Archive of Chirp Sub-Bottom Profile, Imagery, and Navigational Data Collected in June and August 2023 from the Chandeleur Islands, Louisiana

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Arnell S. Forde
Publication_Date: 20240515
Title:
Archive of Chirp Sub-Bottom Profile, Imagery, and Navigational Data Collected in June and August 2023 from the Chandeleur Islands, 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: Jennifer L. Miselis
Originator: Chelsea A. Stalk
Originator: Noreen A. Buster
Publication_Date: 20240515
Title:
Chirp Sub-Bottom Profile Geophysical Data Collected in 2023 From the Chandeleur Islands, Louisiana
Edition: 1.0
Series_Information:
Series_Name: U.S. Geological Survey data release
Issue_Identification: doi:10.5066/P1HOLGKM
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/P1HOLGKM
Description:
Abstract:
As part of the 2022 Disaster Supplemental project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted a nearshore geophysical survey to map the shoreface and inner shelf, as well as characterize stratigraphy near the Chandeleur Islands, Louisiana (LA) in June and August 2023. The purpose of this study was to conduct a morphologic and geologic assessment of the impacts of the 2020 and 2021 hurricane seasons within part of the Breton National Wildlife Refuge (specifically around Hewes Point and Monkey Bayou). These geophysical data will be used to quantify sediment redistribution resulting from storms. 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) 2023-325-FA (subFANs 23BIM05 and 23BIM10). Additional survey and data details are available from the USGS Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov/fan_info.php?fan=2023-325-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: 20230617
Ending_Date: 20230808
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -88.89780
East_Bounding_Coordinate: -88.83650
North_Bounding_Coordinate: 30.07260
South_Bounding_Coordinate: 29.73750
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:f322fa56-209d-41c5-aa83-18e17c5f3f39
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: 2023-325-FA
Place:
Place_Keyword_Thesaurus: Common Geographic Areas
Place_Keyword: Louisiana
Place_Keyword: Plaquemines
Place_Keyword: Eastern Louisiana Coastal
Place_Keyword: Breton National Wildlife Refuge
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 were provided by the Department of Interior Supplemental Appropriations for Disaster Recovery Activities Task 1, part of the Extending Government Funding and Delivering Emergency Assistance Act (Public Law 117-43) and the USGS Coastal and Marine Hazards and Resources Program. The authors thank Andrew Farmer of SPCMSC for his assistance with data collection and piloting the Research Vessel (R/V) Sallenger. Field activity planning was performed by Noreen Buster and Jennifer Miselis; data collection conducted by Chelsea Stalk and Jennifer Miselis; and data processing performed by Arnell Forde. This document was improved by scientific/editorial and metadata reviews from Nancy DeWitt and Breanna Williams of the SPCMSC.
Native_Data_Set_Environment:
Environment as of Metadata Creation: Microsoft Windows 10 Version 6.2 (Build 9200); Environmental Systems Research Institute (Esri) ArcMap 10.8.2; MacOS Ventura 13.6.4; 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:
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
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 collected during two surveys, which occurred on June 17 (Leg 1; subFAN 23BIM05) and August 5–8, 2023 (Leg 2; subFAN 23BIM10).
Completeness_Report:
A total of 40 seismic lines were collected during this field activity.
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 2022.3.5 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 (with unique navigation fixes being recorded every second) and were subsequently converted to decimal degrees latitude and longitude coordinates (World Geodetic System of 1984, WGS84, realization G1150). The approximate 3-m offset between the chirp shot position and the vessel's IANS reference point were 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 from one survey platform that utilized two, different EdgeTech portable sub-bottom profiling (SBP) systems. EdgeTech's 3100-P (aka chirp SB-424; frequency range from 4-24 kilohertz (kHz)) and 3400 (aka chirp SB-216; dual frequency 2-16 kHz transducers) SBPs were towed on the port side of the 26-foot research vessel, the R/V Sallenger. In total, 40 lines, equivalent to a total of 135.1 line-kilometers, were surveyed. The seismic source utilized during 2023-325-FA consisted of an EdgeTech 424 or 216 towfish running DISCOVER version 4.09 acquisition software and towed on the port side of the vessel, 3.56 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 4-20 kHz (DOY 217); 3-12 kHz (DOY 219 and 220); or 3-16 kHz (DOY 168), pulse lengths ranged between 5 ms and 20 ms, and recording lengths were 35.5 ms (DOY 219 and 220), 59.18 ms (DOY 168), and 60.47 ms (DOY 217). Based on survey speeds of 3.5-4.5 knots, the shot spacing was roughly 0.450 m. During acquisition, positions from the POS MV IANS 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, IBM 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 Field Activity Collection System (FACS) logs and acquisition geometry figure are also provided as supplemental information in the download file, 2023-325-FA_logs.zip.
Process_Date: 20230808
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jennifer Miselis
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: jmiselis@usgs.gov
Process_Step:
Process_Description:
Chirp processing and image creation - The EdgeTech 3100 and 3400 chirp systems recorded the sub-bottom data in JSF and SEG-Y rev. 1 formats. 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) removing raw [vessel] navigation data for each shot and converting the SEG-Y file to SU format, (2) applying automatic gain control, (3) trimming the trace data TWT to 30 ms (no observable features, aside from multiples, were encountered below that point in the profiles), (4) generating a PostScript image of the traces, and (5) converting the PostScript image to a GIF image. The sub-bottom profile images have tic marks every 200 shots, with labels, larger tic marks, and dashed grid lines every 1,000 shots.
Source_Used_Citation_Abbreviation: *.sgy
Process_Date: 20240123
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 Reson T50P dual head MBES system and Applanix POS MV Wavemaster II IANS with two Trimble GA830 GNSS antennas (positioned forward-aft near the aft-starboard of the vessel) were 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 antenna 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 using GIS software. The final output files are as follows: (1) 2023-325-FA_nav.csv contains unique shotpoint positions (along each line) for the entire survey – roughly every 5 shots, (2) 2023-325-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) 2023-325-FA_sol.csv has the start-of-line locations for each trackline. The concatenated, comma-delimited text files were later imported into ArcMap 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 2023-325-FA_geospatial_metadata files included in the data release.
Source_Used_Citation_Abbreviation: *.txt
Process_Date: 20240123
Source_Produced_Citation_Abbreviation: 2023-325-FA_nav.csv
Source_Produced_Citation_Abbreviation: 2023-325-FA_1000sht.csv
Source_Produced_Citation_Abbreviation: 2023-325-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: 0.0197889864
Longitude_Resolution: 0.0227019979
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 (2023-325-FA_nav.zip): Navigation files are available as ASCII delimited text files in comma-separated values file format. The survey's shotpoint navigation file, 2023-325-FA_nav.csv (78,038 data records), represents the reprojected survey shotpoint navigation; 2023-325-FA_1000sht.csv (369 data records) provides 1,000-shot-interval locations; and 2023-325-FA_sol.csv (40 data records) contains start of line information. The shapefile version of these data is available in 2023-325-FA_gis.zip. For more information about these geospatial files, refer to the 2023-325-FA_geospatial_metadata files included in the data release. The navigation and geospatial files share the same attribute labels and definitions, aside from "FID" and "Shape", which are specific to the .shp files. 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 (2023-325-FA_segy.zip): Seismic trace data are available as binary files in SEG-Y format (40 files). These files have a .sgy extension and range in size from 10.3 to 254.5 megabytes. The SEG-Y rev. 1 format (Norris and Faichney, 2002) data 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 files (2023-325-FA_seisimag.zip): Printable versions of the processed sub-bottom profiles are available as GIF images (40 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:
2023-325-FA_nav.csv, 2023-325-FA_1000sht.csv, 2023-325-FA_sol.csv, *.sgy, *.gif, DataDictionary_SBP.docx
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 1
Format_Information_Content: The ZIP file contains the SEG-Y data and support information.
File_Decompression_Technique: Winzip or 7zip
Transfer_Size: 2790
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
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: 1.2
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
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: 48.2
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
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: 20240515
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

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