USING THIS DATA SETThe interactive data set consists of a series of Hypertext Markup Language (HTML) pages and hypertext links located in the "html" directory of the disk. The "Table of Contents" page, is entitled "Seismic-Reflection Survey of the Blake Ridge, 1992 and 1995" ("index.htm"). To use this data set, load the file "index.htm" using an HTML browser, such as, Netscape Navigator, or Microsoft Explorer. All text materials describing the data set, including the Introduction, Project Description and Purpose, Data Collection, Data Processing, and Acknowledgments, are accessible from the "Table of Contents" page.Maps showing the locations of the seismic-reflection profiles are also accessible from the base page. The first map is an overview of the Blake Ridge bathymetry and the seismic grid from 1992. Also, a map of the entire seismic grid from all 3 cruises (ch92-12, ch95-17, and ch95-18) is provided to show data coverage for the Blake Ridge. From the base page, a list of raw SEG-Y files, organized by year , cruise and line number , can be viewed. These data can be downloaded from the disk. "SEG-Y" is a standard digital format (Barry et al., 1975) that can be read and manipulated by most seismic-processing software packages. In addition, the navigation that correlates with the seismic data can be found within the nav92 directory on this disk. The files all have the extension '.spnav', and are 3 column ASCII data which contain the longitude, latitude, and shot numbers, respectively. These data have been decimated to decrease the file sizes. The seismic data and navigation files have been compressed using the common GZIP format; a GZIP program specific to the user's platform must be used to decompress the files. The image files are compressed, fast-loading files in "GIF" format (scaled view) for rapid viewing and "TIF"(full-size) format for more detailed analysis. The disk also contains navigation data in ascii format(longitude,latitude and shotpoint), so that the track lines for the seismic profiles can be replotted as desired. The navigation files are organized by line number and are located in the "nav92" and "nav95"directories. TIF images and Navigation file also are compressed with the GZIP program.
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