Search results

Title: DSDP leg 55-the cold war and a test of the Hawaiian hot spot hypothesis,
Description: , , ,
Author: Greene

Title: Tectonic and glacial related seafloor geomorphology as possible demersal shelf rockfish habitat surrogates-Examples along the Alaskan convergent transform plate boundary,
Description: Seafloor geology plays a major role in habitat formation and can be used to remotely identify key habitats for some commercially important fish species. We have used a combination of side-scan sonar mosaics, multibeam bathymetry, and backscatter data, and in situ observations and video from the submersible Delta to investigate marine benthic habitats in the Eastern Gulf of Alaska. The intent of this paper is to review the results of previous marine benthic habitat mapping efforts completed by us along the transform plate boundary of Alaska and to present new information that show how volcanic, plutonic, and glacial submarine geomorphology can be used to identify potentially important discrete habitat areas. Demersal shelf rockfish, a seven-species management complex of nearshore rockfish, including yellow-eye rockfish (Sebastes ruberrimus), are found in rugged and highly rugose geomorphologic features. Eroded volcanic edifices, lava fields, and a pit crater, as well as a small shutterridge, deformed and differentially eroded sedimentary bedrock, and highly fractured and faulted plutonic rock outcrops are features that attract adult rockfish. Volcanic edifices that lie along the leaky (magma-conducting) Fairweather transform fault system intercept ocean currents, in turn producing upward eddies that bring nutrients to species residing on the features. We show that geologic processes such as fault deformation, volcanism, and glaciation are critical to the development of Essential Fish Habitats (EFH) for demersal shelf rockfish. Our work is the first attempt to determine a common geologic link between desperate commercial fishing areas in SE Alaska, USA, and to suggest how tectonic and glacial processes, including sea level rise and transgression, can be used to identify seafloor geologic characteristics as surrogates for marine groundfish habitats. © 2010 Elsevier Ltd., Cited By (since 1996):2, Ecology, Fish and Fisheries, CODEN: CSHRD, ,
Author: Greene, O'Connell, Brylinsky
Date: 2011-01-01T00:00:00Z

Title: Deepwater habitat and fish resources associated with the Big Creek Marine Ecological Reserve,
Description: Big Creek Marine Ecological Reserve (BCER), located off the central California coast, has been closed to fishing since January 1994. We used side scan sonar and an occupied submersible to collect baseline information on species-habitat relationships, density, and species and size composition of fish inside and outside BCER. Forty-three dives were made in the fall of 1997 and 1998, at depths of 20-250 m. From 142 video transects, we identified over 70,000 fish from 82 taxa, including 36 species of rockfish. About 93% of the 25,159 fish inside BCER were rockfishes representing at least 20 species. Young-of-the-year rockfishes dominated rock outcrops in 20-90 m depth inside and outside BCER. Four distinct fish assemblages were associated with (1) fine, smooth sediment in deep water; (2) bedrock with uneven surface in deep water; (3) sand waves and shell hash in shallow water; and (4) boulders and organic habitats on rock in shallow water. There were no significant differences in fish density among locations (inside and outside BCER) and depths or between years. Density was significantly higher in high-relief rock habitat than in low-relief soft and mixed sediments, regardless of location. There were no consistent patterns of larger fish inside compared to outside the protected area. We recommend development of a monitoring program to continue these surveys after increased time of protection and with increased assessment effort in the appropriate habitats of economically valuable species. In addition, extending the boundaries of BCER seaward would protect habitats and fish in water depths greater than 100 m., Cited By (since 1996):18, , , Downloaded from: http://calcofi.org/publications/ccreports.html (05 June 14).
Author: Yoklavich, Cailliet, Starr, Lea, De Marignac, Greene, Field
Date: 2002-01-01T00:00:00Z

Title: Tracking California seafloor seeps with bathymetry, backscatter and ROVs,
Description: The California (USA) margin includes two different tectonic regimes: subduction north of the Mendocino Triple Junction and translation south. Both margins include seeps, and their distribution can be inferred using seafloor bathymetry and backscatter as well as subsurface seismic data. Anomalous bathymetric and backscatter features related to fluid expulsion include headless submarine canyons, fault zones, anticlines, pockmarks, and mud volcanoes. Anomalous backscatter may be caused by authigenic carbonate (related to the bacterial oxidation of methane) or cold seep clams - both have an impedance and roughness that may be higher than the surrounding seafloor. Remote-operated vehicle (ROV) dives to such suspect seep sites document the presence of extensive authigenic carbonate, a really restricted cold seep communities, carpets of chemoautotrophic bacteria, and bubbling gas. Our operations in the Monterey Bay, on the translational California margin, and the Eel River basin, on the convergent margin, indicate that bathymetric and backscatter maps of the seafloor, if sufficiently high resolution, can be used to map seep sites, and that the distribution of such seeps can be used to constrain subsurface conduits of fluid flow. ROVs, due to their combination of visualization, propulsion, manipulation, sonar, and navigation, provide an excellent platform for ground-truthing, mapping, and sampling seafloor seeps. © 2002 Elsevier Science Ltd. All rights reserved., Cited By (since 1996):31, Rocks and cores, CODEN: CSHRD, ,
Author: Orange, Yun, Maher, Barry, Greene
Date: 2002-01-01T00:00:00Z

Title: Interpretation of side-scan sonar records for rockfish habitat analysis: Examples from Monterey Bay
Author: Yoklavich, Cailliet, Greene, Sullivan
Date: 1995-01-01T00:00:00Z

Title: Applying marine habitat data to fishery management on the US west coast,
Description: Recent experience in implementing legal requirements to designate and protect Essential Fish Habitat for groundfish off the US west coast is providing an opportunity to develop a feedback loop between science and policy for habitat- and ecosystem-based management that mirrors the traditional stock assessment/harvest management paradigm. The stock assessment/harvest management feedback loop dates back to the 1940s and has strongly influenced the development of the marine fishery management in frastructure and associated research programs. Assessment of marine habitat and the related establishment of regulatory policies by west coast fishery managers offer the potential for a similar feedback loop and the tailoring of research and infrastructure to improve the information available for decision-making., Cited By (since 1996):2, Fish and Fisheries, ,
Author: Copps, Yoklavich, Parkes, Wakefield, Bailey, Greene, Goldfinger, Burn
Date: 2007-01-01T00:00:00Z

Title: Gas geochemistry of a shallow submarine hydrothermal vent associated with the El Requesón fault zone, Bahía Concepción, Baja California Sur, México,
Description: We investigated hydrothermal gas venting associated with a coastal fault zone along the western margin of Bahía Concepción, B.C.S., México. Copious discharge of geothermal liquid (≈ 90 °C) and gas is occurring in the intertidal and shallow subtidal zones (to a depth of 13 m) through soft sediments and fractures in rocks along a ∼750 m linear trend generally sub-parallel to an onshore fault near Punta Santa Barbara. Hydrothermal activity shows negative correlation with tidal height; temperatures in the area of hydrothermal activity were up to 11.3 °C higher at low tide than at high tide (measured tidal range ≈ 120 cm). Gas samples were collected using SCUBA and analyzed for chemical composition and stable isotope values. The main components of the gas are N2 (≈ 53%; 534 mmol/mol), CO2 (≈ 43%; 435 mmol/mol), and CH4 (≈ 2.2%; 22 mmol/mol). The δ13C values of the CH4 (mean = - 34.3%), and the ratios of CH4 to C2H6 (mean = 89), indicate that the gas is thermogenic in origin. The carbon stable isotopes and the δ15N of the N2 in the gas (mean = 1.7%) suggest it may be partially derived from the thermal alteration of algal material in immature sedimentary organic matter. The He isotope ratios (3He/4He = 1.32 RA) indicate a significant mantle component (16.3%) in the gas. Here, we suggest the name El Requesón fault zone for the faults that likely formed as a result of extension in the region during the late Miocene, and are currently serving as conduits for the observed hydrothermal activity. © 2005 Elsevier B.V. All rights reserved., Cited By (since 1996):14, ,
Author: Forrest, Ledesma-Vázquez, Ussler III, Kulongoski, Hilton, Greene
Date: 2005-01-01T00:00:00Z

Title: Neotectonics of the offshore Oak Ridge fault near Ventura, southern California,
Description: The Oak Ridge fault is a large-offset, south-dipping reverse fault that forms the south boundary of the Ventura Basin in southern California. Previous research indicates that the Oak Ridge fault south of the town of Ventura has been inactive since 200-400 ka ago and that the fault tip is buried by ∼ 1 km of Quaternary sediment. However, very high-resolution and medium-resolution seismic reflection data presented here show a south-dipping fault, on strike with the Oak Ridge fault, that is truncated at 80 m depth by an unconformity that is probably at the base of late Pleistocene and Holocene sediment. Furthermore, if vertically aligned features in seismic reflection data are eroded remnants of fault scarps, then a subsidiary fault within the Oak Ridge system deforms the shallowest imaged sediment layers. We propose that this subsidiary fault has mainly left-slip offset. These observations of Holocene slip on the Oak Ridge fault system suggest that revision of the earthquake hazard for the densely populated Santa Clara River valley and the Oxnard coastal plain may be needed., Cited By (since 1996):6, CODEN: BSSAA, ,
Author: Fisher, Greene, Normark, Sliter
Date: 2005-01-01T00:00:00Z

Title: Preface,
Description: , , ,
Author: Greene, Todd
Date: 2007-01-01T00:00:00Z

Title: Neogene folding and faulting in southern Monterey Bay, Central California, USA,
Description: The goal of this study was to determine the Neogene structural history of southern Monterey Bay by mapping and correlating the shallow tectonic structures with previously identified deeper occurring structures. Side scan sonographs and Uniboom seismic reflection profiles collected in the region suggest that deformation associated with both compressional and transcurrent movement is occurring. Strike-slip movement between the North American and Pacific plates started as subduction ceased 21 Ma, creating the San Andreas fault system. Clockwise rotation of the Pacific plate occurred between 3.4 and 3.9 Ma causing orthogonal convergence between the two plates. This plate rotation is responsible for compressional Neogene structures along the central California coast. Structures exhibit transpressional tectonic characteristics such as thrust faulting, reverse faulting and asymmetrical folding. Folding and faulting are confined to middle Miocene and younger strata. Shallow Mesozoic granitic basement rocks either crop out or lie near the surface in most of the region and form a possible décollement along which the Miocene Monterey Formation has decoupled and been folded. Over 50% of the shallow faults strike normal (NE-SW) to the previously identified faults. Wrench fault tectonics complicated by compression, gradual uplift of the basement rocks, and a change in plate convergence direction are responsible for the observed structures in southern Monterey Bay. © 1993., Cited By (since 1996):3, CODEN: MAGEA, ,
Author: Gardner-Taggart, Greene, Ledbetter
Date: 1993-01-01T00:00:00Z

Title: High-resolution offshore 3D seismic geophysical studies of infrastructure geohazards
Description: As global earthquake activity continues to impact Communities, infrastructure, and lives, the necessity of better identification and characterization of seismic hazards becomes ever clearer. The tragic 2011 Tohoku, Japan earthquake and tsunami increased the attention on critical coastal infrastructure projects exposed to earthquake hazards. Offshore faults are more difficult to identify and characterize than onshore faults. While multibeam bathymetric surveys can reveal surface geomorphologic expression of faults, seismic source characterization studies also require investigations of fault geometry in the subsurface. High-resolution offshore geophysical surveys can be a highly valuable tool for these tasks. Specifically, the use of high-resolution three-dimensional seismic reflection investigations can provide some of the most precise information about fault location, activity, and geometry. This work will discuss how the latest generation of ultra-high-resolution/high-fidelity marine seismic systems can be used to investigate sub-sea faults, and how it applies to complex geologic hazards to coastal infrastructure.
Author: Ebuna, Mitchell, Hogan, Nishenko, Greene
Date: 2013-01-01T00:00:00Z

Title: The offshore Edgecumbe lava field, southeast Alaska: Geologic and habitat characterization of a commercial fishing ground,
Description: The application of geological and geophysical techniques in characterizing marine benthic habitats is increasing among fisheries biologists, marine geologists and fisheries managers. In this paper the results of a comprehensive sidescan sonar survey and seafloor observation/sampling program are applied to characterize fish habitats in a geologically complex volcanic region. Sidescan sonographs, interferometric bathymetric data, and in situ observations using the submersible Delta were used to identify and describe rockfish (Scorpaenidae, genus Sebastes) habitats of the continental shelf seaward of Kruzof Island in southeast Alaska. A major feature of this part of the continental shelf is the offshore Edgecumbe lava field. Mount Edgecumbe, a Holocene shield volcano, last erupted ca. 7000 years ago when it spread lava upon aflat glaciated surface and covered at least 600 km2 of seafloor and coastal plain west of Kruzof Island. The lava surface exhibits well-defined and little-eroded aa and pahoehoe lava, lobate lava fronts, compression ridges, collapsed lava tubes and volcanic cones that mark the distal end of Mount Edgecumbe's southwest rift. The presence of these features, along with the recovered vesicular basalt samplesftom the seafloor and the absence of pillow lava, suggests that the lava field was formed either terrestrially or in a shallow marine environment and, based on the depth of the outer limits of the field, has subsided at least 300 m. The offshore Edgecumbe lava field is defined as a marine benthic megahabitat that contains a variety of mesohabitats conducive to the habitation of rockfishes. The geologic features within this megahabilat give rise to mesohabitats that consist of pinnacles, caves, boulders, cobbles and pebbles, cracks and crevices, and ridges. The diversity and distribution of rockfish species appear to be related to mesohabitat type and depth, with the presence of suitably-sized refuge spaces a key to the occurrence of demersal rockfish. In boulder and ledge areas, such as those that occur around the pinnacles (volcanic cones), yelloweye rockfish (Sebastes ruberrimus), tiger rockfish (S. nigrocinctus), lingcod (Ophiodon elongatus), prowfish (Zaprora silenus) and sharpchin (S. zacentrus) are frequently present. On the pinnacles' crests where broken rock, ledges and platforms exist, the fish assemblage includes lingcod, quillback (S. maliger), Puget Sound (S. emphaeus) and young-of-the-year rockfishes. Similar assemblages of fish inhabit the caves and rubble-strewn floors of collapsed lava tubes. Elsewhere on the lavafield, rosethorn (S. helvomaculatus) and pygmy (S. wilsoni) rockfishes inhabit cracks and crevices in the lava flows and also occur in small boulder, cobble andpebble terranes. Compressional ridges with broken and angular boulders and slabs are frequented by yelloweye and tiger rockfishes. Pelagic rockfishes such as dusky (S. ciliattis), black (S. melanops) and yellowtail (S. flavidus) are found in schools and individually in areas of high relief, such as ridges and angular outcrops of rocks, and schools of pygmy rockfish and unidentified juvenile rockfishes inhabit most mesohabitats from pinnacles to cobble fields., Rocks & Cores, ,
Author: Greene, O'Connell, Wakefield, Brylinsky
Date: 2007-01-01T00:00:00Z

Title: Submarine landslides in the Santa Barbara Channel as potential tsunami sources,
Description: Recent investigations using the Monterey Bay Aquarium Research Institutes (MBARI) Remotely Operated Vehicles (ROVs) "Ventana" and "Tiburon" and interpretation of MBARI's EM 300 30 kHz multibeam bathymetric data show that the northern flank of the Santa Barbara Basin has experienced massive slope failures. Of particular concern is the large (130 km2) Goleta landslide complex located off Coal Oil Point near the town of Goleta, that measures 14.6-km long extending from a depth of 90 m to nearly 574 m deep and is 10.5 km wide. We estimate that approximately 1.75 km3 has been displaced by this slide during the Holocene. This feature is a complex compound submarine landslide that contains both surfical slump blocks and mud flows in three distinct segments. Each segment is composed of a distinct head scarp, down-dropped head block and a slide debris lobe. The debris lobes exhibit hummocky topography in the central areas that appear to result from compression during down slope movement. The toes of the western and eastern lobes are well defined in the multibeam image, whereas the toe of the central lobe is less distinct. Continuous seismic reflection profiles show that many buried slide debris lobes exist and comparison of the deformed reflectors with ODP Drill Site 149, Hole 893 suggest that at least 200 000 years of failure have occurred in the area (Fisher et al., 2005a). Based on our interpretation of the multibeam bathymetry and seismic reflection profiles we modeled the potential tsunami that may have been produced from one of the three surfical lobes of the Goleta slide. This model shows that a 10 m high wave could have run ashore along the cliffs of the Goleta shoreline. Several other smaller (2 km2 and 4 km2) slides are located on the northern flank of the Santa Barbara Basin, both to the west and east of Goleta slide and on the Concepcion fan along the western flank of the basin. One slide, named the Gaviota slide, is 3.8 km2, 2.6 km long and 1.7 km wide. A distinct narrow scar extends from near the eastern head wall of this slide for over 2 km eastward toward the Goleta slide and may represent either an incipient failure or a remnant of a previous failure. Push cores collected within the main head scar of this slide consisted of hydrogen sulfide bearing mud, possibly suggesting active fluid seepage and a vibra-core penetrated ∼50 cm of recent sediment overlying colluvium or landslide debris confirming the age of ∼300 years as proposed by Lee et al. (2004). However, no seeps or indications of recent movement were observed during our ROV investigation within this narrow head scar indicating that seafloor in the scar is draped with mud. © 2006 Author(s). This work is licensed under a Creative Commons License., Cited By (since 1996):19, Oceanography, , , Downloaded from: www.nat-hazards-earth-syst-sci.net/6/63/2006/nhess-6-63-2006.pdf (16 June 2014).
Author: Greene, Murai, Watts, Maher, Fisher, Paull, Eichhubl
Date: 2006-01-01T00:00:00Z

Title: Estimating rocky seafloor extent on the Southern California continental shelf,
Description: High-resolution sonar data are necessary to map bottom substrate for habitat studies but are lacking over much of the continental shelf. With such data, areas covered by sediment can be distinguished from bedrock areas with an accuracy of ̃90%. Without these data, the extent of sediment as thick as 10 m cannot be resolved, and estimates of the extent of rocky seafloor are exaggerated. A study area north of Anacapa Island in Southern California interpreted as a large rocky area after mapping with low-resolution seismic systems was found to have exposed rocky bottom in only 10% of the area when mapped with high-resolution, side-scan sonar. The area of rock was estimated using video-supervised, sonar-image classification of textural derivatives of the data calculated from gray-level co-occurrence matrices. The classification of soft bottom was found to be ̃90% accurate using an independent data set, derived from seafloor sampling records. Two general types of rock exposure are observed-sparse linear outcrops of layered sedimentary rocks and more massive, rounded outcrop areas of volcanic rocks. The percentage of exposed rock in volcanic areas exceeded that in sedimentary rock areas by a factor of 5 in the study area north of Anacapa Island. South of Point Arguello, 80% of the shelf seafloor is underlain by sedimentary rock units. The percentage of area that is exposed, rocky-reef habitat may be greater in other areas of coastal seafloor if the bedrock is predominantly volcanic. © 2009 The Geological Society of America., Oceanography, Rocks and Cores, ,
Author: Cochrane, Greene
Date: 2009-01-01T00:00:00Z

Title: Physiography of the Monterey Bay National Marine Sanctuary and implications about continental margin development,
Description: Combined EM-300 multibeam bathymetric data and satellite photography reveal the physiography of the continental margin between 35°50′ and 37°03′N and from the shoreline west of 122°40′ and 122°37′W, which includes Monterey Bay, in a previously unprecedented detail. Patterns in these images clearly reveal the processes that are actively influencing the current geomorphology of the Monterey Bay region, including the Monterey Bay National Marine Sanctuary (MBNMS). Our data indicates that seafloor physiography within the MBNMS results from plate margin tectonic deformation, including uplift and erosion along structural lineaments, and from fluid flow. Mass wasting is the dominant process active within the Ascension-Monterey and Sur-Partington submarine canyon systems and along the lower slopes. Meanders, slump dams, and constricted channels within the submarine canyons, especially within Monterey Canyon, slow and interrupt down-canyon sediment transport. We have identified for the first time thin sediment flows, rotational slumps, rills, depressions that may be associated with pipes, and other fluid-induced features we call 'scallops' off the Ascension slope, and suggest that fluid flow has sculptured the seafloor morphologies here. These unusual seafloor morphologies are similar to morphologies found in terrestrial areas modified by groundwater flow. © 2002 Elsevier Science B.V. All rights reserved., Cited By (since 1996):57, CODEN: MAGEA, ,
Author: Greene, Maher, Paull
Date: 2002-01-01T00:00:00Z

Title: The effects of dredge material disposal on marine benthic habitats of the Santa Cruz Bight, California,
Description: In March, 2001, the Santa Cruz Small Craft Harbor was permitted to dredge some mixed sand and mud (silt and clay) from the upper harbour onto the surf zone at Twin Lakes Beach. A monitoring program was conducted to determine if any sedimentary changes occurred in nearshore benthic habitats of the Santa Cruz Bight during the experimental dredging period. To map the spatial distribution of benthic habitats at risk, and to determine if sedimentary changes occurred due to harbour dredging, multibeam bathymetry surveys and sediment sample data were collected before, during and after the dredging. These data were analyzed and interpreted into two benthic habitat maps and compared using a new GIS mapping technique to quantify areas of sediment erosion and deposition on the Santa Cruz Bight seafloor. The integration and analyses of the data collected over the monitoring period indicates that the muddy upper harbour sediment did not significantly disturb or change the grainsize characteristics of nearshore marine benthic habitats in the Santa Cruz Bight., Cited By (since 1996):1, Rocks & Cores, ,
Author: Watt, Greene
Date: 2007-01-01T00:00:00Z

Title: Mapping marine habitats with high resolution sidescan sonar,
Description: The application of marine geophysics and GIS techniques to the characterization of benthic habitats has increased the ability of fisheries managers to assess distribution and habitat types beyond common practices. We report upon a 150 kHz sidescan sonar survey offshore of Kruzof Island, Alaska undertaken to characterize rockfish (Sebastes) habitat. Using GIS, MapGrafix and Map*Factory we determined the percentage of seafloor cover that exists in our survey area. Bathymetry in the study area was determined with sidescan interferometry. All XYZ data were gridded using Surfer and plotted in shaded relief, bathymetric contour, and 3-dimensional formats. Contoured bathymetry was used as an overlay in MapGrafix. Small sub-areas were extracted from the bathymetric data for closer study, and gridded in Surfer. Areas of the mosaic where backscatter patterns were not distinct were verified with hand samples and video collected with the submersible Delta. The use of submersibles for verification of interpreted lithologies and surface textures enables a high degree of accuracy for the interpretations. Lithotypes were lumped into larger groups based on morphology and fish associations with different morphologies verified using the submersible. The accuracy of digital maps from high-resolution sidescan sonar data allows a close quantification of the areal extents of these important features, directing the application of management strategies to critical areas., Cited By (since 1996):24, Oceanography, CODEN: OCACD, ,
Author: McRea Jr., Greene, O'Connell, Wakefield
Date: 1999-01-01T00:00:00Z

Title: A geophysical approach to classifying marine benthic habitats: Monterey Bay as a model
Author: Greene, Yoklavich, Sullivan, Cailliet
Date: 1995-01-01T00:00:00Z

Title: A classification scheme for deep seafloor habitats,
Description: Cited By (since 1996):139, , , ,
Author: Greene, Yoklavich, Starr, O'Connell, Wakefield, Sullivan, McRea Jr., Cailliet
Date: 1999-01-01T00:00:00Z

Title: The use of geophysical survey data in fisheries management: A case history from southeast Alaska,
Description: The Alaska Department of Fish and Game (ADF&G) has been conducting a habitat-based stock assessment of yellow-eye rockfish (Sebastes niberrimus) in the eastern Gutf of Alaska since 1989. Yelloweye rockfish occur in rugged rocky terrain on the continental shelf, and are an important commercial species taken in directed, and by-catch bottom-long-line fisheries. The biomass of yelloweye rockfish is derived as the product of density, average weight, and area of habitat. Density is based on line-transect surveys conducted from an occupied submersible. Area estimates of yelloweye habitat are based on the probable distribution of rocky habitat inshore of the 200 m bathymetric contour. Information used to identify rocky habitat include sidescan and multibeam sonar data (ground-truthed using direct observation from the submersible) and commercial logbook data from the directed fishery. In areas with multibeam or sidescan sonar data, the area of rockfish habitat is delineated based on defined substrate types within the mapped area. For areas without these geophysical datasets, position data from commercial fishery logbooks is used. In areas with both logbook and geophysical data, areas of habitat generally overlap but are not identical. Logbook data is mandatory, but self-reported, and may not always be accurate. Geophysical surveys reveal the extent of all rocky habitats, while fishermen target areas of prime habitat. Limiting of surveys to prime habitat may result in inaccurate stock assessments because density may remain stable in the prime habitat, while declining in surrounding habitats. By assessing fish densities in all rockfish habitats, as delineated by geophysical surveys, a better indicator of stock condition is possible. Further unlike logbook data, multibeam data allows us to clearly define boundaries of prime habitats, relevant to management decisions regarding marine reserves or to definition of management units., , ,
Author: O'Connell, Brylinsky, Greene
Date: 2007-01-01T00:00:00Z

Title: A classification scheme for deep seafloor habitats,
Description: A standard, universally useful classification scheme for deepwater habitats needs to be established so that descriptions of these habitats can be accurately and efficiently applied among scientific disciplines In recent years many marine benthic habitats in deep water have been described using geophysical and biological data. These descriptions can vary from one investigator to another, which makes it difficult to compare habitats and associated biological assemblages among geographic regions. Using geophysical data collected with a variety of remote sensor systems and in situ biological and geologic observations, we have constructed a classification scheme that can be used in describing marine benthic habitats in deep water., Cited By (since 1996):117, Rocks and Cores, CODEN: OCACD, ,
Author: Greene, Yoklavich, Starr, O'Connell, Wakefield, Sullivan, McRea Jr., Cailliet
Date: 1999-01-01T00:00:00Z

Title: Net dextral slip, Neogene San Gregorio-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications,
Description: Reinterpretation of onshore and offshore geologic mapping, examination of a key offshore well core, and revision of cross-fault ties indicate Neogene dextral strike slip of 156 ± 4 km along the San Gregorio-Hosgri fault zone, a major strand of the San Andreas transform system in coastal California. Delineating the full course of the fault, defining net slip across it, and showing its relationship to other major tectonic features of central California helps clarify the evolution of the San Andreas system. San Gregorio-Hosgri slip rates over time are not well constrained, but were greater than at present during early phases of strike slip following fault initiation in late Miocene time. Strike slip took place southward along the California coast from the western flank of the San Francisco Peninsula to the Hosgri fault in the offshore Santa Maria basin without significant reduction by transfer of strike slip into the central California Coast Ranges. Onshore coastal segments of the San Gregorio-Hosgri fault include the Seal Cove and San Gregorio faults on the San Francisco Peninsula, and the Sur and San Simeon fault zones along the flank of the Santa Lucia Range. Key cross-fault ties include porphyritic granodiorite and overlying Eocene strata exposed at Point Reyes and at Point Lobos, the Nacimiento fault contact between Salin- ian basement rocks and the Franciscan Complex offshore within the outer Santa Cruz basin and near Esalen on the flank of the Santa Lucia Range, Upper Cretaceous (Cam- panian) turbidites of the Pigeon Point Formation on the San Francisco Peninsula and the Atascadero Formation in the southern Santa Lucia Range, assemblages of Franciscan rocks exposed at Point Sur and at Point San Luis, and a lithic assemblage of Meso- zoic rocks and their Tertiary cover exposed near Point San Simeon and at Point Sal, as restored for intrabasinal deformation within the onshore Santa Maria basin. Slivering of the Salinian block by San Gregorio-Hosgri displacements elongated its northern end and offset its western margin delineated by the older Nacimiento fault, a sinistral strike-slip fault of latest Cretaceous to Paleocene age. North of its juncture with the San Andreas fault, dextral slip along the San Gregorio-Hosgri fault augments net San Andreas displacement. Alternate restorations of the Gualala block imply that nearly half the net San Gregorio-Hosgri slip was accommodated along the offshore Gualala fault strand lying west of the Gualala block, which is bounded on the east by the current master trace of the San Andreas fault. With San Andreas and San Gregorio-Hosgri slip restored, there remains an unresolved proto-San Andreas mismatch of ~100 km between the offset northern end of the Salinian block and the southern end of the Sierran-Tehachapi block. On the south, San Gregorio-Hosgri strike slip is transposed into crustal shortening associated with vertical-axis tectonic rotation of fault-bounded crustal panels that form the western Transverse Ranges, and with kinematically linked deformation within the adjacent Santa Maria basin. The San Gregorio-Hosgri fault serves as the principal link between transrotation in the western Transverse Ranges and strike slip within the San Andreas transform system of central California. © 2005 Geological Society of America., Cited By (since 1996):2, ,
Author: Dickinson, Ducea, Rosenberg, Greene, Graham, Clark, Weber, Kidder, Brabb, Ernst
Date: 2005-01-01T00:00:00Z

Title: Habitat associations of deep-water rockfishes in a submarine canyon: An example of a natural refuge,
Description: A multidisciplinary assessment of benthic rockfishes (genus Sebastes) and associated habitats in deep water was conducted in Soquel Submarine Canyon, Monterey Bay, California. Rock habitats at depths to 300 m were identified by using bathymetric and side-scan sonar imaging, verified by visual observations from a manned submersible, mapped and quantified. Species composition, abundance, size, and habitat specificity of fishes were determined by using a video camera and parallel laser system along transects made by a submersible. We counted 6208 nonschooling fishes representing at least 52 species from 83 10-min strip transects that covered an estimated 33,754 m 2. Rockfishes represented 77% of the total number of individuals, and included a minimum of 24 species. Six distinct habitat guilds of fishes were manifest from habitat-based clustering analysis: small species were associated with mud and cobble substrata of low relief, and larger species of rockfishes were associated with high-relief structures such as vertical rock walls, ridges, and boulder fields. There was remarkable concordance between some of the guilds identified in Soquel Canyon and the results of other habitat-specific assessments of fishes along the west coast of the United States from central California to Alaska. These generalities are valuable in predicting community structure and evaluating changes to that structure, as well as in applying small-scale species-habitat relationships to broader-scale fishery resource surveys. Additionally, establishment of these groups is critical when incorporating the concept of essential fish habitat (EFH), and negative impacts to it, into the management of fisheries in relatively deep water, as required by the Sustainable Fisheries Act of 1996. High numbers of large rockfishes (e.g. Sebastes chlorostictus, S. levis, S. rosenbblatti, and S. ruberrimus) were locally associated with rock ledges, caves, and overhangs at sites having little or no evidence of fishing activity. Abundance and size of several species were lower at fished than at unfished sites. We suggest that rock outcrops of high relief interspersed with mud in deep water of narrow submarine canyons are less accessible to fishing activities and thereby can provide natural refuge for economically important fishes, as exemplified in Soquel Canyon., Cited By (since 1996):106, CODEN: FSYBA, ,
Author: Yoklavich, Greene, Cailliet, Sullivan, Lea, Love
Date: 2000-01-01T00:00:00Z

Title: Erratum: Physiography of an active transpressive margin basin: High-resolution bathymetry of the Santa Barbara basin, Southern California continental borderland,
Description: Oceanography, CODEN: MAGEA, , ,
Author: Eichhubl, Greene, Maher
Date: 2002-01-01T00:00:00Z

Title: Structural control of fluid flow: Offshore fluid seepage in the Santa Barbara Basin, California,
Description: Evidence of active and dormant fluid seepage in the Santa Barbara Basin is observed as active venting of gas and oil, bacterial mats, precipitates of authigenic carbonate, and mud and tar volcanoes. Fluid seepage occurs preferentially in the proximity to faults and faulted anticlines, and to slump scarps. Seepage next to faults and anticlines indicates that hydrocarbon migration and pore fluid expulsion is controlled structurally, with faults acting as preferred conduits for fluid flow across units of low matrix permeability. (C) 2000 Elsevier Science B.V. All rights reserved., Cited By (since 1996):38, Oceanography, CODEN: JGCEA, ,
Author: Eichhubl, Greene, Naehr, Maher
Date: 2000-01-01T00:00:00Z

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