Seismic reflection-tracklines, shotpoints, and profile images collected in the Belfast Bay, Maine pockmark field using an EdgeTech SB-424 subbottom profiler during USGS field activities 2006-024-FA and 2009-037-FA (Esri polyline, and point shapefiles, WGS 84, and JPEG images)

STEP 1. PROCESS SEG-Y FILES
Note: Processing step 1 described here are the same for both of the surveys that collected seismic reflection data (2006-024-FA, and 2009-037-FA)the processing date reflects the most recent (2009) date.
Scripps Institute of Oceanography SIOSEIS and Colorado School of Mines Seismic Unix software was used to process SEG-Y data, extract navigation data, and create JPEG images of the seismic profiles. The processing flows and scripts used are summarized below in the following processing steps.
1) The SIOSEIS script sio_renum read the raw SEG-Y files, with the envelope-detected trace, renumbered shots starting from one, and wrote out new SEG-Y files. The original shot numbers, which were assigned by Discover sequentially over the duration of the entire acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y data.
2) The SIOSEIS script siothresh_pltwbt (which runs the sio_threshwbt script) was used to predict water-bottom times from the envelope SEG-Y traces in each file and write the predicted two-way travel times for the seafloor to a '*.wbt.csv' file. New swell filtered SEG-Y files which are corrected for ship's heave motion were created by statically shifting the difference between water-bottom picks and smoothed water-bottom picks .
3) Seismic Unix (version 4.2) script read424_hc was used to read the swell filtered SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, including shot number, longitude, latitude, year, Julian day, and time of day (UTC). Header information from each SEG-Y file was saved to text files after an AWK (no version) filter was used to maintain the first and last shots, shots at multiples of 100, and shots with unique navigation coordinates. Geographic coordinates (WGS 84) were converted to UTM zone 19 N coordinates (WGS 84) using Proj (version 4.6.0). End shots and shots at multiples of 100 may not have unique navigation coordinates. The unique navigation was output to two different files: "RAFA06024_UniqueSht.csv" and "RAFA09037_UniqueSht.csv" and then merged into "BelfastBay_EdgeTech_424_nav.csv." The 100 shot navigation was output to "RAFA06024_100Sht.csv" and "RAFA09037_100Sht.csv."
4) Seismic Unix (version 4.2)script plot424_hc was used to read all the swell filtered SEG-Y files and plot the data as 8-bit gray-scale Postscript files using the Seismic Unix 'psimage' algorithm. The profiles contain 80 milliseconds of two-way travel time within a 14-inch vertical window, yielding approximately 5.7 milliseconds per inch. Postscript images were converted to JPEG format using ImageMagick. The x-axis units of the images are shot number while the y-axis is two-way travel time in seconds (note: extremely short lines may not display a complete x-axis in these images).
The contact person for this and all subsequent processing steps below is Brian Andrews.

STEP 2. CONVERT NAVIGATION TO SHAPEFILE
The navigation files in csv format from previous step were converted to point and polyline shapefile using ArcMap (v. 10).
Tracklines: RAFA06024_UniqueSht.csv and RAFA09037_UniqueSht.csv were each converted to a point shapefiles using the "Create Feature Class from XY Table" context menu in ArcCatalog, and then merged into one shapefile (BelfastBay_UniqueSht.shp) using the Geographic coordinate system (WGS 84). The merged point shapefile was then converted to a polyline shapefile (BelfastBay_EdgeTech_424_tracklines.shp) using the "Points to Line" tool.
Shotpoints: RAFA06024_100Sht.csv and RAFA09037_100sht.csv were each converted to a point shapefile using the "Create Feature Class from XY Table" context menu in ArcCatalog. The individual 100 shot shapefiles were merged into one point shapefile (BelfastBay_EdgeTech_424_100sht.shp) using the merge tool.
The following string attributes were added and populated in the attribute table of trackline and 100 shot shapefiles "SurveyID, DeviceID, and VehicleID."