Identification_Information: Citation: Citation_Information: Originator: Arnell S. Forde Originator: Nancy T. DeWitt Originator: Jake J. Fredericks Originator: Jennifer L. Miselis Publication_Date: 20181106 Title: Archive of Chirp Subbottom Profile Data Collected in 2017 From the Northern Chandeleur Islands, Louisiana Geospatial_Data_Presentation_Form: multimedia presentation Series_Information: Series_Name: U.S. Geological Survey Data Release Issue_Identification: doi:10.5066/P9E8VRGO Publication_Information: Publication_Place: St. Petersburg, Florida Publisher: U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Online_Linkage: https://doi.org/10.5066/P9E8VRGO Description: Abstract: From August 7 to 16, 2017, the U.S. Geological Survey (USGS) conducted a geophysical survey to investigate the geologic controls on barrier island evolution and medium-term and interannual sediment transport along the sand berm constructed in 2011 (offshore, at the northern end of the Chandeleur Islands, Louisiana) as mitigation of the Deepwater Horizon oil spill. This investigation is part of a broader USGS project, which seeks to better understand barrier island evolution over medium time scales (months to years). This publication serves as an archive of unprocessed, digital chirp subbottom data, survey trackline map, navigation files, geographic information system (GIS) data, and formal Federal Geographic Data Committee (FGDC) metadata. Processed subbottom profile images are also provided. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG Y revision 0 format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). These data are available for viewing using GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean (http://www.virtualocean.org/) multi-platform open source software. In addition, the SEG Y files can be downloaded from the USGS Coastal and Marine Geoscience Data System (CMGDS, https://cmgds.marine.usgs.gov). Purpose: To archive all digital chirp subbottom profile data and associated files collected during Field Activity Number 2017-337-FA. Additional survey and data details are available from CMGDS at, https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-337-FA. Supplemental_Information: All Chirp systems use a signal of continuously varying frequency; the system used during this survey produces high-resolution, shallow-penetration (typically less than 75-milliseconds [ms]) profile images of sub-seafloor stratigraphy. The towfish contains a transducer that transmits and receives acoustic energy and is typically towed 1-2 meters (m) below the sea's surface. As transmitted acoustic energy intersects density boundaries, such as the seafloor or sub-surface sediment layers, energy is reflected toward the transducer, received, and recorded by a PC-based seismic acquisition system. This process is repeated at regular intervals (for example, 0.125 seconds [s]) and returned energy is recorded for a specific duration (for example, 50 ms). In this way, a two-dimensional (2D) vertical image of the shallow geologic structure beneath the towfish is produced. The seismic source utilized during 2017-337-FA consisted of an EdgeTech SB-424 towfish running Discover version 4.09 acquisition software, towed on the port side of the R/V Sallenger, approximately 3.5 m opposite the global positioning system (GPS) reference point. The data were acquired using a frequency sweep of 4-24 kilohertz (kHz), a 43 kHz sample frequency, and recording length was approximately 66.5 ms. Based on survey speeds of 3.5-4.5 knots, the shot spacing was approximately 0.450 m. The binary portion of the unprocessed seismic data is stored in SEG Y rev. 0, IBM float format, which is a standard digital format that can be read and manipulated by most seismic processing software packages; the first 3,200 bytes of the file header are in American Standard Code for Information Interchange (ASCII) format instead of Extended Binary Coded Decimal Interchange Code (EBCDIC) format. The SEG Y formatted trace files have a .sgy extension and may be downloaded and processed with commercial or public domain software such as Seismic Unix (Cohen and Stockwell, 2010). The printable profiles provided are chirp subbottom profile images that were processed using SU software. Survey Field Activity Collection System (FACS) and geophysical logs are also provided as supplemental information in the download file, 2017-337-FA_logs.zip. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20170807 Ending_Date: 20170816 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -88.878025 East_Bounding_Coordinate: -88.850142 North_Bounding_Coordinate: 30.072017 South_Bounding_Coordinate: 30.044906 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: sub-bottom profiling Theme_Keyword: marine geology Theme_Keyword: geology Theme_Keyword: coastal processes Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: distributions Theme_Keyword: physical habitats and geomorphology Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords Theme_Keyword: seismic reflection profiling Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Seismic reflection Theme_Keyword: Chirp Theme_Keyword: Society of Exploration Geophysicists Theme_Keyword: SEG Y Theme_Keyword: Chandleur Islands Theme_Keyword: Barrier Island Mapping Theme_Keyword: 2017-337-FA Place: Place_Keyword_Thesaurus: Common Geographic Areas Place_Keyword: United States Place_Keyword: Louisiana Place_Keyword: Gulf of Mexico Access_Constraints: None. These data are held in the public domain. Use_Constraints: Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of the data in future products or derivative research. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell S. Forde Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Data_Set_Credit: Funding and (or) support for this study was provided by the USGS Coastal and Marine Geology Program. The authors thank Andy Farmer of Cherokee Nation Technologies for his assistance in data collection and piloting the research vessel (R/V) Sallenger. This document was improved by reviews from Stephen Bosse and Chelsea Stalk of the USGS - St. Petersburg, Florida. Native_Data_Set_Environment: Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Environmental Systems Research Institute (Esri) ArcGIS 10.3.1.4959 Cross_Reference: Citation_Information: Originator: Barry, K.M., Cavers, D.A., and Kneale, C.W. Publication_Date: 1975 Title: Recommended standards for digital tape formats Series_Information: Series_Name: Geophysics Issue_Identification: v. 40, no. 2 Other_Citation_Details: pages 344-352 Online_Linkage: http://www.seg.org/publications/tech-stand/ Cross_Reference: Citation_Information: Originator: Cohen, J.K., and Stockwell, J.W., Jr., CWP/SU Publication_Date: 2010 Title: Seismic Un*x Release No. 44: An open source software package for seismic research and processing Publication_Information: Publication_Place: Golden, Colorado Publisher: Center for Wave Phenomena, Colorado School of Mines Online_Linkage: https://github.com/JohnWStockwellJr/SeisUnix Cross_Reference: Citation_Information: Originator: Arnell S. Forde Originator: Nancy T. DeWitt Originator: Jennifer L. Miselis Publication_Date: 20181031 Title: Archive of Chirp Subbottom Profile Data Collected in 2016 from the Northern Chandeleur Islands, Louisiana Geospatial_Data_Presentation_Form: multimedia presentation Series_Information: Series_Name: U.S. Geological Survey Data Release Issue_Identification: doi:10.5066/P9NFK0K4 Publication_Information: Publication_Place: St. Petersburg, Florida Publisher: U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Online_Linkage: https://doi.org/10.5066/P9NFK0K4 Cross_Reference: Citation_Information: Originator: Arnell S. Forde Originator: Nancy T. DeWitt Originator: Jake J. Fredericks Originator: Jennifer L. Miselis Publication_Date: 20180116 Title: Archive of Chirp Subbottom Profile Data Collected in 2015 from the Northern Chandeleur Islands, Louisiana Geospatial_Data_Presentation_Form: multimedia presentation Series_Information: Series_Name: U.S. Geological Survey Data Release Issue_Identification: doi:10.5066/F7668C5C Publication_Information: Publication_Place: St. Petersburg, Florida Publisher: U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Online_Linkage: https://doi.org/10.5066/F7668C5C Cross_Reference: Citation_Information: Originator: Arnell S. Forde Originator: Nancy T. DeWitt Originator: Jake J. Fredericks Originator: Jennifer L. Miselis Publication_Date: 20180117 Title: Chirp Subbottom Profile Data Collected in 2015 from the Northern Chandeleur Islands, Louisiana Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 1077 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Online_Linkage: http://doi.org/10.3133/ds1077 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The validity or accuracy of marine subbottom profiles is highly qualitative and dependent on equipment and operating condition variables. Visual inspection of the images rendered from the data did show the presence of some anomalies, at depth, within the nearshore lines. The cause for this issue was likely due to mechanical interference from a concurrently running piece of equipment. Logical_Consistency_Report: These datasets are from one field activity with consistent instrument calibrations. Completeness_Report: A total of 34 seismic lines were collected during this survey. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: An Applanix POS MV Wavemaster II system was used to provide position information. Manufacture stated accuracy for positioning utilizing differential global positioning system (DGPS) is 0.5-2 m. To ensure consistent spacing between survey lines (for example, 5 m in the nearshore and 10 m for offshore lines), pre-determined trackline locations were imported into HYPACK 2016a navigation software and followed during seismic data collection. Positions from the POS MV inertial aided navigation system (IANS) were recorded and written to seismic trace headers in latitude and longitude coordinates (World Geodetic System of 1984, WGS84, realization G1762) every 1 second (s). The approximate 4-m offset between the chirp shot and ship's GPS reference point was not accounted for during acquisition, nor have the ASCII navigation files and trackline map been corrected to reflect the offset. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: These data are not to be used for bathymetry. Two-way travel (TWT) times shown on the printable profile images are relative to the chirp towfish position, not to the sea surface. Lineage: Process_Step: Process_Description: Chirp processing: The SEG Y data were processed with Seismic Unix (Release 44) software to produce gained Graphics Interchange Format (GIF) images of the subbottom profiles included in this data release. A representative chirp data processing sequence consisted of (1) removing navigation data for each shot and converting the SEG Y file to SU format, (2) applying automatic gain control, (3) generating a PostScript image of the traces, and (4) converting the PostScript image to a GIF image. For additional SU processing and script details, please refer to Data Series 1077 (Forde and others, 2018). Source_Used_Citation_Abbreviation: SEG Y Process_Date: 20180808 Source_Produced_Citation_Abbreviation: SEG Y.gif Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell S. Forde Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Process_Step: Process_Description: Navigation processing: Location data were extracted from the SEG Y headers using Seismic Unix software and output as ASCII text files; PROJ.5.1.0 (https://proj4.org/) software was used to project WGS84 latitude and longitude coordinates to Universal Transverse Mercator (UTM) northings and eastings (WGS84, Zone 16, meters). Raw navigation files for each seismic line, saved by line number, were concatenated into comma-delimited text files for use with Esri ArcGIS software. The final output files are as follows: (1) 2017-337-FA.txt contains unique shotpoint positions (along each line) for the entire survey, (2) s2017-337-FA.txt includes the 1,000-shot-interval locations that were generated to correlate shot locations on the trackline map with evenly spaced 1,000-shot index markers along the top of the printable profile images, and (3) 2017-337-FA_s has the start-of-line locations for each trackline. The concatenated, comma-delimited text files were later imported into ArcGIS and saved as either a point or polyline file (in Esri's shapefile format) for use in the map document (.mxd) included in this archive. Source_Used_Citation_Abbreviation: L01-36.txt and JD221_line14.txt Process_Date: 20180808 Source_Produced_Citation_Abbreviation: 2017-337-FA.txt Source_Produced_Citation_Abbreviation: s2017-337-FA.txt Source_Produced_Citation_Abbreviation: 2017-337-FA_s.txt Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell S. Forde Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Process_Step: Process_Description: Trackline map creation: 2017-337-FA_location.mxd was created with Esri ArcGIS 10.3.1 software. The survey navigation file, 2017-337-FA.txt, was imported into ArcMap 10.3.1 and processed using the ArcScript "Points to Lines" to create a line shapefile of the cruise tracklines called 2017-337-FA_trkln. The 1,000-shot-interval file and the start-of-line file were imported into ArcMap and saved as point shapefiles 2017-337-FA_shots and 2017-337-FA_sol, respectively. The ArcGIS files included in this release are unprojected (geographic coordinates, WGS84). Please refer to the individual shapefile metadata and readme file, included in 2017-337-FA_arc.zip, for detailed information about the geospatial files provided in this data release. Source_Used_Citation_Abbreviation: 2017-337-FA.txt Source_Used_Citation_Abbreviation: s2017-337-FA.txt Source_Used_Citation_Abbreviation: 2017-337-FA_s.txt Process_Date: 2017 Source_Produced_Citation_Abbreviation: 2017-337-FA_trkln.shp Source_Produced_Citation_Abbreviation: 2017-337-FA_shots.shp Source_Produced_Citation_Abbreviation: 2017-337-FA_sol.shp Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell S. Forde Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.0197884765 Longitude_Resolution: 0.0227336944 Geographic_Coordinate_Units: Decimal Degrees Geodetic_Model: Horizontal_Datum_Name: World Geodetic System of 1984 Ellipsoid_Name: WGS 1984 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257223563 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: 2017-337-FA.txt, s2017-337-FA.txt, 2017-337-FA_s.txt Entity_Type_Definition: Shotpoint navigation files Entity_Type_Definition_Source: SEG Y headers, https://seg.org/Publications/tech-stand. Attribute: Attribute_Label: UTMX Attribute_Definition: UTM-X coordinate (Zone 16) Attribute_Definition_Source: Universal Transverse Mercator Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 318979.671 Range_Domain_Maximum: 321636.88 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: UTMY Attribute_Definition: UTM-Y coordinate (Zone 16) Attribute_Definition_Source: Universal Transverse Mercator Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 3325218.753 Range_Domain_Maximum: 3328246.93 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: Line Attribute_Definition: Trackline number Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Unrepresentable_Domain: The naming convention used for each subbottom line is as follows: Lxy, where 'L' is an abbreviation of line and precedes the line number, 'x' is a 2-digit number representing a specific trackline number, and 'y' is a letter (in this case, b) representing a new line if recording was prematurely terminated or reran for quality or acquisition problems. If a trackline exceeded the file size limit/maximum shotpoint number (as determined by the acquisition software, Discover v. 4.09) the filename was appended with sequentially increasing numbers such as .001, .002, etc. A single line, JD221_line14, did not use the previously described naming convention. Attribute: Attribute_Label: Shot Attribute_Definition: Shotpoint number Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 7291 Attribute: Attribute_Label: Lon Attribute_Definition: Longitude (decimal degrees) Attribute_Definition_Source: World Geodetic System 1984 Geographic Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -88.878025 Range_Domain_Maximum: -88.850142 Attribute_Units_of_Measure: decimal degrees Attribute: Attribute_Label: Lat Attribute_Definition: Latitude (decimal degrees) Attribute_Definition_Source: World Geodetic System 1984 Geographic Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 30.044906 Range_Domain_Maximum: 30.072017 Attribute_Units_of_Measure: decimal degrees Attribute: Attribute_Label: YEAR Attribute_Definition: Year Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2017 Range_Domain_Maximum: 2017 Attribute: Attribute_Label: DOY:HR:MIN:SEC Attribute_Definition: Day of year:hour:minute:second Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Unrepresentable_Domain: Day of year, hour, minute and second of data acquisition Overview_Description: Entity_and_Attribute_Overview: Binary data file: Seismic trace data are available as binary files in SEG Y format. These files have a .sgy extension and range in size from 19.3 to 86.1 MB. These data are included in the download file, 2017-337-FA_segy.zip, and can also be found by going to https://cmgds.marine.usgs.gov. The SEG Y rev. 0 format (Barry and others, 1975) presented here consists of the following: a 3,600-byte reel identification header, with the first 3,200 bytes consisting of an ASCII header block followed by a 400-byte binary header block, both of which include information specific to line and reel number; a trace data block that follows the reel identification header, with the first 240 bytes of each trace block consisting of the binary trace identification header; and seismic data samples that follow the trace identification header. Entity_and_Attribute_Overview: Graphic image file: Printable versions of the processed subbottom profiles are available as GIF images and are included in the download file, 2017-337-FA_seisimag.zip. Entity_and_Attribute_Overview: Navigation file: Navigation files are available as ASCII text files. Provided are raw shotpoint navigation files, reprojected survey shotpoint navigation, 1,000-shot-interval locations, and start of line files. The final navigation files are provided in 2017-337-FA_nav.zip. Entity_and_Attribute_Overview: GIS file: The GIS data associated with this survey are provided as a compressed zip file, 2017-337-FA_arc.zip, which is composed of an Esri map document, shapefiles, a folder for the processed profile images, shapefile metadata for each GIS file and a readme document. The shapefiles provided may also be viewed using other versions of Esri desktop software including their free software Explorer for ArcGIS, which is available at http://www.esri.com/software/arcgis/explorer/index.html. Entity_and_Attribute_Detail_Citation: The entity and attribute information were generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell S. Forde Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Contact_Instructions: The SEG Y files included in this data release are also downloadable from the Coastal and Marine Geoscience Data System https://cmgds.marine.usgs.gov. Distribution_Liability: This publication was prepared by an agency of the United States Government. Although these data were processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: SEG Y Format_Version_Number: Revision 0 File_Decompression_Technique: Winzip or 7zip Transfer_Size: 1560 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9E8VRGO/data/2017-337-FA_segy.zip Digital_Form: Digital_Transfer_Information: Format_Name: ASCII File_Decompression_Technique: Winzip or 7zip Transfer_Size: 4.10 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9E8VRGO/data/2017-337-FA_nav.zip Digital_Form: Digital_Transfer_Information: Format_Name: SHP (Esri shapefile) File_Decompression_Technique: Winzip or 7zip Transfer_Size: 22.9 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9E8VRGO/data/2017-337-FA_arc.zip Digital_Form: Digital_Transfer_Information: Format_Name: GIF File_Decompression_Technique: Winzip or 7zip Transfer_Size: 21.5 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9E8VRGO/data/2017-337-FA_seisimag Fees: None Technical_Prerequisites: Use of SEG Y data requires specialized seismic processing software, such as public domain software Seismic Unix http://www.cwp.mines.edu/cwpcodes/index.html. Metadata_Reference_Information: Metadata_Date: 20181105 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell S. Forde Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: aforde@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998