Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2009 Title: SEG-Y format of chirp seismic data collected offshore of the Chandeleur Islands, LA, 2007 Edition: 1.0 Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: https://cmgds.marine.usgs.gov/data/2007_007_FA/ 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: These chirp seismic-reflection data were collected to use for interpretation of shallow subsurface stratigraphy offshore the Chandeleur Islands, Louisiana. Supplemental_Information: For more information on the seismic surveys see https://cmgds.marine.usgs.gov/fan_info.php?fan=2007-007-FA. These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean (http://www.virtualocean.org/) earth science exploration and visualization applications. The JPEG format of these data (along with other data associated with this field activity) were released through the Open-File Report 2008-1195 (https://pubs.usgs.gov/of/2008/1195/). See the cross-reference for full citation information. 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: USGS Metadata Identifier Theme_Keyword: USGS:f2ecb0be-3dd5-4e3b-86c1-be8ff617c1d6 Theme: Theme_Keyword_Thesaurus: None 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: 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: imageryBaseMapsEarthCover Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: distributions Theme_Keyword: substrate Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords Theme_Keyword: seismic reflection profiling Theme_Keyword: marine geophysics Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: seismic reflection methods Theme_Keyword: sub-bottom profiling Theme_Keyword: marine geophysics Place: Place_Keyword_Thesaurus: None 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: https://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/documents/10161/77915/seg_y_rev1.pdf Cross_Reference: 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: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://pubs.usgs.gov/of/2008/1195/ 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. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: unknown Title: Information unavailable from original metadata. 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_Citation_Abbreviation: Information unavailable from original metadata. 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 Process_Step: Process_Description: Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). Attempted to modify http to https where appropriate. Fixed an online link in a cross-reference. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The source information was incomplete and had to be modified to meet the standard. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Process_Date: 20170228 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: This metadata record was modified from one describing JPEG images to reflect the SEG-Y version of the same data (Open-File Report 2008-1195, https://pubs.usgs.gov/of/2008/1195/). Changes were made to the Citation and Distribution_Information. Process_Date: 20171120 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Process_Date: 20171130 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: Mailing and Physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword. Process_Date: 20200908 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@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: SEG-Y Format_Information_Content: Link is to a folder containing SEG-Y files. Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://cmgds.marine.usgs.gov/data/2007_007_FA/ Access_Instructions: The online link gives access to the folder containing the individual SEG-Y files. Fees: none Technical_Prerequisites: These data require software that can read SEG-Y data. Metadata_Reference_Information: Metadata_Date: 20200908 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