Archive of Digital Boomer and Chirp Seismic Reflection Data Collected During USGS Cruises 01RCE05 and 02RCE01 in the Lower Atchafalaya River, Mississippi River Delta, and Offshore Southeastern Louisiana, October 23-30, 2001, and August 18-19, 2002

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Frequently anticipated questions:


What does this data set describe?

Title:
Archive of Digital Boomer and Chirp Seismic Reflection Data Collected During USGS Cruises 01RCE05 and 02RCE01 in the Lower Atchafalaya River, Mississippi River Delta, and Offshore Southeastern Louisiana, October 23-30, 2001, and August 18-19, 2002
Abstract:
In October of 2001 and August of 2002, the U.S. Geological Survey conducted geophysical surveys of the Lower Atchafalaya River, the Mississippi River Delta, Barataria Bay, and the Gulf of Mexico south of East Timbalier Island, Louisiana. This report serves as an archive of unprocessed digital marine seismic reflection data, trackline maps, navigation files, observers' logbooks, GIS information, and formal FGDC metadata. In addition, a filtered and gained GIF image of each seismic profile is provided.
The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and othes, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). Examples of SU processing scripts and in-house (USGS) software for viewing SEG-Y files (Zihlman, 1992) are also provided. Processed profile images, trackline maps, navigation files, and formal metadata may be viewed with a web browser. Scanned handwritten logbooks and Field Activity Collection System (FACS) logs may be viewed with Adobe Reader.
For more information on the seismic surveys see http://walrus.wr.usgs.gov/infobank/g/g601la/html/g-6-01-la.meta.html and http://walrus.wr.usgs.gov/infobank/g/g102gm/html/g-1-02-gm.meta.html
These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean ( http://www.virtualocean.org/) earth science exploration and visualization applications.
Supplemental_Information:
The USGS Florida Integrated Science Center (FISC) - Coastal and Watershed Studies in St. Petersburg, Florida, assigns a unique identifier to each cruise or field activity. The method used to assign the identifier for the activity is as follows: YYPPP##, where YY stands for the last 2 digits of the year in which the fieldwork is conducted, PPP is a 3-letter abbreviation for the project the data are collected for, and ## is a 2-digit event tag that represents a discreet leg or time period of fieldwork. For example, 01RCE05 indicates the data were collected in 2001 for the River Contaminant Evaluation (RCE) Project and the data were collected during the fifth field activity for that project in that calendar year. The naming convention the center uses for each seismic line is as follows: yye###a, where yy is the last 2 digits of the year in which the data were collected, e is a 1-letter abbreviation for the equipment type (i.e., c for chirp and b for boomer), ### is a 3-digit number representing a specific track, and a is a 1-letter abbreviation representing the section of a line if recording was prematurely terminated or rerun for quality or acquisition problems. The boomer is an acoustic energy source that consists of capacitors charged to a high voltage and then discharged through a transducer in the water. The transducer is towed on a sled at the sea surface and emits a short acoustic pulse, or shot, that propagates through the water and sediment column. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), detected by the receiver, and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (e.g., 0.5 s) and recorded for specific intervals of time (e.g., 100 ms). In this way, a two-dimensional vertical image of the shallow geologic structure beneath the ship track is produced. For 01RCE05 boomer data collection, an Applied Acoustic Engineering CSP 300 power supply provided 100 joules per shot. Reflected energy was received by a SN Technology NexGen streamer and recorded by Triton Elics Delph Seismic acquisition software. The streamer contains 10 hydrophones evenly spaced every 2 m. Only data received by elements 7 and 8 were summed. The streamer was positioned parallel to the boomer sled and laterally separated from it by about 7 m. The sample frequency of the data was 12 kHz for lines 01b001-01b007 and 24 kHz for lines 01b023-01b028. Trace length for all tracklines was 100 ms. Based on survey speeds of 3.5-4 knots and a shot rate of every 0.5 s, shot spacing was about 1 m. No data were collected for 01RCE05 lines 01b008-01b022. No boomer data were collected during Cruise 02RCE01. The chirp system uses a signal of continuously varying frequency. The sound source and receiver is a towfish, which is typically flown 2-5 m above the seafloor. For each recorded shot of chirp data, 3 channels of trace data are collected. Channel 3 is the "real," or in-phase component of the signal, channel 2 is the "imaginary," or quadrative component of the signal, and channel 1 is the "envelope," or product of channels 2 and 3. Only channel 1 was used to produce the profiles presented here. However, all channels are included in the SEG-Y data files. The seismic source employed for both 01RCE05 and 02RCE01 chirp data collection consisted of an EdgeTech X-Star SB-424 towfish running Triton Elics Delph Seismic FSSB software. For 01RCE05, the sample frequency of the data was 25 kHz, and all tracklines were recorded to 48 ms. Based on survey speeds of 3.5-4 knots and a shot rate of 0.122 s, shot spacing was about 0.25 m. For 02RCE01 chirp data collection, the sample frequency of the data was 24 kHz, and all tracklines were recorded to 40 ms. Based on survey speeds of 3.5-4 knots and a shot rate of 0.125 s, shot spacing was also about 0.25 m. The frequency range for both cruises was 4-24 kHz. No data were collected for 01RCE05 lines 01c001-01c004. Digital data were not recorded for 01RCE05 lines 01c005-01c006 and 01c013-01c022. The original trace files for 01RCE05 lines 01c008-01c010 and 02RCE01 lines 02c07 and 02c09 were divided into two or more trace files (e.g., 01c008 became 01c008a and 01c008b) because the original total number of traces exceeded the maximum allowed by the processing system. Water depths shown on the chirp profiles are relative to the depth of the towfish and not to sea level. Furthermore, the raising or lowering of the towfish during a survey (to avoid obstacles or follow relief) produces a relative shift in the multiple reflections seen in the profile, which may be confused as a geologic feature. Any elevation change of the towfish is recorded in the science logbooks and is evident on the seismic profiles by steep, abrupt shifts in the seafloor return. The unprocessed digital seismic data were stored in SEG-Y format, which is a standard digital format that can be read and manipulated by most seismic processing software packages (Barry and others, 1975). The SEG-Y file format includes a 3,200-byte descriptive header that contains detailed information regarding the data acquisition and processing parameters. All data presented here are stored in SEG-Y, integer, Motorola format. The SEG-Y formatted trace files have a .TRA extension. Additional recording parameters for each trace file can also be found in the .PAR file associated with each .TRA file. However, the .PAR and .PLN files included here are only needed to process or display the data with Triton Elics Delph Seismic software. Also included on these discs are example Seismic Unix processing scripts that allow the user to strip off navigation fixes from the SEG-Y headers, along with a fix for every 500 shots (boomer) or every 1,000 shots (chirp), and produce a filtered and gained GIF image of each profile. These images can then be displayed using a variety of PC-based shareware programs such as ImageMagick (Unix, Linux) or a web browser. USGS software for viewing the SEG-Y headers is also provided. For both cruises, DGPS navigation was provided to the acquisition system about every 1 s by a CSI Wireless DGPS Max WAAS/Beacon DGPS receiver. The accuracy of this receiver is within 5 m. The navigation data, which have not been corrected to reflect the 20-m offset between the boomer shotpoint and the GPS antenna or the roughly 10-m offset between the chirp shotpoint and the GPS antenna, were used to generate the trackline maps presented here. Position fixes for every 500 shots (boomer) or every 1,000 shots (chirp) and for the start of lines are also provided as an aid for registering of the data after plotting. All navigation files are stored as ASCII text files. The trackline maps provided in this archive are set in geographic coordinates, NAD83 (unprojected). They were created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. These JPEG images are viewable with a web browser. Also included on this disc are the ArcView map documents and shapefiles used to create the trackline maps. The map documents are compatible with ArcGIS 8.1 (Windows). The shapefiles may also be viewed using other versions of ArcView or public domain software ArcExplorer 2.0 (Windows) and 4.0 (Windows, Mac OS X, Unix, Linux), available from the ESRI website at <http://www.esri.com/software/arcexplorer/index.html>. Field Activity Collection System (FACS) logs and scanned versions of the handwritten logbooks are provided as PDF files.
  1. How might this data set be cited?
    Calderon, Karynna, Dadisman, Shawn V., Kindinger, Jack L., Flocks, James G., Ferina, Nicholas F., and Wiese, Dana S., 2004, Archive of Digital Boomer and Chirp Seismic Reflection Data Collected During USGS Cruises 01RCE05 and 02RCE01 in the Lower Atchafalaya River, Mississippi River Delta, and Offshore Southeastern Louisiana, October 23-30, 2001, and August 18-19, 2002: U.S. Geological Survey Data Series 95, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -91.280115
    East_Bounding_Coordinate: -89.087445
    North_Bounding_Coordinate: 29.654969
    South_Bounding_Coordinate: 28.915961
  3. What does it look like?
    DVD/maps/bmr_all.jpg (JPEG)
    Location map of all boomer seismic reflection surveys collected during USGS Cruise 01RCE05. These data were collected in the Lower Atchafalaya River and in South Pass of the Mississippi River Delta, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:1,300,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs. The USGS is not the originator of all layers used in creating this map. The Louisiana waterbodies layer is a Louisiana Oil Spill Coordinator's Office (LOSCO) data set created from Environmental Systems Research Institute (ESRI)/Geographic Data Technology, Inc. (GDT) data.
    DVD/maps/area_a.jpg (JPEG)
    Trackline map of boomer seismic reflection data collected in Area A (refer to Area A of the boomer survey location map) during USGS Cruise 01RCE05. These data were collected in the Lower Atchafalaya River, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:110,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs. The USGS is not the originator of all layers used in creating this map. The Louisiana waterbodies layer is a LOSCO data set created from ESRI/GDT data.
    http://pubs.usgs.gov/ds/95/maps/area_a1.jpg (JPEG)
    Trackline map of boomer seismic reflection data collected in Area A1 (refer to Area A1 of the Area A map) during USGS Cruise 01RCE05. These data were collected in the Lower Atchafalaya River, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:25,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs. The USGS is not the originator of all layers used in creating this map. The Louisiana waterbodies layer is a LOSCO data set created from ESRI/GDT data.
    http://pubs.usgs.gov/ds/95/maps/area_b.jpg (JPEG)
    Trackline map of boomer seismic reflection data collected in Area B (refer to Area B of the boomer survey location map) during USGS Cruise 01RCE05. These data were collected in South Pass of the Mississippi River Delta, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:55,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs.
    http://pubs.usgs.gov/ds/95/maps/area_b1.jpg (JPEG)
    Trackline map of boomer seismic reflection data collected in Area B1 (refer to Area B1 of the Area B map) during USGS Cruise 01RCE05. These data were collected in South Pass of the Mississippi River Delta, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:25,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs.
    http://pubs.usgs.gov/ds/95/maps/chp_all.jpg (JPEG)
    Location map of all chirp seismic reflection surveys collected during USGS Cruises 01RCE05 and 02RCE01. These data were collected in Pass A Loutre of the Mississippi River Delta in October of 2001 and in Barataria Bay and the Gulf of Mexico south of East Timbalier Island in August of 2002. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:1,300,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs. The USGS is not the originator of all layers used in creating this map. The Louisiana waterbodies layer is a LOSCO data set created from ESRI/GDT data.
    http://pubs.usgs.gov/ds/95/maps/area_c.jpg (JPEG)
    Trackline map of chirp seismic reflection data collected in Area C (refer to Area C of the chirp survey location map) during USGS Cruise 01RCE05. These data were collected in Pass A Loutre of the Mississippi River Delta, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:55,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs.
    http://pubs.usgs.gov/ds/95/maps/area_c1.jpg (JPEG)
    Trackline map of chirp seismic reflection data collected in Area C1 (refer to Area C1 of the Area C map) during USGS Cruise 01RCE05. These data were collected in Pass A Loutre of the Mississippi River Delta, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:25,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs.
    http://pubs.usgs.gov/ds/95/maps/area_c2.jpg (JPEG)
    Trackline map of chirp seismic reflection data collected in Area C2 (refer to Area C2 of the Area C map) during USGS Cruise 01RCE05. These data were collected in Pass A Loutre of the Mississippi River Delta, Louisiana, in October of 2001. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:25,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs.
    http://pubs.usgs.gov/ds/95/maps/area_d.jpg (JPEG)
    Trackline map of chirp seismic reflection data collected in Area D (refer to Area D of the chirp survey location map) during USGS Cruise 02RCE01. These data were collected in the Gulf of Mexico south of East Timbalier Island, Louisiana, in August of 2002. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:55,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format.
    http://pubs.usgs.gov/ds/95/maps/area_e.jpg (JPEG)
    Trackline map of chirp seismic reflection data collected in Area E (refer to Area E of the chirp survey location map) during USGS Cruise 02RCE01. These data were collected in Barataria Bay, Louisiana, in August of 2002. This map is in geographic coordinates, NAD83 (unprojected), and was created at a scale of 1:55,000. It was created using ESRI GIS software ArcView 3.2 and 8.1, exported to Adobe Illustrator for further editing, and saved in JPEG format. The coastline layer was derived from 1:100,000 DLGs.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 23-Oct-2001
    Ending_Date: 19-Aug-2002
    Currentness_Reference:
    Data collection interval
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Seismic Reflection Profile Section
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference:
      Horizontal X and Y locations (both Zone 15 UTMs and latitude and longitude) for each shot are provided in ASCII position files, along with the date and time (Greenwich Mean Time) the shot was recorded.
    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 0.000009. Longitudes are given to the nearest 0.000009. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS84.
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137 m.
      The flattening of the ellipsoid used is 1/298.257.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Binary data file: Trace data are available as a binary file in Society of Exploration Geophysicists (SEG) SEG-Y format. The SEG-Y file is useful only if you have access to specialized software designed to process and display seismic reflection data. These SEG-Y files have a .TRA extension and range in size from 9.8 to 253.4 MB.
    Entity_and_Attribute_Overview:
    Graphic image file: Each profile is available as a GIF image. These profiles range in size from 286 KB to 10.4 MB. The trackline maps are JPEG images that range in size from 66 to 142 KB and contain hotlinks to the seismic profile GIF images.
    Entity_and_Attribute_Overview:
    Navigation files: Navigation files are available as ASCII text files. Raw navigation files range in size from 5 to 215 KB. Edited navigation files range in size from 1.3 to 1.8 MB. Edited 500/1,000-shot-interval navigation files range in size from 12 to 21 KB.
    Entity_and_Attribute_Overview:
    GIS files: The GIS project used to create the trackline maps in this archive is provided as a zip file composed of map documents, shapefiles, and metadata. The map documents range in size from 438 to 515 KB. The shapefiles range in size from 1.36 KB to 29 MB.
    Entity_and_Attribute_Detail_Citation:
    Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, v. 40, n.2, p. 344-352. Also available online at: <http://www.seg.org/publications/tech-stand>.
    Entity_and_Attribute_Detail_Citation:
    Flocks, J.G., Kindinger, J.L., Ferina, N.F., Dreher, C.A., 2002, Sediment-hosted contaminants and distribution patterns in the Mississippi and Atchafalaya River deltas: Gulf Coast Association of Geological Societies Transactions, v. 52, p. 277-289.
    Entity_and_Attribute_Detail_Citation:
    Zihlman, F.N., 1992, DUMPSEGY V1.0: A program to examine the contents of SEG-Y disk-image seismic data: U.S. Geological Survey Open-File Report 92-590, 28 p.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Karynna Calderon
    • Shawn V. Dadisman
    • Jack L. Kindinger
    • James G. Flocks
    • Nicholas F. Ferina
    • Dana S. Wiese
  2. Who also contributed to the data set?
    Funding for this study was provided by the USGS Coastal and Marine Geology Program. We thank R/V G.K. Gilbert Captain Richard W. Young of the USGS in St. Petersburg, Florida, for his assistance in data collection. This document was improved by the reviews of Dale W. Griffin and Robert B. Halley of the USGS in St. Petersburg, Florida.
  3. To whom should users address questions about the data?
    Jack L. Kindinger
    U.S. Geological Survey
    Oceanographer
    600 Fourth Street South
    St. Petersburg, FL
    USA

    (727) 803-8747, ext. 3018 (voice)
    jkindinger@usgs.gov

Why was the data set created?

The data archived here were collected as part of the USGS River Contaminant Evaluation (RCE) Project. For further information about this study, refer to <http://gulfsci.usgs.gov/missriv/index.html> and Flocks and others (2002).

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: 2003 (process 1 of 7)
    Boomer processing: Raw SEG-Y data were processed with Seismic Unix to produce the GIF seismic profile images included in this report. A representative boomer data processing sequence consisted of: 1) Bandpass filter: 300-500-2500-3000 Hz, 2) Automatic gain control, 3) Postscript display, and 4) Convert Postscript image to a GIF image.
    Date: 2003 (process 2 of 7)
    Chirp processing: Raw SEG-Y data were processed with Seismic Unix to produce the GIF seismic profile images included in this report. A representative chirp data processing sequence consisted of: 1) Strip off channel 1 for each shot and convert to SU format, 2) Automatic gain control, 3) Postscript display, and 4) Conversion of Postscript image to a GIF image.
    Date: 2003 (process 3 of 7)
    Positional (navigation) data: As the seismic reflection data were acquired, the position of the vessel was continuously determined by a DGPS receiver. The DGPS string was fed to a navigation computer running HYPACK software, which converted the data to Zone 15 UTMs. The navigation data was then fed to the Delph Seismic acquisition system about every 1 s and recorded in the SEG-Y headers. ASCII navigation files were extracted from the SEG-Y headers using Seismic Unix scripts.
    Date: 2003 (process 4 of 7)
    Editing navigation: ASCII navigation files were extracted from the SEG-Y headers and processed using PROJ.4 (http://www.remotesensing.org/proj) to generate latitude and longitude from Zone 15 UTMs and reformat the data for use with ESRI's ArcView GIS software. Both sets of coordinates are provided for all lines.
    Date: 2003 (process 5 of 7)
    Data Series preparation: No processing has been done to the SEG-Y data files provided on these discs, with the exception of dividing the original trace files for 01RCE05 lines 01c008-01c010 and 02RCE01 lines 02c07 and 02c09 into two or more trace files (e.g., line 01c008 became 01c008a and 01c008b) because the original total number of traces exceeded the maximum allowed by the processing system. The data were displayed as 8-bit grayscale Postscript files using the Seismic Unix 'psimage' algorithm. The Postscript images were then converted to GIF images.
    Date: 24-Jan-2017 (process 6 of 7)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 13-Oct-2020 (process 7 of 7)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

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 marine seismic reflection profiles 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. The original trace files for 01RCE05 lines 01c008-01c010 and 02RCE01 lines 02c07 and 02c09 were divided into two or more trace files (e.g., line 01c008 became 01c008a and 01c008b) because the original total number of traces exceeded the maximum allowed by the processing system. Although data were collected in UTM Zones 15 and 16, all equipment was set to Zone 15 throughout both cruises.
  2. How accurate are the geographic locations?
    Positional accuracy for both cruises was determined with a CSI Wireless DGPS Max WAAS/Beacon DGPS receiver, whose accuracy is within 5 m. The boomer sled was towed about 20 m behind the GPS antenna, and the chirp towfish was towed about 10 m behind the GPS antenna. No correction for these offsets has been made.
  3. How accurate are the heights or depths?
    Boomer data are relative to sea level. However, varying recorded static shifts of the data have been known to occur. Chirp data depth is relative to the depth of the towfish. These data are not to be used for bathymetry.
  4. Where are the gaps in the data? What is missing?
    These data are collected along tracklines (2D) and are therefore inherently incomplete. Geologic details between lines must be inferred. 01RCE05 boomer tracklines were recorded to 100 ms, 01RCE05 chirp tracklines to 48 ms, and 02RCE01 chirp tracklines to 40 ms. Only the upper 40 ms of each 01RCE05 chirp profile and the upper 30 ms of each 02RCE01 chirp profile are displayed because little useful information was observed deeper in the sections. No data were collected for 01RCE05 lines 01b008-01b022 and 01c001-01c004. Digital data were not recorded for 01RCE05 lines 01c005-01c006 and 01c013-01c022. Navigation is not available for 01RCE05 line 01c007 or for 02RCE01 line 02c09a between shot numbers 40 and 2,173. On the trackline maps, the location of missing navigation data within a line is inferred by linear interpolation of the first and last known data points and is represented by a blue line.
  5. How consistent are the relationships among the observations, including topology?
    These data sets are from two different field activities. Slight differences occur in navigation, acquisition equipment, and acquisition geometry between field activities. However, for most purposes, the profile data are comparable for all systems used. Refer to the Supplemental Information section for details of equipment and geometry used for each seismic line.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. These data are held in the public domain.
Use_Constraints:
The U.S. Geological Survey requests to be acknowledged as the originator of the data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    Shawn V. Dadisman
    U.S. Geological Survey
    Geologist
    600 Fourth Street South
    St. Petersburg, FL
    USA

    (727) 803-8747, ext. 3029 (voice)
    sdadisman@usgs.gov
    Contact_Instructions:
    Data may be available on-line only by special arrangement with the distributor above.
  2. What's the catalog number I need to order this data set? U.S. Geological Survey Data Series 95
  3. What legal disclaimers am I supposed to read?
    This DVD publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report or represents that its use would not infringe privately owned rights. Reference therein 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. Although all data and software published on this DVD have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data, software, or related materials.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: The SEG-Y standard format (Barry and others, 1975) 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. in format SEG-Y Size: 3601
      Media you can order: DVD (format ISO 9660)
      Note: UNIX, LINUX, DOS, Macintosh
      Data format: GIS project used to create the trackline maps presented in this archive and associated metadata in format ESRI map documents, shapefiles, metadata Size: 20.7
      Network links: https://pubs.usgs.gov/ds/95/software/arc/arc.zip
      Data format: The SEG-Y standard format (Barry and others, 1975) 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. in format SEGY data download Size: 3601
      Network links: http://cmgds.marine.usgs.gov/data/01rce05/boomer/
      http://cmgds.marine.usgs.gov/data/02rce01/
    • Cost to order the data: Prices vary.

    • Special instructions:
      Publications are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225-0046 (telephone: 1-888-ASK-USGS, email: infoservices@usgs.gov).
  5. What hardware or software do I need in order to use the data set?
    Use of SEG-Y data requires specialized seismic processing software, such as Unix or Linux-based public domain software Seismic Unix developed by the Colorado School of Mines Center for Wave Phenomena and downloadable at <http://www.cwp.mines.edu/cwpcodes/index.html>.

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
Karynna Calderon
ETI Professionals, Inc.
Geographer, Data Management Group
U.S. Geological Survey, 600 Fourth Street South
St. Petersburg, FL
USA

(727) 803-8747, ext. 3143 (voice)
kcalderon@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/ds-95metadata.faq.html>
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