PNG formatted images of Edgetech SB-512i chirp seismic-reflection profiles collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA, 2014

Scripts within SIOSEIS (version 2010.2.25) and Seismic Unix (version 4.2) were used to process SEG-Y data, create navigation files, and plot images. The processing flow and scripts used to produce swell-filtered PNG images are summarized below: 1. Siorenum was used to read SEG-Y files, renumber shots starting from one, and write out new SEG-Y files. The original shot numbers, which were assigned by SonarWiz sequentially over the duration of an acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y and JSF data. 2. Sio_medianstk was used to remove S-boom cross talk (when multi-channel streamer lines were recorded simultaneously: Julian Day 169-178) with a two-trace median stack and improve water bottom picking. This script was used for all lines even after multi-channel streamer was turned off, due to the improvements made to water bottom picks. 3. Read512i_mstk reads median filtered stacked trace data, saves it as an SU file, extracts raw navigation from SEG-Y headers and writes navigation files. 4. Plot512i_mstk creates a plot to determine if swell filtering is required. Swell-filtering was applied to all profiles in cruise 2014-002-FA. 5. Siothresh_mpltwbt and siopeak_pltwbt are used to pick the water bottom using amplitude threshold or peak amplitude, respectively (depending on user determined best pick of water bottom), mute water column noise that could cause problems with bottom picks and a write a water-bottom file with two-way travel time to the seafloor as an ASCII file and Kingdom Suite (version 8.8) Line. Seafloor picks for three lines on JD170: l5f1,l5f2, and t5f2 were not successful with the siothresh and siopeak scripts, so seafloor picks were edited to remove spikes within Kingdom Suite software. Edited water-bottom picks for these lines were exported from Kingdom Suite for swell-filtering 6. Plot512i_s creates a swell-filtered PNG image using ImageMagick (version 6.6.1) of each seismic line that is 12 inches high. Images show two-way travel time (seconds) along the y-axis (left margin) and distance along profile (in 10,000 shot intervals) on the x-axis (along top of profile).

The online links to the data were updated to reflect the new server hosting the data. The original data download file (2014-002-FA_512images.zip) was over 5 GB. In order to facilitate downloads, this file was broken into 5 smaller files, each zip file approximately 1 GB in size. Each file contains a portion of the seismic-reflection profile images, the browse graphic, and the CSDGM metadata. The breakdown of the seismic-refleciton profiles is as follows: 2014-002-FA_512images1of5.zip contains lines 1-22 2014-002-FA_512images2of5.zip contains lines 23-49 2014-002-FA_512images3of5.zip contains lines 50-72 2014-002-FA_512images4of5.zip contains lines 73-106 2014-002-FA_512images5of5.zip contains lines 107-163 and the tie lines. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes.