Archive of Digitized Analog Boomer Seismic-Reflection Data Collected in 1990 and 1991 during the ERDA90-2 and MB91-1 Surveys in Mobile Bay, Alabama

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Frequently anticipated questions:

What does this data set describe?

Title:
Archive of Digitized Analog Boomer Seismic-Reflection Data Collected in 1990 and 1991 during the ERDA90-2 and MB91-1 Surveys in Mobile Bay, Alabama
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 long. As part of the National Geological and Geophysical Data Preservation Program (NGGDPP, https://www.usgs.gov/programs/national-geological-and-geophysical-data-preservation-program) scientists from the USGS St. Petersburg Coastal and Marine Science Center 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 industry standard Society of Exploration Geophysicists (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, profile trackline files, and survey logbook. The HRSP data were collected between August 12 and August 19, 1990, for ERDA90-2, and May 15 and May 18, 1991, for MB91-1, using an EG&G Uniboom acoustic (boomer) system, onboard research vessel (R/V) ERDA 1 in Mobile Bay and into the Gulf of America. Data conversion methods are described in USGS Data Series 1047 (Bosse and others, 2017).
Supplemental_Information:
The USGS-St. Petersburg Coastal and Marine Science Center (SPCMSC) currently holds 13 major geophysical surveys from the northern Gulf of America in its paper repository. Over 2,000 line-kilometers (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 National Geological and Geophysical Data Preservation Program (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). 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 (TIFF) for standard accessibility by raster image processors. The TIFF 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 Portable Network Graphics (.png) 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 using an EG&G Uniboom profiler. The transducer was mounted on a towed sled, with a power supply of 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 18.75 meter (m) intervals along the preplotted line. Positioning was provided by long-range navigation (LORAN). A hyperbolic radio navigation system was used with an estimated accuracy of +/-0.02 to 0.08 km. Following SPCMSC data management protocols, these surveys were assigned a USGS field activity number (FAN), 1990-306-FA. Additional survey and data detail are available on the Coastal and Marine Geoscience Data System (CMGDS) at https://cmgds.marine.usgs.gov/services/activity.php?fan=1990-306-FA.
  1. How might this data set be cited?
    Smullen, Blake F., Forde, Arnell S., and Flocks, James G., 20260610, Archive of Digitized Analog Boomer Seismic-Reflection Data Collected in 1990 and 1991 during the ERDA90-2 and MB91-1 Surveys in Mobile Bay, Alabama:.

    This is part of the following larger work.

    Smullen, Blake F., Forde, Arnell S., and Flocks, James G., 20260610, Archive of Digitized Analog Boomer Seismic-Reflection Data Collected in 1990 and 1991 During the ERDA90-2 and MB91-1 Surveys in Mobile Bay, Alabama: U.S. Geological Survey data release doi:10.5066/P1V6EDD5, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.1244
    East_Bounding_Coordinate: -87.7883
    North_Bounding_Coordinate: 30.6487
    South_Bounding_Coordinate: 30.2636
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 14-Aug-1990
    Ending_Date: 18-May-1991
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: SEG-Y, tabular, and raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • String (384)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0197864699. Longitudes are given to the nearest 0.0228595953. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    erda_90-2-nav.csv
    Navigation file (.csv) containing seismic profile data for cruise ERDA90-2. Time stamps in the data file were 4 hours off the time stamps written on the profiles. Times in the data file were adjusted to match the times written on the profiles. (Source: USGS)
    j.d.
    Julian date associated with each shot (Source: USGS)
    Range of values
    Minimum:226
    Maximum:231
    date
    Date associated with each shot (Source: USGS)
    Range of values
    Minimum:8/14/1990
    Maximum:8/19/1990
    hour
    Hour value of time that shot was recorded, in 24-hour time format (Source: USGS)
    Range of values
    Minimum:12
    Maximum:21
    min
    Minute value of time that shot was recorded (Source: USGS)
    Range of values
    Minimum:00
    Maximum:57
    long
    Longitude degree value of position of vessel when shot was recorded (Source: USGS)
    Range of values
    Minimum:-88.1244
    Maximum:-87.7883
    lat
    Latitude degree value of location of position of vessel when shot was recorded (Source: USGS)
    Range of values
    Minimum:30.2636
    Maximum:30.6487
    shot
    Shot number (Source: USGS) Numbers from 1 to 24 followed by a letter (A,B, or C) when the line was interrupted due to a turn, course change, a pause in operations to fix equipment, the end of the tape or paper, or the changing of the event numbers. Lines with shots followed by a letter have the specific causes noted in the logbook.
    line
    Line number (Source: USGS) Numbers from 1 to 24 followed by a letter (A,B, or C) when the line was split into multiple segments
    mb91-1_nav.csv
    Navigation file (.csv) containing seismic profile data for cruise MB91-1. Time stamps in the data file were 4 hours off the time stamps written on the profiles. Times in the data file were adjusted to match the times written on the profiles. (Source: USGS)
    J.D.
    Julian date associated with each shot (Source: USGS)
    Range of values
    Minimum:135
    Maximum:140
    Hour
    Hour value of time that shot was recorded, in 24-hour time format (Source: USGS)
    Range of values
    Minimum:12
    Maximum:21
    Min
    Minute value of time that shot was recorded (Source: USGS)
    Range of values
    Minimum:8
    Maximum:17
    Sec
    Second value of time that shot was recorded (Source: USGS)
    Range of values
    Minimum:0
    Maximum:55
    Lat
    Latitude degree value of location of position of vessel when shot was recorded (Source: USGS)
    Range of values
    Minimum:30.2210
    Maximum:30.3732
    Long
    Longitude degree value of position of vessel when shot was recorded (Source: USGS)
    Range of values
    Minimum:-88.3284
    Maximum:-87.8200
    Line
    Line number (Source: USGS) Numbers from 1 to 16 followed by a letter (A) when the line was split into multiple segments
    Shot
    Shot number (Source: USGS)
    Range of values
    Minimum:0
    Maximum:43
    ERDA90-2_Tracklines.shp
    GIS polyline shapefile (.shp) for cruise ERDA90-2. (Source: USGS)
    FID
    Internal feature number (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Shape type of feature (Source: Esri)
    ValueDefinition
    PolylineA line represented by an array of points
    Shape_Leng
    Length of line segment in degrees (Source: Esri)
    Range of values
    Minimum:0.001342
    Maximum:0.157396
    line
    Line number (Source: USGS) Numbers from 1 to 24. Some line numbers are also followed by a letter (A, B, or C), when the line was split into multiple segments.
    MB91-1_Tracklines.shp
    GIS polyline shapefile (.shp) for cruise MB91-1. (Source: USGS)
    FID
    Internal feature number (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Shape type of feature (Source: Esri)
    ValueDefinition
    PolylineA line represented by an array of points
    Shape_Leng
    Length of line segment in degrees (Source: Esri)
    Range of values
    Minimum:0.001342
    Maximum:0.157396
    Line
    Line number (Source: USGS)
    Range of values
    Minimum:1
    Maximum:16

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Blake F. Smullen
    • Arnell S. Forde
    • James G. Flocks
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    James G. Flocks
    U.S. Geological Survey
    Emeritus
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jflocks@usgs.gov Native_Data_Set_Enviroment: Environment as of Metadata Creation: Microsoft Windows 11 Enterprise Version 23H2; Environmental Systems Research Institute (Esri) ArcGIS Pro 3.4.3; Seismic Unix (Relase 44); Adobe Photoshop Creative Cloud 2024; Microsoft Word for Office 365 version 16.

Why was the data set created?

The data release associated with this metadata record serves as an archive of ERDA90-2 and MB91-1 geophysical, navigational, and support data collected between August 12 and August 19, 1990, and May 15 and May 18, 1991, respectively. This data release is part of an ongoing USGS data rescue effort to preserve geologic data that facilitates easier access to legacy datasets by scientists and the public.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2025 (process 1 of 8)
    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. The vellum rolls were scanned using NextImage. The lines were then saved at 200 dots per inch (dpi), grey scaled, in TIFF files. Person who carried out this activity:
    Blake F. Smullen
    U.S. Geological Survey
    Student Services Contractor
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    bsmullen@contractor.usgs.gov
    Data sources used in this process:
    • Paper and vellum rolls
    Data sources produced in this process:
    • TIFF
    Date: 2025 (process 2 of 8)
    Image cropping - The scanned TIFF images were imported into Adobe Photoshop (Ps) Creative Cloud 2024 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, ERDA90-2_15_an.tif). It includes the cruise identification (ERDA90-2), and trackline number (sometimes this also includes a subsection letter after the line number for tracklines split between multiple rolls). Person who carried out this activity:
    Blake F. Smullen
    U.S. Geological Survey
    Student Services Contractor
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    bsmullen@contractor.usgs.gov
    Data sources used in this process:
    • TIFF
    Date: 2025 (process 3 of 8)
    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. Person who carried out this activity:
    James G. Flocks
    U.S. Geological Survey
    Emeritus
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jflocks@usgs.gov
    Data sources produced in this process:
    • CruiseID_*_an.tif
    Date: 2025 (process 4 of 8)
    Correcting scan distortion - Distortion correction was necessary because it was difficult to ensure vellum/paper rolls were fed into the scanner straight. Distortion correction practices occur in Ps and 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 will 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 and Barry and others, 1975). Person who carried out this activity:
    Blake F. Smullen
    U.S. Geological Survey
    Student Services Contractor
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    bsmullen@contractor.usgs.gov
    Data sources used in this process:
    • CruiseID_*_an.tif
    Date: 2025 (process 5 of 8)
    Creation of .csv files - Each cruise has an associated comma-separated values (.csv) file with the date, time (hour, minute, second), latitude, longitude, shot number, associated line, and fix. The .csv files were needed for the creation of the shapefile (.shp). Data for the .csv files were generated using the logbooks and the LORAN-A navigation system. Each shot was logged as a fixed point in Excel then saved and exported as a .csv file. Person who carried out this activity:
    Jim G. Flocks
    U.S. Geological Survey
    Emeritus
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jflocks@usgs.gov
    Data sources produced in this process:
    • CruiseID_nav.csv
    Date: 2025 (process 6 of 8)
    Creation of .shp file - The shapefiles (.shp) were created in ArcGIS Pro using the associated .csv for each cruise. The .csv files were imported into ArcGIS Pro as data tables. The tables were then converted into a point feature class using the "XY Table to Point" geoprocessing tool. Then, the "Points to Line" geoprocessing tool was used to create tracklines for each cruise. Each line was merged into a single feature class. The feature class was then exported to shapefiles using the "Feature Class to Shapefile" tool. Person who carried out this activity:
    Blake F. Smullen
    U.S. Geological Survey
    Student Services Contractor
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    bsmullen@contractor.usgs.gov
    Data sources produced in this process:
    • CruiseID_Tracklines.shp
    Date: 2025 (process 7 of 8)
    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 milliseconds (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, ERDA_90-2_5.seg). It includes the cruise identification (ERDA90-2) and trackline number (sometimes this also includes a subsection letter after the line number for tracklines split between multiple rolls). A text (.txt file) copy of the data is also published alongside the .seg data using the same file naming convention. Person who carried out this activity:
    Blake F. Smullen
    U.S. Geological Survey
    Student Services Contractor
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    bsmullen@contractor.usgs.gov
    Data sources used in this process:
    • CruiseID_*_an.tif
    Data sources produced in this process:
    • CruiseID_*.seg
    • CruiseID_*.txt
    Date: 2025 (process 8 of 8)
    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#_PWS.pdf (for example, MB91-1_5_PWS.pdf). It includes the cruise identification (ERDA90-2), trackline number, and data type (profile with scale [PWS]). A .png copy of the data is also published alongside the .seg data using the same naming convention. Person who carried out this activity:
    James G. Flocks
    U.S. Geological Survey
    Research Geologist
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jflocks@usgs.gov
    Data sources used in this process:
    • CruiseID_*.seg
    Data sources produced in this process:
    • CruiseID_*_PWS.pdf
    • CruiseID_*_PWS.png
  3. What similar or related data should the user be aware of?
    Anderson, J.B., Rodriguez, A., Abdulah, K.C., Fillon, R.H., Banfield, L.A., McKeown, H.A., and Wellner, J.S., 20040101, 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: Society for Sedimentary Geology 79.

    Online Links:

    Other_Citation_Details: pages 1-23
    Barry, K.M., Cavers, D.A., and Kneale, C.W., 197504, Recommended standards for digital tape formats: Geophysics v. 40, no. 2.

    Online Links:

    Other_Citation_Details: pages 344-352
    Bosse, S.T., Flocks, J.G., and Forde, A.S., 20170421, 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: U.S. Geological Survey Data Series 1047.

    Online Links:

    Flocks, J.G., Ferina, N.F., and Kindinger, J.L., 2009, 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: College Station, Texas, Texas A&M University Press 3.

    Online Links:

    Other_Citation_Details: pages 157-173
    Greene, D.L., Jr., Rodriquez, A.B., and Anderson, J.B., 20070201, 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.: Journal of Sedimentary Research 77.

    Online Links:

    Other_Citation_Details: pages 139-158
    Harrison, A.S., Dadisman, S.V., Kindinger, J.L., Morton, R.A., Blum, M.D., Wiese, D.S., and Subino, J.A., 2007, 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: U.S. Geological Survey Data Series 296.

    Online Links:

    Kindinger, J.L., Flocks, J.G., Kulp, M.A., Penland, P.S., and Britsch, L.D., 2001, Sand resources, regional geology, and coastal processes for the restoration of the Barataria barrier shoreline: U.S. Geological Survey Open-File Report 2001-384.

    Online Links:

    Other_Citation_Details: 69 pages
    Kulp, M.A., Howell, P.D., Adiau, S., Penland, P.S., Kindinger, J.L., and Williams, S.J., 2002, Latest Quaternary stratigraphic framework of the Mississippi River delta region: Gulf Coast Association of Geological Societies Transactions 52.

    Online Links:

    Other_Citation_Details: pages 573-582
    Roberts, H.H., Fillon, R.H., Kohl, B., Robalin, J.M., and Sydow, J.C., 2004, 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: Society for Sedimentary Geology 79.

    Online Links:

    Other_Citation_Details: pages 142-189
    Rogers, B.E., Kulp, M.A., and Miner, M.D., 20090916, Late Holocene chronology, origin, and evolution of the St. Bernard shoals, northern Gulf of Mexico, USA: Geo-Marine Letters 29.

    Online Links:

    Other_Citation_Details: pages 379-394
    Sanford, J.M., Harrison, A.S., Wiese, D.S., and Flocks, J.G., 2009, 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: U.S. Geological Survey Data Series 429.

    Online Links:

    Other_Citation_Details: 2009a
    Sanford, J.M., Harrison, A.S., Wiese, D.S., and Flocks, J.G., 2009, 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: U.S. Geological Survey Data Series 428.

    Online Links:

    Other_Citation_Details: 2009b
    Sanford, J.M., Harrison, A.S., Wiese, D.S., and Flocks, J.G., 2009, 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: U.S. Geological Survey Data Series 370.

    Online Links:

    Other_Citation_Details: 2009c
    Trabant, P.K., 1984, Applied High-Resolution Geophysical Methods: Springer Netherlands, Dordrecht, Netherlands.

    Online Links:

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    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. For the ERDA90-2 and MB91-1 navigation data files (.csv), the time stamps were 4 hours off the time stamps written on the profiles. Times in the navigation data files were adjusted to match the times written on the profiles.
  2. How accurate are the geographic locations?
    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 kilometer (km). Positions were recorded in latitude and longitude coordinates (in the World Geodetic System of 1984 [WGS84] coordinate system) at various intervals and appear on the seismic profiles as incremental, hand-annotated vertical event marks. Each vertical line represents a 305-meter (m) or 1000-foot (ft) interval. For this cruise, the time between starting and ending times were interpolated.
  3. How accurate are the heights or depths?
    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.
  4. Where are the gaps in the data? What is missing?
    This dataset is considered complete for the information presented. All analog seismic profiles collected during the original survey, except line 16 in MB91-1, were successfully scanned and converted to digital format. 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.
  5. How consistent are the relationships among the observations, including topology?
    This dataset is from the USGS SPCMSC archive and has consistent instrument calibrations.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints No access constraints. Please see 'Distribution Information' for details.
Use_Constraints These data are marked with a Creative Commons 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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Attn: USGS SPCMSC Data Management
    600 4th Street South
    Saint Petersburg, FL
    United States

    727-502-8000 (voice)
    gs-g-spcmsc_data_inquiries@usgs.gov
  2. What's the catalog number I need to order this data set? ERDA90-2_Tracklines.shp, erda_90-2_nav.csv, ERDA90-2_#_PWS.pdf, EDRA90-2_#.png, ERDA90-2_#.seg, ERDA90-2_#.txt, MB91-1_Tracklines.shp, mb91-1_nav.csv, MB91-1_*_an.tif, MB91-1_#_PWS.png, MB91-1_#.seg, MB91-1_#.txt
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: 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. in format SEG-Y Size: 3080
      Network links: https://coastal.er.usgs.gov/data-release/doi-P1V6EDD5/data/ERDA90-2_SEGY.zip
    • Cost to order the data: None

    • Availability in digital form:
      Data format: 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. in format SEG-Y Size: 745
      Network links: https://coastal.er.usgs.gov/data-release/doi-P1V6EDD5/data/MB91-1_SEGY.zip
    • Cost to order the data: None

  5. What hardware or software do I need in order to use the data set?
    The geospatial files were created for use with Esri ArcGIS Pro 3.2.1 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. Use of SEG-Y data requires specialized seismic processing software, such as public domain software Seismic Unix (https://github.com/JohnWStockwellJr/SeisUnix).

Who wrote the metadata?

Dates:
Last modified: 10-Jun-2026
Metadata author:
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Attn: USGS SPCMSC Data Management
600 4th Street South
Saint Petersburg, FL
United States

727-502-8000 (voice)
gs-g-spcmsc_data_inquiries@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/ERDA90-2_MB91-1_Metadata.faq.html>
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