Chirp seismic reflection - shotpoints, tracklines, profile images, and SEG-Y traces for EdgeTech SB-512i chirp data collected during USGS field activity 2017-002-FA.

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   U.S. Geological Survey, 20200409, Chirp seismic reflection - shotpoints, tracklines, profile images, and SEG-Y traces for EdgeTech SB-512i chirp data collected during USGS field activity 2017-002-FA.: data release DOI:10.5066/P9Y1MSTN, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

   Online Links:

   • https://doi.org/10.5066/P9Y1MSTN
   • https://www.sciencebase.gov/catalog/item/5e1e318fe4b0ecf25c610daf

   This is part of the following larger work.
   Baldwin, Wayne E., Moore, Eric M., Worley, Charles R., Nichols, Alex R., and Ruppel, Carolyn D., 2020, Marine Geophysical Data Collected to Support Methane Seep Research Along the U.S. Atlantic Continental Shelf Break and Upper Continental Slope Between the Baltimore and Keller Canyons During U.S. Geological Survey Field Activities 2017-001-FA and 2017-002-FA.: data release DOI:10.5066/P9Y1MSTN, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9Y1MSTN
   • https://www.sciencebase.gov/catalog/item/5e179176e4b0ecf25c59f97a

   Other_Citation_Details:

   Suggested citation: Baldwin, W.E., Moore, E.M., Worley, C.R., Nichols, A.R., and Ruppel, C.D., 2020, Marine Geophysical Data Collected to Support Methane Seep Research Along the U.S. Atlantic Continental Shelf Break and Upper Continental Slope Between the Baltimore and Keller Canyons During U.S. Geological Survey Field Activities 2017-001-FA and 2017-002-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P9Y1MSTN.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -74.858706
   East_Bounding_Coordinate: -74.146661
   North_Bounding_Coordinate: 37.540206
   South_Bounding_Coordinate: 35.512023
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/5e1e318fe4b0ecf25c610daf/?name=2017-002-FA_SB512i_browse.jpg (JPG)

   Example chirp seismic-reflection profile image.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 26-Aug-2017

   Ending_Date: 05-Sep-2017

   Currentness_Reference:

   ground condition

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: digital data
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is WGS 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
      
7. How does the data set describe geographic features?

   2017-002-FA_SB512iTracklines.shp

   SB-512i Trackline shapefile for survey 2017-002-FA (51 polyline features). (Source: U.S. Geological Survey)

   FID

   Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: Esri) Coordinates defining the features.

   LineName

   Name of the trackline along which seismic-reflection data were collected in the format: Line-FileNumber (i.e.'Line-0004'). (Source: U.S. Geological Survey) Character set

   ImageName

   PNG image name of seismic-reflection profile corresponding to survey line. (Source: U.S. Geological Survey) Character set

   Shot_init

   Shot number at the start of the survey line. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	1
   Maximum:	1
   Units:	shot
   Resolution:	1

   Shot_end

   Shot number at the end of the survey line. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	468
   Maximum:	7287
   Units:	shot
   Resolution:	1

   Year

   Calendar year the data were collected (Source: U.S. Geological Survey) Character set

   JDUTC_init

   Julian day and UTC time at the start of the survey line in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set

   JDUTC_end

   Julian day and UTC time at the end of the survey line in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set

   SurveyID

   WHCMSC field activity identifier (e.g. "2017-002-FA" where 2017 is the survey year, 002 is survey number of that year, and FA is Field Activity). (Source: U.S. Geological Survey) Character set

   VehicleID

   Survey vessel name. (Source: U.S. Geological Survey) Character set

   DeviceID

   Sonar device used to collect seismic-reflection data. (Source: U.S. Geological Survey) Character set

   Length_km

   Length of seismic-reflection data line in kilometers (UTM Zone 18N, WGS 84) calculated in the SQLite database. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	0.92
   Maximum:	16.66
   Units:	kilometers
   Resolution:	0.01

   2017-002-FA_512i_sht100.shp

   SB512i 100-interval shot point shapefile for survey 2017-002-FA (1068 point features). (Source: U.S. Geological Survey)

   FID

   Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: Esri) Coordinates defining the features.

   East

   Easting coordinate in UTM Zone 18 N meters, WGS 84 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	512811.03
   Maximum:	575403.01
   Units:	meters
   Resolution:	.01

   North

   Northing coordinate in UTM Zone 18 N meters, WGS 84 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	3929839.55
   Maximum:	4155008.85
   Units:	meters
   Resolution:	.01

   Lon

   Longitude coordinate in decimal degrees, WGS 84 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-74.858706
   Maximum:	-74.146661
   Units:	degrees
   Resolution:	1E-06

   Lat

   Latitude coordinate in decimal degrees, WGS 84 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	35.512023
   Maximum:	37.540206
   Units:	degrees
   Resolution:	1E-06

   LineName

   Name of the trackline along which seismic-reflection data were collected in the format: Line-FileNumber (i.e.'Line-0004'). (Source: U.S. Geological Survey) Character set

   ImageName

   PNG image name of seismic-reflection profile corresponding to survey line. (Source: U.S. Geological Survey) Character set

   Shot

   Shot number (values are first, last, and every 100 shot between). (Source: U.S. Geological Survey)

   Range of values
   Minimum:	1
   Maximum:	7287
   Units:	shot
   Resolution:	1

   Year

   Year the data were collected YYYY. (Source: U.S. Geological Survey) Character set

   JD_UTC

   Julian day and UTC time for first, last, and every 100 shot point between of the survey line in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set

   SurveyID

   WHCMSC field activity identifier (e.g. "2017-002-FA" where 2017 is the survey year, 002 is survey number of that year, and FA is Field Activity). (Source: U.S. Geological Survey) Character set

   VehicleID

   Survey vessel name. (Source: U.S. Geological Survey) Character set

   DeviceID

   Sonar device used to collect seismic-reflection data. (Source: U.S. Geological Survey) Character set

   East_o

   pre-layback calculation Easting coordinate in UTM Zone 18 meters, WGS84. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	512825.01
   Maximum:	575411.75
   Units:	meters
   Resolution:	.01

   North_o

   pre-layback calculation Northing coordinate in UTM Zone 18 meters, WGS84. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	3929789.81
   Maximum:	4155004.57
   Units:	meters
   Resolution:	.01

   Lon_o

   pre-layback calculation Longitude coordinate in decimal degrees, WGS 84 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-74.858556
   Maximum:	-74.146617
   Units:	degrees
   Resolution:	1E-06

   Lat_o

   pre-layback calculation Latitude coordinate in decimal degrees, WGS 84 (Source: U.S. Geological Survey)

   Range of values
   Minimum:	35.511575
   Maximum:	37.540164
   Units:	degrees
   Resolution:	1E-06

   2017-002-FA_512i_shtnav.csv

   SB512i shot point comma separated values file for survey 2017-002-FA (99549 point features). (Source: U.S. Geological Survey)

   2017-002-FA_512i_Images

   Portable network graphic images of processed SB512i profiles for survey 2017-002-FA (51 PNG images). (Source: U.S. Geological Survey)

   2017-002-FA_512i_SegyData

   SEG-Y format files of processed SB512i profiles for survey 2017-002-FA (51 SEG-Y files). (Source: U.S. Geological Survey)

   Entity_and_Attribute_Overview:

   The column headings and range domain values in '2017-002-FA_SB512i_shtnav.csv' match those in '2017-002-FA_SB512i_sht100.shp'. The PNG seismic reflection images can be hyperlinked to their corresponding trackline or shotpoint locations in ArcGIS using the shapefiles '2017-002-FA_SB512iTracklines.shp' or '2017-002-FA_SB512i_sht100.shp', respectively. The fist, last, and multiple of 100 shot features in '2017-002-FA_SB512i_sht100.shp' correspond to the x-axis ticks on the PNG images, which show two-way travel time (seconds) on the y-axis and distance along profile (annotation at 100 shot intervals) on the x-axis.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • U.S. Geological Survey
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey

   Attn: Wayne Baldwin

   Geologist

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   US

   508-548-8700 x2226 (voice)

   508-457-2310 (FAX)

   wbaldwin@usgs.gov

Why was the data set created?

How was the data set created?

1. From what previous works were the data drawn?

   SEG-Y SB-512i data (source 1 of 1)

   U.S. Geological Survey, unpublished material, SB-512i SEG-Y trace data.

   Type_of_Source_Media: disc
   Source_Contribution:

   Chirp seismic data were collected using an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz), which was towed from the A-frame of the R/V Hugh R. Sharp with the transducer between 10 and 19 m below the water line, and approximately 60 meters astern of the GPS antenna mounted on the aft 01 deck handrail. SonarWiz 6 (version 6.05.001) seismic acquisition software was used to control the Geo-Star FSSB topside unit, digitally log three trace data (envelope, real, and imaginary) in the SEG-Y Rev. 1 format (IEEE floating point), and record GPS navigation coordinates to the SEG-Y trace headers (in arc seconds of Latitude and Longitude, multiplied by a scalar of 100). Data were acquired using 1 - 2 second (ms) shot rates, a 40-ms pulse length, and a 1 to 6 kHz frequency sweep. Traces were recorded with a 46-microsecond sample interval over lengths between approximately 800 and 1600 ms.

2. How were the data generated, processed, and modified?

   Date: Sep-2019 (process 1 of 4)

   PROCESS STEP 1: SIOSEIS (version 2018.1.2), Shearwater Reveal (version 4.1), and python were used to process SEG-Y data and extract navigation data. The processing flows and scripts used are summarized below and in the following processing steps.
   1) The SIOSEIS script sio_renum read the raw SEG-Y files, extracted the envelope-detected trace, renumbered shots starting from one, and wrote 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 data.
   2) The SIOSEIS script siothresh_pltwbt 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.
   3) The Shearwater Reveal flow read_segy called the following modules: SegyTapeRead read the traces. HeaderMath and UTMLatLong converted the navigation reference point lat/lon positions from seconds of arc to decimal degrees, projected them to UTM Zone 18N WGS 84 meters, and wrote each to new header words (NRP_LAT, NRP_LON, NRP_X, and NRP_Y). DBWrite wrote the UTM positions for each shot to an internal Reveal database table '*.shots.db'. Finally, Output wrote the traces to a new file '*.seis' in the internal Reveal format.
   4) Each Reveal '*.seis' file was opened in the trace viewer, and the corresponding 'wbt.csv' was chosen for overlay on the seismic traces so that the SIOSEIS seafloor picks could be evaluated and adjusted where needed using the Reveal line digitizing tool. New '*.wbtedit.csv' files were saved for each line with corrected picks. In addition, a new Reveal table '*.tfd.tbl' was created to contain estimated two-way travel time towfish depths for each line, which were digitized along the reflection of the outgoing pulse off of the sea surface. For Line-0006 and Line-0007 no seafloor reflection was present due to a 100-ms recording delay applied during acquisition, so a static towfish depth two-way travel time estimate of 16 ms was used instead.
   5) The python script swellfilter512i read each '*.wbtedit.csv' file into a numpy array, interpolated picks to the entire range of shots (if needed), and passed the picks through the scipy.ndimage.median_filter algorithm (specifying a window length of 17 and nearest mode) in order to minimize the effects of sea surface heave on the seafloor picks. The median filtered curve was subtracted from the original edited seafloor curve to produce an output series of time shifts approximating the residual heave to be applied by shot to the seismic traces for heave removal. The final swell filtered seafloor picks and static shift values were output to new '*.wbtsfsh.csv' files.
   6) The Reveal flow layback_shift called the following modules: Input read the '*.seis' file and sorted the traces to FFID. The custom Python module ShotlineLayback (developed by Nathan Miller of USGS-WHCMSC) defined the horizontal offset between the GPS antenna and the SB-512i transducer (approximately 60 m astern), which was calculated via Pythagorean geometry per file; where the layback astern from the a-frame block is given by the square root of ((average towfish depth (between 10 and 19 m) + measured vertical offset between the a-frame block and water line (7.5 m))^2 + (the tow wire out beyond the block (48 m))^2); and the total layback is provided by adding the offset from the GPS antenna to the a-frame block (16.15 m). The algorithm interpolated a sail line from the navigation reference point positions (NRP_X and NRP_Y), then computed layback positions for the SB-512i shots by translating them back along the sail line by the total offset, and wrote the calculated layback positions to new header words (SRC_X, SRC_Y, REC_X, REC_Y). UTMLatLong converted the layback positions from UTM Zone 18N WGS 84 meters to decimal degrees and wrote each to new header words (NRP_LAT, NRP_LON, SRC_LAT, SRC_LON, REC_LAT, and REC_LON). HeaderMath converted Lat/Lon values from decimal degrees to seconds of arc with a scalar of 100. DBMerge transferred the swell filtered seafloor picks and static shifts stored in '*.wbtsfsh.csv' files to new header words SWFSF and SWFSHIFT, respectively. Table2Header transferred towfish depth two-way travel times stored in '*.tfd.tbl'to the new header word TFDEPTH. ApplyStatic shifted traces first by the inverse of header word SWSHIFT to apply the calculated heave removal static corrections, then by the header word TFDEPTH to apply the towfish depth static corrections. HeaderMath set header words for navigation coordinate units (geographic seconds of arc with scalar), time basis code (UTC), and chirp sweep characteristics (start/end frequencies and length). Output wrote the processed traces to a new SEG-Y files in which the trace header words SRC_X, SRC_Y, REC_X, and REC_Y represent the calculated layback coordinates. DBWrite wrote new CSV text files for each line containing the layback X and Y coordinates (UTM18N m), layback Lat/Lon coordinates (WGS84 dd), shot, year, day, hour, minute, second, navigation reference point X and Y coordinates (UTM18N m), and navigation reference point Lat/Lon coordinates (WGS84 dd). The output SEG-Y files are included in the archive '2017-002-FA_SB512i_SegyData.zip'.
   7) The python script 512ilbtoSQL imported the pre-layback and layback navigation, shot, year, day, and UTC time data from CSV files into a SpatiaLite (version 4.3.0) enabled SQLite (version 3.26.0) database, creating two tables containing point geometries. The first contained records for all of the input shots with unique navigation coordinates, and the second maintained records for the first and last shots, and shots at multiples of 100. A 100-shot interval was chosen because it corresponds to the annotation and tick interval provided along the top of the seismic-reflection profile images. End shots and shots at multiples of 100 may not have unique navigation coordinates. The resulting database columns for each table consist of East, North (layback UTM18N m), Lon, Lat (WGS84 dd), LineName, ImageName, Shot, Year, JD_UTC (DDD:HH:MM:SS), SurveyID, VehicleID, DeviceID, East_o, North_o (UTM18N m), Lon_o, and Lat_o (WGS84 dd). A third table was created to contain trackline geometries generated from the unique navigation point geometries for each line (sorted by LineName and Shot), and the line length in kilometers was calculated. The resulting database columns of the line geometry table consist of LineName, ImageName, Shot_init, Shot_end, Year, JDUTC_init, JDUTC_end, SurveyID, VehicleID, DeviceID, and Length_km.
   These process steps and all subsequent process steps were conducted by the same person - Wayne Baldwin. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Wayne E. Baldwin

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   (508) 548-8700 x2226 (voice)

   (508) 457-2310 (FAX)

   wbaldwin@usgs.gov

   Date: Sep-2019 (process 2 of 4)

   PROCESS STEP 2: The SB-512i 100 shot and trackline features were added (Add Data) into ArcMap (version 10.7) from the SQLite database, then exported (Right click on database feature class > Data > Export Data) to the new Esri polyline shapefiles '2017-002-FA_SB512i_sht100.shp' and '2017-002-FA_SB512iTracklines.shp', respectively.

   Date: Sep-2019 (process 3 of 4)

   PROCESS STEP 3: The Seismic Unix script Plot512i created variable density postscript plots of the seismic profiles showing two-way travel time (seconds) along the y-axis (left margin) and shots along profile (labeled at 100 shot intervals) on the x-axis (along top of profile). The postscript images were converted to 200 dpi portable network graphic (PNG) images using ImageMagick (version 6.9.9-40).

   Date: 07-Aug-2020 (process 4 of 4)

   Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

3. What similar or related data should the user be aware of?
   Leonte, M., Ruppel, C. D., Ruiz‐Angulo, A., and Kessler, J. D., 2020, Surface methane concentrations along the Mid‐Atlantic Bight driven by aerobic subsurface production rather than seafloor gas seeps.: Journal of Geophysical Research: Oceans vol. 125, American Geophysical Union Publications, Washington, DC.

   Online Links:

   • https://doi.org/10.1029/2019JC015989

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?
   
2. How accurate are the geographic locations?
   The EdgeTech SB-512i subbottom profiler was towed from the a-frame of the R/V Hugh R. Sharp with the transducer between 10 and 19 m below the water line, and approximately 60 meters astern of the DGPS antenna mounted on the aft 01 deck handrail. Navigation data for the SB-512i were collected using a Hemisphere GPS receiver. Positioning data were recorded using SonarWiz 6 (version 6.05.001) acquisition software, which logged coordinates to individual trace headers in SEG-Y format. DGPS horizontal positional accuracy is assumed to be within 3 m; the layback position of the transducer relative to the GPS antenna was accounted for during processing.
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   Sections of tracklines where navigation was recorded but no seismic data were logged are not included such as during testing, some turns, and very short files. Testing files Line-0001 through Line-0003 are not included in the data release.
5. How consistent are the relationships among the observations, including topology?
   Chirp seismic-reflection data were collected during overnight operations (generally between approximately 24:00 and 10:00 UTC) on Aug 26, Sept. 1, and Sept. 3 - 5. '2017-002-FA_SB-512i_sht100.shp' contains the first (1), last (x), and 100-interval shotpoints for each seismic trackline, and '2017-002-FA_SB-512i_shtnav.csv' contains all unique shot point navigation. The attribute fields 'LineName' and 'ImageName' for each polyline feature in '2017-002-FA_SB-512iTracklines.shp' correspond to the SEG-Y data files in '2017-002-FA_SB512i_SegyData.zip' and the PNG profile images in "2017-002-FA_SB512i_Images.zip", respectively. One SEG-Y file, and PNG image exists for each feature. Processed seismic data were converted to PNG format for ease of seismic trace display. Quality control was conducted during processing.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - ScienceBase

   Denver Federal Center

   Denver, CO
   

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? USGS data release of EdgeTech SB512i chirp seismic-reflection data collected along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during USGS field activity 2017-002-FA: includes '2017-002-FA_SB512i_sht100.shp' containing the first, last and 100-interval shotpoint locations, '2017-002-FA_SB512i_shtnav.csv' containing unique shot point locations, '2017-002-FA_SB512iTracklines.shp' containing trackline features, '2017-002-FA_SB512i_Images.zip' containing 51 PNG images named according to line convention, '2017-002-FA_SB512i_SegyData.zip' containing 51 SEG-Y files of the processed traces, the browse graphic 2017-002-FA_SB512i_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file '2017-002-FA_SB512i_meta.xml'. These datasets can be downloaded individually (see the Digital Transfer Option section).
3. What legal disclaimers am I supposed to read?
   Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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.
4. How can I download or order the data?
   • Availability in digital form:

     Data format:	Shapefile of SB512i tracklines collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during field activity 2017-002-FA and the associated metadata. in format Shapefile (version ArcMap 10.7.1) Shapefile Size: 1.6
     Network links:	https://www.sciencebase.gov/catalog/item/5e1e318fe4b0ecf25c610daf https://doi.org/10.5066/P9Y1MSTN

     Data format:	Shapefile of SB512i shotpoints collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during field activity 2017-002-FA and the associated metadata. in format Shapefile (version ArcMap 10.7.1) Shapefile Size: 1.8
     Network links:	https://www.sciencebase.gov/catalog/item/5e1e318fe4b0ecf25c610daf https://doi.org/10.5066/P9Y1MSTN

     Data format:	CSV file of SB512i unique shotpoints collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during field activity 2017-002-FA and the associated metadata. in format CSV (version none) Comma-Separated Values (CSV) Size: 16.7
     Network links:	https://www.sciencebase.gov/catalog/item/5e1e318fe4b0ecf25c610daf https://doi.org/10.5066/P9Y1MSTN

     Data format:

     Zip compressed folder containing SB512i seismic reflection profile images collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during field activity 2017-002-FA and the associated metadata. in format PNG (version ImageMagick (version 6.9.9-40)) Portable Network Graphic (PNG) Size: 165

     Network links:

     https://www.sciencebase.gov/catalog/item/5e1e318fe4b0ecf25c610daf https://doi.org/10.5066/P9Y1MSTN

     Data format:	Zip compressed folder containing processed SB512i seismic reflection trace data collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during field activity 2017-002-FA and the associated metadata. in format SEG-Y (version SEG-Y Rev. 1) SEG-Y Size: 6740
     Network links:	https://www.sciencebase.gov/catalog/item/5e1e318fe4b0ecf25c610daf https://doi.org/10.5066/P9Y1MSTN

   • Cost to order the data: none

5. What hardware or software do I need in order to use the data set?
   To utilize these data, the user must have software capable of reading shapefiles, CSV files, PNG images, and/or SEG-Y seismic trace files.

Who wrote the metadata?

Dates:

Last modified: 19-Mar-2024

Metadata author:

U.S. Geological Survey

Attn: Wayne E. Baldwin

Geologist

384 Woods Hole Rd.

Woods Hole, MA

(508) 548-8700 x2226 (voice)

(508) 457-2310 (FAX)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319)

Metadata standard:

FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)