Any spurious data points were removed during processing. No duplicate navigation fixes exist for the 500 shots shapefile. There is no data for what would be lines 8 and 41.
Sections of survey data where navigation was recorded but no seismic data were logged are not included. Time gaps occurred during this field activity on days when no survey data were collected due to bad weather, rough seas, and stops in surveying for equipment issues (on May 18, 21, and 22, 2016). Any sections of seismic data that were collected outside the survey area (such as short segments during the transit to or from the dock at the Sandwich Marina) were not processed and are therefore not included in this dataset.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: raw seismic navigation
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20160517
Ending_Date: 20160523
Source_Currentness_Reference:
Ground condition of survey dates: 20160517-20160523. No geophysical data were collected on May 18 (JD 139), 21 (JD 142), and 22 (JD 143), 2016; see Completeness_Report for more information.
Source_Citation_Abbreviation: Knudsen 3202 seismic data
Source_Contribution:
Seismic-reflection data acquisition 2016-017-FA: Seismic profile data were collected using a Knudsen Engineering Limited (KEL) Chirp 3202 system with transducers mounted on a rigid pole on the starboard side of the R/V Rafael of Woods Hole, MA. Knudsen SounderSuite seismic acquisition software was used to control the 3202 system, digitally log trace data in the SEG-Y Revision 1 format (Norris and Faichney, 2002), and record DGPS navigation coordinates to the SEG-Y trace headers in arc seconds. The transducer draft was 0.5 m below the water surface, and the draft offset was accounted for during data acquisition. Navigation coordinates and water depths from the 200-kHz channel were logged together in ASCII formatted files for each survey line. Data were acquired at a peak frequency of 3.5 kHz, a 0.25-second fire interval, a 36-38 microsecond sample interval, and record lengths between 26 and 130 milliseconds. A total of 128 km of seismic data were collected. DGPS navigation was supplied by a Hemisphere receiver with the antenna mounted on the aft of the R/V Rafael's cabin just port of the centerline. Seismic-reflection data were processed using SIOSEIS (Henkart, 2011) and Seismic Unix (Cohen and Stockwell, 2011).
Process_Step:
Process_Description:
SIOSEIS (version 2015.3.1) 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 SounderSuite sequentially over the duration of an acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y data. This process step and all subsequent process steps, unless otherwise noted, were performed by the same person - David Foster.
Process_Date: 2016
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David Foster
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2271
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: dfoster@usgs.gov
Process_Step:
Process_Description:
SIOSEIS was used to insert Kingdom Suite corrected sea-floor values into the SEG-Y trace headers, minimize the effect of sea surface heave using process 'swell', and write SEG-Y files for creation of browse images and digital interpretation.
Process_Date: 2016
Process_Step:
Process_Description:
Seismic Unix (version 4.2) was used to read all processed 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). Geographic coordinates (WGS 84) were converted to UTM Zone 19N coordinates (WGS 84) using PROJ (version 4.9.3). Header information from each SEG-Y file was saved to CSV text files after an AWK filter was used to maintain the first and last shots, shots at multiples of 500, and shots with unique navigation coordinates. End shots and shots at multiples of 500 may not have unique navigation coordinates. A 500-shot interval was chosen because it corresponds to the annotation interval provided along the top of the seismic-reflection profile PNG images. In the process of extracting the navigation from the SEG-Y files and saving it to the CSV files, a temporary plot was made to visually check the navigation fixes and identify if there were any issues or extreme outliers.
Process_Date: 2016
Process_Step:
Process_Description:
A Python script (3202intoSQL_2016-017-FA.py), originally written by Wayne Baldwin, was used to import the CSV text files containing navigation information into the SpatiaLite (version 4.3.0a) enabled SQLite (version 3.27.1) database. The geographic locations for each shotpoint were used to create point and line feature geometries in the SQL database. Additional survey information is populated in the SQL database including identifiers for the survey name, vessel, and seismic equipment used. This process step and all subsequent process steps were performed by the same person - Seth Ackerman.
Process_Date: 20190222
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Seth Ackerman
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2315
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: sackerman@usgs.gov
Process_Step:
Process_Description:
An Esri point shapefile for the 500-shotpoint intervals was exported directly from the SQLite database using spatialite-tools (version 4.3.0_3).
spatialite_tool -e -shp 2016-017-FA_SeismicShot500 -d ./2016-017-FA-SQLdb.sqlite -t SeisSht500_pt -g geom_500 -c CP1252 -s 4326 --type POINT
Process_Step:
Process_Description:
CSV files for the unique shot navigation data and the 500-interval shot navigation (including the beginning and end shot) were exported from the SQLite database using Geospatial Data Library (GDAL 2.4.0) ogr2ogr executable with the SpatiaLite option and an SQL query.
ogr2ogr -f "CSV" 2016-017-FA_424_shotunique.csv 2016-017-FA-SQLdb.sqlite -dsco SPATIALITE=yes -sql "SELECT * FROM SeisUnique_pt"
ogr2ogr -f "CSV" 2016-017-FA_424_shot500.csv 2016-017-FA-SQLdb.sqlite -dsco SPATIALITE=yes -sql "SELECT * FROM SeisSht500_pt"
The file '2016-017-FA_knudsen_shotunique.csv', which is provided on the data release landing page for the 500-shot data '2016-017-FA_SeismicShot500', contains the unique navigation. The file '2016-017-FA_knudsen_shot500.csv, on the same landing page, contains the beginning, ending, and 500-shot interval positions.
Process_Step:
Process_Description:
XTools Pro (version 17.0.2734) for ArcGIS Desktop was used (Table Operations - Table Restructure) to clean up the attribute headings in the shapefile's attribute table. The ImageName field was updated to reflect the renamed seismic image names with the field activity prepended to the line name. The ImageName fields in both of the CSV files (2016-017-FA_knudsen_shotunique.csv and 2016-017-FA_SeismicShot500.csv) were updated as well.
Process_Date: 201903
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200807
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
