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At least 163 records · Page 9Linked to original sources
USGS2010

Oblique Aerial Photography of the Arctic Coast of Alaska, Cape Sabine to Milne Point, July 16-19, 2009

The Arctic Coastal Plain of northern Alaska, an area of strategic economic importance to the United States, is home to remote Native American communities and encompasses unique habitats of global significance. Coastal erosion along the Arctic coast is chronic and widespread; recent evidence suggests that erosion rates are among the highest in the world (as high as ~16 m/yr) and may be accelerating. Coastal erosion adversely impacts energy-related infrastructure, natural shoreline habitats, and Native American communities. Climate change is thought to be a key component of recent environmental changes in the Arctic. Reduced sea-ice cover in the Arctic Ocean is one of the probable mechanisms responsible for increasing coastal exposure to wave attack and the resulting increase in erosion. Extended periods of permafrost melting and associated decreases in bluff cohesion and stability are another possible source of the increase in erosion. Several studies of selected areas on the Alaska coast document past shoreline positions and coastal change, but none have examined the entire North coast systematically. Results from these studies indicate high rates of coastal retreat that vary spatially along the coast. To address the need for a comprehensive and regionally consistent evaluation of shoreline change along the North coast of Alaska, the U.S. Geological Survey (USGS), as part of their Coastal and Marine Geology Program's (CMGP) National Assessment of Shoreline Change Study, is evaluating shoreline change from Peard Bay to the United States/Canadian border, using historical maps and photography and a standardized methodology that is consistent with other shoreline-change studies along the Nation's coastlines (see, for example, http://coastal.er.usgs.gov/shoreline-change/, last accessed February 12, 2010). This is the second in a series of publications containing photographs collected during reconnaissance surveys conducted in support of the National Assessment of Shoreline Change Study. An accompanying ESRI ArcGIS shape file (and plaintext copy) indicates the position of the aircraft and time when each photograph was taken. The USGS-CMGP Field Activity ID for the survey is A-5-09-AK, and more information on the survey and how to view the photographs using Google Earth software is available online at http://walrus.wr.usgs.gov/infobank/a/a509ak/html/a-5-09-ak.photos.kmz (last accessed February 12, 2010). The initial report ?Oblique aerial photography of the Arctic coast of Alaska, Nulavik to Demarcation Point, August 7-10, 2006? is available online at http://pubs.usgs.gov/ds/436/, and the associated Google Earth .kmz file is available at http://walrus.wr.usgs.gov/infobank/a/a106ak/html/a-1-06-ak.photos.kmz (last accessed February 12, 2010).

Data Series↗
USGS2011

Lidar vegetation mapping in national parks: Gulf Coast Network

Airborne lidar (Light Detection and Ranging) is an active remote sensing technique used to collect accurate elevation data over large areas. Lidar provides an extremely high level of regional topographic detail, which makes this technology an essential component of U.S. Geological Survey (USGS) science strategy. The USGS Coastal and Marine Geology Program (CMGP) has collaborated with the National Aeronautics and Space Administration (NASA) and the National Park Service (NPS) to acquire dense topographic lidar data in a variety of coastal environments.

Louisiana↗
USGS2015

Offshore geology and geomorphology from Point Piedras Blancas to Pismo Beach, San Luis Obispo County, California

Marine geology and geomorphology were mapped along the continental shelf and upper slope between Point Piedras Blancas and Pismo Beach, California. The map area is divided into the following three (smaller) map areas, listed from north to south: San Simeon, Morro Bay, and Point San Luis. Each smaller map area consists of a geologic map and the corresponding geophysical data that support the geologic mapping. Each geophysical data sheet includes shaded-relief multibeam bathymetry, seismic-reflection-survey tracklines, and residual magnetic anomalies, as well as a smaller version of the geologic map for reference. Offshore geologic units were delineated on the basis of integrated analysis of adjacent onshore geology, seafloor-sediment and rock samples, multibeam bathymetry and backscatter imagery, magnetic data, and high-resolution seismic-reflection profiles. Although the geologic maps are presented here at 1:35,000 scale, map interpretation was conducted at scales of between 1:6,000 and 1:12,000. Sea level was approximately 120 to 130 m lower during the Last Glacial Maximum (about 21 ka). This approximate depth corresponds to the modern shelf break, a lateral change from the gently dipping (0.8° to 1.0°) outer shelf to the slightly more steeply dipping (about 1.5° to 2.5°) upper slope in the central and northern parts of the map area. South of Point San Luis in San Luis Bay, deltaic deposits offshore of the mouth of the Santa Maria River (11 km south of the map area) have prograded across the shelf break and now form a continuous low-angle (about 0.8°) ramp that extends to water depths of more than 160 m. The shelf break defines the landward boundary of slope deposits. North of Estero Bay, the shelf break is characterized by a distinctly sharp slope break that is mapped as a landslide headscarp above landslide deposits. Multibeam imagery and seismic-reflection profiles across this part of the shelf break show evidence of slope failure, such as slumping, sliding, and soft-sediment deformation, along the entire length of the scarp. Notably, this shelf-break scarp corresponds to a west splay of the Hosgri Fault that dies out just north of the scarp, suggesting that faulting is controlling the location (and instability) of the shelf break in this area.

California↗
USGS2010

Swath Bathymetry Surveys of the Monterey Bay Area from Point Ano Nuevo to Moss Landing, San Mateo, Santa Cruz, and Monterey Counties, California

This report describes swath bathymetry and backscatter data acquired by the U.S. Geological Survey on the continental shelf within the Monterey Bay National Marine Sanctuary between Point Año Nuevo and Moss Landing, in San Mateo, Santa Cruz, and Monterey Counties, Calif. The survey was done for the California Seafloor Mapping Program (CSMP) , in field activities S-7-09-MB and S-10-09-MB , by the Western Coastal and Marine Geology (WCMG) Team of the U.S. Geological Survey (USGS). The data were acquired in two separate surveys: (1) between August 13, 2009 and September 3, 2009, personnel from WCMG completed field activity S-7-09-MB, from Point Año Nuevo south to Table Rock, as well as a block west of Soquel Canyon; (2) between October 12 and December 16, 2009, WCMG conducted field activity S-10-09-MB, surveying between Table Rock and Moss Landing.

Data Series↗
USGS2001

Hawaii Beach Monitoring Program: Profile locations

Coastal erosion is widespread and locally severe in Hawaii and other low-latitude areas. Typical erosion rates in Hawaii are in the range of 15 to 30 cm/yr (0.5 to 1 ft/yr; Hwang, 1981; Sea Engineering, Inc., 1988; Makai Ocean Engineering, Inc. and Sea Engineering, Inc.,1991). Recent studies on Oahu (Fletcher et al., 1997; Coyne et al., 1996) have shown that nearly 24%, or 27.5 km (17.1 mi) of an original 115 km (71.6 mi) of sandy shoreline (1940's) has been either significantly narrowed (17.2 km; 10.7 mi) or lost (10.3 km; 6.4 mi). Nearly one-quarter of the islands' beaches have been significantly degraded over the last half-century and all shorelines have been affected to some degree. Oahu shorelines are by far the most studied, however, beach loss has been identified on the other islands as well, with nearly 13 km (8 mi) of beach likely lost due to shoreline hardening on Maui (Makai Engineering, Inc. and Sea Engineering, Inc., 1991). Causes of coastal erosion and beach loss in Hawaii are numerous but, unfortunately, poorly understood and rarely quantified. Construction of shoreline protection structures limits coastal land loss, but does not alleviate beach loss and may actually accelerate the problem by prohibiting sediment deposition in front of the structures. Other factors contributing to beach loss include: a) reduced sediment supply; b) large storms; and, c) sea-level rise. Reduction in sand supply, either from landward or seaward (primarily reef) sources, can have a myriad of causes. Obvious causes such as beach sand mining and emplacement of structures that interrupt natural sediment transport pathways or prevent access to backbeach sand deposits, remove sediment from the active littoral system. More complex issues of sediment supply can be related to reef health and carbonate production which, in turn, may be linked to changes in water quality. Second, the accumulated effect of large storms is to transport sediment beyond the littoral system. Third, rising sea level leads to a natural landward migration of the shoreline. Dramatic examples of coastal erosion, such as houses and roads falling into the sea, are rare in Hawaii, but the impact of erosion is still very serious. The signs of erosion are much more subtle and typically start as a "temporary" hardening structure designed to mitigate an immediate problem which, eventually, results in a proliferation of structures along a stretch of coast. The natural ability of the sandy shoreline to respond to changes in wave climate is lost. The overall goals of this study are to document the coastal erosion history in Hawaii, determine the causal factors of that erosion, provide high-quality data for other "end-users" in applied studies (i.e. coastal engineers, planners, and managers), and increase our general understanding of low-latitude coastal geologic development. This project involves close cooperation between the USGS Coastal and Marine Geology Program and the University of Hawaii.

Hawai'i↗
USGS2014

Hydrologic enforcement of lidar DEMs

Hydrologic-enforcement (hydro-enforcement) of light detection and ranging (lidar)-derived digital elevation models (DEMs) modifies the elevations of artificial impediments (such as road fills or railroad grades) to simulate how man-made drainage structures such as culverts or bridges allow continuous downslope flow. Lidar-derived DEMs contain an extremely high level of topographic detail; thus, hydro-enforced lidar-derived DEMs are essential to the U.S. Geological Survey (USGS) for complex modeling of riverine flow. The USGS Coastal and Marine Geology Program (CMGP) is integrating hydro-enforced lidar-derived DEMs (land elevation) and lidar-derived bathymetry (water depth) to enhance storm surge modeling in vulnerable coastal zones.

Fact Sheet↗
USGS2002

Geological framework data from Long Island Sound, 1981-1990: A digital data release

Introduction Since 1980 the Coastal and Marine Geology Program of the U.S. Geological Survey and Connecticut Department of Environmental Protection have conducted a joint program of cooperative geologic research in Long Island Sound and its vicinity. As part of this program, a highly successful regional-scale study of the geologic framework was completed. Reconnaissance high-resolution seismic reflection data were collected and used to establish the basic stratigraphy within the Sound and to map the major geologic units; field verification of the geologic interpretations of the seismic profiles was primarily accomplished with vibratory cores. These interpretations were in turn used to produce basin-wide syntheses of the late Quaternary depositional history. Unfortunately, the original seismic records and core logs were generated only in analog form. These unique paper documents, which are still under demand for industrial applications and academic research, are fragile and have become ragged from frequent use. The purpose of this report is to preserve these data by converting the seismic profiles, core descriptions, and ancillary reports into digital form, and to organize these files into a product that can be more readily accessed and disseminated. Not all of the existing high-resolution seismic-reflection surveys, collected in Long Island Sound through cooperatives with the U.S. Geological Survey and the Connecticut Department of Environmental Protection, have been incorporated into this report. These surveys, whose records are still in need of preprocessing and annotation, generally cover smaller areas along the Connecticut coast and were originally intended to provide additional detail to the larger, more regional data sets presented herein. The digital release of the omitted data sets is planned as part of a future product.

Connecticut, New York↗
USGS2005

USGS east-coast sediment analysis: Procedures, database, and GIS data

Preface Sediments off the eastern United States vary markedly in texture - the size, shape, and arrangement of their grains. For descriptive purposes, however, it is typically most useful to classify these sediments according to their grain-size distributions. Starting in 1962, the U.S. Geological Survey (USGS) and the Woods Hole Oceanographic Institution (WHOI) began a joint program to study the marine geology of the continental margin off the Atlantic coast of the United States. As part of this program and numerous subsequent projects, thousands of sediment samples were collected and analyzed for grain size. This report describes the field methods used to collect marine sediment sample, the laboratory methods used to determine and characterize grain-size distributions, and presents these data in several formats that can be readily employed by interested parties. By entering data into usSEABED, a large data compilation and mining program (Reid and others, 2005), this study also responds to an increasing demand for regional information on sea-floor sedimentary character with applications to aggregate resources suitable for beach nourishment and coastal restoration, benthic habitat mapping, and sediment transport studies. To this end, the report is divided into three sections: the first discusses field and laboratory procedures, the second contains the grain-size data, and the third provides a GIS data catalog that lists the available data layers and FGDC-compliant metadata.

Open-File Report↗
USGS2011

The ANTOSTRAT legacy: Science collaboration and international transparency in potential marine mineral resource exploitation of Antarctica

The Antarctic Offshore Stratigraphy project (ANTOSTRAT; 1989–2002) was an extremely successful collaboration in international marine geological science that also lifted the perceived “veil of secrecy” from studies of potential exploitation of Antarctic marine mineral resources. The project laid the groundwork for circum-Antarctic seismic, drilling, and rock coring programs designed to decipher Antarctica’s tectonic, stratigraphic, and climate histories. In 2002, ANTOSTRAT evolved into the equally successful and currently active Antarctic Climate Evolution research program. The need for, and evolution of, ANTOSTRAT was based on two simple tenets within SCAR and the Antarctic Treaty: international science collaboration and open access to data. The ANTOSTRAT project may be a helpful analog for other regions of strong international science and geopolitical interests, such as the Arctic. This is the ANTOSTRAT story.

Book chapter↗
USGS1981

Samples from the United States eastern continental margin collected by the U.S. Geological Survey

As part of the National Geophysical and Solar-Terrestrial Data Center's (NGSDC's) project to maintain a computer-accessed list of marine geological samples, the U.S. Geological Survey has inventoried 3,949 samples from the continental margin of the Eastern United States (Fig. 1). Most (3,868) of these samples are grab and dredge samples collected by the U.S. Geological Survey in an earlier cooperative program with the Woods Hole Oceanographic Institution (WHOI) and are stored at WHOI. Samples collected since 1974 are stored by the U.S. Geological Survey. This more recent collection is made up of 3,815.5 m of rotary-drilled cores collected at 19 stations in 1976 by the drill ship GLOMAR CONCEPTION, 243.8 m of piston cores and 38.3 m of gravity cores collected during the 1979 and 1980 cruises of the R/V ENDEAVOR, and &grab samples collected by the M/V STATE ARROW in 1978.

United States eastern continental margin↗
USGS2006

Geologic interpretation and multibeam bathymetry of the sea floor in southeastern Long Island Sound

Digital terrain models (DTMs) produced from multibeam echosounder (MBES) bathymetric data provide valuable base maps for marine geological interpretations (e.g. Todd and others, 1999; Mosher and Thomson, 2002; ten Brink and others, 2004; Poppe and others, 2006a,b). These maps help define the geological variability of the sea floor (one of the primary controls of benthic habitat diversity); improve our understanding of the processes that control the distribution and transport of bottom sediments, the distribution of benthic habitats and associated infaunal community structures; and provide a detailed framework for future research, monitoring, and management activities. The bathymetric survey interpreted herein (National Oceanic and Atmospheric Administration (NOAA) survey H11255) covers roughly 95 km? of sea floor in southeastern Long Island Sound (fig. 1). This bathymetry has been examined in relation to seismic reflection data collected concurrently, as well as archived seismic profiles acquired as part of a long-standing geologic mapping partnership between the State of Connecticut and the U.S. Geological Survey (USGS). The objective of this work was to use these geophysical data sets to interpret geomorphological attributes of the sea floor in terms of the Quaternary geologic history and modern sedimentary processes within Long Island Sound.

Open-File Report↗
USGS2007

Geologic interpretation and multibeam bathymetry of the sea floor in the vicinity of the Race, eastern Long Island Sound

Digital terrain models (DTMs) produced from multibeam bathymetric data provide valuable base maps for marine geological interpretations (Todd and others, 1999; Mosher and Thomson, 2002; ten Brink and others, 2004; Poppe and others, 2006a, b, c, d). These maps help define the geological variability of the sea floor (one of the primary controls of benthic habitat diversity), improve our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures, and provide a detailed framework for future research, monitoring, and management activities. The bathymetric survey interpreted herein (National Oceanic and Atmospheric Administration (NOAA) survey H11250) covers roughly 94 km² of sea floor in an area where a depression along the Orient Point-Fishers Island segment of the Harbor Hill-Roanoke Point-Charlestown Moraine forms the Race, the eastern opening to Long Island Sound. The Race also divides easternmost Long Island Sound from northwestern Block Island Sound (fig. 1). This bathymetry has been examined in relation to seismic reflection data collected concurrently, as well as archived seismic profiles acquired as part of a long-standing geologic mapping partnership between the State of Connecticut and the U.S. Geological Survey (USGS). The objective of this work was to use these acoustic data sets to interpret geomorphological attributes of the sea floor, and to use these interpretations to better understand the Quaternary geologic history and modern sedimentary processes.

Connecticut;New York↗
USGS2018

The U.S. Geological Survey’s Gas Hydrates Project

The Gas Hydrates Project at the U.S. Geological Survey (USGS) focuses on the study of methane hydrates in natural environments. The project is a collaboration between the USGS Energy Resources and the USGS Coastal and Marine Geology Programs and works closely with other U.S. Federal agencies, some State governments, outside research organizations, and international partners. The USGS studies the formation and distribution of gas hydrates in nature, the potential of hydrates as an energy resource, and the interaction between methane hydrates and the environment. The USGS Gas Hydrates Project carries out field programs and participates in drilling expeditions to study marine and terrestrial gas hydrates. USGS scientists also acquire new geophysical data and sample sediments, the water column, and the atmosphere in areas where gas hydrates occur. In addition, project personnel analyze datasets provided by partners and manage unique laboratories that supply state-of-the-art analytical capabilities to advance national and international priorities related to gas hydrates.

Fact Sheet↗
USGS2013

Shallow geology, seafloor texture, and physiographic zones of the Inner Continental Shelf from Nahant to northern Cape Cod Bay, Massachusetts

The Massachusetts inner continental shelf between Nahant and northern Cape Cod Bay has been profoundly affected by the occupation and retreat of glacial ice sheets and relative sea-level change during the Quaternary. Marine geologic mapping of this area is a component of a statewide cooperative effort involving the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management. Interpretation of high-resolution geophysical data (interferometric and multibeam swath bathymetry, lidar, backscatter, and seismic reflection), sediment samples, and bottom photographs was used to produce a series of maps that describe the distribution and texture of seafloor sediments, shallow geologic framework, and physiographic zones of this inner-shelf region. These data and interpretations are intended to aid efforts to inventory and manage coastal and marine resources, and provide baseline information for research focused on coastal evolution and environmental change.

Massachusetts↗
USGS2007

The geology of Six Mile Reef, eastern Long Island Sound

Digital terrain models, which can be produced from multibeam bathymetric data, are ordered arrays of depths for a number of sea-floor positions sampled at regularly spaced intervals. These models provide valuable base maps for marine geological interpretations that help define the variability of the sea floor (one of the primary controls of benthic habitat diversity), improve our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats, and provide a detailed framework to guide and assist future research, monitoring, and management activities. The bathymetry interpreted herein was processed from data collected by National Oceanic and Atmospheric Administration vessels during hydrographic surveys H11361 and H11252. These surveys mapped roughly 156 km² of sea floor in the vicinity of Six Mile Reef, an area of eastern Long Island Sound where the sea floor is characterized by fields of large sand waves and an east-west decreasing gradient of bottom tidal-current speeds (fig. 1). Interpretations of the bathymetry are supplemented by concurrently collected seismic reflection data, as well as archived historic seismic profiles, sediment samples and bottom photography collected as part of a long-standing geologic mapping partnership between the State of Connecticut and the U.S. Geological Survey (fig. 2). The purpose of this digital report is 1) to provide the acoustic data layers produced during the above mentioned surveys, 2) to use them to describe the sea-floor character and bedform morphologies near Six Mile Reef, and 3) to relate these descriptions to ongoing processes and sedimentary environments.

Connecticut, New York↗
USGS1978

Research and development program for outer continental shelf oil and gas operations, report for fiscal year 1978

This report summarizes the contract research program in support of the Geological Survey's Outer Continental Shelf oil and gas operations. The program is technological, though certain environmental investigations are being conducted as a necessary adjunct. The program manager provides a focal point for communicating with the research community in both the university system and private industry as well as with Federal agencies. Interaction is needed not only with. other Government agencies, such as the Bureau of Land Management and the Department of Energy, but within the Geological Survey itself. USGS engineers and scientists are in a unique position to contribute to the success of the program by their specialized knowledge and experience in the many aspects of offshore operations such as marine geology, seismology and petroleum engineering. This document describes the program and reports on the research, development, and evaluation which are being undertaken.

Open-File Report↗
USGS1984

NONFUEL MINERAL RESOURCES OF THE PACIFIC EXCLUSIVE ECONOMIC ZONE.

The Pacific Exclusive Economic Zone contains a variety of hard mineral resources. Sand and gravel and their associated placer deposits of heavy minerals are the most likely to be developed in the near future, but offshore and deep water deposits of phosphorite, abyssal manganese nodules, ferromanganese crusts enriched in cobalt, and massive sulfide deposits all represent future resources. The distribution, extent, and formation of these deposits are poorly understood and will be clarified only with additional exploration, framework geologic mapping, and study of the processes by which these resources form. It is pointed out that the initial discovery of most hard-mineral resources in the EEZ was made during routine scientific marine-geologic surveys aimed at understanding the framework geology and geologic processes of an offshore region.

Conference Paper↗
USGS2016

Archive of Digital Chirp Subbottom Profile Data Collected During USGS Cruise 14BIM05 Offshore of Breton Island, Louisiana, August 2014

From August 11 to 31, 2014, the U.S. Geological Survey ( USGS ), in cooperation with the U.S. Fish and Wildlife Service ( USFWS ), conducted a geophysical survey to investigate the geologic controls on barrier island framework and long-term sediment transport offshore of Breton Island, Louisiana as part of a broader USGS study on Barrier Island Mapping ( BIM ). Additional details related to this activity can be found by searching the USGS's Coastal and Marine Geoscience Data System (CMGDS), for field activity 2014-317-FA (also known as 14BIM05). These surveys were funded through the USGS Coastal and Marine Geology Program ( CMGP ) and the Louisiana Outer Coast Early Restoration Project. This report serves as an archive of unprocessed digital chirp subbottom data, trackline maps, navigation files, Geographic Information System ( GIS ) files, Field Activity Collection System ( FACS ) logs, and formal Federal Geographic Data Committee ( FGDC ) metadata. Gained digital images of the seismic profiles are also provided. Refer to the Abbreviations page for explanations of acronyms and abbreviations used in this report. All chirp systems use an acoustic signal of continuously varying frequency; the EdgeTech 512i system used during this survey produced high-resolution, shallow-penetration (typically less than 50 milliseconds [ ms] ) profile images of sub-seafloor stratigraphy. The towfish contains a transducer that transmits and receives acoustic energy and typically is towed 1–2 meters ( m ) below the sea surface. As transmitted acoustic energy intersects density boundaries, such as the seafloor or sub-surface sediment layers, some energy is reflected back toward the transducer, received, and recorded by a Personal Computer ( PC) -based seismic acquisition system. This process is repeated at regular intervals (for example, 0.125 seconds ( s) ) and returned energy is recorded for a specific duration (for example, 50 ms ). In this way, a two-dimensional ( 2-D ) vertical image of the shallow geologic structure beneath the ship's track is produced. Figure 2 displays the acquisition geometry. Refer to table 1 for a summary of acquisition parameters and table 2 for trackline statistics. The archived trace data are in standard SEG Y rev. 0 format (Barry and others, 1975); the first 3,200 bytes of the card image header are in American Standard Code for Information Interchange ( ASCII ) format instead of Extended Binary Coded Decimal Interchange Code ( EBCDIC ) format. The SEG Y files are available on the DVD version of this report or online, downloadable via the USGS Coastal and Marine Geoscience Data System ( http://cmgds.marine.usgs.gov ). The data are also available for viewing using GeoMapApp ( http://www.geomapapp.org ) and Virtual Ocean ( http://www.virtualocean.org ) multi-platform open source software. The Web version of this archive does not contain the SEG Y trace files. To obtain the complete DVD archive, contact USGS Information Services at 1-888-ASK-USGS or infoservices@usgs.gov. The SEG Y files may be downloaded and processed with commercial or public domain software such as Seismic Unix ( SU ) (Cohen and Stockwell, 2010). See the How To Download SEG Y Data page for download instructions. The printable profiles are provided as Graphics Interchange Format ( GIF ) images processed and gained using SU software and can be viewed from the Profiles page or by using the links located on the trackline maps; refer to the Software page for links to example SU processing scripts.

Louisana↗