Holly F. Ryan
Ray W. Sliter
Patrick E. Hart
20191127
Chirp seismic-reflection data from field activity L-1-06-SF collected offshore Bolinas to San Francisco, California on 2006-09-30
seismic-reflection data in SEG-Y format
data release
DOI:10.5066/P9XDFD92
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey
https://doi.org/10.5066/P9XDFD92
https://www.sciencebase.gov/catalog/item/5cf804c0e4b07f02a7046551
Holly F. Ryan
Ray W. Sliter
Patrick E. Hart
2019
Chirp and minisparker seismic-reflection data of field activity L-1-06-SF collected offshore Bolinas to San Francisco, California, from 2006-09-25 to 2006-10-03
data release
DOI:10.5066/P9XDFD92
Pacific Coastal and Marine Science Center, Santa Cruz, CA
U.S. Geological Survey
https://doi.org/10.5066/P9XDFD92
High-resolution Chirp seismic-reflection data were collected by the U.S. Geological Survey in September 2006 offshore San Francisco, California. Data were collected aboard the R/V Lakota, during field activity L-1-06-SF. Chirp data were collected using an EdgeTech 512 chirp subbottom profiler and recorded with a Triton SB-Logger.
This work was funded by the USGS Coastal and Marine Geology Program’s Marine Geohazards project. The high-resolution seismic-reflection profiles provide fault geometry information of the San Gregorio, San Andreas, and Golden Gate faults to be used to update the USGS Quaternary fault database and in shaking hazard models developed by the Working Group for California Earthquake probabilities. Other objectives of the mission were to determine thickness of Holocene sediments and verify surficial mapping based on multibeam with surficial features and sediment cover based on subbottom systems. These data and information are intended for science researchers, students from elementary through college, policy makers, and general public.
Additional information about the field activities from which these data were derived is available online at:
http://cmgds.marine.usgs.gov/fan_info.php?fan=L106SF
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
20060930
20060930
ground condition at time data were collected
None planned
-122.48652
-122.48624
37.81508
37.75838
USGS Metadata Identifier
USGS:5cf804c0e4b07f02a7046551
ISO 19115 Topic Category
Oceans
Elevation
geoscientificinformation
Data Categories for Marine Planning
Bathymetry and Elevation
USGS Thesaurus
sub-bottom profiling
geospatial datasets
marine geophysics
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
Golden Gate
San Francisco
Ocean Beach
NGA GEOnet Names Server (GNS)
North Pacific Ocean
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
831-427-4747
pcmsc_data@usgs.gov
https://www.sciencebase.gov/catalog/file/get/5cf804c0e4b07f02a7046551?name= L106SF_Chirp_nav.jpg&allowOpen=true
Image showing chirp tracklines
JPEG
SEG-Y Rev
Identified as best available version
Subbottom data were collected during USGS cruise L-1-06-SF using an Edgetech 512 Chirp subbottom profiling system. 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.
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.
Chirp seismic-reflection data were collected using an Edgetech 512 Chirp subbottom profiling system consisting 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 4,500 Hz, and the data are recorded by hydrophones located on the bottom of the fish and recorded in SEG-Y 32-bit floating point using a Triton SB-Logger. 15 lines were collected and line “01” was used as a test line and was not recorded. GPS position information was inserted into the SEG-Y trace headers in header bytes 73 and 77, with a scalar of -1000 (noted in header byte 71).
20060930
Chirp seismic-reflection SEG-Y files consist of the internally transformed amplitude envelope channel corrected for the depth of the fish below the sea surface using Paradigm Geophysical Echos seismic processing software. 1) SEG-Y channel with sequence number “1” was written to a SEG-Y file; 2) The fish depth header word (byte location 49 in SEG-Y file) was read and converted from millimeters to two-way travel time to create a fish-depth static value; and 3) The fish depth static was applied to the data to correct for the vertical up and down movement of the Chirp fish. UTM 10N x and y position data were inserted into SEG-Y header bytes 81 and 85. Additionally, ship-heave statics were calculated using SIOSEIS seismic processing. The statics were created with a seafloor auto-tracker to detect the seafloor two-way travel time for each shot. This tracker defaults to the time value of the previous shot on low amplitude traces. Corrections were applied to the data to filter out the effect of the sea swell. A seafloor mute was applied before the final processed lines were output in SEG-Y format.
20190720
Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.
20201019
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
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.
WGS 1984 UTM Zone 10N
0.9996
-123.0
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
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 - ScienceBase
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
1-888-275-8747
sciencebase@usgs.gov
These data are available in SEG-Y format in a single zip file (L106SF_Chirp_segy.zip).
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
SEGY 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
637.53
https://www.sciencebase.gov/catalog/file/get/5cf804c0e4b07f02a7046551
https://doi.org/10.5066/P9XDFD92
Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download the zipped file of the chirp data, metadata, and a map of the chirp tracklines. The second link points to a landing page for the entire data release that also includes links to other data collected during this field activity.
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.
20201019
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-427-4747
pcmsc_data@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998