex core by a vortex baffle is proposed. The flow numerical simulation is carried out to study the effect of this method. Numerical simulations show that, with the breakdown of the vortex core, many unstable vortices are shed and the energy of the horseshoe vortex is dissipated quickly, and the uniformity of the submarine wake is improved. The submarine wake test in a wind tunnel has verified the effect of the method to control the horseshoe vortex. The vortex baffle can improve the wake uniformity in cases of high Reynolds numbers as well, and it does not have adverse effects on the maneuverability and the speed ability of the submarine.

  14. Dive! Dive! An Introduction to the History and Technology of Submarines.

    Science.gov (United States)

    Department of the Navy, Washington, DC.

    This resource guide for science and social studies classes explores the world of U.S. Navy submarines and other submersibles. The guide consists of background information on the history and development of submarines and a list of cross-curricular activities to challenge, educate, and entertain students. Students learn the inherent challenges that…

  15. The Relationship of Job Performance to Physical Fitness and Its Application to U. S. Navy Submariners

    Science.gov (United States)

    1981-09-29

    hematologic data collected from 1,017 active duty submariners. The results revealed that percent body fat as determined by skinfold thickness ...and ultimately may lead to increased effectiveness and efficiency of the submarine crew. iii TABLE OF CONTENTS page 1.0 INTRODUCTION 1

  16. Ecology and Taxonomy of Water Canyon, Canadian County, Oklahoma, Master's Thesis, University of Oklahoma 1961 [Revised 2013

    Directory of Open Access Journals (Sweden)

    Constance E. Taylor

    2014-03-01

    Full Text Available Numerous canyons have been cut into the Rush Springs Sandstone of Permian age in West Central Oklahoma and subsequently refilled. Some of these canyons have been partly exposed by erosion of the sediment fill. Fossils collected indicate the canyon fill is sub-Pleistocene to geologically recent. The microclimate of these canyons is more mesic compared to the dryer prairie uplands. Sugar maple (Acer saccharum persists there, far west of its other locations in very eastern Oklahoma. Beginning in 1932 several of these sediment-filled canyons began a process of rapid erosion, exposing the rock walls of the canyons. This study is a comparison of Water Canyon and two of its branches: Water Branch Canyon, a stable canyon wooded with mature vegetation including sugar maple and Activity Branch Canyon, a newly excavated canyon branch that began eroding after excessive rainfall in 1932. This study was completed in 1960. Six transects are used to show the distribution of the 233 plant species found in the Water Canyon complex. Herbaceous species generally were unique to each canyon type.

  17. Bottom currents observed in and around a submarine valley on the continental slope of the northern South China Sea

    Science.gov (United States)

    Wu, Lunyu; Xiong, Xuejun; Li, Xiaolong; Shi, Maochong; Guo, Yongqing; Chen, Liang

    2016-12-01

    Bottom currents at about 1000 m depth in and around a submarine valley on the continental slope of the northern South China Sea were studied by a 14-month long experiment from July 2013 to September 2014. The observations reveal that bottom currents are strongly influenced by the topography, being along valley axis or isobaths. Power density spectrum analysis shows that all the currents have significant peaks at diurnal and semi-diurnal frequencies. Diurnal energy is dominant at the open slope site, which is consistent with many previous studies. However, at the site inside the valley the semi-diurnal energy dominates, although the distance between the two sites of observation is quite small (11 km) compared to a typical horizontal first-mode internal tide wavelength (200 km). We found this phenomenon is caused by the focusing of internal waves of certain frequencies in the valley. The inertial peak is found only at the open slope site in the first deployment but missing at the inside valley site and the rest of the deployments. Monthly averaged residual currents reveal that the near-bottom currents on the slope flow southwestward throughout the year except in August and September, 2013, from which we speculate that this is a result of the interaction between a mesoscale eddy and the canyon/sag topography. Currents inside the valley within about 10 mab basically flow along slope and in the layers above the 10 mab the currents are northwestward, that is, from the deep ocean to the shelf. The monthly mean current vectors manifest an Ekman layer-like vertical structure at both sites, which rotate counter-clockwise looking from above.

  18. Bottom Currents Observed in and Around a Submarine Valley on the Continental Slope of the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    WU Lunyu; XIONG Xuejun; LI Xiaolong; SHI Maochong; GUO Yongqing; CHEN Liang

    2016-01-01

    Bottom currents at about 1000m depth in and around a submarine valley on the continental slope of the northern South China Sea were studied by a 14-month long experiment from July 2013 to September 2014. The observations reveal that bottom currents are strongly influenced by the topography, being along valley axis or isobaths. Power density spectrum analysis shows that all the currents have significant peaks at diurnal and semi-diurnal frequencies. Diurnal energy is dominant at the open slope site, which is consistent with many previous studies. However, at the site inside the valley the semi-diurnal energy dominates, although the distance between the two sites of observation is quite small (11km) compared to a typical horizontal first-mode internal tide wavelength (200km). We found this phenomenon is caused by the focusing of internal waves of certain frequencies in the valley. The inertial peak is found only at the open slope site in the first deployment but missing at the inside valley site and the rest of the de-ployments. Monthly averaged residual currents reveal that the near-bottom currents on the slope flow southwestward throughout the year except in August and September, 2013, from which we speculate that this is a result of the interaction between a mesoscale eddy and the canyon/sag topography. Currents inside the valley within about 10mab basically flow along slope and in the layers above the 10mab the currents are northwestward, that is, from the deep ocean to the shelf. The monthly mean current vectors manifest an Ek-man layer-like vertical structure at both sites, which rotate counter-clockwise looking from above.

  19. The depth and pitch control of submarines based on the pump-hydraulic servo

    Directory of Open Access Journals (Sweden)

    XU Chao

    2017-03-01

    Full Text Available This study aims to research submarine motion control features in different conditions and com-plex environments in order to solve the problem of actual submarine control and apply it to building an actu-al hydraulic control platform. The paper focuses on the vertical motion of submarines, designs a fast termi-nal sliding mode control algorithm and analyzes the data using the combined simulation and experiment method to study the robustness and reliability of a submarine's vertical motion control system for hydraulic and control. At the same time, the simulation and experiment results analyze the hysteresis and oscillation of the hydraulic steering gear, and effectively reduce the chattering that may be caused by sliding mode variable structure control. This system can be used in simulations to solve the problems of new submarine control characteristics.

  20. The Study on Fatigue Experiment and Reliability Life of Submarine Pipeline Steel

    Directory of Open Access Journals (Sweden)

    Yan Yifei

    2013-02-01

    Full Text Available The aim of the fatigue experiment study is to solve the fatigue fracture problem of X70 submarine tubing when it is under the scouring effect of offshore current. The multilevel fatigue experiments are carried out following the internation (GB4337-84 recommended method. The standard round bar fatigue specimen was made by the material of submarine pipeline steel. The fatigue life of submarine pipeline steel in different survival probability and P-S-N curve were achieved. According to reliability numerical analysis method, the reliability fatigue life of pipeline steel in different stress level is got. The results show that the fatigue life of X70 submarine pipeline steel obeys the normal distribution. The detection of submarine pipeline scouring condation should be enhanced and the pipeline zone which was scoured seriously should be repaired and controlled effectively in order to reduce the scouring effect of ocean current.

  1. Post-eruptive Submarine Terrace Development of Capelinhos, Azores

    Science.gov (United States)

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

    2017-04-01

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

  2. Submarine periscope thermal imaging: its evolution in the UK

    Science.gov (United States)

    Armstrong, George R.

    1996-06-01

    The first submarine periscope to carry a thermal imaging sensor started sea trials in 1978. As a leading EO company and the sole supplier of periscopes to the Royal Navy since 1917, Pilkington Optronics (Barr & Stroud) has led the evolution of this technology in the UK. As is often the case, the evolutionary path has been IR detector technology- led. The first operational periscope TI system (1981) used a serial/parallel array of first generation photoconductive detectors operating in the LWIR (8 - 12 micrometer) waveband. The advent of SPRITE detectors in the 1980s opened the way to greatly improved performance within a reduced space volume, culminating in 1993 with the entry into fleet service of the SPRITE-based IR028 modular system for Vanguard, the new class of RN ballistic submarines. Today, second generation focal plane array detectors, along with the concept of the non-hull penetrating optronics mast, are ready to revolutionize periscope TI. The Pilkington Optronics CM10 Optronics Mast, presently under development, has been bid for the next class of RN submarines, Trafalgar Batch 2. CM10 exists in two versions, allowing the user to choose the operational waveband most suited to his operational needs. The sensor in the LWIR version is the PO high definition thermal imager (HDTI), which makes optimum use of SPRITEs to achieve very high performance within a compact space. The MWIR version features dual-band (TV plus 3 - 5 micrometer) optics viewing through a single pressure window; the TI sensor is based on a microscanned CMT FPA, yielding high spatial resolution and thermal sensitivity with small aperture optics.

  3. The influence of the San Gregorio fault on the morphology of Monterey Canyon

    Science.gov (United States)

    McHugh, C.M.G.; Ryan, William B. F.; Eittreim, S.; Donald, Reed

    1998-01-01

    A side-scan sonar survey was conducted of Monterey Canyon and the San Gregorio fault zone, off shore of Monterey Bay. The acoustic character and morphology of the sonar images, enhanced by SeaBeam bathymetry, show the path of the San Gregorio fault zone across the shelf, upper slope, and Monterey Canyon. High backscatter linear features a few kilometers long and 100 to 200 m wide delineate the sea-floor expression of the fault zone on the shelf. Previous studies have shown that brachiopod pavements and carbonate crusts are the source of the lineations backscatter. In Monterey Canyon, the fault zone occurs where the path of the canyon makes a sharp bend from WNW to SSW (1800 m). Here, the fault is marked by NW-SE-trending, high reflectivity lineations that cross the canyon floor between 1850 m and 1900 m. The lineations can be traced to ridges on the northwestern canyon wall where they have ~ 15 m of relief. Above the low-relief ridges, bowl-shaped features have been excavated on the canyon wall contributing to the widening of the canyon. We suggest that shear along the San Gregorio fault has led to the formation of the low-relief ridges near the canyon wall and that carbonate crusts, as along the shelf, may be the source of the high backscatter features on the canyon floor. The path of the fault zone across the upper slope is marked by elongated tributary canyons with high backscatter floors and 'U'-shaped cross-sectional profiles. Linear features and stepped scarps suggestive of recent crustal movement and mass-wasting, occur on the walls and floors of these canyons. Three magnitude-4 earthquakes have occurred within the last 30 years in the vicinity of the canyons that may have contributed to the observed features. As shown by others, motion along the fault zone has juxtaposed diverse lithologies that outcrop on the canyon walls. Gully morphology and the canyon's drainage patterns have been influenced by the substrate into which the gullies have formed.

  4. Unusually high food availability in Kaikoura Canyon linked to distinct deep-sea nematode community

    Science.gov (United States)

    Leduc, D.; Rowden, A. A.; Nodder, S. D.; Berkenbusch, K.; Probert, P. K.; Hadfield, M. G.

    2014-06-01

    Kaikoura Canyon, on the eastern New Zealand continental margin, is the most productive, non-chemosynthetic deep-sea habitat described to date, with megafaunal biomass 100-fold higher than those of other deep-sea habitats. The present study, which focused on free-living nematodes, provides the first comparison of faunal community structure and diversity between Kaikoura Canyon and nearby open slope habitats. Results show substantially higher food availability in the canyon relative to open slope sediments, which probably reflects greater levels of primary productivity above the canyon, coupled with downwelling and/or topographically-induced channelling, which serves to concentrate surface-derived organic matter along the canyon axis. This high food availability appears to be responsible for the elevated nematode biomass in Kaikoura Canyon, with values exceeding all published nematode biomass data from canyons elsewhere. There was also markedly lower local species diversity of nematodes inside the canyon relative to the open slope habitat, as well as a distinct community structure. The canyon community was dominated by species, such as Sabateria pulchra, which were absent from the open slope and are typically associated with highly eutrophic and/or disturbed environments. The presence of these taxa, as well as the low observed diversity, is likely to reflect the high food availability, and potentially the high levels of physically and biologically induced disturbance within the canyon. Kaikoura Canyon is a relatively small habitat characterised by different environmental conditions that makes a disproportionate contribution to deep-sea diversity in the region, despite its low species richness.

  5. A real two-phase submarine debris flow and tsunami

    Energy Technology Data Exchange (ETDEWEB)

    Pudasaini, Shiva P.; Miller, Stephen A. [Department of Geodynamics and Geophysics, Steinmann Institute, University of Bonn Nussallee 8, D-53115, Bonn (Germany)

    2012-09-26

    The general two-phase debris flow model proposed by Pudasaini is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model, which includes three fundamentally new and dominant physical aspects such as enhanced viscous stress, virtual mass, and generalized drag (in addition to buoyancy), constitutes the most generalized two-phase flow model to date. The advantage of this two-phase debris flow model over classical single-phase, or quasi-two-phase models, is that the initial mass can be divided into several parts by appropriately considering the solid volume fraction. These parts include a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This innovative formulation provides an opportunity, within a single framework, to simultaneously simulate the sliding debris (or landslide), the water lake or ocean, the debris impact at the lake or ocean, the tsunami generation and propagation, the mixing and separation between the solid and fluid phases, and the sediment transport and deposition process in the bathymetric surface. Applications of this model include (a) sediment transport on hill slopes, river streams, hydraulic channels (e.g., hydropower dams and plants); lakes, fjords, coastal lines, and aquatic ecology; and (b) submarine debris impact and the rupture of fiber optic, submarine cables and pipelines along the ocean floor, and damage to offshore drilling platforms. Numerical simulations reveal that the dynamics of debris impact induced tsunamis in mountain lakes or oceans are fundamentally different than the tsunami generated by pure rock avalanches and landslides. The analysis includes the generation, amplification and propagation of super tsunami waves and run-ups along coastlines, debris slide and deposition at the bottom floor, and debris shock waves. It is observed that the

  6. Submarine glaciated landscapes of central and northern British Columbia, Canada

    Science.gov (United States)

    Shaw, John; Lintern, Gwyn

    2015-04-01

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

  7. Two Submarine Pipelines To Be Built in Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    @@ To ensure the second step forward of CNOOC on oil/gas output for the Ninth -Five-Year Plan period, a transcentury project embarked upon its implementation in an all-round way at the beginning of this year by Bohai Company, i.e. two submarine oil/gas pipelines are going to be built across the Bohai Seabed. The two pipelines are of remarkably strategic significance for delivering the abundant resources of oil and gas developed in the Bohai Sea waters to the coastal cities in support of local economic construction and, in a couple of years, they will become "energy corridors" with great economic expectation.

  8. Submarine landslides along the eastern Mediterranean Israeli continental slope

    Science.gov (United States)

    Reuven, Einav; Katz, Oded; Aharonov, Einat

    2013-04-01

    Numerous shallow submarine slope failures (scars and deposits) are observed in recent high resolution bathymetric grids of the continental slope off the Israeli eastern Mediterranean coast. The nature of these slope failures is currently not comprehensively understood as well as the question of whether the eastern Mediterranean continental slope is continuously or episodically unstable. We report here first steps towards understanding the present state of this submarine landslide system, which include mapping and analyzing the geology of the landslides and the hosting slopes. The continental slope extends from water depths of about 150 to more than 1000 meters with a slope of less than 5 degrees in general. Bathymetric grids with pixel resolution of 15 m till water depth of 700 m and 50 m till water depth of 1700 m were used. Analyzing the bathymetry revealed three main submarine surface features: (a) numerous shallow landslides, within the upper sequence of the post-Messenian sediments. Landslide widths range between hundreds to thousand of meters at the scar, with scar heights up to hundred meters. The toes of the landslides are not always mapable and lay up to a few kilometers down slope from the scar. Slope angles within the scars are 5 to more than15 degrees. At least two types of landslides were detected: presumably young slides with sharp scars, and presumably old slides with secondary slides and secondary drainage systems developed within the scar area; (b) a few kilometers long, north striking step-like lineaments. Step heights are up to 100 meters and the slopes are up to 20 degrees. The offset between parallel steps is less than a kilometer to a few kilometers. The steps are interpreted as surface expressions of growth faults rooted at the Messinian evaporates up to 1.5 kilometers below surface; (c) a few north striking channels were also detected with steep walls of more than 15 degrees, up to two kilometers width and a few kilometers length. The nature

  9. Possible Connections Between the Coronado Bank Fault Zone and the Newport-Inglewood, Rose Canyon, and Palos Verdes Fault Zones Offshore San Diego County, California.

    Science.gov (United States)

    Sliter, R. W.; Ryan, H. F.

    2003-12-01

    High-resolution multichannel seismic-reflection and deep-tow Huntec data collected by the USGS were interpreted to map the Coronado Bank fault zone (CBFZ) offshore San Diego County, California. The CBFZ is comprised of several major strands (eastern, central, western) that change in both orientation and degree of deformation along strike. Between Coronado Bank and San Diego, the CBFZ trends N25W and occupies a narrow 7 km zone. Immediately north of La Jolla submarine canyon (LJSC), the easternmost strand changes orientation to almost due north and appears to be offset in a right-lateral sense across the canyon axis. The strand merges with a prominent fault that follows the base of the continental slope in about 600 m water depth. The central portion of the CBFZ is mapped as a negative flower structure and deforms seafloor sediment as far north as 15 km north of LJSC. Farther north, this structure is buried by more than 400 m of basin sediment. Along the eastern edge of the Coronado Bank, the western portion of the CBFZ is characterized by high angle normal faults that dip to the east. North of the Coronado Bank, the western segment follows the western edge of a basement high; it cuts through horizontal basin reflectors and in places deforms the seafloor. We mapped an additional splay of the CBFZ that trends N40W; it is only observed north and west of LJSC. Although the predominant trend of the CBFZ is about N40W, along strike deviations from this orientation of some of the strands indicate that these strands connect with other offshore fault zones in the area. Based on the limited data available, the trend of the CBFZ south of Coronado Bank suggests that it might connect with the Rose Canyon fault zone (RCFZ) that has been mapped in San Diego Bay. North of Coronado Bank, the CBFZ is a much broader fault zone (about 25 km wide) composed of diverging fault strands. The westernmost strand may merge with the western strand of the Palos Verdes fault zone (PVFZ) south of

  10. Captured in Stone: Women in the Rock Art of Canyon de Chelly.

    Science.gov (United States)

    Travis, Tara

    1997-01-01

    Describes the pictographs (painted images on stone) and petroglyphs (pecked images on stone) found in the Canyon de Chelly National Monument in Arizona. Canyon de Chelly includes one of the largest concentrations of American Indian rock art in the southwest. Discusses the depiction of women in these images. (MJP)

  11. 33 CFR 165.1155 - Security Zone; Diablo Canyon Nuclear Power Plant, Avila Beach, California.

    Science.gov (United States)

    2010-07-01

    ... Nuclear Power Plant, Avila Beach, California. 165.1155 Section 165.1155 Navigation and Navigable Waters... Coast Guard District § 165.1155 Security Zone; Diablo Canyon Nuclear Power Plant, Avila Beach... surface to bottom, within a 2,000 yard radius of Diablo Canyon Nuclear Power Plant centered at position...

  12. Biological Resources Survey of Mountain Springs Canyon on the Naval Weapons Center.

    Science.gov (United States)

    1983-03-01

    Coleo - gyne association (Beatley, 1976) further up the canyon where the aspect of the north- facing slope changes from northwest to north near Mountain...argusensis) was collected in the upper half of the canyon. Although common in Coleo - j ne habitat, it is considered sensitive by BLM (1980) due to its endemic

  13. 78 FR 42799 - Glen Canyon Dam Adaptive Management Work Group Meetings

    Science.gov (United States)

    2013-07-17

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group Meetings AGENCY: Bureau of... AMWG, a technical work group (TWG), a Grand Canyon Monitoring and Research Center, and independent.... Dated: July 11, 2013. Glen Knowles, Chief, Adaptive Management Work Group, Upper Colorado...

  14. 76 FR 584 - Glen Canyon Dam Adaptive Management Program Work Group (AMWG)

    Science.gov (United States)

    2011-01-05

    ... Bureau of Reclamation Glen Canyon Dam Adaptive Management Program Work Group (AMWG) AGENCY: Bureau of... Management Work Group (AMWG), a technical work group (TWG), a Grand Canyon Monitoring and Research Center... addition, there will be updates from the Charter Ad Hoc Group and a follow up report on the work done...

  15. 75 FR 10308 - Fire Management Plan, Final Environmental Impact Statement, Record of Decision, Grand Canyon...

    Science.gov (United States)

    2010-03-05

    ... Doc No: 2010-4414] DEPARTMENT OF THE INTERIOR National Park Service Fire Management Plan, Final... Impact Statement for the Fire Management Plan, Grand Canyon National Park. SUMMARY: Pursuant to the... availability of the Record of Decision for the Fire Management Plan, Grand Canyon National Park, Arizona. On...

  16. Reconstructing the Aliso Canyon natural gas leak incident

    Science.gov (United States)

    Duren, R. M.; Yadav, V.; Verhulst, K. R.; Thorpe, A. K.; Hopkins, F. M.; Prasad, K.; Kuai, L.; Thompson, D. R.; Wong, C.; Sander, S. P.; Mueller, K. L.; Nehrkorn, T.; Lee, M.; Hulley, G. C.; Johnson, W. R.; Aubrey, A. D.; Whetstone, J. R.; Miller, C. E.

    2016-12-01

    Natural gas is a key energy source and presents significant policy challenges including energy reliability and the potential for fugitive methane emissions. The well blowout reported in October 2015 at the Aliso Canyon underground gas storage facility near Porter Ranch, California and subsequent uncontrolled venting was the largest single anthropogenic methane source known to date. Multiple independent estimates indicate that this super-emitter source rivaled the normal methane flux of the entire South Coast Air Basin (SoCAB) for several months until the well was plugged. The complexity of the event and logistical challenges - particularly in the initial weeks - presented significant barriers to estimating methane losses. Additionally, accounting for total gas lost is necessary but not sufficient for understanding the sequence of events and the controlling physical processes. We used a tiered system of observations to assess methane emissions from the Aliso Canyon incident. To generate a complete flux time-series, we applied tracer-transport models and tracer-tracer techniques to persistent, multi-year atmospheric methane observations from a network of surface in-situ and remote-sensing instruments. To study the fine spatio-temporal structure of methane plumes and understand the changing source morphology, we conducted intensive mobile surface campaigns, deployed airborne imaging spectrometers, requested special observations from two satellites, and employed large eddy simulations. Through a synthesis analysis we assessed methane fluxes from Aliso Canyon before, during and after the reported incident. We compared our fine scale spatial data with bottom-up data and reports of activity at the facility to better understand the controlling processes. We coordinated with California stakeholder agencies to validate and interpret these results and to consider the potential broader implications on underground gas storage and future priorities for methane monitoring.

  17. Las presas de Glen Canyon y Flaming Gorge

    Directory of Open Access Journals (Sweden)

    Goodman, D. L.

    1962-04-01

    Full Text Available El Bureau of Reclamation, con sede en Denver, Colorado (EE. UU., está actualmente construyendo dos presas, de hormigón y gran altura. Este Departamento desempeña una función similar a la que vienen desarrollando nuestras Confederaciones hidrográficas nacionales. Las dos presas son: la de Glen Canyon, de 216 m de altura, y la de Flaming Gorge, de 153, que son las más importantes en cuanto a almacenamiento y reserva se refiere.

  18. The benthic communities of the Cap de Creus canyon

    OpenAIRE

    2012-01-01

    The authors thank Fugro Survey, AOA Geophysics and the University of Barcelona for the multibeam bathymetry of the Cap de Creus canyon, the owners of the ROVs (FIELAX, INSTALSUB, Spain and Gavin Newman, UK), as well as the JAGO team (J. Schauer and K. Hissmann) from IFM-GEOMAR (Germany). We also thank the Spanish General Secretariat for the Sea (Ministerio de Agricultura, Alimentación y Medio Ambiente) for the vessel monitoring systems (VMS) data and the Fundación Biodiversidad for t...

  19. An exhumed Late Paleozoic canyon in the rocky mountains

    Science.gov (United States)

    Soreghan, G.S.; Sweet, D.E.; Marra, K.R.; Eble, C.F.; Soreghan, M.J.; Elmore, R.D.; Kaplan, S.A.; Blum, M.D.

    2007-01-01

    Landscapes are thought to be youthful, particularly those of active orogenic belts. Unaweep Canyon in the Colorado Rocky Mountains, a large gorge drained by two opposite-flowing creeks, is an exception. Its origin has long been enigmatic, but new data indicate that it is an exhumed late Paleozoic landform. Its survival within a region of profound late Paleozoic orogenesis demands a reassessment of tectonic models for the Ancestral Rocky Mountains, and its form and genesis have significant implications for understanding late Paleozoic equatorial climate. This discovery highlights the utility of paleogeomorphology as a tectonic and climatic indicator. ?? 2007 by The University of Chicago. All rights reserved.

  20. Large eddy simulation of flow in a street canyon with tree planting under various atmospheric instability conditions

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this work, a large eddy simulation (LES) model, which includes momentum and heat source (or sink) inside the tree planting layer, is proposed for the simulation of flow in a street canyon with tree planting. Vegetation canopy layer simulation shows that this model can be used to simulate the velocity distribution and temperature variation inside the canopy layer. Effects of atmospheric instability on flow and pollutant distribution in a street canyon with tree planting of an aspect ratio of 0.5 are studied. Results show that compared with the canyon with no tree planting (or the exposed street canyon), the canyon with tree planting shows a reduced wind circulation and pollutant exchange rate (PER) at the top layer of the street canyon, which induces the increase in the pollutant concentrations near road surface, leeward wall and windward wall. When street canyon atmosphere is under a strongly unstable condition, wind velocity decreases while pollutant concentration is increased in the areas near the street canyon top, road surface, leeward and windward walls, compared with the wind velocity in the street canyon with the neutral stratification. When street canyon atmosphere is under a weakly unstable condition, wind velocity weakens near the street canyon top and windward wall, but strengthens near the road surface and leeward wall, and pollutant concentration is decreased near the leeward and windward walls and is increased between the two rows of trees. When the street canyon atmosphere is under an unstable condition, PER is lower than that under the neutral stratification.

  1. Some giant submarine landslides do not produce large tsunamis

    Science.gov (United States)

    Løvholt, Finn; Bondevik, Stein; Laberg, Jan Sverre; Kim, Jihwan; Boylan, Noel

    2017-08-01

    Landslides are the second most important cause of tsunamis after earthquakes, and their potential for generating large tsunamis depend on the slide process. Among the world's largest submarine landslides is the Storegga Slide that generated a large tsunami over an ocean-wide scale, while no traces of a tsunami generated from the similar and nearby Trænadjupet Slide have been found. Previous models for such landslide tsunamis have not been able to capture the complexity of the landslide processes and are at odds with geotechnical and geomorphological data that reveal retrogressive landslide development. The tsunami generation from these massive events are here modeled with new methods that incorporate complex retrogressive slide motion. We show that the tsunamigenic strength is closely related to the retrogressive development and explain, for the first time, why similar giant landslides can produce very different tsunamis, sometimes smaller than anticipated. Because these slide mechanisms are common for submarine landslides, modeling procedures for dealing with their associated tsunamis should be revised.

  2. Finite volume methods for submarine debris flows and generated waves

    Science.gov (United States)

    Kim, Jihwan; Løvholt, Finn; Issler, Dieter

    2016-04-01

    Submarine landslides can impose great danger to the underwater structures and generate destructive tsunamis. Submarine debris flows often behave like visco-plastic materials, and the Herschel-Bulkley rheological model is known to be appropriate for describing the motion. In this work, we develop numerical schemes for the visco-plastic debris flows using finite volume methods in Eulerian coordinates with two horizontal dimensions. We provide parameter sensitivity analysis and demonstrate how common ad-hoc assumptions such as including a minimum shear layer depth influence the modeling of the landslide dynamics. Hydrodynamic resistance forces, hydroplaning, and remolding are all crucial terms for underwater landslides, and are hence added into the numerical formulation. The landslide deformation is coupled to the water column and simulated in the Clawpack framework. For the propagation of the tsunamis, the shallow water equations and the Boussinesq-type equations are employed to observe how important the wave dispersion is. Finally, two cases in central Norway, i.e. the subaerial quick clay landslide at Byneset in 2012, and the submerged tsunamigenic Statland landslide in 2014, are both presented for validation. The research leading to these results has received funding from the Research Council of Norway under grant number 231252 (Project TsunamiLand) and the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement 603839 (Project ASTARTE).

  3. Large-eddy simulations of a propelled submarine model

    Science.gov (United States)

    Posa, Antonio; Balaras, Elias

    2015-11-01

    The influence of the propeller on the wake as well as the evolution of the turbulent boundary layers over an appended notional submarine geometry (DARPA SUBOFF) is reported. The present approach utilizes a wall-resolved LES, coupled with an immersed boundary formulation, to simulate the flow model scale Reynolds numbers (Re = 1 . 2 e + 06 , based on the free-stream velocity and the length of the body). Cylindrical coordinates are adopted, and the computational grid is composed of 3.5 billion nodes. Our approach has been validated on the appended submarine body in towed conditions (without propeller), by comparisons to wind tunnel experiments in the literature. The comparison with the towed configuration shows profound modifications in the boundary layer over the stern surface, due to flow acceleration, with higher values of turbulent kinetic energy in the inner layer and lower values in the outer layer. This behavior was found tied to a different topology of the coherent structures between propelled and towed cases. The wake is also highly affected, and the momentum deficit displays a non-monotonic evolution downstream. An axial peak of turbulent kinetic energy replaces the bimodal distribution of the stresses in the wake, observed in the towed configuration. Supported by ONR Grant N000141110455, monitored by Dr. Ki-Han Kim.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed and suspen......A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed...... and suspended load descriptions forming the basis for seabed morphology. The model was successfully validated against experimental measurements involving scour development and eventual equilibrium in pure-current flows over a range of Shields parameters characteristic of both clear-water and live-bed regimes....... This validation complements previously demonstrated accuracy for the same model in simulating pipeline scour processes in pure-wave environments. The model was subsequently utilized to simulate combined wave-plus-current scour over a wide range of combined Keulegan–Carpenter numbers and relative current strengths...

  5. Similarities in the chemistry of shallow submarine hydrothermal vents

    Energy Technology Data Exchange (ETDEWEB)

    Prol-Ledesma, R.M. [UNAM, Mexico City (Mexico). Instituto de Geofisica

    2003-12-01

    Shallow submarine hydrothermal activity has been observed in Western Mexico related to extensional tectonic faults. Hydrothermal vents occur at Punta Banda on the Pacific coast of Baja California, at Bahia Concepcion on the eastern coast of Baja California, and in Punta Mita on the Pacific coast of central Mexico. Submarine discharge of geothermal fluids is located at depths varying between 5 and 30 m. Water and gas discharge at temperatures between 40 and more than 100{sup o}C. The composition of the thermal end-member can be calculated for Mg=0 using the chemistry data of the water samples. A linear regression of the concentration values vs magnesium content is used to determine the concentration of the end-member thermal water. The chemical composition of the thermal end-member indicates that the water is more dilute than seawater and enriched in Ca, Mn, Ba, I, Cs, B, Li, Rb, Sr and Si. The results show that the water chemistry is similar in these coastal hydrothermal systems. The thermal water is probably of meteoric origin, penetrating through the extensional faults, and heated by the high geothermal gradient. The components in the thermal water are contributed by the deep strata. (author)

  6. LES of a submarine model in self-propulsion

    Science.gov (United States)

    Posa, Antonio; Balaras, Elias

    2016-11-01

    Wall-resolved LES computations are presented on the flow over a notional submarine geometry in self-propelled conditions at Re=1.2e+06 (based on the free-stream velocity and the length of the body). The rotational speed of the propeller was dynamically adjusted during the simulation using a proportional-integral controller, in order for the propeller thrust to balance the overall drag on the system. An immersed-boundary methodology was adopted to enforce boundary conditions over the body. Comparisons with the same submarine geometry in the towed configuration allowed us to verify that the boundary layer over the hull surface is affected only in the stern region, while that over the cylindrical mid-body is roughly in equilibrium in both towed and self-propelled conditions. The quasi-streamwise structures of the turbulent boundary layer and their development along the stern dominate the flow ingested by the propeller. The wake and junction flows from the fins break the axial symmetry of such flow. Comparisons with the towed configuration verify that the propeller affects substantially its own inflow, defined by the overlapping effects of adverse pressure gradient, due to the tapered geometry of the stern, and suction generated by the same propeller. This work is supported by the Office of Naval Research, under Grant No. N000141110455, monitored by Dr. Ki-Han Kim.

  7. ATTICA family of thermal cameras in submarine applications

    Science.gov (United States)

    Kuerbitz, Gunther; Fritze, Joerg; Hoefft, Jens-Rainer; Ruf, Berthold

    2001-10-01

    Optronics Mast Systems (US: Photonics Mast Systems) are electro-optical devices which enable a submarine crew to observe the scenery above water during dive. Unlike classical submarine periscopes they are non-hull-penetrating and therefore have no direct viewing capability. Typically they have electro-optical cameras both for the visual and for an IR spectral band with panoramic view and a stabilized line of sight. They can optionally be equipped with laser range- finders, antennas, etc. The brand name ATTICA (Advanced Two- dimensional Thermal Imager with CMOS-Array) characterizes a family of thermal cameras using focal-plane-array (FPA) detectors which can be tailored to a variety of requirements. The modular design of the ATTICA components allows the use of various detectors (InSb, CMT 3...5 μm , CMT 7...11 μm ) for specific applications. By means of a microscanner ATTICA cameras achieve full standard TV resolution using detectors with only 288 X 384 (US:240 X 320) detector elements. A typical requirement for Optronics-Mast Systems is a Quick- Look-Around capability. For FPA cameras this implies the need for a 'descan' module which can be incorporated in the ATTICA cameras without complications.

  8. Multidisciplinary Investigations of Submarine Flow to Biscayne Bay, Florida

    Science.gov (United States)

    Halley, R. B.; Reich, C. D.; Swarzenski, P. W.; Langevin, C. D.

    2005-05-01

    Biscayne Bay and Biscayne National Park (BNP) are located next to the Miami-Dade urban complex and are adjacent to the Dade County South Dade Landfill Facility and the Miami-Dade Water and Sewer South District Plant. The base of the landfill is lined to separate it from the underlying Miami Limestone, the host rock for the surficial Biscayne Aquifer. The sewage-treatment facility injects treated sewage into the lower Florida Aquifer (750 m) that is overlain by an aquitard termed the Middle Confining Unit (450 m). The Biscayne Aquifer (up to 50 m thick) borders the western margin of BNP, and the Floridan Aquifer underlies the entire park. There is concern about leakage of contaminated aquifer water into BNP and its potential effects on water quality. Groundwater flux to Biscayne Bay is being studied using pressure measurements and geochemical analyses from submarine wells, electromagnetic seepage meters, streaming resistivity profiling, and local and regional model simulations. Both seepage meters and water analyses provide point information that can be placed into the regional context provided by flow models and geochemical and geophysical profiling, which, in turn, constrain the groundwater contribution. Water samples were collected approximately quarterly from August 2002 until March 2004 from submarine wells along a transect through Biscayne Bay and across the reef to the shelf edge. Samples were analyzed for conductivity (salinity), dissolved oxygen, temperature, redox potential, nutrients, metals, strontium isotopes, radon, sulfate, and wastewater compounds. Low-salinity water was identified from nearshore wells and indicates seepage from the Biscayne Aquifer and/or surface-water intrusion into the rocks along western Biscayne Bay. Analyses of water samples (n = 109) collected from wells across the Florida shelf show no consistent evidence of wastewater contaminants occurring in groundwater beneath BNP. No significant leakage from the Floridan Aquifer

  9. Multidimensional analysis of Drosophila wing variation in Evolution Canyon

    Indian Academy of Sciences (India)

    Vincent Debat; Raphael Cornette; Abraham B. Koral; Eviatar Nevo; David Soulet; Jean R. David

    2008-12-01

    Environmental stress has been suggested to be a major evolutionary force, both through inducing strong selection and because of its direct impact on developmental buffering processes that alter the evolvability of organisms. In particular, temperature has attracted much attention because of its importance as an ecological feature and the relative ease with which it can be experimentally manipulated in the lab. Evolution Canyon, Lower Nahal Oren, Israel, is a well studied natural site where ecological parameters are suspected to drive evolutionary differentiation. In this study, using Drosophila melanogaster isofemale lines derived from wild flies collected on both slopes of the canyon, we investigated the effect of developmental temperature upon the different components of phenotypic variation of a complex trait: the wing. Combining geometric and traditional morphometrics, we find only limited evidence for a differentiation among slopes. Investigating simultaneously phenotypic plasticity, genetic variation among isofemale lines, variation among individuals and fluctuating asymmetry, we could not identify a consistent effect of the stressful conditions encountered on the south facing slope. The prevailing structuring effect is that of the experimentally manipulated temperature which clearly influences wing mean size and shape. Variability, in contrast, is not consistently affected by temperature. Finally, we investigated the specific relationship between individual variation and fluctuating asymmetry. Using metric multi-dimensional scaling we show that the related patterns of wing shape variation are not identical, supporting the view that the underlying developmental processes are to a certain extent different.

  10. Trial by fire: underbalanced drilling for Horseshoe Canyon coals

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, K. [Nexen Inc., Calgary, AB (Canada)

    2008-07-01

    Four wells were drilled in August 2007 in the lower portion of Horseshoe Canyon. These wells were underbalanced and used air as the drilling fluid. The purpose was to establish the feasibility of under-reaming. This presentation discussed under balanced drilling for Horseshoe Canyon coals. It presented a review of the project and discussed the various project phases. Phase one involved under balanced drilling and under-reaming. The presentation of this phase addressed risk management; review of results; lessons learned; and recommended practices. An illustration of the risk management process was offered. This illustration included identification of hazards, categorization, evaluation, management, and communication. A risk matrix was also provided. Phase two was also presented which included a discussion of planning considerations; revised risk management; underbalanced redesign; and implementation. It was concluded that in order to eliminate the risk, oxygen must be removed or lowered to less than four per cent. It was also found that caution must be used when evaluating whether downhole conditions are in the explosive envelope. figs.

  11. Geologic map of the Paintbrush Canyon Area, Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, R.P. [Geological Survey, Denver, CO (United States); Drake, R.M. II [Pacific Western Technologies, Ltd., Lakewood, CO (United States)

    1998-11-01

    This geologic map is produced to support site characterization studies of Yucca Mountain, Nevada, site of a potential nuclear waste storage facility. The area encompassed by this map lies between Yucca Wash and Fortymile Canyon, northeast of Yucca Mountain. It is on the southern flank of the Timber Mountain caldera complex within the southwest Nevada volcanic field. Miocene tuffs and lavas of the Calico Hills Formation, the Paintbrush Group, and the Timber Mountain Group crop out in the area of this map. The source vents of the tuff cones and lava domes commonly are located beneath the thickest deposits of pyroclastic ejecta and lava flows. The rocks within the mapped area have been deformed by north- and northwest-striking, dominantly west-dipping normal faults and a few east-dipping normal faults. Faults commonly are characterized by well developed fault scarps, thick breccia zones, and hanging-wall grabens. Latest movement as preserved by slickensides on west-dipping fault scarps is oblique down towards the southwest. Two of these faults, the Paintbrush Canyon fault and the Bow Ridge fault, are major block-bounding faults here and to the south at Yucca Mountain. Offset of stratigraphic units across faults indicates that faulting occurred throughout the time these volcanic units were deposited.

  12. Massive Rock Detachments from the Continental slope of the Balsas River Submarine Delta that occur due to Instability of Sediments which Produce Turbidity Currents and Tsunamis

    Science.gov (United States)

    Sandoval-Ochoa, J.; Aguayo-Camargo, J.

    2007-05-01

    During the NOAA oceanographic delivery cruise of the US R/V "Roger Revelle" to the Scripps Institution of Oceanography at the University of California in San Diego, California USA, in July 1996; a well calibrated bathymetric equipment, the SeaBeam* 2012, was tested. Good resolutions in data allowed bathymetric mapping to visualize the sea floor relief. Detailed colorful chartographic images showed a portion of the continental slope between the Balsas River Delta and the Middle America Trench and between the Balsas Canyon and La Necesidad Canyon. The surveyed area covered more than 3 000 square kilometers. After the delivery cruise, one of the goals was to measure and analyze the Morphobathymetry of the uneven lower portion of the Balsas River Submarine Delta. So far some of the findings with the morphometric analyses consist of several isolated slump scars that each comprise more than 12 cubic kilometers in volume and a multiple slump scar with an evident steep hollow about 200 cubic kilometers absent of rock. These volumes of rock apparently underwent a remobilization from the slope during the Late Quaternary. The rock detachments occured in relatively small portions but in instantaneous massive displacements because of their instability as well as other identified factors in the region. Over time more and more authors have accepted that coastal cuts or submarine slump scars have been left by sudden movements of rock and fluids. The phenomena that occur in the region in general, are accompanied on one side by potential and kinetic energies like falling bodies, flows and gravity waves, and on the other side, by mass transfer of rock and fluid mobilization like turbidity currents, accumulations, sea wave surges or tsunamis. In some cases the phenomena is produced by another natural triggering forces or by an earthquake. We propose that events like these, i.e. massive detachments and their products such as accumulations, turbidity currents and depositional debrites

  13. Magnetohydrodynamic (MHD) nuclear weapons effects on submarine cable systems. Volume 1. Experiments and analysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1987-06-01

    This report presents a study of the nuclear weapons magnetohydrodynamic (MHD) effects on submarine communications cables. The study consisted of the analysis and interpretation of currently available data on submarine cable systems TAT-4, TAT-6, and TAT-7. The primary result of the study is that decrease of the effective resistivity with frequency over the available experimental range, coupled with the model results, leads to quite small effective resistivities at the MHD characteristic frequencies, and hence small earth potential differences. Thus, it appears that submarine cable systems are less susceptible to an MHD threat than their land-based counter-parts.

  14. The Needed Minimum Submergence Depth When a Submarine Runs into Typhoon

    Institute of Scientific and Technical Information of China (English)

    Zhang Deyu

    2003-01-01

    In this paper,the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge;Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.

  15. Design specifications of the Human Robotic interface for the biomimetic underwater robot "yellow submarine project"

    CERN Document Server

    Bheemaiah, Anil

    2010-01-01

    This paper describes the design of a web based multi agent design for a collision avoidance auto navigation biomimetic submarine for submarine hydroelectricity. The paper describes the nature of the map - topology interface for river bodies and the design of interactive agents for the control of the robotic submarine. The agents are migratory on the web and are designed in XML/html interface with both interactive capabilities and visibility on a map. The paper describes mathematically the user interface and the map definition languages used for the multi agent description

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-09-09

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

  17. Lung deposited surface area concentrations in a street canyon

    Science.gov (United States)

    Kuuluvainen, Heino; Hietikko, Riina; Järvinen, Anssi; Saukko, Erkka; Irjala, Matti; Niemi, Jarkko V.; Timonen, Hilkka; Keskinen, Jorma; Rönkkö, Topi

    2017-04-01

    Street canyons are interesting environments with respect to the dispersion of traffic emissions and human exposure. Pedestrians may be exposed to relatively high concentrations of fine particles and the vertical dispersion affects the human exposure above the ground level in buildings. Previously, particle concentrations have been measured in street canyons at a few different heights (Marini et al., 2015). The information on the lung deposited surface area (LDSA) concentration, which is a relevant metric for the negative health effects, is very limited even at the ground level of street canyons (Kuuluvainen et al., 2016). More information especially on the vertical dispersion and the ground level concentrations is needed, for instance, for the use of urban planning and the design of ventilation systems in buildings. Measurements were carried out in a busy street canyon in Helsinki, Finland, at an urban super-site measurement station (Mäkelänkatu 50). The data included vertical concentration profiles measured in an intensive measurement campaign with a Partector (Naneos GmbH) installed into a drone, long-term measurements with an AQ Urban particle sensor (Pegasor Ltd.), and an extensive comparison measurement in the field with different devices measuring the LDSA. These devices were an AQ Urban, Partector, DiSCmini (Testo AG), NSAM (TSI Inc.), and an ELPI+ (Dekati Ltd.). In addition, continuous measurements of gas phase components, particle size distributions, and meteorology were run at the supersite. The vertical profile measurements were con-ducted in November 2016 during two days. In the measurements, the drone was flown from the ground level to an altitude of 50 or 100 m, which is clearly above the roof level of the buildings. Altogether, 48 up-and-down flights were conducted during the two days. The vertical profiles were supported by continuous measurements at the ground level on both sides of the street canyon. The long-term measurements were conducted

  18. The thermal regime around buried submarine high-voltage cables

    Science.gov (United States)

    Emeana, C. J.; Hughes, T. J.; Dix, J. K.; Gernon, T. M.; Henstock, T. J.; Thompson, C. E. L.; Pilgrim, J. A.

    2016-08-01

    The expansion of offshore renewable energy infrastructure and the need for trans-continental shelf power transmission require the use of submarine high-voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70 °C and are typically buried 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the heat flow pattern and potential effects on the sedimentary environments around such anomalously high heat sources in the near-surface sediments are poorly understood. We present temperature measurements from a 2-D laboratory experiment representing a buried submarine HV cable, and identify the thermal regimes generated within typical unconsolidated shelf sediments—coarse silt, fine sand and very coarse sand. We used a large (2 × 2.5 m2) tank filled with water-saturated spherical glass beads (ballotini) and instrumented with a buried heat source and 120 thermocouples to measure the time-dependent 2-D temperature distributions. The observed and corresponding Finite Element Method simulations of the steady state heat flow regimes and normalized radial temperature distributions were assessed. Our results show that the heat transfer and thus temperature fields generated from submarine HV cables buried within a range of sediments are highly variable. Coarse silts are shown to be purely conductive, producing temperature increases of >10 °C up to 40 cm from the source of 60 °C above ambient; fine sands demonstrate a transition from conductive to convective heat transfer between cf. 20 and 36 °C above ambient, with >10 °C heat increases occurring over a metre from the source of 55 °C above ambient; and very coarse sands exhibit dominantly convective heat transfer even at very low (cf. 7 °C) operating temperatures and reaching temperatures of up to 18 °C above ambient at a metre from the source at surface temperatures of only 18 °C. These findings are important for the surrounding near

  19. Submarine ground-water discharge: nutrient loading and nitrogen transformations

    Science.gov (United States)

    Kroeger, Kevin D.; Swarzenski, Peter W.; Crusius, John; Bratton, John F.; Charette, Matthew A.

    2006-01-01

    Eutrophication of coastal waters due to nonpoint source land-derived nitrogen (N) loads is a worldwide phenomenon and perhaps the greatest agent of change altering coastal ecology (National Research Council, 2000; Howarth and others, 2000). Within the United States, a majority of estuaries have been determined to be moderately to severely impaired by eutrophication associated with increasing nutrient loads (Bricker and others, 1999).In coastal watersheds with soils of high hydraulic conductivity and permeable coastal sediments, ground water is a major route of transport of freshwater and its solutes from land to sea. Freshwater flowing downgradient from aquifers may either discharge from a seepage face near the intertidal zone, or flow directly into the sea as submarine ground-water discharge (SGD) (fig. 1). In the coastal aquifer, entrainment of saline pore water occurs prior to discharge, producing a gradient in ground-water salinity from land to sea, referred to as a subterranean estuary (Moore, 1999). In addition, processes including density-driven flow and tidal pumping create brackish and saline ground-water circulation. Hence, submarine ground-water discharge often consists of a substantial amount of recirculating seawater. Mixing of fresh and saline ground waters in the context of coastal sediments may alter the chemical composition of the discharging fluid. Depending on the biogeochemical setting, removal of fixed N due to processes leading to N2 (dinitrogen gas) production in the nearshore aquifer and subterranean estuary may significantly attenuate land-derived N loads; or, processes such as ion exchange and tidal pumping in the subterranean estuary may substantially accelerate the transport of both land-derived and sediment re-mineralized N to estuarine water columns.As emphasized by Burnett and others (2001, 2002), a fundamental problem in evaluating the importance of ground-water discharge in marine geochemical budgets is the difficulty of collecting

  20. OPTIMIZING LAYOUT OF URBAN STREET CANYON USING NUMERICAL SIMULATION COUPLING WITH MATHEMATICAL OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-song; ZHAO Bao-qing; YE Chun; YANG De-qing; HUANG Zhen

    2006-01-01

    Optimizing the layout of the urban street canyon to achieve the maximum environmental benefits should become a new idea for modern urban street design and planning. This paper aims to find out the optimized street canyon from a viewpoint of environmental protection by using the two-dimensional numerical simulation model with the turbulence model, coupling with the mathematical optimization method. The total pollutant concentration within and at top of the specific street canyons was taken as the objective function, and the height of one side of the canyon as the constrained condition. A nonlinearly improved constrained variable metric solver was used. The effect of the height of the leeward building and windward building on the integrated pollutant dispersion was studied to achieve the most beneficial configuration of the urban geometry. The optimization of layout for an asymmetrical street canyon was obtained. It is further found that the step-down street canyon with a large height difference is generally a good layout favoring to reduce the concentration accumulation in the street canyon.