Publications
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Origin, structure, and evolution of a reattachment bar, Colorado River, Grand Canyon, Arizona
In a channel expansion, flow can separate from the bank, creating a zone of relatively weak recirculating current. Bars that accumulate in this weak flow near the point where flow reattaches to the bank are called reattachment bars. As a reattachment bar evolves, the recirculation zone may fill with sediment and restrict flow from the main channel. The increasingly restricted flow over the bar cau
Authors
David M. Rubin, John C. Schmidt, Johnnie N. Moore
Flume experiments on the alignment of transverse, oblique, and longitudinal dunes in directionally varying flows
For more than a century geologists have wondered why some bedforms are orientated roughly transverse to flow, whereas others are parallel or oblique to flow. This problem of bedform alignment was studied experimentally using subaqueous dunes on a 3–6-m-diameter sand-covered turntable on the floor of a 4-m-wide flume.
In each experiment, two flow directions (relative to the bed) were produced
Authors
David M. Rubin, Hiroshi Ikeda
Major off-axis hydrothermal activity on the northern Gorda Ridge
The first hydrothermal field on the northern Gorda Ridge, the Sea Cliff hydrothermal field, was discovered and geologic controls of hydrothermal activity in the rift valley were investigated on a dive series using the DSV Sea Cliff. The Sea Cliff hydrothermal field was discovered where predicted at the intersection of axis-oblique and axis-parallel faults at the south end of a linear ridge at mid-
Authors
Peter A. Rona, Roger P. Denlinger, M. R. Fisk, K. J. Howard, G. L. Taghon, Kim D. Klitgord, James S. McClain, G. R. McMurray, J. C. Wiltshire
Impact assessment of exploratory wells offshore South Florida
No abstract available
Authors
Eugene A. Shinn, Barbara H. Lidz, Phillip A. Dustan
High-energy carbonate-sand accumulation, the Quicksands, southwest Florida Keys
High-resolution seismic-reflection profiles of the Quicksands, located along a broad ridge on the platform shelf west of Key West, Florida, indicate a significant deposit of non-oolitic carbonate sand occurs in a belt 47 km long by 28 km wide. The surface of the belt is ornamented by large (5 m), migrating tidal bars, oriented in a north-south direction, on which sand waves, oriented in an east-we
Authors
Eugene A. Shinn, Barbara H. Lidz, Charles W. Holmes
A numerical study of some potential sources of error in side-by-side seismometer evaluations
This report presents the results of a series of computer simulations of potential errors in test data, which might be obtained when conducting side-by-side comparisons of seismometers. These results can be used as guides in estimating potential sources and magnitudes of errors one might expect when analyzing real test data. First, the derivation of a direct method for calculating the noise levels
Authors
L. Gary Holcomb
Preliminary maps showing landslide deposits and related features in New Mexico
No abstract available.
Authors
Mauro Cardinali, Fausto Guzzetti, Earl E. Brabb
Effect of wave-current interaction on wind-driven circulation in narrow, shallow embayments
The effect of wind waves on the steady wind-driven circulation in a narrow, shallow bay is investigated with a two-dimensional (y, z) circulation model and the Grant and Madsen [1979] bottom-boundary layer model, which includes wave-current interaction. A constant wind stress is applied in the along-channel x direction to a channel with a constant cross-sectional profile h(y). The wind-induced flu
Authors
Richard P. Signell, Robert C. Beardsley, H. C. Graber, A. Capotondi
Accumulation of bank-top sediment on the western slope of Great Bahama Bank: rapid progradation of a carbonate megabank
High-resolution seismic profiles and submersible observations along the leeward slope of western Great Bahama Bank show large-scale export of bank-top sediment and rapid progradation of the slope during the Holocene. A wedge-shaped sequence, up to 90 m thick, is present along most of the slope and consists of predominantly aragonite mud derived from the bank since flooding of the platform 6-8 ka.
Authors
R. Jude Wilber, John D. Milliman, Robert B. Halley
The San Andreas Fault System, California
Maps of northern and southern California printed on flyleaf inside front cover and on adjacent pages show faults that have had displacement within the past 2 million years. Those that have had displacement within historical time are shown in red. Bands of red tint emphasize zones of historical displacement; bands of orange tint emphasize major faults that have had Quaternary displacement before hi
By
Energy and Minerals Mission Area, Natural Hazards Mission Area, Earthquake Hazards Program, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Earthquake Science Center, Geologic Hazards Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: December 1990
No abstract available.
Authors
John B. Townshend, Richard V. O'Connell, Carol Ann Varner
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: November 1990
No abstract available.
Authors
John B. Townshend, Richard V. O'Connell, Carol Ann Varner