ASV_SEISMICSHOT500 - Shot Points at 500 Shot Intervals for Seismic Data Collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. George Sound, 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 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 shotpoints at a 500 shot interval derived from the navigation for seismic-reflection profiles collected from the ASV IRIS during USGS field activity 06001 in Apalachicola Bay and St. George Sound, Florida. The purpose of these data is to provide geographic locations of shot points so that features in the seismic profiles can be properly located along the tracklines.

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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.

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RTK GPS was used to navigate the survey systems for seismic-reflection systems. The GPS antenna was mounted over the seismic system.

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.

Shot points are not available for sections of the survey lines where seismic data were not logged.

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