PNG formatted images of EdgeTech SB-512i seismic-reflection profiles collected by the U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center offshore of the Gulf Islands, MS, 2010.

An executable C-shell script called on Seismic Unix (version 4.1) to: 1) read the raw SEG-Y data and write a Seismic Unix file; 2) apply automatic gain control; and 3) write the processed traces to new SEG-Y files.

An executable C-shell script called on SIOSEIS (version 10.2.25) to: 1) read the processed SEG-Y data from the previous step and create shot gathers containing two consecutive traces; 2) create a stacked trace from the two trace gathers while maintaining the navigation coordinates (in arc-seconds) from the header of the first trace in each; and 3) write the stacked traces to new SEG-Y files. This stacking flow ensured that the resulting traces were spaced greater than 0.5 m apart along the trackline, which is a prerequisite for the traces to be loaded into GeoGraphix SeisVision (version R5000) for digital interpretation.

An executable C-shell script called on SIOSEIS (version 10.2.25) to use the process WBT specifying the threshold option to predict the vertical location of the sea floor by identifying the first amplitude in each trace that exceeded a user defined value. Two-way travel times (milliseconds) to the sea floor at each trace were recorded the trace headers and saved to an ASCII text file.

All SEG-Y trace data were imported into GeoGraphix SeisVision (version R5000), a 2-dimensional, digital seismic interpretation software, and seafloor values were imported as ASCII text horizon data. The horizon smooth utility was used to remove spurious seafloor values for discrete traces and corrected values were exported to a new ASCII text file.

An executable C-shell script called on SIOSEIS (version 10.2.25) to remove sea surface heave and mute water column portions of the traces by: 1) loading the corrected seafloor times into the SEG-Y trace headers; 2) using process 'SWELL' to suppress the heave by shifting traces vertically; and 3) muting each trace between time zero and the time of the smoothed sea floor pick using process 'MUTE', thus removing noise within the water column. Changes to the traces within each profile were saved to new "heave corrected" SEG-Y files, which were used for creation of PNG browse images and digital interpretation.

A script was run that used Seismic Unix (version 4.1) to read the SEG-Y files and plot the data as 8-bit gray scale Postscript files using the Seismic Unix 'psimage' algorithm. All images were created with a horizontal scale of 200 traces per inch. Images were plotted within a constant 12-inch vertical window of 50 milliseconds (Two-Way Travel Time) duration. The Postscript images were then converted to PNG format using ImageMagick (version 5.5.6).

Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The link to the data in the Identification_Information section had to be fixed. The link to the data in the Distribution_Information section had to be fixed. Attempted to modify http to https where appropriate. Added a landing page link as the first link in the identification section. Updated the link to the field activity. The source information was incomplete and had to be modified to meet the standard. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.

Added keywords section with USGS persistent identifier as theme keyword.