Metadata: Identification_Information: Citation: Citation_Information: Originator: Arnell S. Harrison Originator: Shawn V. Dadisman Originator: James G. Flocks Originator: Dana S. Wiese Originator: Karynna Calderon Publication_Date: 2007 Title: Archive of Digital Chirp Seismic Reflection Data Collected During USGS Cruise 05SCC01 Offshore of Port Fourchon and Timbalier Bay, Louisiana, August 2005 Geospatial_Data_Presentation_Form: Seismic Reflection Profile Section Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 242 Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey Online_Linkage: https://pubs.usgs.gov/ds/2007/242/ Description: Abstract: In August of 2005, the U.S. Geological Survey conducted geophysical surveys offshore of Port Fourchon and Timbalier Bay, Louisiana, and in nearby waterbodies. This report serves as an archive of unprocessed digital Chirp seismic reflection data, trackline maps, navigation files, GIS information, Field Activity Collection System (FACS) logs, observer's logbook, and formal FGDC metadata. Filtered and gained digital images of the seismic profiles are also provided. The archived trace data are in standard Society of Exploration Geophysicists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded and processed with commercial or public domain software such as Seismic Unix (SU). Example SU processing scripts and USGS software for viewing the SEG-Y files (Zihlman, 1992) are also provided. For more information on the seismic surveys see http://walrus.wr.usgs.gov/infobank/g/g105la/html/g-1-05-la.meta.html These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean ( http://www.virtualocean.org/) earth science exploration and visualization applications. Purpose: The data archived here were collected as part of the USGS Subsidence and Coastal Change (SCC) Study. Supplemental_Information: The USGS Florida Integrated Science Center (FISC) - St. Petersburg assigns a unique identifier to each cruise or field activity. For example, 05SCC01 tells us the data were collected in 2005 for the Subsidence and Coastal Change (SCC) Study and the data were collected during the first field activity for that study in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the cruise ID. The naming convention used for each seismic line is as follows: yye##a, where yy is the last two digits of the year in which the data were collected, e is a 1-letter abbreviation for the equipment type (for example, b for boomer and c for Chirp), ## is a 2-digit number representing a specific track, and a is a letter representing the section of a line if recording was prematurely terminated or rerun for quality or acquisition problems. The Chirp system uses a signal of continuously varying frequency. The sound source and receiver is a towfish, which is typically flown 2-5 m above the seafloor. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), detected by a receiver, and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (for example, 0.125 s) and recorded for specific intervals of time (for example, 50 ms). In this way, a two-dimensional vertical image of the shallow geologic structure beneath the ship track is produced. The seismic source employed for 05SCC01 Chirp data collection consisted of an EdgeTech SB-424 towfish running FSSB v. 2.7 software and towed about 14 m behind the GPS antenna. The frequency range was 4-24 kHz. Sample frequency of the data was 25 kHz, and record length was 53-59 ms. Shot rate was 0.125 s, and shot spacing was about 0.261 m. For each recorded shot of the Chirp data, three channels of trace data are collected. Channel 3 is the "real," or in-phase component of the signal, channel 2 is the "imaginary," or quadrature component of the signal, and channel 1 is the "envelope," or product of channels 2 and 3. Only channel 1 was used to produce the profiles presented here; however, all channels are included in the SEG-Y data files. The unprocessed seismic data are stored in SEG-Y, integer, Motorola format, which is a standard digital format that can be read and manipulated by most seismic processing software packages (Barry and others, 1975). The SEG-Y formatted trace files have a .TRA extension. Additional recording parameters for each trace file can also be found in the .PAR file associated with each .TRA file. However, the .PAR and .PLN files included here are only needed to process or display the data with Delph Seismic software. The SEG-Y files do not all fit on one disc and have been distributed onto two DVDs. Disc 1 contains SEG-Y files for lines 05c01_a through 05c13_b, and disc 2 contains SEG-Y files for lines 05c14 through 05c21. Also provided are example Seismic Unix scripts that allow the user to strip off navigation fixes from the SEG-Y headers, along with a fix for every 1,000 shots, and produce a gained GIF image of each profile. The printable profiles provided here are GIF images that were gained using Seismic Unix software. The processed SEG-Y data were exported to Chesapeake Technology, Inc. (CTI) SonarWeb software to produce interactive versions of the profiles that allow the user to obtain a geographic location and depth from the profile for a cursor position. This information is displayed in the status bar of the browser. Warning! The only supported Web browsers that properly display all features of the interactive profiles are Internet Explorer 6 for Windows and Firefox 1.5 for all platforms. For all browsers, the status bar and JavaScript must be enabled. Firefox also requires "Change status bar text" to be checked under Advanced JavaScript Settings. Cautionuse of other browsers may result in spurious or no information given in the status window. Firefox may be downloaded at http://www.mozilla.org/products/firefox. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20050808 Ending_Date: 20050811 Currentness_Reference: Data collection interval Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -90.417814 East_Bounding_Coordinate: -89.955575 North_Bounding_Coordinate: 29.114426 South_Bounding_Coordinate: 29.022212 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:c21f0128-85a4-4577-9e7e-02f46eac733c Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificinformation Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: marine seismic reflection Theme_Keyword: Chirp Theme_Keyword: SEG-Y Theme_Keyword: 05SCC01 Theme_Keyword: Subsidence and Coastal Change 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 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: Port Fourchon Place_Keyword: Timbalier Bay Place_Keyword: Gulf of Mexico Access_Constraints: None. These data are held in the public domain. Use_Constraints: The U.S. Geological Survey requests to be acknowledged as originator of the data in future products or derivative research. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: J. Flocks Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747, ext. 3012 Contact_Electronic_Mail_Address: jflocks@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/ds/2007/242/maps/cruisenav/05scc01_full_area_map.jpg Browse_Graphic_File_Description: Location map of all digital Chirp seismic reflection data collected during USGS Cruise 05SCC01. This map was created at a scale of 1:530,187. Refer to the Lineage section below for the trackline map creation process. Browse_Graphic_File_Type: JPEG Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/ds/2007/242/maps/cruisenav/05scc01_areaa.jpg Browse_Graphic_File_Description: Trackline map of digital Chirp seismic reflection data collected in Area A (refer to Area A of the full survey area location map) during USGS Cruise 05SCC01. This map was created at a scale of 1:89,471. Refer to the Lineage section below for the trackline map creation process. Browse_Graphic_File_Type: JPEG Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/ds/2007/242/maps/cruisenav/05scc01_areab.jpg Browse_Graphic_File_Description: Trackline map of digital Chirp seismic reflection data collected in Area B (refer to Area B of the full survey area location map) during USGS Cruise 05SCC01. This map was created at a scale of 1:51,495. Refer to the Lineage section below for the trackline map creation process. Browse_Graphic_File_Type: JPEG Data_Set_Credit: Funding and (or) support for this study was provided by the USGS Coastal and Marine Geology Program. We thank R/V G.K. Gilbert captain Dave Bennett of Eckerd College for his assistance in data collection. This document was improved by the reviews of Nancy Dewitt (USGS) and Sarah Kruse (University of South Florida) of the USGS in St. Petersburg, Florida. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The validity or accuracy of marine seismic reflection profiles is highly qualitative and depends on equipment and operating condition variables. Visual inspection of the images rendered from the data did not show any major anomalies. Logical_Consistency_Report: This data set is from one cruise with consistent instrument calibrations. Completeness_Report: These data are collected along tracklines (2-D) and are therefore inherently incomplete. Geologic details between lines must be inferred. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: As the seismic reflection data were acquired, the position of the vessel was continuously determined by a CSI Wireless DGPS WAAS Max receiver, which is accurate within 1-3 m. Positions were recorded and written to the trace headers in Zone 15 UTMs about every 1 s. Although data were collected in UTM Zones 15 and 16, all equipment and data processing were set to Zone 15 for this cruise. The ASCII navigation files and trackline maps have not been corrected to reflect the approximately 14-m offset between the Chirp and GPS antenna. Refer to figure 1 included with this archive (Data Series 242) for a diagram of the acquisition geometry, including the GPS offset measurements. Line navigation maps and interactive profiles generated with CTI SonarWeb software have been corrected for the GPS offset. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: These data are not to be used for bathymetry. Depths shown on the Chirp profiles are relative to the depth of the towfish, not to sea level. Furthermore, the raising or lowering of the towfish during a survey (to avoid obstacles or follow relief) produces a relative shift in the multiple reflections seen in the profile, which may be confused as a geologic feature. Any elevation change of the towfish is recorded in the logbooks and is evident on the seismic profiles by steep, abrupt shifts in the seafloor return. Lineage: Process_Step: Process_Description: Chirp processing: The original trace files for lines 05c01, 05c02, 05c03, 05c04a, 05c05, 05c06, 05c07, 05c08, 05c10, 05c11, 05c12, 05c13, 05c14a, 05c18, 05c19, and 05c20 were divided into two trace files each (for example, 05c01 became 05c01_a and 05c01_b) because the original total number of traces exceeded the maximum allowed by the processing software. The SEG-Y data were processed with Seismic Unix to produce GIF images of the seismic profiles included in this report. A representative Chirp data processing sequence consisted of (1) Stripping off channel 1 for each shot and converting to SU format, (2) applying automatic gain control, (3) displaying PostScript, and (4) converting of PostScript image to a GIF image. The processed SEG-Y data were then exported to CTI SonarWeb software to produce an interactive version of each profile that allows the user to obtain a geographic location and depth from the profile for a cursor position. Refer to the Supplemental Information section above for details on how to use the interactive profiles. Process_Date: 2006 Process_Step: Process_Description: Navigation processing: Shotpoint navigation files and 1,000-shot-interval location files were extracted from the trace headers of each line using Seismic Unix software. These files were then processed with PROJ.4 software (http://www.remotesensing.org/proj) to generate latitude and longitude from UTMs and reformatted for use with Environmental Systems Research Institute (ESRI) GIS software. Process_Date: 2006 Process_Step: Process_Description: Trackline map creation: The trackline maps provided in this archive were created using the Points to Lines ArcScript (D. Rathert, http://arcscripts.esri.com/details.asp?dbid=12702) along with ESRI ArcGIS 9.0 software and then exported to Adobe Illustrator for further editing. The maps were later converted into JPEG format by Adobe GoLive. The maps are unprojected (geographic coordinates, NAD83). The coastline layer is a Louisiana Oil Spill Coordinator's Office (LOSCO) dataset. The USGS is the originator of all other layers used. A map of trackline navigation for each seismic profile was also produced with CTI SonarWeb software. Process_Date: 2006 Process_Step: Process_Description: Data Series preparation: In addition to the process steps described above, the following steps were taken to produce this Data Series report: the handwritten logs were scanned and saved as PDF files, digital FACS logs were created using the handwritten logs and personal accounts of the crew members and saved as PDF files, and an HTML-based format was used to present the various parts of this archive. Process_Date: 2006 Process_Step: Process_Description: Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Process_Date: 20170124 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 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: 20201013 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: Indirect_Spatial_Reference: Horizontal X and Y locations (latitude and longitude and Zone 15 UTMs) for each shot are provided as ASCII text files, along with the date and time (UTC) the shot was recorded. Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000009 Longitude_Resolution: 0.000009 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS84 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Binary data file: Trace data are available as binary files in SEG-Y format. These files have a .TRA extension and range in size from 48 to 506 MB. Entity_and_Attribute_Overview: Graphic image file: Printable profiles are available as GIF images. Interactive profiles are available as HTML pages with accompanying JPEG images. The line navigation maps and trackline maps are JPEG images. The trackline maps contain links to the seismic profiles and line navigation maps. Entity_and_Attribute_Overview: Navigation file: Navigation files are available as ASCII text files. Provided are raw (unprocessed) shotpoint navigation files, processed shotpoint navigation files, and processed 1,000-shot-interval location files. Entity_and_Attribute_Overview: GIS file: The GIS project used to create the trackline maps is provided as a zip file composed of ESRI map documents, shapefiles, and metadata. Entity_and_Attribute_Detail_Citation: Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, v. 40, no. 2, p. 344-352. Also available online at http://www.seg.org/publications/tech-stand. Entity_and_Attribute_Detail_Citation: Zihlman, F.N., 1992, DUMPSEGY V1.0: A program to examine the contents of SEG-Y disk-image seismic data: U.S. Geological Survey Open-File Report 92-590, 28 p. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Shawn Dadisman Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747, ext. 3029 Contact_Electronic_Mail_Address: sdadisman@usgs.gov Contact_Instructions: Data may be available on-line only by special arrangement with the distributor above. Resource_Description: U.S. Geological Survey Data Series 242 Distribution_Liability: This DVD publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Although all data and software published on this DVD have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data, software, or related materials. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: SEG-Y Format_Information_Content: The SEG-Y standard format (Barry and others, 1975) consists of the following: a 3,600-byte reel identification header, with the first 3,200 bytes consisting of an ASCII header block followed by a 400-byte binary header block, both of which include information specific to line and reel number; a trace data block that follows the reel identification header, with the first 240 bytes of each trace block consisting of the binary trace identification header; and seismic data samples that follow the trace identification header. File_Decompression_Technique: None Transfer_Size: 5500 Digital_Transfer_Option: Offline_Option: Offline_Media: DVD Recording_Format: ISO 9660 Compatibility_Information: UNIX, Linux, DOS, Macintosh Digital_Form: Digital_Transfer_Information: Format_Name: map document, shapefile, metadata Format_Information_Content: The GIS project used to create the trackline maps is composed of map documents, shapefiles, and metadata. Map documents were created with ESRI ArcGIS 9.0 software. The shapefiles provided may also be viewed using other versions of ArcView, ArcGIS, or public domain software ArcExplorer (http://www.esri.com/software/arcexplorer/index.html). File_Decompression_Technique: unzip Transfer_Size: 41.6 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://pubs.usgs.gov/ds/2007/242/software/arc/arc.zip Digital_Form: Digital_Transfer_Information: Format_Name: Download SEGY data Format_Information_Content: The SEG-Y standard format (Barry and others, 1975) consists of the following: a 3,600-byte reel identification header, with the first 3,200 bytes consisting of an ASCII header block followed by a 400-byte binary header block, both of which include information specific to line and reel number; a trace data block that follows the reel identification header, with the first 240 bytes of each trace block consisting of the binary trace identification header; and seismic data samples that follow the trace identification header. File_Decompression_Technique: none Transfer_Size: 5500 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://cmgds.marine.usgs.gov/data/05scc01/chirp/ Fees: Prices vary. Ordering_Instructions: Publications are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225-0046 (telephone: 1-888-ASK-USGS, e-mail: infoservices@usgs.gov). Technical_Prerequisites: Use of SEG-Y data requires specialized seismic processing software, such as public domain software Seismic Unix. Metadata_Reference_Information: Metadata_Date: 20201013 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Arnell Harrison Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747, ext. 3111 Contact_Electronic_Mail_Address: aharrison@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998