Metadata: Identification_Information: Citation: Citation_Information: Originator: Arnell S. Forde Originator: Jake J. Fredericks Originator: James G. Flocks Publication_Date: 20190503 Title: Archive of Chirp Subbottom Profile Data Collected in 2017 from the Louisiana Chenier Plain Geospatial_Data_Presentation_Form: multimedia presentation Series_Information: Series_Name: U.S. Geological Survey Data Release Issue_Identification: doi:10.5066/P9XOZIBV 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/P9XOZIBV Description: Abstract: June 2–10 and July 2, 2017, the U.S. Geological Survey (USGS) conducted geophysical surveys offshore of the Louisiana Chenier Plain to document the changing morphology of the coastal environment. Data were collected under the Barrier Island Coastal Monitoring (BICM) program, an ongoing collaboration between the State of Louisiana Coastal Protection and Restoration Authority (CPRA), the University of New Orleans (UNO) Pontchartrain Institute for Environmental Sciences (PIES), and the USGS. Project objectives include compiling historical shoreline bathymetric datasets and comparing them to other bathymetric data collected during the BICM project. At the same time, subsurface geophysical data were collected to investigate the geomorphology and geologic controls on barrier-shoreline evolution. This publication serves as an archive of unprocessed, digital chirp subbottom data, survey trackline maps, 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 Numbers 2017-323-FA (project ID, 17BIM01) and 2017-324-FA (17BIM05). Additional survey and data details are available from CMGDS at, https://cmgds.marine.usgs.gov/. 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. Transducers and receivers are contained within the towfish, which 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 both surveys consisted of an EdgeTech SB-424 towfish running Discover version 4.09 acquisition software and towed on the port side of the R/V Sallenger, approximately 3.5 m opposite the global positioning system (GPS) antenna. These data have not been corrected for layback. 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_Chenier_logs.zip. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20170602 Ending_Date: 20170702 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -93.45203935 East_Bounding_Coordinate: -91.66824965 North_Bounding_Coordinate: 30.386034533 South_Bounding_Coordinate: 28.801240467 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: Barrier Island Mapping Theme_Keyword: 2017-323-FA Theme_Keyword: 2017-324-FA Place: Place_Keyword_Thesaurus: Common Geographic Areas Place_Keyword: United States Place_Keyword: Louisiana Place_Keyword: Vermilion Place_Keyword: Grand Chenier Place_Keyword: Cheniere Au Tigre Place_Keyword: Pecan Island Place_Keyword: Sabine Pass Place_Keyword: White Lake 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 and Barrier Island Coastal Monitoring programs. 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 scientific/editorial and metadata reviews from reviewer 1 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 10.6.1 (Build 8321). 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 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 not show the presence of any anomalies. Logical_Consistency_Report: These datasets are from two field activities with consistent instrument calibrations. Completeness_Report: A total of 86 seismic lines were collected during these surveys. For 2017-323-FA, some lines contained little or no data; consequently, only 67 lines were processed and are included in this data release. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: An Ashtech Proflex 800 GPS receiver 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 DGPS 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 antenna 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. Source_Used_Citation_Abbreviation: SEG Y Process_Date: 20190326 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 15, 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) 2017-323-FA.txt and 2017-324-FA.txt contain unique shotpoint positions (along each line) for the entire survey, (2) s2017-323-FA.txt and s2017-324-FA.txt include 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) 2017-323-FA_s and 2017-324-FA_s.txt have 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: *.txt Process_Date: 20190326 Source_Produced_Citation_Abbreviation: 2017-323-FA.txt, 2017-324-FA.txt Source_Produced_Citation_Abbreviation: s2017-323-FA.txt, s2017-324-FA.txt Source_Produced_Citation_Abbreviation: 2017-323-FA_s.txt, 2017-324-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_Chenier_location.mxd was created with Esri ArcGIS 10.6 software. The survey navigation files, 2017-323-FA.txt and 2017-324-FA, were imported into ArcMap 10.6 and processed using the ArcScript "Points to Lines" to create line shapefiles of the cruise tracklines called 2017-323-FA_trkln and 2017-324-FA_trkln. The 1,000-shot-interval files and the start-of-line files were imported into ArcMap and saved as point shapefiles 2017-323-FA_shots, 2017-324-FA_shots, 2017-323-FA_sol, and 2017-324-FA_sol. The trackline shapefiles for each survey were saved as layer files (.lyr) so a non-proprietary version of the tracklines could be created using the "Layer to KML" tool within ArcToolbox and subsequently output in keyhole markup language (kml) format. 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_Chenier_arc.zip, for detailed information about all the geospatial files provided in this data release. Source_Used_Citation_Abbreviation: 2017-323-FA.txt, 2017-324-FA.txt Source_Used_Citation_Abbreviation: s2017-323-FA.txt, s2017-324-FA.txt Source_Used_Citation_Abbreviation: 2017-323-FA_s.txt, 2017-324-FA_s.txt Process_Date: 20190401 Source_Produced_Citation_Abbreviation: 2017-323-FA_trkln.shp, 2017-323-FA.kmz, 2017-324-FA_trkln.shp, 2017-324-FA.kmz Source_Produced_Citation_Abbreviation: 2017-323-FA_shots.shp, 2017-324-FA_shots.shp Source_Produced_Citation_Abbreviation: 2017-323-FA_sol.shp, 2017-324-FA_sol.shp Source_Produced_Citation_Abbreviation: 2017-323-FA.kmz, 2017-324-FA.kmz 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: 2017-323-FA.txt, 2017-324-FA Entity_Type_Definition: Survey shotpoint navigation files in ASCII text format. Entity_Type_Definition_Source: SEG Y headers, https://seg.org/Publications/tech-stand. Attribute: Attribute_Label: UTMX Attribute_Definition: UTM-X coordinate (Zone 15) Attribute_Definition_Source: Universal Transverse Mercator Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 464124.548 Range_Domain_Maximum: 621277.163 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: UTMY Attribute_Definition: UTM-Y coordinate (Zone 15) Attribute_Definition_Source: Universal Transverse Mercator Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 3257705.318 Range_Domain_Maximum: 3290452.884 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: DOY_year_Lxy or Lxy, where 'DOY' represents the day of year the line was collected, 'year' is 2017, 'L' is an abbreviation of line and precedes the line number, 'x' is a 2- or 3-digit number representing a specific trackline number, and 'y' is a letter 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. 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: 16910 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: -93.370958 Range_Domain_Maximum: -91.749331 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: 29.443167 Range_Domain_Maximum: 29.744108 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 10.2 to 190 MB. These data are included in the download file, 2017_Chenier_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_Chenier_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_Chenier_nav.zip. Entity_and_Attribute_Overview: GIS file: The GIS data associated with these surveys are provided in a compressed zip file, 2017_Chenier_arc.zip, which is composed of an Esri map document, shapefiles, a folder containing 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 was 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: 4500 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9XOZIBV/data/2017_Chenier_segy.zip Digital_Form: Digital_Transfer_Information: Format_Name: ASCII File_Decompression_Technique: Winzip or 7zip Transfer_Size: 7.67 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9XOZIBV/data/2017_Chenier_nav.zip Digital_Form: Digital_Transfer_Information: Format_Name: shapefile File_Decompression_Technique: Winzip or 7zip Transfer_Size: 63.6 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9XOZIBV/data/2017_Chenier_arc.zip Digital_Form: Digital_Transfer_Information: Format_Name: GIF File_Decompression_Technique: Winzip or 7zip Transfer_Size: 60.4 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P9XOZIBV/data/2017_Chenier_seisimag Fees: None Technical_Prerequisites: Use of SEG Y data requires specialized seismic processing software, such as public domain software Seismic Unix https://github.com/JohnWStockwellJr/SeisUnixindex.html. Metadata_Reference_Information: Metadata_Date: 20190409 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