Filters: partyWithName: Natural Hazards (X) > partyWithName: Laura Brothers (X)
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These data are a qualitatively derived interpretive polygon shapefile defining surficial sediment type and distribution, and geomorphology, for nearly 1,400 square kilometers of sea floor on the inner-continental shelf from Fenwick Island, Maryland to Fisherman’s Island, Virginia, USA. These data are classified according to Barnhardt and others (1998) bottom-type classification system, which was modified to highlight changes in secondary sediment-types such as mud and gravel across this primarily sandy shelf. Most of the geophysical and sample data used to create this interpretive layer were collected as part of the Linking Coastal Processes and Vulnerability: Assateague Island Regional Study project (GS2-2C), supported...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Assateague Island,
Assateague Island National Seashore,
Assawoman Island,
Atlantic Ocean,
Backscatter,
In June 2022, the U.S. Geological Survey, in collaboration with the Massachusetts Office of Coastal Zone Management, collected high-resolution geophysical data, in Nantucket Sound to understand the regional geology in the vicinity of Horseshoe Shoal. This effort is part of a long-term collaboration between the USGS and the Commonwealth of Massachusetts to map the State’s waters, support research on the Quaternary evolution of coastal Massachusetts, resolve the influence of sea-level change and sediment supply on coastal evolution, and strengthen efforts to understand the type, distribution, and quality of subtidal marine habitats. This collaboration produces high-resolution geologic data that serve the needs of...
Tags: Marine geology
Geologic, sediment texture, and physiographic zone maps characterize the sea floor south and west of Martha's Vineyard and north of Nantucket, Massachusetts. These maps were derived from interpretations of seismic-reflection profiles, high-resolution bathymetry, acoustic-backscatter intensity, bottom photographs, and surficial sediment samples. The interpretation of the seismic stratigraphy and mapping of glacial and Holocene marine units provided a foundation on which the surficial maps were created. This mapping is a result of a collaborative effort between the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management to characterize the surface and subsurface geologic framework offshore of...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Aquinnah,
Atlantic Ocean,
Chappaquiddick Island,
Children's Beach,
Chilmark,
The present-day distribution of subsea permafrost beneath high-latitude continental shelves has implications for sea level rise and climate change since the Last Glacial Maximum (~20,000 years ago). Because permafrost can be spatially associated with gas hydrate (which may be thermodynamically stable within the several hundred meters above and below the base of permafrost), the contemporary distribution of subsea permafrost also has implications for the persistence of permafrost-associated gas hydrate beneath shallow waters at high latitudes, particularly on margins that were not glaciated at the Last Glacial Maximum. On the U.S. Beaufort Sea margin offshore northern Alaska, researchers have sometimes assumed that...
Two marine geological surveys were conducted in Nantucket Sound, Massachusetts, in May 2016 and May 2017 by the U.S. Geological Survey as part of an agreement with the Massachusetts Office of Coastal Zone Management to map the geology of the sea floor offshore of Massachusetts. Samples of surficial sediment and photographs of the sea floor were collected at 76 sampling sites within the survey area, and sea-floor videos were collected at 75 of the sites. The sediment data and the observations from the photos and videos are used to explore the nature of the sea floor; in conjunction with high-resolution geophysical data, the observations are used to make interpretive maps of sedimentary environments and validate acoustic...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Atlantic Ocean,
Marine Geology,
Massachusetts,
Nantucket,
Nantucket Sound,
The U.S. Geological Survey, Woods Hole Coastal and Marine Science Center in cooperation with the University of Maine mapped approximately 50 square kilometers of the seafloor within Belfast Bay, Maine. Three geophysical surveys conducted in 2006, 2008 and 2009 collected swath bathymetric (2006 and 2008) and chirp seismic reflection profile data (2006 and 2009). The project characterized the spatial, morphological and subsurface variability of the Belfast Bay, Maine pockmark field. Pockmarks are large seafloor depressions that are associated with seabed fluid escape.
Geologic structure and isopach maps were constructed by interpreting over 19,890 trackline kilometers of co-located multichannel boomer, sparker and chirp seismic reflection profiles from the continental shelf of the Delmarva Peninsula, including Maryland and Virginia state waters. In this region, Brothers and others (2020) interpret 12 seismic units and 11 regional unconformities. They interpret the infilled channels as Late Tertiary and Quaternary courses of the Susquehanna, Potomac, Rappahannock, York and James Rivers and tributaries, in addition to a broad drainage system. These regional unconformities form a composite unconformity interpreted as the Quaternary-Tertiary (Q-T) unconformity. A depth to Tertiary...
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