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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

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

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

Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: October 1990

No abstract available.
Authors
John B. Townshend, Richard V. O'Connell, Carol Ann Varner