Our operational group provides the technical expertise and innovations to plan, acquire, process, interpret, archive, and publish Sea-floor Mapping products to support the USGS and WHSC's coastal, and inner-continental shelf geology, sediment transport, environmental geoscience, and energy/tectonics research programs. The WHSC research is located mostly off the Atlantic seaboard, with additional surveys conducted in various lacustrine, river, and estuarine sites. The geophysical tools we use include seismic-reflection, sidescan-sonar, resistivity, and bathymetric systems to remotely map the sea floor and subsurface. These systems are deployed from the fantail or a sidemount of a ship and towed continuously throughout a survey area. Operations vary from round-the-clock when using larger vessels during offshore operations, to long days for nearshore and more restricted-area small-boat operations. Navigational systems are run concurrently to precisely locate the data gathered from the different sources. Additionally, ground-truth efforts -- sampling, coring, still photographic, and video -- are used to validate, or ground-truth the geophysical data.
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| Schematic drawing of the various systems used by the WHSC. |
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Presently, shipboard capabilities are such that processing and preliminary map production are completed in the field, along with extensive and redundant data archival to insure against data loss.
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| Example of shipboard data capability from Lake Mead, NV and AZ, in 2003. The WHSC, along with cooperators, conducted reconnaissance mapping of the lake floor to provide a regional geologic framework, with a focus on the sediment distribution since the completion of Hoover Dam. The photograph above shows the field setting. The imagery to the right is an example of digitally mosaicked sidescan-sonar data and and a processed seismic profile, with basic interpretations identified. |
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