Multichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06

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Frequently anticipated questions:

What does this data set describe?

Multichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06
This data release contains approximately 190 line-kilometers of processed, high-resolution multichannel seismic-reflection (MCS) profiles that were collected aboard the R/V Snavely in 2015 on U.S. Geological Survey cruise 2015-617-FA in Monterey Bay, offshore central California. The majority of MCS profiles collected are oriented north-south across the Monterey Canyon head to address marine geohazards and submarine canyon evolution. The MCS profiles were acquired using a 700-Joule minisparker source and a 24-channel digital streamer.
Additional information about the field activities from which these data were derived is available online at:
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?
    Balster-Gee, Alicia F., Maier, Katherine L., Brothers, Daniel S., Johnson, Samuel Y., Hart, Patrick E., and Hartwell, Stephen R., 2018, Multichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06: data release DOI:10.5066/F7T43SBK, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.305
    East_Bounding_Coordinate: -121.82436523
    North_Bounding_Coordinate: 36.9441115
    South_Bounding_Coordinate: 36.63534156
  3. What does it look like? (JPEG)
    index map
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 23-Feb-2015
    Ending_Date: 06-Mar-2015
    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?
      Horizontal X and Y locations for the seismic profile locations are provided and stored in the SEG-Y data trace headers in header bytes 81 and 85 locations
    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.
      Depth_Datum_Name: Local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    Navigation and seismic shots with Time Stamp in standard SEG-Y file format
    Society of Exploration Geophysicists (SEG) Technical Standards, available for download at

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
    • Katherine L. Maier
    • Daniel S. Brothers
    • Samuel Y. Johnson
    • Patrick E. Hart
    • Stephen R. Hartwell
  2. Who also contributed to the data set?
  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

    831-460-4747 (voice)

Why was the data set created?

The U.S. Geological Survey (USGS) collected high-resolution multichannel seismic-reflection (MCS) profiles in 2015 across Monterey Bay, offshore central California. The goals of the MCS survey were to provide higher-resolution imaging of a buried paleochannel complex recently identified below the continental shelf adjacent to Monterey Canyon head and to complete a grid of subbottom data with existing single-channel seismic reflection profiles across Monterey Bay (Sliter and others, 2013). This cruise was funded by the USGS Coastal and Marine Geology Program and provided an extended shakedown test of a new multichannel streamer.

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: 06-Mar-2015 (process 1 of 3)
    The multichannel seismic-reflection profiles were acquired with a 700-Joule minisparker source towed at 2 meters depth below the sea surface and fired at 1.2 to 1.4 seconds, depending on water depth. Data were recorded at 1.1 and 1.3 seconds and 0.25 milisecond sample interval in SEGD format using a 24-channel digital streamer with 3.125 receiver group spacing, 100m total length including lead-in section, towed at 2 meters below the sea surface. Survey speeds were approximately 4.5 knots.
    Date: 10-Dec-2015 (process 2 of 3)
    Seismic-reflection data were processed using Echos by Paradigm Geophysical. The following processing steps were applied to each line: bad traces killed, water column mute applied, full trace AGC applied, normal moveout correction (constant 1450 m/s velocity), swell static correction, stack, 80-600 post-stack bandpass filer, 80-600 butterworth filter, three trace mean post-stack runmix filter, time migration, and correct navigation was written to header bytes 81 and 85 in UTM coordinates.
    Date: 19-Oct-2020 (process 3 of 3)
    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)
  3. What similar or related data should the user be aware of?
    Sliter, Ray W., Johnson, Samuel Y., Watt, Janet T., Scheirer, Daniel S., Allwardt, Parker, and Triezenberg, Peter J., 2013, High-resolution seismic-reflection and marine-magnetic data from offshore central California--San Gregorio to Point Sur.

    Online Links:

    Sliter, R. Johnson, S.Y., Watt, J.T., Scheirer, D.S., Allwardt, P. and Triezenberg, P.J., 2013, High-resolution seismic-reflection and marine-magnetic data from offshore central California—San Gregorio to Point Sur: U.S. Geological Survey Open-File Report 2013–1071.

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 Positioning System (DGPS) navigation receiver.
  3. How accurate are the heights or depths?
    Depths shown in the seismic data files are in milliseconds (round trip travel time) and are referenced to sea level.
  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?
    Subbottom data were collected during USGS cruise 2015-617-FA using a 24-channel Geometrics GeoEel digital hydrophone streamer and a 700-Joule minisparker 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
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)
  2. What's the catalog number I need to order this data set? contains high-resolution seismic-reflection (SEG-Y) data collected during PCMSC field activity 2015-617-FA. These data are divided up and presented by navigation line, as reflected in the individual file names. Equipment malfunction resulted in some lines having multiple parts (e.g 05 and 05T, 07A 07B and 07C).
  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?
  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?

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

831-460-4747 (voice)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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