Metadata:
Identification_Information:
Citation:
Citation_Information:
Originator: Arnell S. Forde
Publication_Date: 20250312
Title: Archive of Chirp Sub-Bottom Profile, Imagery, and Navigational Data Collected During USGS Field Activity Number 2024-320-FA in 2024 Offshore of Breton Island, Louisiana
Edition: 1.0
Geospatial_Data_Presentation_Form: SEG-Y, tabular, and raster digital data
Larger_Work_Citation:
Citation_Information:
Originator: Arnell S. Forde
Originator: Chelsea A. Stalk
Originator: James G. Flocks
Publication_Date: 20250312
Title: Chirp Sub-Bottom Profile Geophysical Data Collected in 2024 Offshore of Breton Island, Louisiana
Edition: 1.0
Series_Information:
Series_Name: U.S. Geological Survey data release
Issue_Identification: doi:10.5066/P13SMFT7
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/P13SMFT7
Description:
Abstract: As part of the Breton Island Post Construction Monitoring project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted a nearshore geophysical survey in August 2024 to map the borrow site created during the Breton Island, Louisiana (LA) restoration effort that began in December 2020. The restoration effort was part of the Deepwater Horizon oil spill settlement to restore natural resources and services injured by the spill. Following restoration, monitoring efforts of the island and surrounding seafloor are necessary to evaluate the programmatic goals of the restoration. This survey, funded by the Louisiana Outer Coast Restoration project, reoccupies a subset of sub-bottom profile tracklines originally acquired in August 2022, refer to Forde and others (2023) for details. The data provided in this publication provide baseline information regarding the physical structure of the dredge pit and help researchers monitor morphologic evolution over time. The data release associated with this metadata record serves as an archive of high-resolution chirp sub-bottom trace data and navigation files. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y revision 1 format (Norris and Faichney, 2002). Processed sub-bottom profile images, survey trackline map, geographic information system (GIS) data, and formal Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) are also provided.
Purpose: The purpose of the data release described herein is to archive and disseminate digital chirp sub-bottom profile data and associated files collected during USGS Field Activity Number (FAN) 2024-320-FA. Additional survey and data details are available from the USGS Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov/services/activity.php?fan=2024-320-FA.
Supplemental_Information: 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) image of the shallow geologic structure beneath the towfish is produced.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20240809
Ending_Date: 20240809
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -89.129594
East_Bounding_Coordinate: -89.093728
North_Bounding_Coordinate: 29.480681
South_Bounding_Coordinate: 29.457006
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:6cca6731-4c79-4860-a1ae-4100c389f301
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_Keyword: navigational data
Theme_Keyword: geospatial datasets
Theme_Keyword: field activity logs
Theme_Keyword: image collections
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: 2024-320-FA
Place:
Place_Keyword_Thesaurus: Common Geographic Areas
Place_Keyword: Breton Islands
Place_Keyword: Breton National Wildlife Refuge
Place_Keyword: Breton Sound
Place_Keyword: Breton Wilderness
Place_Keyword: Louisiana
Access_Constraints: No access constraints. Please see 'Distribution Information' for details.
Use_Constraints: These data are marked with a Creative Common CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations.
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 Hazards and Resources Program. The authors thank Captain Andrew Farmer of the SPCMSC for his assistance in data collection and piloting the Research Vessel (R/V) Sallenger. Field activity planning was performed by James Flocks; data collection conducted by Chelsea Stalk and James Flocks; and data processing performed by Arnell Forde. This document was improved by scientific/editorial and metadata reviews from Christopher Bemelmans and Tess Rivenbark-Terrano of the SPCMSC.
Native_Data_Set_Environment: Environment as of Metadata Creation: Microsoft Windows 11 Enterprise Version 23H2; Environmental Systems Research Institute (Esri) ArcGIS Pro 3.2.1; MacOS Sonoma 14.6.1; Seismic Unix (Release 44); PROJ.5.1.0.
Cross_Reference:
Citation_Information:
Originator: Norris, M.W.
Originator: Faichney, A.K.
Publication_Date: 2002
Title: SEG-Y rev 1 data exchange format
Series_Information:
Series_Name: Society of Exploration Geophysicists, SEG Technical Standards Committee
Issue_Identification: Release 1.0, May 2002
Online_Linkage: https://library.seg.org/pb-assets/technical-standards/seg_y_rev1.pdf
Cross_Reference:
Citation_Information:
Originator: Cohen, J.K.
Originator: Stockwell, J.W., Jr.
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: Forde, A.S.
Originator: Flocks, J.G.
Originator: Farmer, A.S.
Publication_Date: 20231101
Title: Archive of chirp subbottom profile data collected in 2022 from Breton Island, Louisiana
Series_Information:
Series_Name: U.S. Geological Survey data release
Issue_Identification: doi:10.5066/P9Q28MFD
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/P9Q28MFD
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report: The validity or accuracy of marine sub-bottom profiles is highly qualitative and dependent on equipment and operating condition variables.
Logical_Consistency_Report: These datasets are from one field activity with consistent instrument calibrations. Seismic data were acquired during a single survey, 2024-320-FA, which occurred between August 2 and 12, 2024.
Completeness_Report: A total of 28 seismic lines were collected during this field activity. Additional survey and data details are available from the Field Activity Collection System (FACS) logs and acquisition geometry figure, which are included as supplemental information in the download file, 2024-320-FA_logs.zip.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report: As the sub-bottom profile data were acquired, the position of the vessel was continuously determined by an Applanix POS MV Wavemaster II inertial aided navigation system (IANS), which is accurate to within 0.5-2 meters (m). To ensure consistent spacing between survey lines acquired aboard the R/V Sallenger, pre-determined trackline locations were imported into HYPACK® 2023 Q3 navigation software and followed during seismic data collection. During acquisition, positions from the POS MV IANS were recorded and written to the seismic trace headers in arcseconds every 0.20 s and were subsequently converted to decimal degrees latitude and longitude coordinates (World Geodetic System of 1984, WGS84, realization G1150). The approximate 4-m offset between the chirp shot position and the vessel's IANS reference point of the Applanix system, the Inertial Measurement Unit (IMU), was not accounted for during acquisition, nor have the American Standard Code for Information Interchange (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 or navigation. Two-way travel times (TWT) shown on the printable profile images are relative to the chirp towfish position (below the sea surface), not to the sea surface.
Lineage:
Process_Step:
Process_Description:
Chirp acquisition - Sub-bottom data were acquired using an Edgetech 3400 Portable Sub-Bottom Profiler (SBP), which was towed by the 26-foot research vessel, the R/V Sallenger. A total of 28 lines were surveyed. The seismic source utilized during FAN 2024-320-FA consisted of an EdgeTech 3400 towfish running DISCOVER version 42.0.1.115 acquisition software and towed on the port side of the vessel, approximately 4 m across-track from the IANS reference point. The data were acquired in J-STAR standard format (JSF) and SEG-Y format at 5 hertz (Hz), which equates to one ping per 0.20 seconds. The frequency sweep was 1-26 kilohertz (kHz) and 3-10 kHz, pulse lengths were 5 ms and 20 ms, and the recording length was 65.1 ms. Based on survey speeds of 3.5-4.5 knots, the shot spacing was roughly 0.450 m. During acquisition, positions from the antenna were recorded and written to the seismic trace headers in arcseconds every 0.20 s.
The binary portion of the seismic data provided in the data release is stored in SEG-Y rev. 1, IEEE 32-bit float [big-endian byte order] 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 ASCII format instead of Extended Binary Coded Decimal Interchange Code (EBCDIC) format. The SEG-Y formatted envelope trace files have a .sgy extension and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU) (Cohen and Stockwell, 2010). The printable profiles (provided in .gif format) are chirp sub-bottom profile images that were processed using SU software. Survey FACS logs and acquisition geometry figure are also provided as supplemental information in the download file, 2024-320-FA_logs.zip.
Process_Date: 20240809
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: James G. Flocks
Contact_Organization: U.S. Geological Survey
Contact_Position: Research Geologist
Contact_Address:
Address_Type: Mailing and physical
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: jflocks@usgs.gov
Process_Step:
Process_Description: Chirp processing and image creation - The EdgeTech 3400 dual frequency SBP system recorded the sub-bottom data in JSF and SEG-Y rev. 1 formats. SEG-Y data were saved (with alternating pings supplied by each transducer) as separate files for the 1-26 kHz and 3-10 kHz frequencies. 1-26 kHz data have “A” appended to the end of the file name, for example, 20240809144450A.sgy. The raw JSF data are not provided in the data release but are available upon request. Using the jsf2segy software package (https://github.com/Geosvy/jsf2segy), JSF files were converted to analytic and envelope SEG-Y traces. The envelope SEG-Y files are comprised of the combined frequency data. Enveloped SEG-Y trace data were processed with custom scripts and SU Release 44 (Cohen and Stockwell, 2010) software to produce gained Graphics Interchange Format (GIF) images of the sub-bottom profiles included in the data release. A representative chirp data processing sequence consisted of (1) creating the envelope seismic data file from the analytic data (envelope converted files included in this publication have "_env" appended to the line name), (2) removing raw [vessel] navigation data for each shot and converting the SEG-Y file to SU format, (3) setting the initial FFID value (trace header bytes 9-12) to one before incrementally increasing it by 1 and then applying automatic gain control to the profile, (4) trimming the trace data TWT to 30 ms (no observable features, aside from multiples, were encountered below that point in the profiles), (5) generating a PostScript image of the traces, and (6) converting the PostScript image to a GIF image. The SBP images have tic marks every 200 shots, with labels, larger tic marks, and dashed grid lines every 1,000 shots. Shot numbers shown on the SBP images correspond to the trace sequence number within the line (trace header bytes 1-4) or trace sequence number within the reel (bytes 5-8) included in the SEG-Y headers for each profile.
Source_Used_Citation_Abbreviation: *.sgy
Process_Date: 20240822
Source_Produced_Citation_Abbreviation: *.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: 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 acquisition and processing - A Teledyne T50-P multibeam system with an integrated Applanix Pos MV Wavemaster II V5 IANS with two Trimble GA830 global navigation satellite system antennas (positioned amidships) and an associated IMU was used for positioning onboard the R/V Sallenger. Real-time positions from the Applanix system were recorded and written to the seismic trace headers via a RS232 cable running from the Applanix receiver to the topside unit of the chirp system every 0.20 seconds, with unique navigation fixes being recorded every second. During sub-bottom processing, location data were extracted from the SEG-Y headers of the processed chirp profiles, using bespoke scripts and SU (Cohen and Stockwell, 2010) software and output as ASCII text files; PROJ.5.1.0 (https://proj.org/) software was used to project WGS84 latitude and longitude coordinates to Universal Transverse Mercator (UTM) northings and eastings (WGS84, Zone 16 North [N], meters). Navigation files for each sub-bottom line, saved by line number, were concatenated into comma-separated values (.csv) files so they could be represented geospatially in GIS software. The final output files are as follows: (1) 2024-320-FA_nav.csv contains unique shotpoint positions (along each line) for the entire survey – roughly every 5 shots, (2) 2024-320-FA_1000sht.csv includes the 1,000-shot-interval locations that were generated to correlate shot locations along the tracklines with evenly spaced 1,000-shot index markers along the top of the printable profile images, and (3) 2024-320-FA_sol.csv has the start-of-line locations for each trackline. The concatenated, comma-delimited text files were later imported into ArcGIS Pro and saved as either a point or polyline file (in Esri's shapefile format, .shp) for subsequent use in GIS software packages. For more information about these geospatial files, refer to the 2024-320-FA_geospatial_metadata file included in this data release.
Source_Used_Citation_Abbreviation: *.txt
Process_Date: 20240822
Source_Produced_Citation_Abbreviation: 2024-320-FA_nav.csv
Source_Produced_Citation_Abbreviation: 2024-320-FA_1000sht.csv
Source_Produced_Citation_Abbreviation: 2024-320-FA_sol.csv
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: 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: 0.0197577306
Longitude_Resolution: 0.0248912658
Geographic_Coordinate_Units: Decimal Degrees
Geodetic_Model:
Horizontal_Datum_Name: WGS_1984
Ellipsoid_Name: WGS_84
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257223563
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview: Navigation files (2024-320-FA_nav.zip): Navigation files are available as ASCII delimited text files in comma-separated values file format. The survey shotpoint navigation files, 2024-320-FA_nav.csv (20,731 data records), represent the reprojected survey shotpoint navigation; 2024-320-FA_1000sht.csv (91 data records) provides 1,000-shot-interval locations; and 2024-320-FA_sol.csv (28 data records) contains start of line information. The shapefile version of this dataset is available in 2024-320-FA_gis.zip. For more information about these geospatial files, refer to the 2024-320-FA_geospatial_metadata file included in the data release. The navigation and geospatial files mainly share the same attribute labels and definitions, aside from "FID" and "Shape", which are specific to the .shp files. Due to ArcGIS Pro character restrictions, the point shapefile attribute labels (for date and time) were changed to “DOY_HR_MIN” within the attribute tables. The detailed attribute descriptions for the navigation files are provided in the data dictionary (DataDictionary_SBP.docx); the metadata are not complete without this file.
Entity_and_Attribute_Overview: Binary data files (2024-320-FA_segy.zip): Seismic trace data are available as binary files in SEG-Y format (56 files). These files have a .sgy extension and range in size from 3.8 to 45.8 megabytes. The SEG-Y rev. 1 format (Norris and Faichney, 2002) data presented here consist 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 files (2024-320-FA_seisimag.zip): Printable versions of the processed sub-bottom profiles are available as GIF images (28 files).
Entity_and_Attribute_Detail_Citation: The entity and attribute information were generated by the individual 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: SPCMSC Data Management Group
Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
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: gs-g-spcmsc_data_inquiries@usgs.gov
Resource_Description: 2024-320-FA_nav.csv, 2024-320-FA_1000sht.csv, 2024-320-FA_sol.csv, *.sgy, *.gif, DataDictionary_SBP.docx
Distribution_Liability: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: SEG-Y
Format_Version_Number: revision 1
Format_Information_Content: The ZIP file contains the SEG-Y data and support information.
File_Decompression_Technique: Winzip or 7zip
Transfer_Size: 1170
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P13SMFT7/data/2024-320-FA_segy.zip
Digital_Form:
Digital_Transfer_Information:
Format_Name: Comma-delimited text
Format_Information_Content: The ZIP file contains the survey navigation data and support information.
File_Decompression_Technique: Winzip or 7zip
Transfer_Size: 0.367
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P13SMFT7/data/2024-320-FA_nav.zip
Digital_Form:
Digital_Transfer_Information:
Format_Name: GIF
Format_Information_Content: The ZIP file contains images of the processed sub-bottom profile data and support information.
File_Decompression_Technique: Winzip or 7zip
Transfer_Size: 11.9
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P13SMFT7/data/2024-320-FA_seisimag.zip
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/SeisUnix).
Metadata_Reference_Information:
Metadata_Date: 20250312
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: SPCMSC Data Management Group
Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
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: gs-g-spcmsc_data_inquiries@usgs.gov
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998