Marine sparker source SEG-Y seismic data recorded aboard the R/V Parke Snavely during USGS field activity 2021-619-FA offshore Santa Cruz, California in April of 2021

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Frequently anticipated questions:

What does this data set describe?

Title:
Marine sparker source SEG-Y seismic data recorded aboard the R/V Parke Snavely during USGS field activity 2021-619-FA offshore Santa Cruz, California in April of 2021
Abstract:
Seismic data were recorded aboard the R/V Parke Snavely (RVPS; source vessel) during USGS field activity 2021-619-FA. Data were recorded with a broadband spherical reference Reson TC4034 hydrophone positioned directly below the SIG ELP790 or the Applied Acoustics Delta sparker source which were towed from the stern of the vessel. Source data were recorded as the R/V Parke Snavely made several passes along 7 different water depth transects and are presented in SEG-Y format. Shot point navigation are provided in an accompanying comma-delimited text file, as well as in a shapefile for visualization purposes. Navigation data for the source and receiver vessels, as well as seismic data from the receiver vessel, sound velocity, and other survey data, are provided elsewhere in this data release.
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=2021-619-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., Baldwin, Wayne E., and Hart, Patrick E., 20220920, Marine sparker source SEG-Y seismic data recorded aboard the R/V Parke Snavely during USGS field activity 2021-619-FA offshore Santa Cruz, California in April of 2021: data release DOI:10.5066/P9EHITBI, 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., Baldwin, Wayne E., and Hart, Patrick E., 2022, Calibrated marine sparker source amplitude decay versus offset offshore Santa Cruz, California: data release DOI:10.5066/P9EHITBI, 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: -122.47431993
    East_Bounding_Coordinate: -121.81507587
    North_Bounding_Coordinate: 37.09648707
    South_Bounding_Coordinate: 36.72920243
  3. What does it look like?
    2021-619-FA_source_SEG-Y_L200_b.png (PNG)
    Image of seismic line recorded aboard the R/V Parke Snavely (RVPS; source vessel) with the SIG ELP790 sparker source (power 700 joules) at depth site L200, pass ‘b’. Peak amplitudes per trace are shown in magenta.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 19-Apr-2021
    Ending_Date: 28-Apr-2021
    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 (19511)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is WGS 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      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?
    2021-619-FA_RVPS_SrcSegy.zip
    Zip archive of seismic shots with time stamp in standard SEG-Y file format (Source: Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards)
    2021-619-FA_RVPS_SrcSegyNav.csv
    SEG-Y shot point navigation and associated attributes. The first line of the csv file is a header line. (Source: U.S. Geological Survey)
    filename
    Name of navigation line (Source: Assigned unique line identifier name)
    ValueDefinition
    PS-L25_S_a_f2Pass ‘a’ part 2 with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25_S_a_f3Pass ‘a’ part 3 with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25_S_cPass ‘c’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25A_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the second 25-meter depth site ‘25A’
    PS-L25A_S_a2Pass ‘a2’ (part two of pass a) with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site ‘25A’
    PS-L25A_S_a3Pass ‘a3’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site ‘25A’
    PS-L25A_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site ‘25A’
    PS-L50_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site
    PS-L50_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site
    PS-L50A_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site ‘50A'
    PS-L50A_S_a2Pass ‘a2’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site ‘50A’
    PS-L50A_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site ‘50A’
    PS-L100_S_a_f1Pass ‘a’ (part 1) with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_a_f2Pass ‘a’ (part 2) with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_c_f1Pass ‘c’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_c_f2Pass ‘c2’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_c2Pass ‘c2’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L200_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 200-meter depth site
    PS-L200_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 200-meter depth site
    PS-L200_S_cPass ‘c’ with the SIG ELP790 minisparker source (power 700 joules) at the 200-meter depth site
    PS-L200_D10_aPass ‘a’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site
    PS-L200_D10_bPass ‘b’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site
    PS-L200_D10_cPass ‘c’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site
    PS-L200_D10_dPass ‘d’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site Enumerated_Domain_Value_Definition_Source: Producer defined
    PS-L600_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 600-meter depth site
    PS-L600_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 600-meter depth site
    PS-L600_D24_aPass ‘a’ with the Delta sparker source (power 2.4 kilojoules) at the 600-meter depth site
    PS-L600_D24_bPass ‘b’ with the Delta sparker source (power 2.4 kilojoules) at the 600-meter depth site
    hpid
    Hydrophone Identifier (Source: producer defined) model number TC4034 (Reson)
    lbsrc_lon
    longitude of the sparker source layback position from the stern of the source vessel (RVPS) (Source: producer defined)
    Range of values
    Minimum:-122.360614
    Maximum:-121.897050
    Units:decimal degrees
    Resolution:0.000001
    lbsrc_lat
    latitude of the sparker source layback position from the stern of the source vessel (RVPS) (Source: producer defined)
    Range of values
    Minimum:36.763513
    Maximum:36.992312
    Units:decimal degrees
    Resolution:0.000001
    rec_lon
    longitude of the RVPS receive hydrophone (Source: producer defined)
    Range of values
    Minimum:-122.337685
    Maximum:-121.924577
    Units:decimal degrees
    Resolution:0.000001
    rec_lat
    latitude of the RVPS receive hydrophone (Source: producer defined)
    Range of values
    Minimum:36.778772
    Maximum:36.975878
    Units:decimal degrees
    Resolution:0.000001
    signoffset
    offset distance between the instrument layback position of the sparker source off the stern of the source vessel and the hydrophone receiver positioned below the RVSL. Positive values are when the source is northwest of the receiver and negative when the source is southeast of the receiver (Source: producer defined)
    Range of values
    Minimum:-5356
    Maximum:4736
    Units:meters
    Resolution:1
    y
    Year collected (Source: time stamp from GGA navigation string from source vessel R/V Parke Snavely)
    Range of values
    Minimum:2021
    Maximum:2021
    Units:year collected
    Resolution:1
    jd
    Julian Day collected (Source: time stamp from GGA navigation string from source vessel R/V Parke Snavely)
    Range of values
    Minimum:111
    Maximum:119
    Units:Julian day collected
    Resolution:1
    h
    hour collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:14
    Maximum:20
    Units:hour of day collected
    Resolution:1
    m
    minute collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:0
    Maximum:59
    Units:minute of hour collected
    Resolution:1
    s
    second collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:0
    Maximum:59
    Units:second of minute collected
    Resolution:1
    us
    microsecond collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:68436
    Maximum:932070
    Units:microsecond of second of minute collected
    Resolution:1
    utc_dt
    Coordinated Universal Time (UTC) Day Time string (Source: producer defined) Sequential unique whole numbers that are automatically generated. For example, 2021-04-23 18:31:02.999936+00:00 represents 2021-04-23 as the date collected and 18:31:02.999936+00:00 is the UTC time that the navigation point was taken.
    surveyid
    USGS field activity number (FAN) assigned to data collection activity (Source: producer defined) 2021-619-FA, details for which may be found at https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-619-FA
    vehicleid
    name of the source vessel from which data were collected (Source: producer defined) R/V Parke Snavely
    deviceid
    Sparker source type and power level (in joules) (Source: producer defined)
    ValueDefinition
    Applied Acoustics Delta Sparker (2400 J)Brand name and model of sparker source and power level measured in joules
    Applied Acoustics Delta Sparker (1000 J)Brand name and model of sparker source and power level measured in joules
    SIG ELP790 Sparker (700 J)Brand name and model of sparker source and power level measured in joules
    2021-619-FA_RVPS_SrcSegyNav_shapefile.zip
    Zip file contains a point shapefile (.shp) of the location of each SEG-Y shot point along the navigated tracklines of the source vessel (R/V Parke Snavely; RVPS) and associated files (Source: U.S. Geological Survey)
    filename
    Name of navigation line (Source: Assigned unique line identifier name)
    ValueDefinition
    PS-L25_S_a_f2Pass ‘a’ part 2 with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25_S_a_f3Pass ‘a’ part 3 with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25_S_cPass ‘c’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site
    PS-L25A_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the second 25-meter depth site ‘25A’
    PS-L25A_S_a2Pass ‘a2’ (part two of pass a) with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site ‘25A’
    PS-L25A_S_a3Pass ‘a3’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site ‘25A’
    PS-L25A_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 25-meter depth site ‘25A’
    PS-L50_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site
    PS-L50_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site
    PS-L50A_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site ‘50A'
    PS-L50A_S_a2Pass ‘a2’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site ‘50A’
    PS-L50A_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 50-meter depth site ‘50A’
    PS-L100_S_a_f1Pass ‘a’ (part 1) with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_a_f2Pass ‘a’ (part 2) with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_c_f1Pass ‘c’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_c_f2Pass ‘c2’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L100_S_c2Pass ‘c2’ with the SIG ELP790 minisparker source (power 700 joules) at the 100-meter depth site
    PS-L200_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 200-meter depth site
    PS-L200_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 200-meter depth site
    PS-L200_S_cPass ‘c’ with the SIG ELP790 minisparker source (power 700 joules) at the 200-meter depth site
    PS-L200_D10_aPass ‘a’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site
    PS-L200_D10_bPass ‘b’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site
    PS-L200_D10_cPass ‘c’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site
    PS-L200_D10_dPass ‘d’ with the Delta sparker source (power 1.0 kilojoules) at the 200-meter depth site Enumerated_Domain_Value_Definition_Source: Producer defined
    PS-L600_S_aPass ‘a’ with the SIG ELP790 minisparker source (power 700 joules) at the 600-meter depth site
    PS-L600_S_bPass ‘b’ with the SIG ELP790 minisparker source (power 700 joules) at the 600-meter depth site
    PS-L600_D24_aPass ‘a’ with the Delta sparker source (power 2.4 kilojoules) at the 600-meter depth site
    PS-L600_D24_bPass ‘b’ with the Delta sparker source (power 2.4 kilojoules) at the 600-meter depth site
    hpid
    Hydrophone Identifier (Source: producer defined) model number TC4034 (Reson)
    lbsrc_lon
    longitude of the sparker source layback position from the stern of the source vessel (RVPS) (Source: producer defined)
    Range of values
    Minimum:-122.360614
    Maximum:-121.897050
    Units:decimal degrees
    Resolution:0.000001
    lbsrc_lat
    latitude of the sparker source layback position from the stern of the source vessel (RVPS) (Source: producer defined)
    Range of values
    Minimum:36.763513
    Maximum:36.992312
    Units:decimal degrees
    Resolution:0.000001
    rec_lon
    longitude of the RVPS receive hydrophone (Source: producer defined)
    Range of values
    Minimum:-122.337685
    Maximum:-121.924577
    Units:decimal degrees
    Resolution:0.000001
    rec_lat
    latitude of the RVPS receive hydrophone (Source: producer defined)
    Range of values
    Minimum:36.778772
    Maximum:36.975878
    Units:decimal degrees
    Resolution:0.000001
    signoffset
    distance between the layback position of the sparker source off the stern of the R/V Parke Snavely and the position of the hydrophone receiver on the R/V San Lorenzo. Positive values are when the source is northwest of the receiver and negative when the source is southeast of the receiver (Source: producer defined)
    Range of values
    Minimum:-5356
    Maximum:4736
    Units:meters
    Resolution:1
    y
    Year collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:2021
    Maximum:2021
    Units:year collected
    Resolution:1
    jd
    Julian Day collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:111
    Maximum:119
    Units:Julian day collected
    Resolution:1
    h
    hour collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:14
    Maximum:20
    Units:hour of day collected
    Resolution:1
    m
    minute collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:0
    Maximum:59
    Units:minute of hour collected
    Resolution:1
    s
    second collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:0
    Maximum:59
    Units:second of minute collected
    Resolution:1
    us
    microsecond collected (Source: time stamp from GGA navigation string from source vessel (RVPS))
    Range of values
    Minimum:48592
    Maximum:999936
    Units:microsecond of second of minute collected
    Resolution:1
    utc_dt
    Coordinated Universal Time (UTC) Day Time string (Source: producer defined) Sequential unique whole numbers that are automatically generated. For example, 2021-04-23 18:31:02.999936+00:00 represents 2021-04-23 as the date collected and 18:31:02.999936+00:00 is the UTC time that the navigation point was taken
    surveyid
    USGS field activity number (FAN) assigned to data collection activity (Source: producer defined) 2021-619-FA, details for which may be found at https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-619-FA
    vehicleid
    name of the source vessel from which data were collected (Source: producer defined) R/V Parke Snavely
    deviceid
    Sparker source type and power level (in joules) (Source: producer defined)
    ValueDefinition
    Applied Acoustics Delta Sparker (2400 J)Brand name and model of sparker source and power level measured in joules
    Applied Acoustics Delta Sparker (1000 J)Brand name and model of sparker source and power level measured in joules
    SIG ELP790 Sparker (700 J)Brand name and model of sparker source and power level measured in joules
    Entity_and_Attribute_Overview:
    Sparker source data in SEG-Y format, with shot-point navigation presented in both shapefile and csv file formats.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

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
    • Wayne E. Baldwin
    • Patrick E. Hart
  2. Who also contributed to the data set?
    The authors acknowledge our fellow participants of the sparker testing field activity 2021-619-FA (Pete Dal Ferro, Gerry Hatcher, Jared Kluesner, Rachel Marcuson, Jenny McKee, Dan Powers, and Rob Wyland) and our team involved in survey planning and execution (Jackson Currie, William Danforth, Jane Denny, Tim Elfers, Dave Foster, Nathan Miller, Eric Moore, and Carolyn Ruppel).
  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 two-vessel survey was designed to quantify the decay of sound emitted from the SIG ELP790 minisparker (powered at 700 joules) and from the Applied Acoustics Delta Sparker (powered at 1.0 and 2.4 kilojoules) as a function of distance during marine geophysical surveys. Seven transect sites were surveyed at five different water depths (25, 50, 100, 200, and 600 meters) to compare the effects of water depth on peak sound level. The source vessel (RVPS) towed the sparker sound source as well as a calibrated hydrophone (TC4034) to record the near-field outgoing signal along the transects. The receive vessel (RVSL) maintained a nearly stationary position at the midpoint of each transect and continuously recorded sound with a calibrated hydrophone (CR3101 or CR3102) at depths between 10 and 20 meters, depending on deployed cable length.

How was the data set created?

  1. From what previous works were the data drawn?
    SrcNav (source 1 of 2)
    Balster-Gee, Alicia F., Baldwin, Wayne E, and Hart, Patrick E., 2022, Navigation and instrument layback positions for marine sparker source vessel, and offset distances to receiver vessel, from data collected in April 2021 offshore Santa Cruz, California (USGS field activity 2021-619-FA): U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    Type_of_Source_Media: online data
    Source_Contribution:
    Navigation from the source vessel was used to calculated the offset between the sound source and the hydrophone on the receiver vessel
    RecNav (source 2 of 2)
    Balster-Gee, Alicia F., Baldwin, Wayne E, and Hart, Patrick E., 2022, Navigation data for marine sparker receiver vessel, and offset distances to source vessel, from data collected in April 2021 offshore Santa Cruz, California (USGS field activity 2021-619-FA): U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    Type_of_Source_Media: online data
    Source_Contribution:
    Navigation from the receiver vessel was used to calculated the offset between the sound source and the hydrophone on the receiver vessel
  2. How were the data generated, processed, and modified?
    Date: 27-Apr-2021 (process 1 of 4)
    Aboard the R/V Parke Snavely the Sparker source (either the SIG ELP790 or the Applied Acoustics Delta Sparker) was towed 20 meters from the stern (source layback position = lbsrc). The SIG ELP790 sparker was powered at 700 joules at all water depths. The Delta Sparker was powered at 1000 joules at the 200-meter depth site and powered at 2.4 kilojoules at the 600 meter depth site. Continuous waveform data (TDMS format) was acquired using SignalExpress software sampling at 192 kHz and a Reson TC4034 hydrophone was positioned approximately 1-meter below the sparker source to measure the outgoing source signal. Navigation data was acquired using an Applanix PosMV Elite differential Global Positioning System (DGPS) while the RVPS made several passes along 7 planned survey tracklines and the RVSL (receive vessel) maintained a stationary position at the midpoint of each trackline. Two tracklines were planned for both the 25- and 50-meter depth sites (named L25 and L25A and L50 and L50A, respectively). Both the Delta Sparker and SIG ELP790 minisparker were used as sources at the 200- and 600-meter depth sites and files were named L200_S for the SIG sparker, L200_D10 for the Delta Sparker, L600_S for the SIG sparker and L600_D24 for the Delta Sparker. Passes were lettered sequentially starting at 'a' for all data files. Filenames are defined in the Entity/Attribute section below.
    Date: 27-Apr-2021 (process 2 of 4)
    Aboard the R/V San Lorenzo, receive vessel, one or two Cetacean Research CR3 omnidirectional hydrophones (CR3101 and CR3102) recorded continuous waveform data (.wav format) using SpectraPlus software sampling at 192 KHz. Navigation data was acquired with a Garmin GPSMAP 4212 Differential Global Positioning System (DGPS). RBR Solo-D depth loggers were positioned near the hydrophones to record the receive hydrophone depth data (HPdepth_m column when available). The R/V San Lorenzo attempted to maintain a stationary position at the center of each of the 7 planned track lines at 25, 50, 100, 200, and 600-meter water depths as the R/V Parke Snavely (source vessel) made several passes along each navigation line. Data sources used in this process:
    • RecNav
    Date: 27-Apr-2021 (process 3 of 4)
    Navigational data from both the RVPS source and RVSL receiver vessels were recorded in raw GGA format. The UTC timestamp, latitude and longitude were extracted using a series of Python notebooks. The layback position of the sparker source was estimated to be 20 meters from the stern of the source vessel. The Python tool PyProj.Geod WGS84 was used to merge the data frames of the source layback latitude and longitude positions (lbsrc_lat and lbsrc_lon, respectively) and to calculate and assign the offset distance, in meters, between the sparker source and the RVSL receive hydrophone for each UTC time sample (utc_dt). To orient the offsets from separate passes relative to each other, a signed offset (signoffet) value was assigned which is the source offset value in meters that is positive when the RVPS is northwest of the RVSL and negative when the RVPS is southeast of the RVSL. Data sources used in this process:
    • SrcNav
    • RecNav
    Date: 27-Apr-2022 (process 4 of 4)
    SignalExpress software was used to output TDMS float files from the Reson TC4034 hydrophone on the source vessel (RVPS). The Python package npTDMSb (https://nptdms.readthedocs.io/en/stable/apireference.html#module-nptdms) was used to read the recorded hydrophone float voltage and write to an ObsPy trace (https://docs.obspy.org). Aboard the receiver vessel (RVSL), SpectraPlus .wav files were output in 16-bit format from the Cetacean Research model CR3 receiver hydrophones. ObsPy and NumPy (https://numpy.org) Python packages were used to unscale the 16-bit voltage readings to float format ObsPy traces. For each pass at each depth site, the timing of the electromagnetic spike as the power supply (aboard the source vessel) discharges power to the sparker source relative to the nearest offset shot time was used to shift the continuous waveform start time. For both source and receiver ObsPy traces, a 70-7000Hz bandpass filter was applied. ObsPy traces were sliced from the continuous waveform using the shot timing (record lengths for RVPS SEG-Y are 0.2 seconds and the RVSL SEG-Y are 2 seconds with offset dependent start times written to the Delay Recording time DELRT header in header bytes 109-110), resampled to 16 kHz, and standard SEG-Y headers were written (https://seg.org/Portals/0/SEG/News%20and%20Resources/Technical%20Standards/seg_y_rev1.pdf). The source vessel navigation (The position of the sparker source is recorded in SEG-Y header bytes 73/77 in decimal degrees. The position of the hydrophone receiver is recorded in SEG-Y header bytes 81/85 in decimal degrees), shot times, and source vessel hydrophone depths (when recorded) were written to SEG-Y headers (2021-619-FA_RVPS_SrcSegy.zip). A CSV file that contains source vessel shot point navigation, offset, shot times, vessel, device, and SEG-Y filename summary information was created (2021-619-FA_RVPS_SrcSegyNav.csv), along with a shapefile of shot point navigation for visual purposes (2021-619-FA_RVPS_SrcSegyNav_shapefile.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?
    The Reson TC4304 hydrophone (S/N: 2710001) was towed approximately 1 meter below the SIG ELP790 minisparker or the Applied acoustics Delta sparker source and is a broad band spherical hydrophone that provides uniform omni-directional characteristics between 1Hz and 480kHz (http://www.teledynemarine.com/reson-tc-4034). The hydrophone was calibrated on 2014-01-13 and measured a sensitivity of -225.4dB. The SIG ELP790 sparker was operated at 700 joules(https://www.marine-seismic-equipments.net/sparker-sound-sources/). The Applied Acoustics Delta Sparker was operated at 1000 joules at the 200-meter depth site and at 2400 joules at the 600-meter depth site (https://www.subseatechnologies.com/applied-acoustics/sub-bottom-profiling/sound-source-sparker/delta-sparker/). For both sparker sources operated at the stated power levels the Reson TC3404 hydrophone was positioned properly to record the full spectrum of sound output. Aboard the R/V San Lorenzo, the stationary receive vessel, Cetacean Research CR3 hydrophones were deployed portside between 10-20 meters below the surface. Receive hydrophones CR3101 and CR3102 have measured sensitivities of -208.2db and -208.6dB, respectively. RBR solo depth loggers were attached above the CR3 hydrophones to record tow depths which has a stated accuracy of +/-0.05percent full scale(about 1 cm water depth).
  2. How accurate are the geographic locations?
    An Applanix POS-MV (Position and Orientation System for Marine Vessels) Elite was used to position the source vessel during data collection. The Applanix POS-MV Elite has a stated positional accuracy of 0.5-2 meters (https://www.applanix.com/downloads/products/specs/posmv/POS-MV-ELITE.pdf). Accuracies of final products may be lower due to total propagated uncertainties of the mapping systems, which include position and motion compensation system, navigation, as well as data processing that includes calculating the source layback from the stern of the vessel (20 meters based on the length of the cable), and PyProj.Geod calculation of offset distance between the sparker source position and the position of the hydrophone on the receiver vessel.
  3. How accurate are the heights or depths?
    Two-way travel time in milliseconds is recorded in SEG-Y files. An RBR Solo-D depth logger was mounted above the TC3404 hydrophone for most of the survey lines to estimate depths with the RBR Ltd. Ruskin utility (v2.7.3.201905031233) via the simplified derivation, where depth in meters = (measured pressure in dbar - atmospheric pressure (set to default 10.1325 dbar)) / (density (set to default 1.0281 g/mL) * 0.980665). The RBR Solo-D units used are rated to 20 meters, and RBR Ltd. states that they are accurate to +/- 0.05 percent of full scale (about 1 cm water depth). If this depth information was recorded, it is populated in the Receiver Group Elevation header (bytes 41-44).
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Some records do not include depth from the RBR logger due to instrument failure. 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?
    Quality control was conducted during processing to ensure consistency of SEG-Y source data recorded aboard the RVSL and of depths logged by the RBR solo depth logger. The position of the sparker source is recorded in SEG-Y header bytes 73/77 in decimal degrees. The position of the hydrophone receiver is recorded in SEG-Y header bytes 81/85 in decimal degrees. Navigation data zip files are available in csv format and as a trackline shape file in the ‘Data Files’ section

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 2021-619-FA_RVPS_SrcSegy.zip that contains 30 standard SEG-Y format files of seismic shots with time stamp (Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards). SEG-Y files were named PS-LDDD-S-P_TC4034_Vp.segy where PS is the vessel ID (R/V Parke Snavely), LDDD is the Line depth site (meters), S is the Source instrument used (S for SIG-ELP790 sparker at 700J power, D10 for the Applied Acoustics Delta sparker at 1000J power, and D24 for the Applied Acoustics Delta sparker at 2400J power), P is the pass label (a, b, c, etc.), and TC4034 is the hydrophone model number. A shapefile of the SEG-Y shot-track navigation is available in the zip file 2021-619-FA_RVPS_SrcSegyNav_shapefile.zip. These same shot-track navigation data are also contained in a single csv file (2021-619-FA_RVPS_SrcSegyNav.csv).
  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 raw seismic data per navigation line in format SEG-Y (version SEG-Y rev 1) Size: 426.8
      Network links: https://doi.org/10.5066/P9EHITBI
      Data format: csv file contains SEG-Y shot-point navigation in format comma-delimited text (version RFC 4180) Size: 3.5
      Network links: https://doi.org/10.5066/P9EHITBI
      Data format: Zip file contains a shapefile with SEG-Y shot point navigation in format shapefile (version ArcGIS Pro (version 2.4.1)) Size: 1.1
      Network links: https://doi.org/10.5066/P9EHITBI
    • 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. CSV data can be viewed with any text editing or spreadsheet software. Users must have software capable of reading shapefile (.shp) format to use the shot point shapefile.

Who wrote the metadata?

Dates:
Last modified: 20-Sep-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_P9EHITBI/2021-619-FA_RVPS_SrcSegy_metadata.faq.html>
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