Archive of Datasonics SIS-1000 Chirp Subbottom Data
Collected During USGS Cruise ALPH 98013
New York Bight, 8 September - 23 October, 1998

U.S. Geological Survey Open-File Report 99-37

by
David S. Foster¹, William C. Schwab¹, William W. Danforth¹, Jane F. Denny¹, Jenna Hill², Barry J. Irwin¹,
David R. Nichols¹, Thomas F. O'Brien¹

¹U.S. Geological Survey, Woods Hole, MA 02543
²Oberlin College, Oberlin, OH 44074


INTRODUCTION

This CD-ROM (Compact Disc-Read Only Memory) has been produced in accordance with the ISO 9660 CD-ROM Standard and is therefore capable of being read on any computing platform that has appropriate CD-ROM driver software installed.

Access to the data and information contained on this CD-ROM was developed using the HyperText Markup Language (HTML) utilized by the World Wide Web (WWW) project. Development of the CD-ROM documentation and user interface in HTML allows a user to access the information by using a variety of WWW information browsers (i.e. NCSA Mosaic, Netscape) to facilitate browsing and locating information and data. To access the information contained on this disk with a WWW client browser, open the file 'index.htm' at the top level directory of this CD-ROM with your selected browser. The HTML documentation is written utilizing some HTML 3.0 enhancements. The disk should be viewable by all WWW browsers but may not properly format on some older WWW browsers.

Also, some links to USGS collaborators and other agencies are available on this CD-ROM. These links are only accessible if access to the Internet is available during browsing of the CD-ROM.

The Chirp subbottom data are in standard Society of Exploration Geologists (SEG) SEG-Y format (Barry and others, 1975) and may be downloaded for processing with software such as Seismic Unix or SIOSEIS. DOS and Microsoft Windows compatible software for plotting SEG-Y files (PLOTSEIS) and viewing SEG-Y headers (DUMPSEGY) is located in the PLOTSEIS directory. Processed Chirp profiles (GIF images) may be viewed on this CD-ROM with your WWW browser.


BACKGROUND

This CD-ROM contains copies of the navigation and field chirp subbottom data collected aboard the R/V Alpha & Omega II. The USGS Cruise Alph98013 was conducted from September 10 - 23, 1998, and is a collaborative involving the U.S Army Corps of Engineers, New York District and the United States Geological SurveyCoastal and Marine Geology Program, Woods Hole Field Center

In 1995, the USGS, in cooperation with the U.S Army Corps of Engineers (USACOE), New York District, began a program to generate reconnaissance maps of the sea floor offshore of the New York-New Jersey metropolitan area, one of the most populated coastal regions of the United States. The goal of this mapping program is to provide a regional synthesis of the sea-floor environment, including a description of sedimentary environments, sediment texture, sea-floor morphology, and geologic history to aid in understanding the impacts of anthropogenic activities, such as ocean dumping. This mapping effort differs from previous studies of this area by obtaining digital, sidescan sonar images that cover 100 percent of the sea floor.

This investigation was motivated by the need to develop an environmentally acceptable solution for the disposal of dredged material from the New York - New Jersey Port, by the need to identify potential sources of sand for renourishment of the southern shore of Long island, and by the opportunity to develop a better understanding of the transport and long-term fate of contaminants by investigations of the present distribution of materials discharged into the New York Bight over the last 100+ years (Schwab and others, 1997).

Sidescan-sonar data collected during USGS Cruises Seax95007 and Seax96004 (May 1995 and May 1996, respectively) were digitally mosaicked to provide a base suitable for use in Geographic Information Systems of the New York Bight Apex region. During USGS Cruise Alph98013, supplemental sidescan sonar and seismic reflection data were collected within the New York Bight Apex region, primarily to augment the seismic reflection portion of the mapping project. Additional sidescan sonar and seismic reflection data were collected east of the Seax95007 and Seax96004 survey areas. These data abut sidescan sonar and seismic reflection data collected off the Southern Long Island shoreline during USGS Cruises Dian96040, Dian97011, and Dian97032 (September 1996, May 1997, October 1997, respectively). 


This CD-ROM contains seven main directories:

Directory BIN:

    Subdirectory PLOTSEIS:  This directory contains the DOS programs for plotting SEG-Y files and viewing SEG-Y headers.
     
   Subdirectory QMIPS: Contains the source code for the C program QMIPSTOSEGY in the QMIPS subdirectory.
      
   Subdirectory SU: Contains the Seismic Unix scripts used to process and plot the Chirp subbottom data and extract shot navigation from the SEG-Y headers

Directory HTMLDOCS:

Contains the necessary HTML files and supporting graphics to allow the user access to the CD-ROM via any World Wide Web (WWW) browser.

Directory IMAGES:

Contains GIF and JPEG images that are used by HTML hyperlinks.

Directory MAPS:

This directory contains basemap and shot navigation themes. The data may be displayed with ARCVIEW version 3.1 or above, or ARCEXPLORER. You may need to copy the directories to disk and edit the .apr file in the PROJECT subdirectory to reflect the new directory paths.

Directory NAV:

    Subdirectory RAWNAV: This directory contains raw DGPS navigation files as the data became available during the cruise.

    Subdirectory SHOTNAV:
Contains the shot navigation data that were collected during the cruise using a USGS differential GPS system.

Directory SEGY:

Contains the Chirp subbottom data. These data were collected using a Datasonics SIS-1000 100-kHz sidescan-sonar and Chirp subbottom system and were logged on a Triton Technologies, Inc., ISIS system. The raw Chirp subbottom channel was converted to SEG-Y 16-bit integer format with the C  program Qmipstosegy. Qmipstosegy was also used to decimate the trace data by a factor of two and apply a static shift from the sonar fish pressure depth. The SEG-Y format is documented in HTML format.

Directory SEISIMAG:

Contains the GIF format files of the Chirp subbottom profiles generated with Seismic Unix.


DISCLAIMER

This Compact Disc-Read Only Memory (CD-ROM) 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, make 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 necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Although all data published on this CD-ROM 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.


REFERENCES

Barry, R.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats, Geophysics, v. 40, p. 344-352

Schwab, W.C., Corso, W., Allison, M.A., Butman, B., Denny, J.F., Lotto, L., Danforth, W.W., Foster, D.S., O'Brien, T.F., Nichols, D.A., Irwin, B.J., and Parolski, K.F., 1997, Mapping the Sea Floor Geology Offshore of the New York-New Jersey Metropolitan Area Using Sidescan-Sonar: Preliminary Report, U.S. Geological Survey Open-File Report 97-61, 3 Sheets.

Zihlman, F.N., 1992a, DUMPSEGY V1.0: A program to examine the contents of SEG-Y disk-image seismic ata; U.S. Geological Survey Open File 92-590.

Zihlman, F.N., 1992b, PLOTSEGY V1.0: A DOS graphics program to display SEG-Y disk-image seismic data; U.S. Geological Survey Open File 92-349A and 92-349B.


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