Metadata: Identification_Information: Citation: Citation_Information: Originator: Blake F. Smullen Originator: Arnell S. Forde Originator: James G. Flocks Publication_Date: 20250626 Title: Archive of Digitized Analog Boomer Seismic Reflection Data Collected Offshore of Mississippi, Alabama, and Florida: MAFLA 1975 Geospatial_Data_Presentation_Form: SEG-Y, tabular, and raster digital data Larger_Work_Citation: Citation_Information: Originator: Blake F. Smullen Originator: Arnell S. Forde Originator: James G. Flocks Publication_Date: 20250626 Title: Archive of Digitized Analog Boomer Seismic Reflection Data Collected Offshore of Mississippi, Alabama, and Florida: MAFLA 1975 Series_Information: Series_Name: U.S. Geological Survey data release Issue_Identification: doi:10.5066/P14HK9XR Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P14HK9XR Description: Abstract: The U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program has actively collected geophysical and sedimentological data in the northern Gulf of America (Gulf of Mexico) for several decades, including shallow subsurface data in the form of high-resolution seismic reflection profiles (HRSP). Prior to the mid-1990s, most HRSP data were collected in analog format as paper rolls of continuous profiles up to 25 meters (m) long. As part of the National Geological and Geophysical Data Preservation Program (NGGDPP; https://datapreservation.usgs.gov/), scientists from the USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) converted analog paper records to digital format using a large-format continuous scanner. The scanned image files were subsequently processed to fix distortions and crop out blank spaces prior to exporting them as geophysical industry standard Society of Exploration Geophysicists (SEG) SEG-Y data exchange formatted files. This data release serves as an archive of HRSP profiles annotated with header information, converted SEG-Y files, navigation data, cruise trackline map, and associated report, Pyle and others (1975). The HRSP data were collected between July 25 and August 17, 1975, using an EG&G Uniboom acoustic system, onboard merchant vessel (M/V) DECCA PROFILER. More than 3,700 kilometers (km) of HRSP were collected in the outer continental shelf waters of Mississippi, Alabama, and Florida (MAFLA-OCS). See Pyle and others (1975) for acquisition methodology. Data conversion methods are described in USGS Data Series 1047 (Bosse and others, 2017). Purpose: The data release associated with this metadata record serves as an archive of MAFLA-OCS geophysical, navigational, and support data collected between July 25 and August 17, 1975. This data release is part of an ongoing USGS data rescue effort to preserve the geologic data that facilitates easier access to legacy datasets by scientists and the public. Supplemental_Information: The USGS SPCMSC currently holds 13 major geophysical surveys from the northern Gulf of America in its paper repository. Over 2,000 line-km of data are available. Paper copies of data are difficult and expensive to duplicate and share with other facilities and cannot be analyzed using standard geographic information systems (GIS) and interpretative software. Conversion of this data into a usable digital format is necessary to archive the geologic information that otherwise might be lost, requiring additional redundant and expensive marine geophysical surveys. The USGS NGGDPP addresses the need to preserve, catalog, and provide access to geological and geophysical data for scientific research and economic development. In addition to the current efforts under the NGGDPP, four geophysical investigations from the 1980s and 1990s were previously archived through a preservation project in collaboration with the Bureau of Ocean Energy Management (Harrison and others, 2007; Sanford and others, 2009a, b, c; and Bosse and others 2017). The USGS SPCMSC scans its analog HRSP holdings using a large-format continuous scanner. The analog to digital conversion process used for this dataset is similar to the processes used previously in Harrison and others (2007) and Sanford and others (2009a, b, c). The digital files were converted into Tagged Image File Format (TIF) for standard accessibility by raster image processors. The TIF images of the seismic profiles were also converted into SEG-Y format. This standard non-proprietary format is the accepted industry standard for seismic data and can be accessed by all major seismic data processing and interpretation systems. Accompanying the HRSP are navigation and metadata files, which are generated for use in GIS, database and Internet Message Access Protocol (IMAP) services. Processed seismic profile images are also provided. The processed profiles provided in this data release are Portable Document Format (PDF) and TIF images that were created using Seismic Unix and/or ImageMagick software. The northern Gulf of America is a passive continental margin, where minimal structural change to the shallow stratigraphy has occurred during the last few thousand years (Anderson and others, 2004). Therefore, subsurface data collected from this environment for the purposes of geologic assessment can be considered useful in perpetuity. The geologic information collected by the USGS in the northern Gulf remains a valuable resource for sea floor and stratigraphic investigations and is continuously revisited by researchers interested in Holocene and recent earth processes. For example, decades-old geologic data are commonly used in sediment resource studies in coastal Louisiana (Kindinger and others, 2001; Kulp and others, 2002; Rogers and others, 2009) and previously collected datasets across the Mississippi-Alabama shelf have been used in recent geologic-framework assessments (Roberts and others, 2004; Greene and others, 2007; Flocks and others, 2009). Geophysical data were acquired for the Bureau of Land Management under contract 08550-CTS-30. The survey was conducted between July 25 and August 17, 1975, on board the M/V DECCA PROFILER. Geophysical data were acquired using an EG&G Uniboom profiler. The transducer was mounted on a towed sled, power supply was 300 Joule. Data were recorded using an EPC 4100 recorder, with a bandpass of 0.4 – 1.6 kilohertz (kHz). Navigation events, or shots, were recorded using mark events corresponding to approximately 305 m intervals along the pre-plotted line. Positioning was provided by a long-range navigation (LORAN), a hyperbolic radio navigation system with an estimated accuracy of +/-0.2 to 0.8 km. Following SPCMSC data management protocols, this survey was assigned a USGS field activity number (FAN), 1975-304-FA. Additional survey and data details are available on the Coastal and Marine Geoscience Data System (CMGDS) at https://cmgds.marine.usgs.gov/services/activity.php?fan=1975-304-FA. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19750725 Ending_Date: 19750817 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -88.585329 East_Bounding_Coordinate: -82.229942 North_Bounding_Coordinate: 30.189803 South_Bounding_Coordinate: 26.370648 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:932f4066-08af-4616-8f1b-a309a85e1f2a Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: marine geology Theme_Keyword: geology Theme_Keyword: sediment transport Theme_Keyword: ocean processes Theme_Keyword: coastal processes Theme_Keyword: seismic reflection methods Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Marine Theme_Keyword: Society of Exploration Geophysicists Theme_Keyword: SEG-Y Theme_Keyword: M/V Decca Profiler Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Gulf of America Place_Keyword: State of Mississippi Place_Keyword: State of Florida Place_Keyword: State of Alabama Place_Keyword: Sanibel Island Place_Keyword: Pascagoula 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: James G. Flocks Contact_Organization: U.S. Geological Survey Contact_Position: Emeritus 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 Browse_Graphic: Browse_Graphic_File_Name: MAFLA_75_Nav_map6_georef.tif Browse_Graphic_File_Description: Supplemental scanned paper map (available in MAFLA_TracklineMap.zip), which shows all analog seismic profiles collected during the MAFLA 1975 survey, including the lines that were not located and scanned from the repository at the USGS SPCMSC (tracklines 4, 7, 30, and 41) . Browse_Graphic_File_Type: TIF 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; Seismic Unix (Release 44); Microsoft Word for Office 365 (version 16); Adobe Photoshop Creative Cloud (version 2019); Chesapeake Technology's ImageToSEGY (version 2.2). Cross_Reference: Citation_Information: Originator: Anderson, J.B., Rodriguez, A., Abdulah, K.C., Fillon, R.H., Banfield, L.A., McKeown, H.A., and Wellner, J.S. Publication_Date: 20040101 Title: Late Quaternary stratigraphic evolution of the northern Gulf of Mexico margins—A synthesis, in Anderson, J., and Fillon, R., eds., Late Quaternary stratigraphic evolution of the Northern Gulf of Mexico Series_Information: Series_Name: Society for Sedimentary Geology Issue_Identification: 79 Other_Citation_Details: pages 1-23 Online_Linkage: https://doi.org/10.2110/pec.04.79.0001 Cross_Reference: Citation_Information: Originator: Barry, K.M., Cavers, D.A., and Kneale, C.W. Publication_Date: 197504 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: https://library.seg.org/doi/pdf/10.1190/1.1440530 Cross_Reference: Citation_Information: Originator: Bosse, S.T., Flocks, J.G., and Forde, A.S. Publication_Date: 20170421 Title: Digitized analog boomer seismic-reflection data collected during U.S. Geological Survey cruises Erda 90-1_HC, Erda 90-1_PBP, and Erda 91-3 in Mississippi Sound, June 1990 and September 1991 Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 1047 Online_Linkage: https://doi.org/10.3133/ds1047 Cross_Reference: Citation_Information: Originator: Flocks, J.G., Ferina, N.F., and Kindinger, J.L. Publication_Date: 2009 Title: Recent geologic framework and geomorphology of the Mississippi-Alabama shelf, northern Gulf of Mexico, in, Buster, N.A., and Holmes, C.W., eds., Gulf of Mexico origin, waters, and biota: Volume III, Geology Series_Information: Series_Name: College Station, Texas, Texas A&M University Press Issue_Identification: 3 Other_Citation_Details: pages 157-173 Online_Linkage: https://muse.jhu.edu/book/1783 Cross_Reference: Citation_Information: Originator: Greene, D.L., Jr., Rodriquez, A.B., and Anderson, J.B. Publication_Date: 20070201 Title: Seaward-branching coastal-plain and piedmont incised-valley systems through multiple sea-level cycles: Late Quaternary examples from Mobile Bay and Mississippi Sound, U.S.A. Series_Information: Series_Name: Journal of Sedimentary Research Issue_Identification: 77 Other_Citation_Details: pages 139-158 Online_Linkage: https://doi.org/10.2110/jsr.2007.016 Cross_Reference: Citation_Information: Originator: Pyle, T.E., Henry, V. A., McCarthy, R. T., Giles, R.T., and Neurauter, T.W. Publication_Date: 19750728 Title: Geophysical Investigations for Biolithologic Mapping of the MAFLA-OCS Lease Area Series_Information: Series_Name: Bureau of Land Management Issue_Identification: 5 Other_Citation_Details: pages 0-264 Online_Linkage: https://upload.wikimedia.org/wikipedia/commons/a/ad/Baseline_monitoring_studies%2C_Mississippi%2C_Alabama%2C_Florida_outer_continental_shelf%2C_1975-1976_%28IA_baselinemonit97805flor%29.pdf Cross_Reference: Citation_Information: Originator: Harrison, A.S., Dadisman, S.V., Kindinger, J.L., Morton, R.A., Blum, M.D., Wiese, D.S., and Subino, J.A. Publication_Date: 2007 Title: Archive of digital and digitized analog boomer seismic reflection data collected during USGS cruise 96CCT02 in Copano, Corpus Christi, and Nueces Bays and Corpus Christi Bayou, Texas, July 1996 Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 296 Online_Linkage: https://doi.org/10.3133/ds296 Cross_Reference: Citation_Information: Originator: Kindinger, J.L., Flocks, J.G., Kulp, M.A., Penland, P.S., and Britsch, L.D. Publication_Date: 2001 Title: Sand resources, regional geology, and coastal processes for the restoration of the Barataria barrier shoreline Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 2001-384 Other_Citation_Details: 69 pages Online_Linkage: https://doi.org/10.3133/ofr01384 Cross_Reference: Citation_Information: Originator: Kulp, M.A., Howell, P.D., Adiau, S., Penland, P.S., Kindinger, J.L., and Williams, S.J. Publication_Date: 2002 Title: Latest Quaternary stratigraphic framework of the Mississippi River delta region Series_Information: Series_Name: Gulf Coast Association of Geological Societies Transactions Issue_Identification: 52 Other_Citation_Details: pages 573-582 Online_Linkage: https://archives.datapages.com/data/gcags/data/052/052001/0573.htm Cross_Reference: Citation_Information: Originator: Roberts, H.H., Fillon, R.H., Kohl, B., Robalin, J.M., and Sydow, J.C. Publication_Date: 2004 Title: Depositional architecture of the Lagniappe Delta: Sediment characteristics, timing of depositional events, and temporal relationship with adjacent shelf-edge deltas, in Anderson, J.B., and Fillon, R., eds., Late Quaternary stratigraphic evolution of the northern Gulf of Mexico Series_Information: Series_Name: Society for Sedimentary Geology Issue_Identification: 79 Other_Citation_Details: pages 142-189 Online_Linkage: https://archives.datapages.com/data/sepm_sp/SP79/Depositional_Architecture_of_the_Lagniappe_Delta.pdf Cross_Reference: Citation_Information: Originator: Rogers, B.E., Kulp, M.A., and Miner, M.D. Publication_Date: 20090916 Title: Late Holocene chronology, origin, and evolution of the St. Bernard shoals, northern Gulf of Mexico, USA Series_Information: Series_Name: Geo-Marine Letters Issue_Identification: 29 Other_Citation_Details: pages 379-394 Online_Linkage: https://doi.org/10.1007/s00367-009-0162-6 Cross_Reference: Citation_Information: Originator: Sanford, J.M., Harrison, A.S., Wiese, D.S., and Flocks, J.G. Publication_Date: 2009 Title: Archive of digitized analog boomer seismic reflection data collected from the Mississippi-Alabama-Florida shelf during cruises onboard the R/V Kit Jones, June 1990 and July 1991 Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 429 Other_Citation_Details: 2009a Online_Linkage: https://doi.org/10.3133/ds429 Cross_Reference: Citation_Information: Originator: Sanford, J.M., Harrison, A.S., Wiese, D.S., and Flocks, J.G. Publication_Date: 2009 Title: Archive of digitized analog boomer and minisparker seismic reflection data collected from the Alabama-Mississippi-Louisiana shelf during cruises onboard the R/V Carancahua and R/V Gyre, April and July, 1981 Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 428 Other_Citation_Details: 2009b Online_Linkage: https://doi.org/10.3133/ds428 Cross_Reference: Citation_Information: Originator: Sanford, J.M., Harrison, A.S., Wiese, D.S., and Flocks, J.G. Publication_Date: 2009 Title: Archive of digitized analog boomer seismic reflection data collected from Lake Pontchartrain, Louisiana, to Mobile Bay, Alabama, during cruises onboard the R/V ERDA-1, June and August 1992 Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 370 Other_Citation_Details: 2009c Online_Linkage: https://doi.org/10.3133/ds370 Cross_Reference: Citation_Information: Originator: Trabant, P.K. Publication_Date: 1984 Title: Applied High-Resolution Geophysical Methods Publication_Information: Publication_Place: Dordrecht, Netherlands Publisher: Springer Netherlands Online_Linkage: https://doi.org/10.1007/978-94-009-6493-8 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The validity or accuracy of boomer seismic profiling data is highly qualitative and depends on equipment and operating condition variables. Visual inspection of the images rendered from the data did not show any major anomalies. Logical_Consistency_Report: This dataset is from the USGS SPCMSC paper repository and has consistent Contex SD3600 scanner calibrations. Completeness_Report: This dataset is considered complete for the information presented. All analog seismic profiles collected during the original survey were successfully scanned and converted to digital format except lines 4, 7, 30, and 41 which were not able to be found and scanned. The data associated with those lines are included in the trackline map (MAFLA_75_Nav_map6_georef.tif), as this data was available for preservation. The seismic profiles provide a two-dimensional (2D) representation of the subsurface along the acquisition tracklines. Users are advised to read the rest of the metadata record carefully for additional details. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: As the seismic reflection data were acquired, the position of the vessel was recorded using a LORAN-A navigation system. The accuracy of the LORAN-A varied from 0.2 to 0.8 km. Positions were recorded in latitude and longitude coordinates at various intervals and appear on the seismic profiles as incremental, hand-annotated vertical event marks. Each vertical line represents a 305 m or 1000-foot (ft) interval. For this cruise, the time between starting and ending times were interpolated. 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 local sea level at the time of data acquisition. Lineage: Process_Step: Process_Description: Raw data scanning - The seismic data collected from this survey is housed in the USGS SPCMSC archive. The analog boomer data are in the form of 30 centimeter (cm)-wide paper and vellum rolls. The various rolls can be up to 6 m long and contain multiple seismic tracklines. The rolls contain the seismic profile image with pertinent collection characteristics annotated during acquisition, such as shot number and time and may also include environmental conditions and equipment details. Horizontal lines across the profiles represent TWT time in milliseconds (ms), and vertical lines represent navigation fixes acquired and annotated as the survey was underway. Vellum rolls were scanned using NextImage software. The lines were saved as TIF files at 200 (dots per inch) dpi and greyscale. Process_Date: 2025 Source_Produced_Citation_Abbreviation: TIF Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Blake F. Smullen Contact_Organization: U.S. Geological Survey Contact_Position: Student Services Contractor 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: bsmullen@contractor.usgs.gov Process_Step: Process_Description: Image cropping - The scanned TIF images were imported into Adobe Photoshop (Ps) Creative Cloud 2019 and blank edge areas were cropped out to further reduce file size. For rolls that included more than one line of seismic data, the file was separated into individual lines. Separation was completed by cropping everything except for the line of interest, determined by the raw navigation information, from the original scan and saving it as a new file with its associated line name. The file naming convention is as follows: CruiseID_trackline#_an.tif (for example, MAFLA_75_35_an.tif). It includes the cruise identification (MAFLA_75) and trackline number (for some lines, this also includes a subsection letter and/or number after the line number for tracklines split between multiple rolls, for example, 1A, 1B1, or 14_1). Source_Used_Citation_Abbreviation: TIF Process_Date: 2025 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Blake F. Smullen Contact_Organization: U.S. Geological Survey Contact_Position: Student Services Contractor 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: bsmullen@contractor.usgs.gov Process_Step: Process_Description: Image headers - Each image of the scanned seismic profiles also includes a header with associated information including cruise- and line-specific information and processing details. The header files were created in Microsoft Word for Office 365 version 16, exported as PDF files, appended to the far left of the image frame in Adobe Ps, and then flattened onto the image to reduce file size. Source_Used_Citation_Abbreviation: TIF Process_Date: 2025 Source_Produced_Citation_Abbreviation: MAFLA_75_*.tif Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: James G. Flocks Contact_Organization: U.S. Geological Survey Contact_Position: Emeritus 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: jflocks@usgs.gov Process_Step: Process_Description: Correcting scan distortion - Distortion correction was necessary because it is difficult to ensure vellum/paper rolls are fed into the scanner straight. Distortion correction was obtained by placing a guideline over the 0 ms line (water level) on the scan. It was important that horizontal lines were perpendicular to the vertical lines on the scans, or the image to SEG-Y conversion would not be accurate. The distortion was corrected by using the Rectangular Marquee Tool in Adobe Ps to select and create a new layer of the distorted area of the scan. A skewed transform was performed, and the corrected images were saved into a new folder without layers (flattened) to reduce file size (Bosse and others, 2017). Source_Used_Citation_Abbreviation: MAFLA_75_*.tif Process_Date: 2025 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Blake F. Smullen Contact_Organization: U.S. Geological Survey Contact_Position: Student Services Contractor 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: bsmullen@contractor.usgs.gov Process_Step: Process_Description: Image to SEG-Y - The scanned, distortion-corrected images were converted to digital SEG-Y (the .seg file extension was used, which has the same properties as .sgy) format revision 0 (Barry and others, 1975) using the proprietary software ImageToSEGY 2.2 from Chesapeake Technology. The scanned images were opened in ImageToSEGY and the export area was defined by assigning values to the top, bottom, left, and right pixel locations using the imaged water surface (0 ms), maximum TWT time (for example, 112.5 ms) and raw navigation data for each line. Trace amplitudes in the scanned profiles are represented by pixels, so each pixel becomes a trace sample and the sample rate of the converted SEG-Y version is the record length divided by the number of vertical pixels in the profile. For example, if the profile is 4,435 pixels vertically and the two-way travel time is 112.5 ms, then the sample rate for the SEG-Y file version is 0.000025 seconds (s). The file naming convention is as follows: CruiseID_Trackline#.seg (for example, MAFLA_75_35.seg). It includes the cruise identification (MAFLA_75) and trackline number (for some lines, this also includes a subsection letter and/or number after the line number for tacklines split between multiple rolls, for example, 1B1). Source_Used_Citation_Abbreviation: MAFLA_75_*.tif Process_Date: 2025 Source_Produced_Citation_Abbreviation: MAFLA_75_*.seg Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Blake F. Smullen Contact_Organization: U.S. Geological Survey Contact_Position: Student Services Contractor 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: bsmullen@contractor.usgs.gov Process_Step: Process_Description: Seismic processing - The SEG-Y data were processed with Seismic Unix (SU, Release 44) software to produce PDF images of the seismic profiles included in this data release. A representative data processing sequence consisted of (1) converting the SEG-Y file to SU format, (2) applying horizontal (number of traces) and vertical (TWT time) scales and generating a PostScript image of the traces, (3) converting the header file to a PostScript image then merging with the seismic profile image, and (4) converting the merged PostScript image to a PDF. The file naming convention is as follows: CruiseID_Trackline#.pdf (for example, MAFLA_75_35.pdf). It includes the cruise identification (MAFLA_75) and trackline number (for some lines, this also includes a subsection letter after the line number for tacklines split between multiple rolls, for example 1B1). Along with the PDFs, Portable Network Graphics (.png) files are included as Adobe Acrobat limits PDF files to <200 inches. When opening images >200 inches in size, Acrobat it will give the following error: "The dimensions of this page are out-of-range. Page content might be truncated." This can be mitigated by opening the PDF through Google Chrome or Microsoft Edge; or by opening the file in provided .png format. Source_Used_Citation_Abbreviation: CruiseID_trackline#.seg Process_Date: 2025 Source_Produced_Citation_Abbreviation: MAFLA_75_*.pdf Source_Produced_Citation_Abbreviation: MAFLA_75_*.png Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: James G. Flocks Contact_Organization: U.S. Geological Survey Contact_Position: Emeritus 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: jflocks@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 11308 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: GRS_1980 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: MAFLA_75_navigation.csv Entity_Type_Definition: Navigation file containing seismic profile data for the cruise. Entity_Type_Definition_Source: USGS Attribute: Attribute_Label: LAT Attribute_Definition: Latitude (NAD83) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 26.370648 Range_Domain_Maximum: 30.189803 Attribute_Units_of_Measure: Decimal Degrees Attribute: Attribute_Label: LONG Attribute_Definition: Longitude (NAD83) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -88.5853 Range_Domain_Maximum: -82.2519 Attribute_Units_of_Measure: Decimal Degrees Attribute: Attribute_Label: LINE Attribute_Definition: Line number Attribute_Definition_Source: USGS Attribute_Domain_Values: Unrepresentable_Domain: Alphanumeric character string representing unique line numbers ranging from 1 to 52 with sub letters designating different sections of the line. In cases where there are more sub letters associated with SEG-Y, Profiles With Headers (PWH), and Profiles With Scales (PWS) files than navigation fixes, the lines needed to be split further due to technical issues and bad weather that left major time gaps in the record. A non-continuous record resulted in poor conversions within the ImageToSEGY software. Attribute: Attribute_Label: FIX Attribute_Definition: Shot Point Number Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 579 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center Contact_Person: USGS SPCMSC Data Management Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: United States Contact_Voice_Telephone: 727-502-8000 Contact_Electronic_Mail_Address: gs-g-spcmsc_data_inquiries@usgs.gov Resource_Description: MAFLA_75_*.seg, MAFLA_75_*.tif, MAFLA_75_*.pdf, MAFLA_75_navigation.csv, MAFLA_75_*.png 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_Information_Content: 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 American Standard Code for Information Interchange (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. File_Decompression_Technique: Unzip using 7zip for PC users and BetterZip for Mac users. Transfer_Size: 2400 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P14HK9XR/data/MAFLA_SEGY.zip Fees: None Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Portable Document Format, PNG Format_Information_Content: Processed seismic profile images with axis scales and headers (.pdf, .png). File_Decompression_Technique: Unzip using 7zip for PC users and BetterZip for Mac users. Transfer_Size: 854 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P14HK9XR/data/MAFLA_ProfilesWithScales.zip Fees: None Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Format_Information_Content: Printable seismic profiles with headers containing cruise, line, and scanning information (.tif). File_Decompression_Technique: Unzip using 7zip for PC users and BetterZip for Mac users. Transfer_Size: 1920 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P14HK9XR/data/MAFLA_ProfilesWithHeaders.zip Fees: None Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Comma-delimited text Format_Information_Content: Cruise navigation data (.csv). File_Decompression_Technique: Unzip using 7zip for PC users and BetterZip for Mac users. Transfer_Size: 0.377 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://coastal.er.usgs.gov/data-release/doi-P14HK9XR/data/MAFLA_Navigation.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: 20250626 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center Contact_Person: USGS SPCMSC Data Management Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: United States 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