USING THIS DATA SET

The interactive data set consists of a series of Hypertext Markup Language (HTML) pages and hypertext links located in the "html" directory of each disk. The "Table of Contents" page, or base page, is the one entitled "High-Resolution Seismic-Reflection Surveys of Lake Baikal, Siberia, 1990-1992" ("contents.htm"). To use this data set, load the file "contents.htm" or "cover.htm" using an HTML browser such as NCSA Mosaic, Netscape Navigator, or Microsoft Explorer. All text materials related to the data set, including an Introduction, Project Description and Purpose, Data Collection, Data Processing, Discussion, Acknowledgments, and References section, are accessible directly from the contents base page.

Maps showing the locations of the seismic-reflection profiles are also accessible from the base page. The first map is an overview of Lake Baikal and the seismic grid. From this overview map, four detailed maps of different sections of the lake can be reached. The detailed maps show labeled seismic lines, from which line numbers can be read. These line numbers are the key to viewing images of the seismic data.

From the base page, a table of seismic lines, organized by area and line number, can be viewed. This table contains the seismic line number, the time sweep (depth) included in the related image, and the date and time on which the seismic profile was collected. The entry for each seismic line in the table contains links to both a preview and a full-scale image for that seismic profile.

The image files are compressed, fast-loading files in "GIF" format for rapid viewing. The complete original data files, in "SEGY" format, are available in the directories "seis92" (Disk 1) and "seis91" (Disk 2). "SEGY" is a standard digital format that can be read and manipulated by most seismic-processing software packages. The seismic data files have been compressed using the common GZIP format; a GZIP program specific to the user's platform (generally available for free) must be used to decompress the files. The data CD-ROMs also contain all of the original navigation data, so that the track lines for the seismic profiles can be replotted at any scale or map projection that is desired. The navigation files are organized by year collected and are located in the "nav" directory on Disk 1. They are in ASCII text format, and the beginning of each seismic line is marked by a comment such as "##Start of Line 1". Each line ends where the next consecutive line begins, unless denoted by a comment such as "##End of Line 1".

For most of the seismic lines, 3.5 kHz data were collected concurrently with the water-gun data. The 3.5 kHz profiles were collected in analog form and processing enhancement for them is limited, so only a few examples are included here as image files, accessible from the base page.

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