Sparker seismic reflection data collected during USGS field activity C109NC offshore of Arcata

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Frequently anticipated questions:

What does this data set describe?

Title:
Sparker seismic reflection data collected during USGS field activity C109NC offshore of Arcata
Abstract:
This processed high-resolution sparker seismic-reflection (Seismic) data for the Offshore of Arcata, California, map area is part of USGS Data Series 781 (Golden and Cochrane, 2019). The map area is one of 83 map areas of the California State Waters Map Series. The data were collected aboard Humboldt State University’s R/V Coral Sea in 2009 on U.S. Geological Survey cruise C109NC on the shelf between Cape Blanco, Oregon, and Cape Mendocino, California. Seismic data were collected to characterize quaternary deformation and sediment dynamics on the continental shelf offshore of Humboldt Bay.
Supplemental_Information:
Additional information about the field activities from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=C109NC
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Cochrane, Guy R., 20240325, Sparker seismic reflection data collected during USGS field activity C109NC offshore of Arcata: data release DOI:10.5066/P9J1K4QX, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Cochrane, Guy R., 2024, Bathymetry, backscatter intensity, seismic reflection, and benthic habitat offshore of Arcata, California: data release DOI:10.5066/P9J1K4QX, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Cochrane, G.R., 2024, Bathymetry, backscatter intensity, seismic reflection, and benthic habitat offshore of Arcata, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9J1K4QX.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.251071
    East_Bounding_Coordinate: -124.136520
    North_Bounding_Coordinate: 41.001493
    South_Bounding_Coordinate: 40.841419
  3. What does it look like?
    SeismicReflection_OffshoreArcata.jpg (JPG)
    Preview image of seismic tracklines offshore of Arcata.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Jul-2009
    Ending_Date: 02-Aug-2009
    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 the seismic profile locations 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 10N.
      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.
  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)
    • Guy R. Cochrane
  2. Who also contributed to the data set?
    Data acquisition was a joint effort between the U.S. Geological Survey, California State University Monterey Bay, and Humboldt State University. The authors acknowledge the crew of Humboldt State University’s R/V Coral Sea and all those involved in in survey planning and execution. Funding was provided by the California Ocean Protection Council Cochrane, G.R., 2024, Bathymetry, backscatter intensity, seismic reflection, and benthic habitat offshore of Arcata, California, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9J1K4QX
  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?

The USGS collected high-resolution sparker Seismic profiles in 2009 in California State waters from the northern California State boundary to the northern edge of Cape Mendocino, California. Primary goals of this survey were to image the offshore portion of the Quaternary unconsolidated sediment. Other goals were to image the any recent fault offsetting of sedimentary units. Seismic data were collected using a Delta Sparker source and recorded on a digital streamer. These data and information are intended for science researchers, students, 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: 19-Oct-2018 (process 1 of 2)
    The seismic-reflection profiles were acquired with a sparker source towed at 3 meters depth below the sea surface and fired at 10 second intervals, depending on water depth. Record lengths of 2 seconds were recorded in SEGD format using a digital streamer towed at 3 meters below the sea surface. Survey speeds were approximately 4.5 knots.
    Date: 01-Nov-2018 (process 2 of 2)
    Seismic-reflection data processing steps included conversion from SEGD to SEGY, navigation conversion to UTM zone 10N, trim statics to correct for swell variations along the streamer, bandpass filter, gated gap deconvolution designed every trace, 300ms ACG, water column mute, and output to SEGY format.
  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?
    Position data were provided by a Differential Global Postitioning System (DGPS) navigation receiver. 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?
  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?
    Sparker seismic reflection data were collected during USGS field activity C109NC using an 88-channel Geometrics GeoEel digital hydrophone streamer (1.5625 m and 3.25 m group spacings), a 6.4 kJ Applied Acoustics power supply, and a Delta Sparker sound source. Quality control was conducted during the collection process.

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? SeismicReflection_OffshoreArcata.zip This zip file contains single channel minisparker (SEG-Y) data collected during USGS field activity C109NC. These data are divided up and presented by navigation line, as reflected in the individual file names.
  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: 785.3
      Network links: https://doi.org/10.5066/P9J1K4QX
    • 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: 25-Mar-2024
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)
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