SV_SEISMICLINES- Survey Lines along which seismic data were collected aboard R/V RAFAEL (field activities 05001 and 06001) in Apalachicola Bay, FL

These data were collected under a cooperative mapping program between the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration Office for Coastal Management (NOAA\OCM), and the Apalachicola National Estuarine Research Reserve (NERR). The primary objectives of this program were to collect marine geophysical data to develop a suite of seafloor maps to better define the extent of oyster habitats, the overall seafloor geology of the bay and provide updated information for management of this resource. In addition to their value for management of the bay's oyster resources, the maps also provide a geologic framework for scientific research and the public.

High-resolution bathymetry, backscatter intensity, and seismic profile data were collected over 230 square kilometers of the floor of the bay. The study focused on the Apalachicola Bay and Western St. George Sound portions of the estuary in mostly in depths > 2.0 meters.

Original contact information:

Contact Name: Brian Andrews

Contact Org: U.S. Geological Survey

Title: Geographer

Phone: 508-548-8700 x2348

Email: bandrews@usgs.gov

This shapefile represents the trackline along which seismic profile data collected aboard the R/V RAFAEL during USGS field activities 05001 and 06001 in Apalachicola Bay and St. George Sound, Florida. The seismic data that were collected from the R/V RAFAEL were acquired differently in 2005 than in 2006. During the first seven survey days of the 2005 field season (Julian days 076-083) a Knudsen 320 b chirp profiler (3.5-12 kHz) was used and during the remaining part of the 2005 season a towed Edgetech FSSB 424 (2-24 kHz) system was used. In 2006, the Edgetech FSSB 424 was used for the entire field season, but it was mounted on a pole rather than being towed on a cable. In 2005 both the Knudsen and Edgetech seismic data were logged in SEG-Y format using Delph Seismic +. In 2006 the Edgetech seismic data were logged in SEG-Y format using SBLogger. The purpose of these data is to manage the filenames and geographic locations of seismic profile images that are hyperlinked to each trackline.

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Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

None

These data should not be used at resolutions for which they are not intended.

Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350

RTK GPS was used to navigate the seismic-reflection systems. The GPS antenna was mounted over the bathymetric sonar and a layback of 4 meters was used for the seismics.

Navigation was recorded to all data acquisition systems using Real Time Kinematic GPS at a one second interval.

Horizontal accuracy of the navigation is assumed to be +/- 1 meter. The shot point file and survey line file for the

seismic data are both derived from the same navigation file that was logged by the seismic acquisition system, but

because the two were processed differently, the shot points do not always fall directly on the survey line. To create

the shot point file, the navigation was queried to extract every 500th point starting with shot point 500. By

contrast, to create the survey line file, the navigation was queried at a one minute interval (every 60th point), and

then a line was drawn using these points. Because of the different processing approaches, many of the shot points,

although close, do not fall exactly on the survey line. If meter accuracy is truely needed, it would be best to

extract the navigation from the archived SEG-Y seismic files.

Sections of tracklines where seismic data were not logged were deleted

Data was compared to sediment grabs and was collected following standard best practices for recording sub-bottom profile data.