U.S. Geological Survey
2014
WC_seisimages: PNG format images of EdgeTech SB-512i chirp seismic-reflection data collected in May 2012 by the U.S. Geological Survey within the Washington Canyon, mid-Atlantic Margin
1.0
Open-File Report
2014-1118
Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts
U.S. Geological Survey, Coastal and Marine Geology Program
https://pubs.usgs.gov/of/2014/1118/data/Washington_Canyon/images/WashingtonCanyon_seisimages.zip
Jeffrey Obelcz
Daniel S. Brothers
Uri S. ten Brink
Jason D. Chaytor
Charles R. Worley
Eric M. Moore
2014
Chirp Seismic-Reflection Data From the Baltimore, Washington, and Norfolk Canyons, U.S. Mid-Atlantic Margin
1.0
Open-File Report
2014-1118
Reston, Virginia
U.S. Geological Survey
https://dx.doi.org/10.3133/ofr20141118
https://pubs.usgs.gov/of/2014/1118/
A large number of high-resolution geophysical surveys between Cape Hatteras and Georges Bank have been conducted by federal, state, and academic institutions since the turn of the century. A major goal of these surveys is providing a continuous view of bathymetry and shallow stratigraphy at the shelf edge in order to assess levels of geological activity during the current sea level highstand. In 2012, chirp seismic-reflection data was collected by the U.S. Geologial Survey aboard the motor vessel Tiki XIV near three United States mid-Atlantic margin submarine canyons. These data can be used to further our understanding of passive continental margin processes during the Holocene, as well as providing valuable information regarding potential submarine geohazards. For more information on the U.S. Geological Survey involvement in this effort, see <http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2012-005-FA>.
PNG images of each seismic profile were generated in order to enable incorporation of images of the seismic profiles into Geographic Information System (GIS) projects and data archives. The PNG images represent over 170 km of EdgeTech SB-512i chirp seismic-reflection profiles collected within and around Washington Canyon. These images are provided as a convenient and rapid method for viewing the seismic-reflection data.
20120524
1819 (UTC)
20120527
2355 (UTC)
ground condition of survey on dates 20120524-20120527
None planned
-74.555219
-74.389564
37.532892
37.381344
General
U.S. Geological Survey
USGS
Woods Hole Coastal and Marine Science Center
WHCMSC
Coastal and Marine Geology Program
CMGP
Seafloor
Marine Geology
PNG
seismic reflection
SEGY
seismic profile
subbottom
EdgeTech
512i
image
chirp
M/V Tiki XIV
M/V Tiki 14
field activity 2012-005-FA
field activity number 12005
USGS CMG InfoBank ID T-05-12-MC
submarine canyon
geohazards
continental margin
ISO 19115 Topic Category
oceans
geoscientificInformation
General
North America
United States
Atlantic Ocean
mid-Atlantic margin
Maryland
Washington Canyon
Baltimore Canyon Trough
General
Seafloor
Subsurface
sea floor
General
2012
None.
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the source of this information.
Jeffrey Obelcz
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x. 2245
508-457-2310
jobelcz@usgs.gov
https://pubs.usgs.gov/of/2014/1118/data/Washington_Canyon/images/seisimage.jpg
Thumbnail of a sample seismic-reflection profile.
JPEG
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.1850
John Stockwell
2011
Seismic Uni*x
Golden, CO
Center for Wave Phenomena - Colorado School of Mines
<http://www.cwp.mines.edu/cwpcodes/>
Paul Henkart
2011
SIOSEIS
La Jolla, CA
Scripps Institution of Oceanography, UC San Diego
<http://sioseis.ucsd.edu/>
Michael W. Norris and Alan K. Faichney
2002
SEGY Rev. 1 Data Exchange Format 1
Tulsa, OK
Society of Exploration Geophysicists
<http://www.seg.org/documents/10161/77915/seg_y_rev1.pdf>
Processed seismic data were converted to PNG format for ease of seismic trace display. Quality control was conducted during processing.
Lines were serially recorded during the survey in the format "LXF1". When a file is named "LXF2" or has a file number greater than 2, the recording parameters were usually changed (record length and shot rate), as recorded in the ship's log. The following lines were either not recorded or excluded from this data release: L61F3 (negligible length), L157F1 (line was overwritten in the field, L160F1 is a duplicate), L182F1 (incorrectly named L182F2). Line l169f1_topmute_sf trancates a portion of the sea floor. The recording window only went to 400 ms on this line, which resulted in truncating the sea floor.
U.S. Geological Survey
Unpublished Material
raw seismic data
disc
20120524
1819 (UTC)
20120527
2355 (UTC)
ground condition
Seismic-reflection data acquisition: Chirp seismic data were collected using an EdgeTech SB-0512i towfish (0.5-4.5 kHz pulse, 50 ms pulse length, except for L53F1-L62F1, which were 0.5-2.7 kHz, 40 ms pulse length), which was towed astern of the M/V Tiki XIV of Ocean City, MD. Chesapeake Technologies' SonarWiz (v.4.04.0031) seismic acquisition software was used to control the chirp, digitally log trace data in the SEG-Y Rev. 1 format (IEEE floating point), and record GPS navigation coordinates to the SEG-Y trace headers (in arc seconds of Latitude and Longitude, multiplied by a scalar of 100). Traces lengths are constant within lines, but vary from line to line due to variable water depth in the survey area (the minimum trace length was 250 ms and the maximum 1400 ms). This yields a range of samples per trace from approximately 5435 (250 ms trace length) to 30435 (1400 ms trace length). Sample interval was kept at a constant .000046 s. The ping rate was set to be consistent with the trace length, so it varied between 250 ms and 1400 ms.
SIOSEIS (version 2010.2.11) was used to mute the first 10 ms of each seismic trace of select lines (this process step is indicated in the line name by the _topmute suffix). SIOSEIS was then used to predict the vertical location of the sea floor for traces by identifying the first downtrace instance of an amplitude that exceeded a user-defined threshold value. This seafloor pick was then used by SIOSEIS process 'swell' to minimize the effect of sea surface heave. The output SEG-Y file is in the format <LxFx_topmute_sf>, and these files were then used to create browse images and digital interpretation.
201206
Jeffrey Obelcz
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x. 2245
jobelcz@usgs.gov
SEG-Y trace data of lines that SIOSEIS could not seafloor autopick (usually due to an acoustically faint seafloor-sediment interface) were imported into IHS Kingdom Suite (version 8.7.1), a digital seismic interpretation software. The seafloor was manually picked using an interactive horizon digitizer tool, and seafloor horizons for these lines were exported as trace-time (one-way travel time) pair ASCII text files.
201206
Jeffrey Obelcz
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x. 2245
jobelcz@usgs.gov
SIOSEIS is used to insert the trace-time pairs exported from Kingdom Suite (detailed in process step 2) into the SEG-Y trace headers and minimize the effect of sea surface heave using process 'swell'. The output files are in the format <LxFx_sf> (images that are in the format LxFx_topmute_sf describe in process step 1 did not need to be manually picked in Kingdom Suite), and were the SEG-Y files used for creation of browse images and digital interpretation.
201206
Jeffrey Obelcz
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x. 2245
jobelcz@usgs.gov
Seismic Unix (version 4.2) was used to read all SEG-Y files produced in process steps 1 and 3 and write a Seismic Unix file for each corresponding SEG-Y file. Seismix Unix was then used to plot the SU files as 8 bit grayscale Postscript files using the SU 'psimage' algorithm. Images were created with a variable horizontal scale and variable TWTT depending on trace length of a given line. Each image is not representative of the entire SEG-Y file; the top and bottom of each profile is cropped to only display areas of subbottom penetration. Postscript images were converted to PNG format using ImageMagick (version 6.7.0). The x-axis of the images represents ffid and the y-axis is two-way travel time in seconds.
201206
Jeffrey Obelcz
U.S Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-457-8700 x. 2245
jobelcz@usgs.gov
Raster
Pixel
Jeffrey Obelcz
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x. 2245
jobelcz@usgs.gov
Downloadable Data
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Portable Network Graphics (PNG)
Zip-compressed PNG images and associated metadata for processed EdgeTech SB-512i chirp seismic-reflection profiles collected in and around Washington Canyon by the U.S. Geological Survey in 2012. This metadata file describes both the uncompressed (149 MB) and zip-compressed images.
Use WinZip, 7zip, Peazip or pkUnzip. Compressed with WinZip v. 14.0.
80.6
https://pubs.usgs.gov/of/2014/1118/data/Washington_Canyon/images/WashingtonCanyon_seisimages.zip
https://pubs.usgs.gov/of/2014/1118/ofr2014-1118-data-catalog.html
Data can be downloaded via the World Wide Web (WWW)
none
These data can be viewed with any PNG image viewing software. The zip files must be uncompressed in order to view the PNG images.
20130514
Jeffrey Obelcz
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-457-2245
508-457-2310
jobelcz@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time