JPEG images of seismic data collected offshore of the Chandeleur Islands, LA, 2007.

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2009
Title:
JPEG images of seismic data collected offshore of the Chandeleur Islands, LA, 2007.
Edition: 1.0
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Series_Name: USGS Open-File Report
Issue_Identification: 2008-1195
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey
Online_Linkage:
<http://pubs.usgs.gov/of/2008/1195/GIS_catalog/Seisimage/seisimage_07007.zip>
Larger_Work_Citation:
Citation_Information:
Originator: Wayne E. Baldwin
Originator: Elizabeth A. Pendleton
Originator: David C. Twichell
Publication_Date: 2009
Title:
Geophysical Data from offshore of the Chandeleur Islands, Eastern Mississippi Delta
Edition: 1.0
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Series_Name: Open-File Report
Issue_Identification: 2008-1195
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey
Online_Linkage: <http://pubs.usgs.gov/of/2008/1195/>
Description:
Abstract:
In 2006 and 2007, the U.S. Geological Survey, in partnership with Louisiana Department of Natural Resources and the University of New Orleans, conducted geologic mapping to characterize the sea floor and shallow subsurface stratigraphy offshore of the Chandeleur Islands in Eastern Louisiana. The mapping was carried out during two cruises on the R/V Acadiana. Data were acquired with the following equipment: an SEA Ltd SwathPlus interferometric sonar (234 kHz), Klein 3000 dual frequency sidescan sonar, and an Edgetech 512i chirp subbottom profiling system. The long-term goal of this mapping effort is to produce high-quality geologic maps and geophysical interpretations that can be utilized to investigate the impact of Hurricane Katrina in 2005 and to identify sand resources within the region.
Purpose:
JPEG images of each seismic profile were generated in order to incorporate images of the seismic data into Geographic Information System (GIS) projects and data archives utilizing HTML. These JPEG images represent approximately 1655 km of chirp seismic data collected with the Edgetech 512i in 2007. This format is universal and yields an easily browseable pictorial view of the seismic profiles. Each profile image is hotlinked to its corresponding trackline navigation contained within a polyline shapefile (seismic_trk_07007.shp), and even 500 shot-point locations are available in a point shapefile (seismic_sht_07007.shp). All of these data are available in an ESRI ArcMap project, as well as separate .zip archives on this digital data DVD archive (<http://pubs.usgs.gov/of/2008/1195/GIS_catalog/>).
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20070610
Ending_Date: 20070622
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -89.293553
East_Bounding_Coordinate: -88.883122
North_Bounding_Coordinate: 29.661442
South_Bounding_Coordinate: 29.381022
Keywords:
Theme:
Theme_Keyword_Thesaurus: General
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Woods Hole Science Center
Theme_Keyword: WHSC
Theme_Keyword: Coastal and Marine Geology Program
Theme_Keyword: CMGP
Theme_Keyword: JPG
Theme_Keyword: JPEG
Theme_Keyword: seismic-reflection
Theme_Keyword: SEGY
Theme_Keyword: profiles
Theme_Keyword: seismic
Theme_Keyword: subbottom
Theme_Keyword: image
Theme_Keyword: chirp
Theme_Keyword: WHSC field activity serial number 06015
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: geoscientificInformation
Theme_Keyword: oceans
Theme_Keyword: oceans and coastal
Theme_Keyword: oceans and estuaries
Theme_Keyword: imageryBaseMapsEarthCover
Place:
Place_Keyword_Thesaurus: General
Place_Keyword: Louisiana
Place_Keyword: Chandeleur Islands
Place_Keyword: Breton Island
Place_Keyword: Gosier Island
Place_Keyword: Curlew Island
Place_Keyword: Mississippi River Gulf Outlet
Place_Keyword: New Harbor Islands
Place_Keyword: North Islands
Place_Keyword: North-Central Gulf Coast
Place_Keyword: United States
Place_Keyword: Gulf of Mexico
Place_Keyword: MRGO
Access_Constraints: none
Use_Constraints:
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 originator of the dataset.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David C. Twichell
Contact_Organization: U.S. Geological Survey
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2266
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: dtwichell@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name: <http://pubs.usgs.gov/of/2008/1195/images/seis_imag.jpg>
Browse_Graphic_File_Description: JPEG image of seismic-reflection profile
Browse_Graphic_File_Type: JPEG
Native_Data_Set_Environment:
Microsoft Windows XP Professional x64 Edition Version 2003 Service Pack 2
Cross_Reference:
Citation_Information:
Originator: John Stockwell
Publication_Date: 2008
Title: CWP/SU: Seismic Uni*x
Geospatial_Data_Presentation_Form: document
Publication_Information:
Publication_Place: Golden, CO
Publisher: Center for Wave Phenomena - Colorado School of Mines
Online_Linkage: <http://www.cwp.mines.edu/cwpcodes/index.html>
Cross_Reference:
Citation_Information:
Originator: Paul Henkart
Publication_Date: 2007
Title: SIOSEIS
Geospatial_Data_Presentation_Form: document
Publication_Information:
Publication_Place: LaJolla, CA
Publisher:
Scripps Institution of Oceanography, University of California - San Diego
Online_Linkage: <http://sioseis.ucsd.edu/index.html>
Cross_Reference:
Citation_Information:
Originator: Michael W. Norris and Alan K. Faichney
Publication_Date: 2002
Title: SEGY Rev.1 Data Exchange Format1
Geospatial_Data_Presentation_Form: document
Publication_Information:
Publication_Place: Tulsa, OK
Publisher: Society of Exploration Geophysicists
Online_Linkage:
<http://www.seg.org/SEGportalWEBproject/prod/SEG-Publications/Pub-Technical-Standards/Documents/seg_y_rev1.pdf>
Data_Quality_Information:
Logical_Consistency_Report:
Processed seismic data were converted to JPEG format for ease of seismic trace display. Quality control was conducted during processing.
Data Quality Problems: Poor sea-state conditions periodically created problems with acquisition of the chirp seismic data during the ACAD07007 cruise. In most instances, heave removal processing (described in processing steps 2-4) greatly minimized the effects of sea state in the final trace data. However, the effects of particularly larger swells do remain within some of the final profiles. In the interest of preserving as much potentially interesting seafloor information as possible, we decided not to lengthen seafloor smoothing filters to the widths that would have been required to remove larger swells. We suggest viewing the JPEG image of line l44f1_000_h.jpg as a reference for the type of seismic artifacts that have been introduced as a result of excessive heave. In general, the artifacts will typically consist of a predictably undulating seafloor reflection that will often be accompanied by a reduction in along-track balance of the seismic traces (ie. vertical striping that alternates between lighter and darker groups of traces, producing a "fencepost"-like appearance). In light of these problems, we caution the interpretation of seafloor features that appear to be at the same scale of heave artifacts within profiles that are obviously affected by problematic sea states.
Completeness_Report:
All acquired seismic data were processed and JPEG images produced.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The SB-0512i was towed approximately 6 m astern and approximately 1.5 m below the sea surface. DGPS navigation (assumed to be accurate within 1-2 m) was obtained from the receiver mounted above the interferometric sonar head, but towfish layback was not accounted for. The layback of the towfish adds additional uncertainty due to changes in angle and scope of the tow cable in response to sea state and vessel speed. The use of J-Star acquisition software during the ACAD07007 cruise caused a reduction in the resolution of navigation values recorded to the trace headers from the onboard DGPS. During acquisition, J-Star truncates the three least significant digits from the raw navigation string, which reduces the resolution of each navigation fix on the order of 1-2 meters. This error is evident in the ship-track polylines in the shapefile "seismic_trk_07007.shp", which display a "sawtooth" pattern when viewed at scales finer than approximately 1:3000. Based on horizontal offsets between the fish and GPS receiver, fish motion behind the vessel, and error associated with the acquisition system, the resulting positional accuracy is assumed to be +/- 20 m.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20070610
Ending_Date: 20070622
Source_Currentness_Reference: ground condition
Source_Contribution:
Approximately 1655 km of high-resolution chirp seismic-reflection profiles were collected using an EdgeTech Geo-Star FSSB system and an SB-0512i towfish (0.5-12 kHz) on the R/V Acadiana of Loreauville, LA. EdgeTech J-Star acquisition software was used to control the Geo-Star topside unit and digitally log trace data in the JSF format. Data were acquired using a 0.25-s fire rate, a 5-ms pulse length, and a 0.5 to 8 kHz sweep (swept frequency). Tracklines are spaced 100 to 125 m apart in the shore parallel direction and about 1 km apart in the shore perpendicular direction.
Process_Step:
Process_Description:
jsftosegy (no version), a C script developed by Tom O'Brien (USGS - Woods Hole Seafloor Mapping Group) was used to convert raw chirp traces in the JSF format to chirp-processed, envelope traces in the SEG-Y rev. 1 standard format.
Process_Date: 2007
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
A script was run that used SIOSEIS (version 96.4) to shift all traces by -2 ms vertically to account for the position of the 512i towfish beneath the sea surface. A second SIOSEIS script was used to predict the vertical location of the sea floor by identifying peak amplitudes within a vertical window. Two-way travel times (milliseconds) to the sea floor at each trace were recorded to an ASCII text file.
Process_Date: 2006
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
All SEG-Y trace data were imported into Seisworks 2-D(version: R2003.12.0.0; Landmark Graphics Corp.), a 2-dimensional, digital seismic interpretation software, and seafloor values were imported as Seisworks horizon data. Spurious seafloor values were edited for discrete traces through heads-up digitization of the Seisworks horizon, and corrected values were exported to a new ASCII text file.
Process_Date: 2006
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
An additional script was run that used SIOSEIS to remove sea surface heave and mute water column portions of the traces by: 1) loading the corrected seafloor times into the SEG-Y trace headers; 2) smoothing the sea floor picks using an along-track filter that approximates twice the period of sea surface heave to be removed (the filter window was set to use 46 traces); 3) creating a series of difference values between the raw and smoothed seafloor picks for each trace; 4) shifting traces up or down according to the difference values; and 5) muting each trace between time zero and the time of the smoothed sea floor pick, thus removing noise within the water column. Changes to the traces within each profile were saved to new "heave corrected" SEG-Y files, which were used for creation of JPEG browse images and digital interpretation.
Process_Date: 2006
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
A script was run that used Seismic Unix (version 4.1) to read the SEG-Y files and plot the data as 8-bit gray scale Postscript files using the Seismic Unix 'psimage' algorithm. All images were created with a horizontal scale of 200 traces per inch. Images were plotted within a constant 8-inch vertical window of 50 milliseconds (Two-Way Travel Time) duration, yielding a vertical resolution of about 8.3 milliseconds per inch. The Postscript images were then converted to JPEG format using ImageMagick (version 5.5.6).
Process_Date: 2006
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: pixel
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Resource_Description: Downloadable Data
Distribution_Liability:
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.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: WinZip
Format_Version_Number: 9.0
Format_Specification: Joint Photographic Experts Group
Format_Information_Content:
WinZip files contains compressed images of processed seismic-reflection profiles as well as associated metadata.
File_Decompression_Technique: Use WinZip or pkUnzip
Transfer_Size: 500 MB
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
<http://pubs.usgs.gov/of/2008/1195/GIS_catalog/Seisimage/seisimage_07007.zip>
Access_Instructions: Data can be downloaded via the World Wide Web (WWW)
Offline_Option:
Offline_Media: DVD-ROM
Recording_Capacity:
Recording_Density: 4.75
Recording_Density_Units: Gbytes
Recording_Format: UDF
Fees: none
Custom_Order_Process:
Digital copies of these chirp seismic data may also be obtained in the SEG-Y Rev. 1 standard format upon request. The data would be packaged on DVD, and contain the chirp-processed, envelope traces subsequent to conversion from raw JSF format.
Technical_Prerequisites: These data can be viewed with any JPEG image viewing software.
Metadata_Reference_Information:
Metadata_Date: 20080403
Metadata_Review_Date: 2008
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Wayne E. Baldwin
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile
Generated by mp version 2.9.6 on Wed Jan 28 16:10:28 2009