Arnell S. Forde 20240515 1.0 Vector digital data (point and polyline) Arnell S. Forde Jennifer L. Miselis Chelsea A. Stalk Noreen A. Buster 20240515 1.0 U.S. Geological Survey data release doi:10.5066/P1HOLGKM St. Petersburg, Florida U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center https://doi.org/10.5066/P1HOLGKM 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. Shapefiles (.shp) provided in the data release represent point and polyline vector datasets of Field Activity Number (FAN) 2023-325-FA chirp sub-bottom profile trackline, start of line, and 1,000-shot-interval locations. 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 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. Additional survey and data details are available from the Field Activity Collection System (FACS) logs, which are included in the download file, 2023-325-FA_logs.zip. 20230617 20230808 ground condition Complete None planned -88.89780 -88.83650 30.07260 29.73750 USGS Metadata Identifier USGS:96c1ff05-96bc-4d58-8f4f-4b66ccdcadca ISO 19115 Topic Category geoscientificInformation oceans location USGS Thesaurus sub-bottom profiling marine geology geology coastal processes navigational data geospatial datasets None trackline locations start of line locations 1,000-shot-interval locations barrier island mapping seismic reflection 2023-325-FA chirp Common Geographic Areas Louisiana Plaquemines Eastern Louisiana Coastal Breton National Wildlife Refuge Gulf of Mexico None. These data are held in the public domain. 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. Arnell S. Forde U.S. Geological Survey Geologist Mailing and physical

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Saint Petersburg FL 33701 USA (727) 502-8000 aforde@usgs.gov 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 in data collection and piloting the Research Vessel (R/V) Sallenger. Field activity planning 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. 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. Cohen, J.K. Stockwell, J.W., Jr. 2010 Golden, Colorado Center for Wave Phenomena, Colorado School of Mines https://github.com/JohnWStockwellJr/SeisUnix 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). A total of 40 seismic lines were collected during this field activity. 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). Positions from the POS MV IANS were recorded and written to the seismic trace headers every 0.20 seconds, with unique navigation fixes being recorded every second. The approximately 3-meter offset between the chirp and vessel's IANS reference point has not been accounted for in the comma-delimited American Standard Code for Information Interchange (ASCII) navigation or geospatial files. Navigation information was extracted from the seismic trace headers (seismic data available from the data release) using Seismic Unix release 44 software (Cohen and Stockwell, 2010), processed with PROJ.5.1.0 software (https://proj.org/) to generate Universal Transverse Mercator (UTM) Zone 16 North (N) coordinates from latitude and longitude coordinates (World Geodetic System of 1984, WGS84), and then saved as ASCII text files in comma-separated values (CSV) format. Navigation files for each sub-bottom line, saved by line number, were concatenated into comma-delimited text files (.csv) so they could be represented geospatially in geographic information system (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, (2) 2023-325-FA_1000sht.csv includes the 1,000-shot-interval locations that were generated to correlate shot locations along the trackline 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. These CSV files are provided in 2023-325-FA_nav.zip. *.txt 20240123 2023-325-FA_nav.csv 2023-325-FA_1000sht.csv 2023-325-FA_sol.csv Arnell S. Forde U.S. Geological Survey Geologist Mailing and physical

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St. Petersburg FL 33701 USA 727-502-8000 aforde@usgs.gov The reformatted text files referenced in the previous process step were then further processed using Esri ArcMap 10.8.2 software to generate shapefiles. The 1,000-shot navigation file, 2023-325-FA_1000sht.csv, provided in the data release was imported into Esri ArcMap software to produce a geographic representation of the 1,000 shotpoint data collected within the survey area. A 1,000-shot-interval point shapefile (2023-325-FA_1000sht.shp) was generated to correlate shot locations with evenly spaced 1,000-shot index markers along the top of the printable profile images. Likewise, a point shapefile containing the start of line locations for all chirp tracklines, that is based on the reformatted text file 2023-325-FA_sol.csv, was used to create 2023-325-FA_sol.shp. Finally, the 2023-325-FA_nav.csv file containing unique shotpoint positions was imported to ArcGIS to produce a geographic representation of the sub-bottom profile tracklines collected within the survey area. The 'PointsToLine' script (located in the ArcToolbox) was used to create a shapefile (2023-325-FA_trkln.shp) in which individual chirp shotpoints were connected to form tracklines. A non-proprietary version of the shapefiles was created by utilizing the ArcToolbox "Map to KML" tool, which converted each layer to keyhole markup language (KML) format prior to them being compressed (zipped) and saved as a .kmz file (2023-325-FA.kmz). All geospatial files can be found in 2023-325-FA_gis.zip. 2023-325-FA_1000sht.csv 2023-325-FA_sol.csv 2023-325-FA_nav.csv 20240123 2023-325-FA_shots.shp 2023-325-FA_sol.shp 2023-325-FA_trkln.shp 2023-325-FA.kmz Arnell S. Forde U.S. Geological Survey Geologist Mailing and physical

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St. Petersburg FL 33701 (727) 502-8000 aforde@usgs.gov Vector 0.0197889864 0.0227019979 Decimal Degrees WGS_1984 WGS_84 6378137.0 298.257223563 The shapefiles created as part of this geospatial dataset are a derivative of the ASCII CSV navigation files provided in 2023-325-FA_nav.zip, which is 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 these files are provided in the data dictionary (DataDictionary_SBP.docx), the metadata are not complete without this file. The survey's trackline file, 2023-325-FA_trkln.shp (40 data records), is a polyline geospatial dataset of all the chirp sub-bottom profile tracklines; 2023-325-FA_1000sht.shp (369 data records) is a point geospatial dataset representing the 1,000th shot interval; and 2023-325-FA_sol.shp (40 data records) provides the start of each seismic line as a point geospatial dataset. 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. SPCMSC Data Management Group U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center Mailing and physical

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St. Petersburg FL 33701 USA (727) 502-8000 gs-g-spcmsc_data_inquiries@usgs.gov 2023-325-FA_shots.shp, 2023-325-FA_sol.shp, 2023-325-FA_trkln.shp, 2023-325-FA.kmz, DataDictionary_SBP.docx 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. KML 2023-325-FA_gis.zip contains the survey navigation data represented geospatially using a Google Earth Keyhole Markup Language Zipped (KMZ) file, which is a non-proprietary format, and support information. Winzip or 7zip 1.1 https://coastal.er.usgs.gov/data-release/doi-P1HOLGKM/data/2023-325-FA_gis.zip shapefile 2023-325-FA_gis.zip contains the survey navigation data represented geospatially using point and polyline shapefiles, which can be read by most GIS software packages, and support information. Winzip or 7zip 1.1 https://coastal.er.usgs.gov/data-release/doi-P1HOLGKM/data/2023-325-FA_gis.zip None The geospatial files were created for use with Esri ArcGIS 10.8.2 software. They may also be viewed with QGIS (https://www.qgis.org/en/site/, 2024), Google Earth (https://earth.google.com/, 2024), or other GIS software capable of importing the data. 20240515 SPCMSC Data Management Group U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center Mailing and physical

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St. Petersburg FL 33701 USA (727) 502-8000 gs-g-spcmsc_data_inquiries@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998