Alicia F. Balster-Gee
Ray W. Sliter
James E. Conrad
Thomas D. Lorenson
Antoinette G. Papesh
Daniel J. Kennedy
Jonathan A. Warrick
2021
High-resolution chirp seismic-reflection data collected offshore San Francisco, California, during field activity 2019-649-FA from 2019-10-11 to 2019-10-18
seismic-reflection data in SEG-Y format
data release
DOI:10.5066/P9LBG9H5
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey
https://doi.org/10.5066/P9LBG9H5
Ray W. Sliter
James E. Conrad
Thomas D. Lorenson
Antoinette G. Papesh
Alicia F. Balster-Gee
Janet T. Watt
Jonathan A. Warrick
2021
Geophysical and core sample data collected offshore San Francisco, California, during field activity 2019-649-FA from 2019-10-11 to 2019-10-18
data release
DOI:10.5066/P9LBG9H5
Pacific Coastal and Marine Science Center, Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/P9LBG9H5
This part of the data release contains approximately 783 line-kilometers of processed, high-resolution, chirp seismic-reflection data that were collected aboard the R/V Bold Horizon in 2019 on U.S. Geological Survey cruise 2019-649-FA offshore San Francisco, California. The chirp profiles were acquired using an Edgetech 3200 5-16 chirp sub-bottom profiling system. These data are divided up and presented by navigation line, as reflected in the individual file names.
The U.S. Geological Survey (USGS) collected high-resolution chirp seismic-reflection profiles in 2019 offshore San Francisco, California. The along-shore and across-shore chirp profiles collected are oriented to assess sand and gravel resources in Federal and State waters for potential use in future beach nourishment projects along stretches of the coast where critical erosion hotspots have been identified. This cruise was funded through partnerships with the Bureau of Ocean Energy Management (BOEM) and the State of California Ocean Protection Council (OPC).
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2019-649-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
20191011
20191018
ground condition at time data were collected
As needed
-122.87083
-122.39324
38.01347
37.49665
USGS Metadata Identifier
USGS:e46b69a4-81bd-4224-b2ae-9028d3e6900d
ISO 19115 Topic Category
oceans
geoscientificInformation
Data Categories for Marine Planning
Substrate
USGS Thesaurus
sub-bottom profiling
marine geophysics
geospatial datasets
Marine Realms Information Bank (MRIB) keywords
seismic reflection profiling
None
U.S. Geological Survey
USGS
Coastal and Marine Hazards and Resources Program
CMHRP
Pacific Coastal and Marine Science Center
PCMSC
Geographic Names Information System (GNIS)
Pacific Ocean
State of California
San Francisco
Bolinas
Ocean Beach
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.
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-460-4747
pcmsc_data@usgs.gov
2019-649-FA_tracks_and_cores.png
Map showing locations of vibracore sites (purple dots) and tracklines (blue) along which chirp seismic data were collected.
PNG
SEG-Y Rev
Identified as best available version
Subbottom data were collected during USGS cruise 2019-649-FA using an Edgetech 3200 5-16 Chirp sub-bottom profiling system. This system consists of a source transducer and an array of receiving hydrophones housed in a 500-lb “fish” towed at a depth of several meters below the sea surface. The swept-frequency “chirp” source signal is between 500 and 16,000 Hz, and data are recorded by hydrophones located on the bottom of the fish. Quality control was conducted during the collection process.
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. Equipment malfunction, shutdowns due to mammals in the area, and operation hour constrains resulted in some lines having multiple parts.
Position data were provided by a Hemisphere V100 Global Positioning System using L1, C/A code and carrier phase smoothing with a stated accuracy of 60 centimeters.
Depths shown in the seismic data files are in milliseconds (round trip travel time) and are referenced to sea level.
The chirp seismic-reflection profiles were acquired with a swept frequency source towed at about 5 meters depth below the sea surface and fired at roughly every 1 to 2 meters, depending on water depth. Data were recorded to Edgetech JSF format using Edgetech recording software. Survey speeds were approximately 4.5 knots.
20191018
Chirp seismic-reflection data were first converted from JSF to SEG-Y format. The SEG-Y files were then processed using Sioseis software. The following processing steps were applied to each line: 1)The fish depth header word was read and converted from millimeters to two-way travel time to create a fish-depth static value; 2) The fish-depth static value was applied to the data to correct for changing tow depth of the chirp fish; 3) swell correction was applied to the data to correct for the motion of the sea; 4) water column mute; and 5) final processed SEG-Y was output with correct navigation written to header bytes 81 and 85 in UTM coordinates.
20191018
Performed minor edits to the metadata to correct typos. No data were changed
20211013
U.S. Geological Survey
Susan A. Cochran
Geologist
Mailing and Physical
2885 Mission Street
Santa Cruz
CA
95060
831-460-7545
scochran@usgs.gov
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
WGS 1984 UTM Zone 11N
0.9996
-117.0
0.0
500000.0
0.0
coordinate pair
0.0001
0.0001
Meter
D WGS 1984
WGS 1984
6378137.0
298.257223563
Local surface
0.1
meters
Attribute values
Navigation and seismic shots with Time Stamp in standard SEG-Y file format
Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards
U.S. Geological Survey – Pacific Coastal and Marine Science Center
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
1-831-427-4747
pcmsc_data@usgs.gov
2019-649-FA_chirp_data.zip contains high-resolution seismic-reflection (SEG-Y) data collected during PCMSC field activity 2019-649-FA. These data are divided up and presented by navigation line, as reflected in the individual file names. Equipment malfunction, shutdowns due to mammals in the area, and restricted operation hours resulted in some lines having multiple parts.
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.
SEG-Y
SEG-Y rev 1
Zip file contains the processed seismic data per navigation line
Winzip, 7-zip, or Winrar are free software that will open .zip files
1820
https://doi.org/10.5066/P9LBG9H5
Data can be downloaded using the Network_Resource_Name link, then scroll down to the Seismic Data section.
None.
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.
20211013
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-460-4747
pcmsc_data@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998