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Giant sand waves at the mouth of San Francisco Bay

Eos, Transactions American Geophysical Union

By:
, , , and
DOI: 10.1029/2006EO290003

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Abstract

A field of giant sand waves, among the largest in the world, recently was mapped in high resolution for the first time during a multibeam survey in 2004 and 2005 through the strait of the Golden Gate at the mouth of San Francisco Bay in California (Figure la). This massive bed form field covers an area of approximately four square kilometers in water depths ranging from 30 to 106 meters, featuring more than 40 distinct sand waves with crests aligned approximately perpendicular to the dominant tidally generated cross-shore currents, with wavelengths and heights that measure up to 220 meters and 10 meters, respectively.


Sand wave crests can be traced continuously for up to two kilometers across the mouth of this energetic tidal inlet, where depth-averaged tidal currents through the strait below the Golden Gate Bridge exceed 2.5 meters per second during peak ebb flows. Repeated surveys demonstrated that the sand waves are active and dynamic features that move in response to tidally generated currents. The complex temporal and spatial variations in wave and tidal current interactions in this region result in an astoundingly diverse array of bed form morphologies, scales, and orientations. Bed forms of approximately half the scale of those reported in this article previously were mapped inside San Francisco Bay during a multibeam survey in 1997 [Chin et al., 1997].

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Giant sand waves at the mouth of San Francisco Bay
Series title:
Eos, Transactions American Geophysical Union
DOI:
10.1029/2006EO290003
Volume
87
Issue:
29
Year Published:
2006
Language:
English
Publisher:
Wiley
Contributing office(s):
Coastal and Marine Geology Program
Description:
3 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Eos, Transactions American Geophysical Union
First page:
287
Last page:
289
Country:
United States
State:
California
Other Geospatial:
San Francisco Bay