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Bradford Butman

Publications and source records attributed to Bradford Butman.

95 records · Page 6Linked to original sources
USGS1980

Semidiurnal bottom pressure and tidal currents on Georges Bank and in the Mid-Atlantic Bight

Observations of the semidiurnal (M 2 ) tidal current, bottom pressure, and coastal sea level from Nova Scotia to Cape May, New Jersey) show that: 1) the surface pressure at the edge of the Continental Shelf in the study area has a relatively uniform amplitude (40 cm) and phase (12 hr Greenwich); 2) in the Mid-Atlantic Bight, the semidiurnal M 2 tide is co-oscillating, and the onshore M 2 tidal current reaches a maximum 2 approximately 90° or 3.1 hr before high water; 3) in the Georges Bank region of the shelf, the M tide is more progressive than it is in the 2 Mid-Atlantic Bight, and the onshore M 2 tidal current in the Georges Bank 2 region of the shelf reaches a maximum about 7 ° or 14 min before high water; 4) the strongest M 2 tidal currents observed in the study area are 2 near the crest of Georges Bank (typical amplitudes are 74 cm/s near the surface); 5) the M 2 tidal currents are weaker in the Mid-Atlantic Bight 2 (typical amplitudes are 16 cm/s near the surface) than on Georges Bank; and 6) the tidal currents are weakest near the bottom south of Cape Cod in a region of transition between progressive and co-oscillating tides.

Georges Bank, Mid-Atlantic Bight↗
USGS1979

Summary report of the sediments, structural framework, petroleum potential, and environmental conditions of the United States Mid-Atlantic continental margin in area of proposed Oil & Gas Lease Sale No. 59

This report has been compiled to update and summarize the geological information concerning the area of the Atlantic continental margin off the U.S. Mid-Atlantic proposed for Oil and Gas Lease Sale No. 59 (fig. 1). The region of interest lies between 35° and 41° N and 70.5° and 76° W. The north-south dimension is about 660 km (356 nautical miles, 410 statute miles) and the maximum east-west dimension is approximately 250 km (135 nautical miles, 155 statute miles). The area is centered toward the outer Continental Shelf off Delaware and contains more than 154,000 km2 (38,000,000 acres) off the coasts of North Carolina, Virginia, Maryland, Delaware, New Jersey and New York. Water depths within the region range from 20 to slightly more than 4,000 m (fig. 1). This report begins with a discussion of the regional geology and geophysics, followed by a description of the oil and gas potential and potential environmental hazards.

Delaware, Maryland, New Jersey, New York, North Ca↗
USGS1978

An instrument system for long-term sediment transport studies on the continental shelf

A bottom-mounted instrument system has been designed and built to monitor processes of bottom-sediment movement on the Continental Shelf. The system measures bottom current speed and direction, pressure, temperature, and light transmission, and photographs the bottom. The instrument operates in a burst sample mode. The system can be deployed for periods of 2-6 months to monitor intermittent processes of sediment movement such as storms, and to assess seasonal variability. Deployments of the system on the U.S. East Coast Continental Shelf show sediment resuspension and changes in bottom microtopography due to surface waves, tidal currents, and storms.

East Coast Continental Shelf↗
USGS1978

Bottom currents and bottom sediment distribution in Massachusetts Bay

Massachusetts Bay is a coastal Bay 100 km long and 40 km wide located in the western Gulf of Maine. The Bay is open only to the Gulf to the east; the opening is partially blocked by a shallow bank. The bottom sediment distribution in the bay is complex; fine grained material is found in the deep basin, sand and gravel on the shallow bank, and mixtures of sand, gravel and finer sediments nearshore. Richardson current meters were moored l m from the bottom over a one-year period at several locations in the Bay to define the bottom currents and to determine the frequency of bottom sediment movement due to currents. The measurements suggest that the bottom sediments can be expected to move occasionally in certain areas. The maximum bottom current speeds were determined principally by the strong tidal currents in the basin. In winter, the near bottom currents were dominated by wind stress associated with storms. Bottom currents in the shallow areas were generally in the direction of the wind while currents in the deep portion of the basin were often opposite to the direction of the wind. Sea-surface setup in the direction of the wind was observed, as well as variations in sea level attributed to changes in the adjacent Gulf of Maine. Adjustment of the bottom current to windstress required approximately 12 hours. Total concentrations of suspended particulate matter, in general, were found to be higher in the near-shore and near-bottom waters and lower in the offshore and near-surface waters. Near-bottom concentrations tended to increase as the grain size of the bottom sediments decreases. The greatest concentrations of suspended matter were observed in waters adjacent to Boston Harbor.

Open-File Report↗