Arnell S. Forde
20220503
Archive of Chirp Subbottom Profile, Imagery, and Geospatial Data Collected in 2021 Near Pensacola Beach, Florida
SEG-Y, tabular, vector, and raster digital data
Arnell S. Forde
Nancy T. DeWitt
James G. Flocks
20220503
Archive of Chirp Subbottom Profile and Single-Beam Bathymetry Data Collected in 2021 From Santa Rosa Island, Florida
U.S. Geological Survey data release
doi:10.5066/P9VRSD9J
St. Petersburg, Florida
U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
https://doi.org/10.5066/P9VRSD9J
From June 2 through 9, 2021, researchers from the U.S. Geological Survey (USGS) conducted an inshore and offshore geophysical survey to map the shoreface and determine Holocene stratigraphy near Pensacola Beach, Florida (FL). The Coastal Resource Evaluation for Management Applications (CREMA) project objective includes the investigation of nearshore geologic controls on surface morphology. This publication serves as an archive of high-resolution chirp subbottom trace data, survey trackline map, navigation files, geographic information system (GIS) data, and formal Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). 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). In addition to this data release, the SEG-Y files can be downloaded from the USGS Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov. Coastal multibeam bathymetry data were also collected for this project offshore of the Santa Rosa Island coast (during USGS Field Activity Number 2019-326-FA) and are provided in another data release (Farmer and others, 2020).
The purpose of this data release is to facilitate the archival of digital chirp subbottom profile data and associated files collected during USGS Field Activity Number 2021-322-FA. Additional survey and data details are available from the USGS CMGDS at, https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-322-FA.
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.
20210602
20210609
ground condition
None planned
-87.36180
-87.16920
30.34120
30.27280
USGS Metadata Identifier
USGS:5c5dfaf2-d4ab-40a9-80ea-f9f962c9af81
ISO 19115 Topic Category
geoscientificInformation
oceans
USGS Thesaurus
sub-bottom profiling
marine geology
geology
coastal processes
navigational data
geospatial datasets
field activity logs
image collections
Data Categories for Marine Planning
distributions
physical habitats and geomorphology
Marine Realms Information Bank (MRIB) Keywords
seismic reflection profiling
None
seismic reflection
chirp
Society of Exploration Geophysicists
SEG-Y
barrier island mapping
2021-322-FA
Common Geographic Areas
Santa Rosa
Pensacola
Escambia
Okaloosa
Florida
Gulf Islands National Seashore
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
600 4th Street South
Saint Petersburg
FL
33701
USA
(727) 502-8000
aforde@usgs.gov
Funding and (or) support for this study were provided by the USGS Coastal and Marine Hazards and Resources Program. The authors thank Jake Fredericks (former employee) of the USGS for his assistance in data collection and piloting the R/V (Research Vessel) Sallenger. This document was improved by scientific/editorial and metadata reviews from Emily Wei and Breanna Williams of the St. Petersburg Coastal and Marine Science Center.
Environment as of Metadata Creation: Microsoft Windows 10 Version 6.2 (Build 9200); Environmental Systems Research Institute (Esri) ArcGIS 10.7.1.11595.
Barry, K.M.
Cavers, D.A.
Kneale, C.W.
1975
Recommended standards for digital tape formats
Geophysics
v. 40, no. 2
pages 344-352
https://doi.org/10.1190/1.1440530
Cohen, J.K.
Stockwell, J.W., Jr.
2010
Seismic Un*x Release No. 44: An open source software package for seismic research and processing
Golden, Colorado
Center for Wave Phenomena, Colorado School of Mines
https://github.com/JohnWStockwellJr/SeisUnix
Farmer, A.S.
Fredericks, J.J.
Flocks, J.G.
20201006
Coastal Coastal multibeam bathymetry data collected in 2019 off of Santa Rosa Island, Florida
U.S. Geological Survey data release
doi:10.5066/P9IKP27T
St. Petersburg, Florida
U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
https://doi.org/10.5066/P9IKP27T
The validity or accuracy of marine subbottom profiles is highly qualitative and dependent on equipment and operating condition variables. All lines were acquired with a deep-water delay of 1 ms recorded to the headers. The cause of this issue is unknown but the survey's Electronics Technician, Jake Fredericks, assumed it was attributable to the dual-frequency setting on the EdgeTech SB-3400 rental unit. This deep-water delay was removed during processing by A. Forde; all the corrected SEG-Y files are provided in Forde and others (2022).
These datasets are from one field activity with consistent instrument calibrations.
A total of 95 seismic lines were collected during this field activity, but only 91 were processed. Lines 3.008, 4.002, and inshore_4A were partial lines (< 1 megabyte [MB]) containing no usable data and inshore2A was corrupted during acquisition; consequently, all these lines were excluded from this data release (Forde and others, 2022). For line inshore1, the number of samples was changed (from 1318 to 2290) during recording, which resulted in an issue with the original file. Using the topside unit, the line was played back until shot 1290 and saved (with a shorter two-way travel (TWT) time (~25 ms) than all other lines). This line was processed successfully and has been included in Forde and others (2022).
As the subbottom 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 2021 navigation software and followed during seismic data collection. During acquisition, positions from the POS MV IANS were recorded and written to seismic trace headers in arcseconds every 1 second (s) and were subsequently converted to latitude and longitude coordinates (World Geodetic System of 1984, WGS84, realization G1762). The approximate 3-m offset between the chirp shot position and ship's global positioning system (GPS) antenna 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.
These data are not to be used for bathymetry. TWT times shown on the printable profile images are relative to the chirp towfish position (just below the sea surface), not to the sea surface.
Chirp acquisition - Subbottom data were acquired from the chirp towfish, which was towed by the 26-foot research vessel, the R/V Sallenger and positioned approximately 1 m below the water surface. 95 lines, equivalent to a total of 219 line-kilometers, were surveyed. The seismic source utilized during 2021-322-FA was a rental unit from Echo81 that consisted of an EdgeTech SB-3400 towfish running DISCOVER version 4.09 acquisition software and towed on the port side of the R/V Sallenger, approximately 3 m behind the GPS reference point. The data were acquired at 5 hertz (Hz), which equates to a 0.2 s sample interval, using a frequency sweep of 3-8 kilohertz (kHz), and recording length was approximately 45.86 ms. Based on survey speeds of approximately 4 knots, the shot spacing is approximately 0.450 m.
The binary portion of the seismic data is stored in SEG-Y rev. 0, 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 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 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, 2021-322-FA_logs.zip.
20210602
James G. Flocks
U.S. Geological Survey
Research Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
(727) 502-8000
jflocks@usgs.gov
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 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 profile), (4) generating a PostScript image of the traces, and (5) converting the PostScript image to a GIF image.
SEG-Y
20210805
SEG-Y.gif
Arnell S. Forde
U.S. Geological Survey
Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
(727) 502-8000
aforde@usgs.gov
Navigation acquisition and processing - An Applanix POS MV IANS (positioned amidship) was used for positioning onboard the R/V Sallenger. Real-time positions from the POS MV were recorded and written to the seismic trace headers via a RS232 cable running from the POS MV receiver to the topside unit of the chirp system every second. During subbottom processing, location data were extracted from the SEG-Y headers of the processed chirp profiles, using Seismic Unix (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 subbottom line, saved by line number, were concatenated into comma-delimited text files so they could be represented geospatially using Esri ArcGIS software. The final output files are as follows: (1) 2021-322-FA_nav.csv contains unique shotpoint positions (along each line) for the entire survey, (2) 2021-322-FA_1000sht.csv 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) 2021-322-FA_sol.csv 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.
1*-6*.txt; inshore*.txt
20210805
2021-322-FA_nav.csv
2021-322-FA_1000sht.csv
2021-322-FA_sol.csv
Arnell S. Forde
U.S. Geological Survey
Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
(727) 502-8000
aforde@usgs.gov
Trackline map creation - 2021-322-FA_location.mxd and associated shapefiles (.shp) were created with Esri ArcGIS 10.7 software. The survey navigation file, 2021-322-FA_nav.csv, was imported into ArcMap 10.7.1.11595 and processed using the ArcScript "Points to Line" to create a polyline shapefile of the cruise tracklines called 2021-322-FA_trkln. The 1,000-shot-interval and start-of-line files, 2021-322-FA_1000sht.csv and 2021-322-FA_sol.csv, were imported into ArcMap and saved as point shapefiles. A non-proprietary version of the location map was created by utilizing the ArcToolbox "Map to KML" tool, which converted each layer included in the .mxd document to keyhole markup language (.kml) format prior to them being compressed and saved as a .kmz file. The ArcGIS and Google Earth geospatial files provided in this publication are unprojected (geographic coordinates, WGS84). For detailed information about the ArcGIS files provided in this data release, please refer to the individual metadata records (*_metadata.txt and *.shp.xml) accompanying each shapefile and the readme file included in 2021-322-FA_gis.zip.
2021-322-FA_nav.csv
2021-322-FA_1000sht.csv
2021-322-FA_sol.csv
20220216
2021-322-FA_trkln.shp
2021-322-FA_shots.shp
2021-322-FA_sol.shp
2021-322-FA.kmz
Arnell S. Forde
U.S. Geological Survey
Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
(727) 502-8000
aforde@usgs.gov
Point
0.0197875056
0.0227943825
Decimal Degrees
WGS_1984
WGS_84
6378137.0
298.257223563
2021-322-FA_nav.csv (493434 data records), 2021-322-FA_1000sht.csv (458 data records), 2021-322-FA_sol.csv (91 data records).
These files, which are located in 2021-322-FA_nav.zip, represent the June 2021 subbottom navigation data. The attributes described below are for the survey's shotpoint navigation file, 2021-322-FA_nav.csv. For detailed information specific to the ArcGIS data, please see the associated shapefile metadata.
U.S. Geological Survey
UTMX
UTM-X coordinate (Zone 16N)
Universal Transverse Mercator Coordinate System
465216.59
483734.39
meters
UTMY
UTM-Y coordinate (Zone 16N)
Universal Transverse Mercator Coordinate System
3349049.293
3356611.581
meters
Line
Trackline name
U.S. Geological Survey
Line numbers were automatically assigned by the EdgeTech 3400 chirp topside unit during data acquisition and are composed of sequentially increasing numbers. Lines that were collected inshore are denoted by the addition of a prefix, "inshore" or "inshore_", immediately before the line number. If recording was prematurely terminated or reran, due to quality or acquisition issues, sequentially increasing numbers, beginning at .001, were appended to the trackline name (for example, 1.001, 1.002, etc.).
Shot
Shotpoint number
U.S. Geological Survey
1
20507
Lon
Longitude (decimal degrees)
World Geodetic System 1984 Geographic Coordinate System
-87.361772
-87.169178
decimal degrees
Lat
Latitude (decimal degrees)
World Geodetic System 1984 Geographic Coordinate System
30.272756
30.341225
decimal degrees
YEAR
Year of data acquisition
U.S. Geological Survey
2021
2021
DOY:HR:MIN:SEC
Day of year:hour:minute:second
U.S. Geological Survey
Day of year, hour, minute and second of data acquisition, in Coordinated Universal Time (UTC).
Navigation file: Navigation files are available as ASCII delimited text files in comma-separated values (CSV) file format. The final navigation files are provided in 2021-322-FA_nav.zip (Forde and others, 2022) and represent the reprojected survey shotpoint navigation, 1,000-shot-interval locations, and start of line files.
Binary data file: Seismic trace data are available as binary files in SEG-Y format (91 files). These files have a .sgy extension and range in size from 1.9 to 124 MB. These data are included in the download file, 2021-322-FA_segy.zip, and can also be found by going to the USGS CMGDS at, https://cmgds.marine.usgs.gov. The SEG-Y rev. 0 format (Barry and others, 1975) 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.
Graphic image file: Printable versions of the processed subbottom profiles are available as GIF images (91 files) and are included in the download file, 2021-322-FA_seisimag.zip.
GIS file: The GIS data associated with this survey are provided as a compressed zip file, 2021-322-FA_gis.zip, which is composed of an Esri map document, shapefiles, individual shapefile metadata, a Google Earth KMZ file, a folder of processed subbottom profile images, and a readme file.
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.
Arnell S. Forde
U.S. Geological Survey
Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
aforde@usgs.gov
The SEG-Y files included in this data release are also downloadable from the Coastal and Marine Geoscience Data System at, https://cmgds.marine.usgs.gov.
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.
SEG-Y
Revision 0
The ZIP file contains the SEG-Y data and support information.
Winzip or 7zip
2320
https://coastal.er.usgs.gov/data-release/doi-P9VRSD9J/data/2021-322-FA_segy.zip
Comma-delimited ASCII
The ZIP file contains the survey navigation data and support information.
Winzip or 7zip
4.2
https://coastal.er.usgs.gov/data-release/doi-P9VRSD9J/data/2021-322-FA_nav.zip
Shapefile, MXD, KMZ, GIF
The ZIP file contains the survey navigation data represented geospatially as GIS files, a folder of processed subbottom profile images (accessible via hyperlinks included in the MXD), and support information.
Winzip or 7zip
50.5
https://coastal.er.usgs.gov/data-release/doi-P9VRSD9J/data/2021-322-FA_gis.zip
GIF
The ZIP file contains images of the processed subbottom profile data and support information.
Winzip or 7zip
47.1
https://coastal.er.usgs.gov/data-release/doi-P9VRSD9J/data/2021-322-FA_seisimag.zip
None
Use of SEG-Y data requires specialized seismic processing software, such as public domain software Seismic Unix (https://github.com/JohnWStockwellJr/SeisUnix).
20220503
Arnell S. Forde
U.S. Geological Survey
Geologist
Mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 502-8000
aforde@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998