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U.S. Geological Survey Data Series 346

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Originator: Arnell S. Harrison
Originator: Shawn V. Dadisman
Originator: Amy Swancar
Originator: Ann B. Tihansky
Originator: James G. Flocks
Originator: Dana S. Wiese
Publication_Date: 2008
Archive of Digital Boomer Seismic Reflection Data Collected During USGS Field Activity 96LCA04 in Lakes Mabel and Starr, Central Florida, August 1996
Geospatial_Data_Presentation_Form: Seismic Reflection Profile Section
Series_Name: U.S. Geological Survey Data Series
Issue_Identification: 346
Publication_Place: St. Petersburg, FL
Publisher: U.S. Geological Survey
In August of 1996, the U.S. Geological Survey conducted geophysical surveys in Lakes Mabel and Starr, Florida. This report serves as an archive of unprocessed digital boomer seismic reflection data, trackline maps, navigation files, GIS information, cruise log, and formal FGDC metadata. For detailed information about the hydrologic setting of Lake Starr and the interpretation of some of these seismic reflection data, see Swancar and others (2000) at 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.
The data archived here were collected as part of the Central Highlands Lakes project, which is part of a larger USGS Lakes and Coastal Aquifers (LCA) study.
The USGS Florida Integrated Science Center (FISC) - St. Petersburg assigns a unique identifier to each cruise or field activity. For example, 96LCA04 tells us the data were collected in 1996 for the Lakes and Coastal Aquifers (LCA) project and the data were collected during the fourth field activity for that project in that calendar year. Refer to for a detailed description of the method used to assign the cruise ID. The naming convention used for each seismic line is as follows: xxmyy_#a, where xx is an abbreviation of the discipline the data were collected for and myy is the month and year the trackline was collected, # is a 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 floating on the water 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 lake bottom), detected by the receiver (hydrophone streamer), 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). In this way, a 2-D vertical image of the shallow geologic structure beneath the ship track is produced.

An ORE GeoPulse power supply provided 105 Joules per shot. Reflected energy was received by an Innovative Transducers, Inc. (ITI) ST-5 streamer and recorded by Delph Seismic acquisition software. The streamer contains 10 hydrophones evenly spaced every 0.610 m. For all lines, phones 5 - 8 were used. The streamer was directly behind the research vessel positioned parallel to the boomer sled and laterally separated from it by about 4 m. Refer to figure 1 included with this archive for a diagram of the acquisition geometry. The sample frequency of the data was 16 kHz, and record length was 100 ms. The shot spacing was highly variable, however, based on survey speeds of 2 knots and a shot rate of every 0.5 s, shot spacing was about 0.514 m.

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 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 shots, and produce a filtered and gained GIF image of each profile. NOTE: Navigation data were recorded to 2 different sections of the SEG-Y trace headers, creating 2 navigation data sets. For details, see the Horizontal Positional Accuracy Report under the Data Quality Information section below.

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 or greater for Windows and Firefox 1.5 or greater 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

Beginning_Date: 19960806
Ending_Date: 19960807
Currentness_Reference: Data collection interval
Progress: Complete
West_Bounding_Coordinate: -81.592886
East_Bounding_Coordinate: -81.583153
North_Bounding_Coordinate: 27.973098
South_Bounding_Coordinate: 27.953200
Theme_Keyword_Thesaurus: None
Theme_Keyword: marine seismic reflection
Theme_Keyword: boomer
Theme_Keyword: SEG-Y
Theme_Keyword: 96LCA04
Theme_Keyword: Lakes and Coastal Aquifers
Theme_Keyword: Central Highlands Lakes
Place_Keyword_Thesaurus: None
Place_Keyword: Florida
Place_Keyword: Lake Mabel
Place_Keyword: Lake Starr
Access_Constraints: None. These data are held in the public domain.
The U.S. Geological Survey and Southwest Florida Water Management District (SWFWMD) request to be acknowledged as originators of the data in future products or derivative research.
Contact_Person: Amy Swancar
Contact_Position: Hydrologist
Address_Type: mailing and physical
Address: 10500 University Center Drive, Suite 215
City: Tampa
State_or_Province: FL
Postal_Code: 33612
Country: USA
Contact_Voice_Telephone: (813) 975-8620, ext. 118
Browse_Graphic_File_Name: CD/maps/cruisenav/96lca04_location.jpg
Location map of digital boomer seismic reflection data collected during USGS Field Activity 96LCA04. This map was created at a scale of 1:64,000. Refer to the Lineage section below for the trackline map creation process.
Browse_Graphic_File_Type: JPEG
Browse_Graphic_File_Name: CD/maps/cruisenav/96lca04_mabel.jpg
Trackline map of digital boomer seismic reflection data collected in Lake Mabel (refer to Lake Mabel on the location map) during USGS Field Activity 96LCA04. This map was created at a scale of 1:5,900.
Browse_Graphic_File_Type: JPEG
Browse_Graphic_File_Name: CD/maps/cruisenav/96lca04_starr.jpg
Trackline map of digital boomer seismic reflection data collected in Lake Starr (refer to Lake Starr on the location map) during USGS Field Activity 96LCA04. This map was created at a scale of 1:6,145.
Browse_Graphic_File_Type: JPEG
Funding and (or) support for this study were provided by the USGS Water Resources Discipline (Central Highlands Lakes project - FL59100), Coastal and Marine Geology Program, and the SWFWMD. This document was improved by the reviews of Chandra Dreher (Jacobs Technology Inc.) and Nathan Smiley (USGS) of the FISC in St. Petersburg, FL.

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.
This data set is from one cruise with consistent instrument calibrations.
These data are collected along tracklines (2-D) and are therefore inherently incomplete. Geologic details between lines must be inferred. Although lines WR896_1 through WR896_4 are recorded in the logbook, only lines WR896_1 and WR896_2 were recovered and archived with this report.
As the seismic reflection data were acquired, the position of the vessel was continuously determined by a Rockwell PLGR GPS receiver, which is accurate to within 3 to 5 m. Positions were recorded and written to the trace headers in latitude and longitude coordinates about every 60 s. The ASCII navigation files and trackline maps have not been corrected to reflect the approximately 6-m offset between the boomer and GPS antenna. Refer to figure 1 included with this archive for a diagram of the acquisition geometry, including the GPS offset measurements. NOTE: The navigation data written to the "Source coordinates" SEG-Y trace headers (bytes 73 - 80) were used to create the trackline maps; however, these data are only accurate within 1 s of arc, or 32 m. Additional navigation data were recorded more accurately to the "Unassigned" trace headers (bytes 181 - 240) by the Delph Seismic acquisition software. Please see the SEG-Y Format page for a detailed description of the SEG-Y data format including byte number assignments and header value descriptions. The Delph Seismic navigation data can be accessed from the Navigation page under the Raw Shotpoint Navigation section.
Boomer data are relative to lake level. However, varying recorded static shifts of the data have been known to occur. Therefore, these data are not to be used for bathymetry.
Boomer processing: These data were originally recorded in Delph Seismic format on MO discs. They were later converted to SEG-Y format using Delph Seismic processing software and archived onto compact disc. The original trace files for line WR896_2 were each divided into two or more trace files (for example, WR896_2 became WR896_2a and WR896_2b) 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 boomer 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.
Process_Date: 2007
Navigation processing: Shotpoint navigation files and 500-shot-interval location files were extracted from the trace headers of each line using Seismic Unix software. The navigation files were then processed with PROJ.4 software ( to generate UTM coordinates from latitude and longitude coordinates and reformatted for use with Environmental Systems Research Institute (ESRI) GIS software.
Process_Date: 2007
Trackline map creation: The trackline maps provided in this archive were created using the Points to Lines ArcScript (D. Rathert, along with ESRI ArcGIS 9.2 software and then exported to Adobe Illustrator for further editing. The maps were later converted into JPEG format by Adobe GoLive. Please see the ARC readme file for detailed information about the GIS files used in this report.
Process_Date: 2007
Data Series preparation: In addition to the process steps described above, the following steps were taken to produce this Data Series report: the handwritten cruise log was scanned and saved as a PDF file, digital logs were created using the cruise log 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

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

Latitude_Resolution: 0.0000027
Longitude_Resolution: 0.0000027
Geographic_Coordinate_Units: decimal degrees
Horizontal_Datum_Name: WGS84
Ellipsoid_Name: WGS84
Semi-major_Axis: 6378137.00
Denominator_of_Flattening_Ratio: 298.257

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 40 to 83 MB.
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 on-line at
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 on-line at
Graphic image file: Printable profiles are available as GIF images. The line navigation maps and trackline maps are JPEG images. The trackline maps contain links to the seismic profiles.
Navigation file: Navigation files are available as ASCII text files. Provided are raw (unprocessed) shotpoint navigation files, processed shotpoint navigation files, and processed 500-shot-interval location files.
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.

Contact_Person: Shawn Dadisman
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
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
All of this report is available on-line.
Resource_Description: U.S. Geological Survey Data Series 346
This CD 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, 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 herein. Reference herein 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.
Format_Name: SEG-Y
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: 122 MB
Offline_Media: CD
Recording_Format: ISO 9660
Compatibility_Information: UNIX, Linux, DOS, Macintosh
Format_Name: map document, shapefile, metadata
The GIS project used to create the trackline maps is composed of map documents, shapefiles, and metadata. Map documents were created with ESRI ArcGIS 9.2 software. The shapefiles provided may also be viewed using other versions of ArcView, ArcGIS, or public domain software ArcExplorer (
File_Decompression_Technique: unzip
Transfer_Size: 45.0 MB
Network_Resource_Name: CD/software/arcgis/
Prices vary.
Publications are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225-0046 (telephone: 1-888-ASK-USGS, e-mail:
Use of SEG-Y data requires specialized seismic processing software, such as public domain software Seismic Unix (

Metadata_Date: 20080509
Contact_Person: Arnell Harrison
Contact_Organization: Jacobs Technology Inc., contracted with the U.S. Geological Survey
Contact_Position: Geologist
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
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

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