Publications

Methane concentrations in the Beaufort Sea under the winter ice canopy offshore from northern Alaska are 3 to 28 times greater than they are in late summer when the ice is absent in a similar region offshore from northern Canada where methane is in approximate equilibrium with the atmosphere. These observations suggest that methane concentrates in the water under the sea‐ice cover during...

Natural gas hydrates occur worldwide in polar regions, normally associated with onshore and offshore permafrost, and in sediment of outer continental and insular margins. The total amount of methane in gas hydrates likely exceeds 1019 g of methane carbon. Three aspects of gas hydrates are important: their fossil fuel resource potential, their role as a submarine geohazard, and their...

Continuum models were constructed to describe large‐scale deformation of the Aleutian Island Arc over the past 5 m.y. These models consider the island arc as a continuum in the horizontal plane with the velocity boundary condition at the Pacific edge stated as a fraction of Pacific plate convergence transferred to the arc. First, a simple model of uniformly distributed strain is...

High‐quality bottom boundary layer measurements and bottom photographs were obtained over a sand substrate during a 10‐day deployment of the GEOPROBE tripod at an inner shelf (35‐m water depth) location off northern California. The seafloor surrounding the tripod was composed of well‐sorted medium‐grained (mean diameter, 0.25 mm) sand which was formed into symmetrical wave ripples with...

Geophysical and regional geologic data provide evidence that parts of the oceanic crust in the abyssal basins of the Bering Sea have been created or altered by crustal extension and back‐arc spreading. These processes have occurred during and since early Eocene time when the Aleutian Ridge developed and isolated oceanic crust within parts of the Bering Sea. The crust in the Aleutian...

Side-scan sonar images provide a view of an actively changing delta front in a marine outwash fjord in Glacier Bay, Alaska. Numerous interconnected gullies and chute-like small channels form paths for the transport of sand and coarse silt from the braided glacial outwash streams on the delta plain to the sinuous turbidity-current channels incised into the fjord floor. These turbidity...

Experimental investigations confirm an increase of quartz solubility in sea-water relative to distilled water. Combination of the experimental data with published data, most of which related to distilled water, permitted construction of a database for calculating an equation that fits all the data. Application of the equation indicates a shallower depth of circulation for sea- floor...

The range of present knowledge on the subject of gas hydrates and related federal research programs was the topic of discussion at the National Workshop on Gas Hydrates, April 23–24. The intention of the meeting was to provide the impetus for an expanded and broader‐based national research program in both academia and government. Held at the U.S. Geological Survey National Center, Reston...

Five sonobuoy seismic-refraction records were collected along the Leg 119 geophysical transect across the Prydz Bay shelf. Velocity-depth profiles are computed from the sonobuoy data and are used to produce a depth section for the principal acoustic unit boundaries observed in the seismic-reflection data along the transect. Traveltime curves generated by ray-tracing for models...

Prydz Bay is situated on the MacRobertson Land coast of East Antarctica at the seaward end of a 700-km-long transverse rift zone, the Lambert Rift. New and reprocessed seismic reflection data are combined with drilling results from five Leg 119 sites across Prydz Bay to study the regional stratigraphy and structure of the continental shelf and upper slope. Severe seismic multiples hamper

As a result of the October 17, 1989, Loma Prieta (Santa Cruz Mountains, California) earthquake, liquefaction of the fluvial, estuarine, eolian, and beach sediments under a sand spit destroyed the Moss Landing Marine Laboratories and damaged other structures and utilities. Initial studies suggested that the liquefaction was a local phenomenon. More detailed offshore investigations...

No abstract available.