Multichannel sparker seismic reflection data collected offshore southeast Alaska during USGS Field Activity 2017-621-FA

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Frequently anticipated questions:

What does this data set describe?

Title:
Multichannel sparker seismic reflection data collected offshore southeast Alaska during USGS Field Activity 2017-621-FA
Abstract:
High-resolution multichannel seismic reflection data were collected by the U.S. Geological Survey in July and August 2017 offshore southeast Alaska to expand data coverage along the Queen Charlotte Fault system.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-621-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Balster-Gee, Alicia F., Brothers, Daniel S., Kluesner, Jared W., Miller, Nathan C., Haeussler, Peter J., O’Brien, Thomas F., Marcuson, Rachel K., Hart, Patrick E., Conrad, James E., Walton, Maureen L., and Nichols, Alex R., 20221223, Multichannel sparker seismic reflection data collected offshore southeast Alaska during USGS Field Activity 2017-621-FA: data release DOI:10.5066/P9QXL00L, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Balster-Gee, Alicia F., Brothers, Daniel S., Kluesner, Jared W., Miller, Nathan C., Haeussler, Peter J., O’Brien, Thomas F., Marcuson, Rachel K., Hart, Patrick E., Conrad, James E., Walton, Maureen L., and Nichols, Alex R., 2022, Multichannel sparker and chirp seismic reflection data collected offshore southeast Alaska during USGS Field Activity 2017-621-FA: data release DOI:10.5066/P9QXL00L, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -138.07189
    East_Bounding_Coordinate: -136.86450
    North_Bounding_Coordinate: 58.54134
    South_Bounding_Coordinate: 57.73123
  3. What does it look like?
    2017-621-FA_mcs_trackline_map.png (PNG)
    Map of multichannel sparker seismic reflection profiles acquired during USGS field activity 2017-621-FA.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 27-Jun-2017
    Ending_Date: 26-Jul-2017
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: seismic-reflection data in SEG-Y format
  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):
      • Point (7)
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 UTM Zone 8N.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -135.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0001
      Ordinates (y-coordinates) are specified to the nearest 0.0001
      Planar coordinates are specified in Meter
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Zip archive of seismic traces with Time Stamp in standard SEG-Y file format
    Entity_and_Attribute_Detail_Citation:
    Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Alicia F. Balster-Gee
    • Daniel S. Brothers
    • Jared W. Kluesner
    • Nathan C. Miller
    • Peter J. Haeussler
    • Thomas F. O’Brien
    • Rachel K. Marcuson
    • Patrick E. Hart
    • James E. Conrad
    • Maureen L. Walton
    • Alex R. Nichols
  2. Who also contributed to the data set?
    The authors acknowledge the crew of the R/V Ocean Starr and everyone involved in survey planning and execution.
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

This dataset contains processed multichannel seismic-reflection SEG-Y data collected by the U.S. Geological Survey during field activity 2017-621-FA. Data were acquired to study earthquake hazards, fault mechanics and submarine mass wasting processes along the Queen Charlotte fault system, a 1200 km long transform boundary that separates the Pacific and North American tectonic plates. These data are intended for science researchers, students from elementary through college, policy makers, and general 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: 14-Nov-2022 (process 1 of 1)
    Raw SEG-D format seismic shots were imported into Shearwater Reveal seismic software for processing. Navigation data were converted to UTM zone 8N and offset geometry was calculated, and common midpoint (CMP) were binned at 3.125-meter intervals. The following processing steps were applied; 50-Hz highpass Butterworth filter, 40-50-900-1100Hz bandpass filter, FK amplitude coherence enhancement, despike, top mute, FK filter, velocity semblance analysis, normal moveout, two passes of pre-stack deconvolution, 60-80-900-1000Hz bandpass filter, trim statics, median gather filter, stack, bottom mute, trace kills, phase shift time migration at 1400m/s, post migration spiking deconvolution, and 200ms automatic gain control application. Processed data were exported to SEG-Y format with standard header byte locations. Common Midpoint (CMP) X and Y navigation points are written to header bytes 181 and 185 in UTM zone 8N coordinates. SEG-Y data files were compressed into the zip file 2017-621-FA.mcs.segy.zip.
  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?
    Quality control was conducted during acquisition. Some seismic profiles have gaps in them due to system crashes, or intentional shutdowns as required under terms of our operating permit to protect marine mammals.
  2. How accurate are the geographic locations?
    +/- 0.6m 95 percent confidence (DGPS) (http://dev.wr.usgs.gov/idb/media/service_materials/2022/12/07/101121522789/Hemisphere_V100specsheet.pdf)
  3. How accurate are the heights or depths?
    Two-way travel time in milliseconds is recorded in SEG-Y files.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Data release will be updated with additional SEG-Y profiles as data are processed.
  5. How consistent are the relationships among the observations, including topology?
    Quality control was conducted during acquisition and processing to ensure consistency of SEG-Y header navigation and seismic-reflection data that matches bathymetry along the tracklines.

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 USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? SEG-Y data are available in the zip file 2017-621-FA.mcs.segy.zip that contains seven standard SEG-Y format files of seismic traces with time stamp (Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards).
  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 on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Zip file contains the processed seismic data per navigation line. in format SEG-Y (version SEG-Y rev 1) Size: 534.8
      Network links: https://doi.org/10.5066/P9QXL00L
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    Use of SEG-Y data requires specialized software, such as ProMax and Seisworks by Landmark Geophysical; FOCUS and SeisX by Paradigm Geophysical; SPW by Parallel Geoscience; VISTA by Seismic Image Software; SeiSee by Dalmorneftegeophysica (DMNG); amongst others.

Who wrote the metadata?

Dates:
Last modified: 23-Dec-2022
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P9QXL00L/2017-621-FA.mcs.metadata.faq.html>
Generated by mp version 2.9.51 on Wed Jan 4 11:32:24 2023