San FranciscoAlcatraz Island

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Sand Waves at the Mouth of San Francisco Bay, California

Golden Gate Bridge

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GIP-54_Sand_Waves_postcard2.pdf 7/30/07 1:51:50 PM

Place Stamp Here

The U.S. Geological Survey; California State University, Monterey Bay; U.S. Army Corps of Engineers; National Oceanic and Atmospheric Administration; and Center for Integrative Coastal Observation, Research and Education partnered to map central San Francisco Bay and its entrance under the Golden Gate Bridge using multibeam echosounders. To learn more, visit http://pubs.usgs.gov/sim/2006/2944/ and http://pubs.usgs.gov/sim/2006/2917/

View eastward, through the Golden Gate into central San Francisco Bay. Depth of sea floor color coded: red (less than 10 m deep) to purple (more than 100 m deep). Land from USGS digital orthophotographs (DOQs) overlaid on USGS digital elevation models (DEMs). Sand waves in this view average 6 m in height and 80 m from crest to crest. Golden Gate Bridge is about 2 km long. Vertical exaggeration is approximately 4x for sea floor, 2x for land.

U.S. Department of the InteriorU.S. Geological Survey

GIP 542007

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GIP-54_Sand_Waves_postcard2b.pdf 7/30/07 1:53:32 PM