Multichannel minisparker and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Balster-Gee, Alicia F., Hart, Patrick E., Sliter, Ray W., and Parsons, Thomas E., 20200422, Multichannel minisparker and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013: data release DOI:10.5066/P92R2I8J, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P92R2I8J
   • https://www.sciencebase.gov/catalog/file/get/5e71021fe4b01d5092682261

   This is part of the following larger work.
   Balster-Gee, Alicia F., Hart, Patrick E., Sliter, Ray W., and Parsons, Thomas E., 2020, Chirp, multichannel minisparker, and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013: data release DOI:10.5066/P92R2I8J, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

   Online Links:

   • https://doi.org/10.5066/P92R2I8J

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -146.850361
   East_Bounding_Coordinate: -145.923748
   North_Bounding_Coordinate: 61.248782
   South_Bounding_Coordinate: 60.939989
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/5e71021fe4b01d5092682261?name=G-01-13-GA_mcs_trackline_map.png&allowOpen=true (PNG)

   G-01-13-GA MCS trackline map

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 03-Sep-2013

   Ending_Date: 13-Sep-2013

   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?
      

      Indirect_Spatial_Reference:

      Horizontal X and Y locations for each seismic profile location are provided in ASCII position files and are stored in the SEG-Y data trace headers in header bytes 81 and 85.

   2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 UTM Zone 6N.
      

      Projection parameters:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.0
      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
      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.
      

      Vertical_Coordinate_System_Definition:

      Depth_System_Definition:

      Depth_Datum_Name: local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: two-way travel time in milliseconds
      Depth_Encoding_Method: attribute values
      

7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview:

   Navigation and seismic shots 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
   • Patrick E. Hart
   • Ray W. Sliter
   • Thomas E. Parsons
2. Who also contributed to the data set?

   We thank Peter Haeussler, Emily Roland, Rob Wesson, Chuck Worley, John Childs, Rob Wyland, Pete Dal Ferro, Jackson Currie, and Holly Ryan for assistance with survey planning and data acquisition.

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?

High-resolution multichannel seismic-reflection data were acquired to support the U.S. Geological Survey Alaska coastal and marine hazards project to explore the sedimentary structure of tsunamigenic landslide deposits around an IODP drill site in Port Valdez. These data and information 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: 10-Nov-2013 (process 1 of 2)

   Multichannel minisparker (MCS) and boomer seismic-reflection data were collected aboard the USGS R/V Alaskan Gyre using either a 500-Joule SIG 2-mille minisparker or an Applied Acoustics triple plated S-Boomer sound source and recorded using a 24-channel, 150-meter Geometrics digital hydrophone streamer. Source is noted as either boomer or minisparker in the SEG-Y file names within the zip file. Data were sampled at 125 microseconds. Processing steps included; conversion from SEGD to SEGY, geometry assignment, 80-800Hz bandpass filter, CDP sort, application of a spherical divergence gain, Normal Moveout at water velocity, stack, trace balancing, post stack time migration at water velocity and navigation conversion to UTM zone 6N (header bytes 81 and 85).

   Date: 19-Oct-2020 (process 2 of 2)

   Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 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?
   Identified as best available version.
2. How accurate are the geographic locations?
   A formal accuracy assessment of the horizontal positional information in the data set has not been conducted.
3. How accurate are the heights or depths?
   A formal accuracy assessment of the vertical positional information in the data set has not been conducted.
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.
5. How consistent are the relationships among the observations, including topology?
   No formal logical accuracy tests were conducted but quality control was conducted during data acquisition.

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 - ScienceBase

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? Zip file contains mcs seismic-reflection (SEG-Y) data collected during USGS field activity G-01-13-GA. Data are presented by navigation line.
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 mcs seismic data per navigation line in format SEG-Y (version SEG-Y rev 1) Size: 987
     Network links:	https://www.sciencebase.gov/catalog/file/get/5e71021fe4b01d5092682261 https://www.sciencebase.gov/catalog/item/5e71021fe4b01d5092682261 https://doi.org/10.5066/P92R2I8J

   • 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 Reveal by Shearwater Geophysical; 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: 19-Oct-2020

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)