U.S. Geological Survey Data Series 308

FGDC Metadata


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Identification_Information:
Citation:
Citation_Information:
Originator: Arnell S. Harrison
Originator: Shawn V. Dadisman
Originator: Christopher D. Reich
Originator: Dana S. Wiese
Originator: Jason W. Greenwood
Originator: Peter W. Swarzenski
Publication_Date: 2007
Title:
Archive of Digital Boomer and Chirp Seismic Reflection Data Collected During USGS Cruise 06FSH03 Offshore of Fort Lauderdale, Florida, September 2006
Geospatial_Data_Presentation_Form: Seismic Reflection Profile Section
Series_Information:
Series_Name: U.S. Geological Survey Data Series
Issue_Identification: Data Series 308
Publication_Information:
Publication_Place: St. Petersburg, FL
Publisher: U.S. Geological Survey
Description:
Abstract:
In September of 2006, the U.S. Geological Survey conducted geophysical surveys offshore of Fort Lauderdale, FL. This report serves as an archive of unprocessed digital boomer and 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.

Purpose:
The data archived here were collected as part of the USGS Florida Shelf Habitat (FLaSH) Mapping Project.
Supplemental_Information:
The USGS Florida Integrated Science Center (FISC) - St. Petersburg assigns a unique identifier to each cruise or field activity. For example, 06FSH03 tells us the data were collected in 2006 for the Florida Shelf Habitat (FLaSH) Mapping Project and the data were collected during the third 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 boomer plate is an acoustic energy source that consists of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled at the sea surface and when discharged emits a short acoustic pulse, or shot, that propagates through the water and sediment column. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), detected by the receiver, and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (for example, 0.5 s) and recorded for specific intervals of time (for example, 100 ms). The resulting profiles are two-dimensional (2-D) vertical images of the shallow geologic structure beneath the ship track.

A C System C-Boom power supply provided 105 Joules per shot. Reflected energy was received by a Benthos 1210 hydrophone streamer and recorded by Delph Seismic acquisition software. The streamer contains 10 hydrophones evenly spaced every 0.5 m. For lines 06b01 through 06b21 all phones were used. The streamer was positioned approximately 9 m behind the research vessel and laterally separated from the boomer sled by about 4 m. Refer to figure 1 included with this archive (Data Series 308) for a diagram of the acquisition geometries. The sample frequency of the data was 24 kHz, and record length was 50 ms. Based on survey speeds of 1.5 - 2 knots and a shot rate of every 0.500 s, shot spacing was about 0.386 - 0.514 m.

The Chirp system uses a signal of continuously varying frequency. The towfish is a sound source and receiver, which is typically towed 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). Likewise, the resulting profiles are two-dimensional vertical images of the shallow geologic structure beneath the ship track.

The seismic source employed for Chirp data collection consisted of an EdgeTech SB-424 towfish running Triton Imaging SB Logger (FSSB) V. 1.6.421 acquisition software and towed about 10 m behind the GPS antenna. The frequency range was 4 - 24 kHz. Sample frequency of the data was 25 kHz, the shot rate was every 0.250 s and the record length was approximately 50 ms. Shot spacing was approximately 0.193 - 0.257 m.

For each recorded shot of the Chirp data, three channels of trace data are collected. Channel 2 is the "real," or in-phase component of the signal, channel 1 is the "imaginary," or quadrature component of the signal, and channel 0 is the "envelope," or product of channels 1 and 2. Only channel 0 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, 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 .SEG or .TRA extensions. Additional recording parameters for each trace file can also be found in the .PAR file associated with each .TRA file. However, the .PAR files included here are only needed to process or display the data with Delph Seismic software. 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 500 and (or) 1,000 shots, and produce a filtered and gained GIF image of each profile.

The printable profiles provided here are GIF images that were filtered and 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. NOTE: 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. Use 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: 20060925
Ending_Date: 20060927
Currentness_Reference: Data collection interval
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -80.108050
East_Bounding_Coordinate: -80.065080
North_Bounding_Coordinate: 26.248973
South_Bounding_Coordinate: 26.072968
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: marine seismic reflection
Theme_Keyword: Boomer
Theme_Keyword: Chirp
Theme_Keyword: SEG-Y
Theme_Keyword: 06FSH03
Theme_Keyword: Florida Shelf and Habitat Mapping
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Florida
Place_Keyword: Fort Lauderdale
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: Christopher D. Reich
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. 3032
Contact_Electronic_Mail_Address: creich@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name: DVD/maps/cruisenav/06fsh03_location.jpg
Browse_Graphic_File_Description:
Location map of all digital seismic reflection data collected during USGS Cruise 06FSH03. This map was created at a scale of 1:159,400. Refer to the Lineage section below for the trackline map creation process.
Browse_Graphic_File_Type: JPEG
Browse_Graphic:
Browse_Graphic_File_Name: DVD/maps/cruisenav/06fsh03_survey_boomer.jpg
Browse_Graphic_File_Description:
Trackline map of digital boomer seismic reflection data collected in the survey area during USGS Cruise 06FSH03. This map was created at a scale of 1:115,000. Refer to the Lineage section below for the trackline map creation process.
Browse_Graphic_File_Type: JPEG
Browse_Graphic:
Browse_Graphic_File_Name: DVD/maps/cruisenav/06fsh03_survey_chirp.jpg
Browse_Graphic_File_Description:
Trackline map of digital Chirp seismic reflection data collected in the survey area during USGS Cruise 06FSH03. This map was created at a scale of 1:125,000. 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 and the Department of Planning and Environmental Protection (DPEP), Broward County, FL. This document was improved by the reviews of Karen Morgan (USGS) and Jordan Sanford (CSC) of the USGS in St. Petersburg, FL.

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. Malfunctions associated with the boomer acquisition software caused incorrect dates to be recorded to the trace headers; therefore, the processed and shotpoint navigation files have the wrong years (for example, 2000 and (or) 2011) listed.
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 Furuno GP1650DF DGPS WAAS Max receiver, which is accurate within 3 m. The navigation driver cent_rms.pln was also used during data acquisition, see the Navigation page to download file. Positions were recorded and written to the trace headers in latitude and longitude coordinates about every 1 s. The ASCII navigation files and trackline maps have not been corrected to reflect the approximately 9-m offset between the boomer and GPS antenna and 4-m Chirp and GPS offset. Refer to figure 1 included with this archive (Data Series 308) 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:
Boomer data are relative to sea level. However, varying recorded static shifts of the data have been known to occur. Therefore, these data are not to be used for bathymetry.
Lineage:
Process_Step:
Process_Description:
Boomer processing: The SEG-Y data were processed with Seismic Unix to produce GIF images of the seismic profiles included in this report. A representative boomer data processing sequence consisted of (1) running a bandpass filter of 300-500-2500-3000 Hz, (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.
Chirp processing: 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 0 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 SupplementalĀ Information section above for details on how to use the interactive profiles.
Process_Date: 2007
Process_Step:
Process_Description:
Navigation processing: Incorrect dates were written to the SEG-Y headers for many of the boomer tracklines, see table 2A for details. Shotpoint navigation files and 500- and (or) 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 UTM coordinates from latitude and longitude coordinates and reformatted for use with Environmental Systems Research Institute (ESRI) GIS software.
Process_Date: 2007
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 9.1 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 USGS is the originator of all layers used. A map of trackline navigation for each seismic profile was also produced with CTI SonarWeb software and is in UTM Zone 17 projection.
Process_Date: 2007
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: 2007

Spatial_Data_Organization_Information:
Indirect_Spatial_Reference:
Horizontal X and Y locations (latitude and longitude and Zone 17 UTMs) for each shot are provided as ASCII text files, along with the date and time (UTC) the shot was recorded.

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 .TRA or .SEG extensions and range in size from 3 to 16 MB (boomer) and 5 to 311 MB (Chirp).
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. Also available online at http://pubs.er.usgs.gov/usgspubs/ofr/ofr92590.
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 500- and 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.

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 308
Distribution_Liability:
This DVD publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, 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 imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained therein. 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.
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: 2,995 MB
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 9.1 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/).
File_Decompression_Technique: unzip
Transfer_Size: 20.9 MB
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: DVD/software/arc/arc.zip
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 (http://www.cwp.mines.edu/cwpcodes/).

Metadata_Reference_Information:
Metadata_Date: 20070920
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Arnell Harrison
Contact_Organization: Jacobs Technology Inc., contracted by 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

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