Chirp sub-bottom data collected in 2019 in Whiskeytown Lake, California during USGS field activity 2018-686-FA

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Frequently anticipated questions:

What does this data set describe?

Chirp sub-bottom data collected in 2019 in Whiskeytown Lake, California during USGS field activity 2018-686-FA
These metadata describe high-resolution chirp sub-bottom data collected in May 2019 in Whiskeytown Lake, California. Data were collected and processed by the the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) with fieldwork activity number 2018-686-FA. The chirp sub-bottom data are provided in SEG-Y format.
Additional information about the field activity 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?
    Dartnell, Peter, Brothers, Daniel S., East, Amy E., Currie, Jackson, Ferro, Pete Dal, and Logan, Joshua B., 20210520, Chirp sub-bottom data collected in 2019 in Whiskeytown Lake, California during USGS field activity 2018-686-FA: data release DOI:10.5066/P958Q0DX, 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: -122.595
    East_Bounding_Coordinate: -122.522
    North_Bounding_Coordinate: 40.653
    South_Bounding_Coordinate: 40.597
  3. What does it look like? (JPEG)
    Map showing transect lines where Chirp data were collected in Whiskeytown Lake.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 15-May-2019
    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 each seismic profile location are stored unscaled 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.
      Depth_Datum_Name: local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: two-way travel time
      Depth_Encoding_Method: attribute values
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview: 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)
    • Peter Dartnell
    • Daniel S. Brothers
    • Amy E. East
    • Jackson Currie
    • Pete Dal Ferro
    • Joshua B. Logan
  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

    831-427-4747 (voice)

Why was the data set created?

High-resolution chirp sub-bottom data were collected by the U.S. Geological Survey Pacific Coastal and Marine Science Center in May of 2019 in Whiskeytown Reservoir, California using an Edgetech SB-512i sub-bottom profiler. These data were collected to measure possible debris flows into the lake during the 2018-2019 rainy season following the July-August 2018 Carr fire that burned vegetation around the entire lake. Post-fire hillslope sediment yields are commonly substantially greater than pre-fire yields, but the degree to which they increase can vary substantially. Effects of wildfire on sediment yield have important implications for hazards (debris-flow risk), ecosystem disturbance and recovery, and downstream water resources (storage capacity in lakes, as well as water quality). These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify bathymetric features. These data are not intended to be used for navigation.

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: 2019 (process 1 of 1)
    Chirp sub-bottom data were collected using an Edgetech-512i sub-bottom profiler and converted to envelope format. Sub-bottom tow fish depth is stored in header byte 49 with an elevation scalar of -1000 (header byte 69). Navigation was converted from seconds of arc to UTM zone 10N and stored unscaled in header bytes 81 and 85.
  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 data acquisition and quality was assured during data processing
  2. How accurate are the geographic locations?
    Estimated to be no less than 3 m due to total propagated uncertainties of navigation as well as data processing.
  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 consistency tests were conducted, but quality control was conducted during 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
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? Zip file ( containing chirp sub-bottom (SEG-Y) data collected during USGS field activity 2019-686-FA, accompanied by FGDC-compliant CMGDS metadata and a location map of transect lines. The data are divided up and presented by navigation line, as reflected in the individual file names. Chirp file sizes are limited to 200 MB so there may be several line parts per 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?
  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?

Last modified: 20-May-2021
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)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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