Post-stack migrated SEG-Y multi-channel seismic data collected by the U.S. Geological Survey in U.S. Atlantic Seaboard in 2014

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Frequently anticipated questions:


What does this data set describe?

Title:
Post-stack migrated SEG-Y multi-channel seismic data collected by the U.S. Geological Survey in U.S. Atlantic Seaboard in 2014
Abstract:
In summer 2014, the U.S. Geological Survey conducted a 21-day geophysical program in deep water along the Atlantic continental margin by using R/V Marcus G. Langseth (Field Activity Number 2014-011-FA). The purpose of the seismic program was to collect multichannel seismic reflection and refraction data to determine sediment thickness. These data enable the United States to delineate its Extended Continental Shelf (ECS) along the Atlantic margin. The same data can also be used to understand large submarine landslides and therefore assess their potential tsunami hazard for infrastructure and communities living along the eastern seaboard. Supporting geophysical data were collected as marine magnetic data, gravity data, 3.5-kilohertz shallow seismic reflections, multibeam echo sounder bathymetry, and multibeam backscatter. 
The survey was conducted from water depths of approximately 1,500 meters to abyssal seafloor depths greater than 5,000 meters. Approximately 2,761 kilometers of multi-channel seismic data was collected along with 30 sonobuoy profiles.
This field program had two primary objectives: (1) to collect some of the data necessary to establish the outer limits of the U.S. Continental Shelf, or Extended Continental Shelf, as defined by Article 76 of the United Nations Convention of the Law of the Sea and (2) to study the sudden mass transport of sediments down the continental margin as submarine landslides that pose potential tsunamigenic hazards to the Atlantic and Caribbean coastal communities.
Supplemental_Information:
For more information on the field activity, see the field activity page https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-011-FA
  1. How might this data set be cited?
    U.S. Geological Survey, 2017, Post-stack migrated SEG-Y multi-channel seismic data collected by the U.S. Geological Survey in U.S. Atlantic Seaboard in 2014: data release DOI:10.5066/F7V69HHS, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Arsenault, M.A., Miller, N.C., Hutchinson, D.R., Baldwin, W.E., Moore, E.M., Foster, D.S., O'Brien, T.F., and Fortin, W.F., 2017, Geophysical data collected along the Atlantic continental slope and rise 2014, U.S. Geological Survey Field Activity 2014-011-FA, cruise MGL1407: data release DOI:10.5066/F7V69HHS, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation:
    Arsenault, M.A., Miller, N.C., Hutchinson, D.R., Baldwin, W.E., Moore, E.M., Foster, D.S., O’Brien, T.F., and Fortin, W.F., 2017, Geophysical data collected along the Atlantic continental slope and rise 2014, U.S. Geological Survey Field Activity 2014-011-FA, cruise MGL1407: U.S. Geological Survey data release, https://doi.org/10.5066/F7V69HHS.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -76.339338
    East_Bounding_Coordinate: -65.769170
    North_Bounding_Coordinate: 40.064540
    South_Bounding_Coordinate: 30.677010
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2014-011-FA/data/seismics/2014-011-FA_poststmsegy.jpg (JPEG)
    Thumbnail image of multi-channel seismic data collected by the U.S. Geological Survey on the R/V Marcus G. Langseth in 2014.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 23-Aug-2014
    Ending_Date: 11-Sep-2014
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: SEG-Y digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 19N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -69.000000
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 1
      Ordinates (y-coordinates) are specified to the nearest 1
      Planar coordinates are specified in meters
      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 1/298.257224.
  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Nathan C. Miller
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x 2293 (voice)
    508-457-2310 (FAX)
    ncmiller@usgs.gov

Why was the data set created?

These SEG-Y files represent 2761 kilometers of multi-channel seismic data collected by the U.S. Geological Survey during USGS survey 2014-04-FA. These data were collected off the U.S. Seaboard Atlantic as part of the U.S. Extended Continental Shelf project and investigations of tsunami hazards. The ECS objectives of the survey are primarily beyond 200 nm in water depths greater than 4000 m. The 2014 ECS tracks were laid out primarily parallel to the margin to map along-strike variations in sediment thickness and to test the hypothesis that oceanic fracture zones might be loci of thicker sediments
The submarine landslide objectives were along two transects that extend from the headwall of the slide near or on the slope to the distal extent of the run-out on the abyssal plain. The data were intended to image the points of failure, glide planes, relative ages of multiple smaller landslides, and relative volumnes of material displaced and redeposited. Imaging an entire submarine landslide system provides a comprehensive dataset for modeling landslide occurrence and therefore understanding the associated natural hazard.

How was the data set created?

  1. From what previous works were the data drawn?
    original raw data (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, Raw seismic data.

    Type_of_Source_Media: online
    Source_Contribution:
    Multi-channel seismic data were acquired with a 36-element, 6600 cubic inch airgun source array, and 8-km-long solid state digital hydrophone streamer towed behind the R/V Marcus G. Langseth. The source air guns were configured in four parallel, 9-gun strings and towed at the rear of the ship at a depth of 9 meters. The Sentry Solid Streamer Sercel hydrophone cable consists of 12 hydrophones, which are summed in analog, and the spacing between the center of these groups is 12.5 m. Streamer depth was set to 9 m for all lines. Approximately 2,761 km of data were collected. Data were recorded at a 4-millisecond (ms) sample rate and in Society of Exploration Geophysicists D (SEG-D) format.
    Source and receiver positions were determined by LDEO staff using Concept Systems's Spectra multichannel seismic navigation software. Source positions were logged using differential GPS antennas on three of the four source sub arrays. Receiver positions were calculated using data from Digicourse Digirange acoustic pods on the source array and on the head, middle, and tail of the streamer; depth and heading data from Digicourse depth control birds located every 300 m along the streamer; and a differential GPS on the streamer tail buoy. All survey positions use the World Geodetic System 1984 datum (WGS84), and both global and local geodetic calculations utilized the WGS84 reference ellipsoid with a semi-major axis of 6378137.0 m and an inverse flattening of 298.257224.
  2. How were the data generated, processed, and modified?
    Date: 2017 (process 1 of 4)
    Post-stack migration processing of all MCS reflection data was done at the USGS WHMSC, and was primarily performed using OpenCPS software (version 3.3.0). Data were imported into OpenCPS from SEG-Y files, and processed through a standard sequence of trace editing, common-midpoint (CMP) sorting, bandpass filtering, deconvolution, velocity analysis, normal moveout correction, stretch muting, stacking, and post-stack time migration. Streamer geometry (true group and source locations) were applied from the P190 navigation files provided by the Langseth staff. Trace headers in these SEG-Y data include CMP number (bytes 20-22), Number of samples in a trace (bytes 115-116), Sample interval (bytes 116-117), Source Coordinates (bytes 72-74, bytes 76-78), Group Coordinates (bytes 80-82, bytes 84-86), and Trace Positions (bytes 180-182, bytes 184-186). A scalar for the geoposition is set in bytes 71-71. All coordinates are written in UTM19N, EPSG code 32619. A full text header is written to include all of the processing information:
    Description: Post-stack phase shift time migration to 200 Hz using auto-picked velocities guided by a 1D velocity function hung between picked water-bottom,basement, and Moho.
    Prestack gains: Spherical divergence Poststack gains: None Band: 6-200 Hz
    Cruise:MGL1407 Line:MGL1407MCS01 Coordinate projection:WGS84/UTM 19N ESPG:32619 WKT:"+proj=utm +zone=19 +datum=WGS84 +units=m +no_defs" Files were written to SEG-Y format from within OpenCPS. Nathan C. Miller performed this and all subsequent process steps. Person who carried out this activity:
    Nathan C. Miller
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2293 (voice)
    508-457-2310 (FAX)
    ncmiller@usgs.gov
    Date: 2017 (process 2 of 4)
    Files were written to SEG-Y format from using OpenCPS (version 3.3.0). Person who carried out this activity:
    Nathan C. Miller
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2293 (voice)
    508-457-2310 (FAX)
    ncmiller@usgs.gov
    Date: 29-Jan-2018 (process 3 of 4)
    An error was fixed in one of the originator names. Also fixed in the suggested citation. 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
    Date: 08-Sep-2020 (process 4 of 4)
    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?
    Shearwater GeoServices Software, Inc., 2017, OpenCPS Seismic Processing Software: Journal of Coastal Research Version 3.3.0, Shearwater Geophysical, Houston, TX.

    Online Links:

    Observatory, Lamont-Doherty Earth, 2014, Rolling Deck to Repository (R2R): UNCLOS, UNCLOS.

    Online Links:

    Other_Citation_Details:
    Standard data products listed on the Rolling Deck to Repository website include cruise level metadata with an expedition summary including cruise id, vessel, operator, project titles and funding awards, science party, ports, dates, survey targets, and trackline geometry. There is also quality-controlled shiptrack navigation, and scientific sampling event logs. Some post-processed geophysical trackline profiles (underway gravity, magnetics, bathymetry, etc), for vessels equipped with these instrument types; and hydrographic profiles (depth, temperature, salinity, etc from CTD).
    Michael W. Norris, ed., and Alan K. Faichney, ed., 2002, SEG Y rev 1 Data Exchange format: Society of Exploration Geophysicist, Houston, TX.

    Online Links:


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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    Navigation was acquired using the R/V Marcus G. Langseth's fully integrated multicomponent navigation system, consisting of echosounder, speedlog, Differential Global Positioning System (DGPS), gyrocompass, POS/MV Integrated Navigation System, Kongsberg Seapath 200 Inertial Navigation System and Lamont Data Systems (LDS) data logger. All survey positions use the World Geodetic System 1984 datum (WGS84), and both global and local geodetic calculations utilized the WGS84 reference ellipsoid with a semi-major axis of 6378137.0 m and an inverse flattening of 298.257224. Streamer geometry calculations were performed in Universal Transverse Mercator (UTM) northern hemisphere projection 19 North . Water bottom topography in stacked sections agrees well with multi beam bathymetry data gridded to 50 m, implying that these CMP locations are accurate to <50m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    16 multi-channel seismic lines were collected in total, and the lines are not sequentially numbered, and some lines are partitioned into A and B sections.
  5. How consistent are the relationships among the observations, including topology?
    Seismic reflection data collection was the primary objective of the cruise, and data collection started on Julian Day 235 and was interupted only when absolutely necessary; Hurricane Cristobal on Julian Day JD238 and a medevac on Julian Day JD241. Although data quality was in general excellent, there are several known problems with the data, including noisy channels (up to 71 channels out of 636 in the 8-km configuration, and 65 channels out of 480 in the 6-km configuration), extreme feathering of the streamer on lines which crossed the Gulf Stream, occasional reduced source size for maintenance on the airgun strings, and one 12-minute power down for a protected species. Rough weather also produced wave noise on the streamer. Data collection ended on Julian Day 254.
    The file naming convention is: SHPCCCCMCSXX.poststm-v1dcm.segy, where SHP = Ship name abbreviation; CCCC = Cruise number; MCS= Type of data; XX = Line number. The rest of the filename notes the processing (poststm = post-stack migration) and the v1dcm denotes the 1D velocity model that was applied. The SEG-Y format is noted in the file extension name.
    An example would be MGL1407MCS01.poststm-v1dcm.segy; MGL = The R/V Marcus G. Langseth, 1407 = the Cruise ID, MCS = multi-channel seismic, 01 = Line 01.
    Important events that contribute to the overall quality of the data were recorded in the ship logs and archived on the Rolling Deck to Repository Archive system. For a complete list of these events, the logs should be referenced on the R2R website (http://www.rvdata.us/catalog/MGL1407).

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
Use_Constraints:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    Nathan C. Miller
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x 2293 (voice)
    508-457-2311 (FAX)
    ncmiller@usgs.gov
  2. What's the catalog number I need to order this data set? A series of SEG-Y files representing seismic-reflection profiles collected during USGS field activity 2014-011-FA, the browse graphic, and FGDC CSDGM metadata in xml, txt and html formats.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm 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?
  5. What hardware or software do I need in order to use the data set?
    These data can be viewed with any SEG-Y viewing software.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
Matthew A. Arsenault
U.S. Geological Survey
Geologist
384 Woods Hole Road
Woods Hole, MA
USA

508-548-8700 x2354 (voice)
508-457-2310 (FAX)
marsenault@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/field_activities/2014_011_fa/2014-011-FA_poststmsegy_meta.faq.html>
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