Seismic Unix Scripts

Note: The web version of this archive does not contain the SEG-Y Trace files. These files are very large and would require extremely long download times. To obtain the complete CD-ROM archive, contact USGS Information at (888) ASK-USGS.

Seismic Unix (SU) is a public-domain, seismic-processing, software package written and maintained by the Center for Wave Phenomena at the Colorado School of Mines, in Golden, Colorado. The current web site for SU is http://www.cwp.mines.edu/cwpcodes . SU can run on numerous Unix operating systems and also on Linux. The SU scripts provided on this disc and listed below were modified from scripts written by the USGS Seafloor Mapping Group in Woods Hole, Mass., and run on a Linux workstation. These SU scripts and other needed files and software are located in the Unix tar file called boom.tar (30 K Archive TAR file) within the SEISUNIX subfolder in the Software folder at the top level of this CD-ROM. These scripts are provided as examples only. They may need to be modified to run on another system. They also require the use of several shareware programs such as ImageMagick, and ghostscript.

The SU scripts provided here will allow the user to strip off unique navigation fixes from the SEG-Y headers along with a fix for every 500th shot. The seismic data is then converted to SU format, filtered, gained and both Postscript and GIF formatted images are produced. These images can then be displayed using a variety of shareware programs such as ghostview (Unix, Linux, MAC, Windows), kview (Linux), or a web browser.

To use the scripts provided here you must first install SU on a Unix or Linux system. The scripts require that the following 4 subdirectories (all at the same hierarchical level) be created before the scripts are run; 1. SU, 2. segy, 3. seisimag, and 4. nav. If you untar the boom.tar file these subdirectories will be created for you. The scripts and all associated files (see below) will be placed in the subdirectory called SU. The SEG-Y data should be placed in the segy subdirectory. After the scripts are run Seismic Unix will write the Postscript and GIF images in the seisimag subdirectory and the navigation data in the nav subdirectory. It will also reformat the SEG-Y data into an SU format and place that file in the SU subdirectory. Note: The web version of this archive does not contain the SEG-Y Trace files. These files are very large and would require extremely long download times. To obtain the complete CD-ROM archive, contact USGS Information at (888) ASK-USGS.

Provided below is a step by step example of the processing sequence and example parameters required by each script. For more information please refer to the SU documentation also provided on the web or online if Seismic Unix is installed on the computer. Remember these scripts are provided as examples only. There are many differences in versions of Unix and Linux. We developed these scripts to run on Red Hat Linux 6.1.

Step 1. Untar the boom.tar file and it will create subdirectories SU, segy, seisimag, and nav.

Step 2. Make sure the permissions for all files in the SU subdirectory have been set to allow execution (i.e. chmod +x scriptname).

These 2 steps do not need to be repeated.

Step 3. Run readsegy. readsegy wants the following information in this order on one line separated by spaces

1= the directory location of the segy file (can be absolute or relative path).
2= the file name (without the .tra extension).
3= the output directory (minus the /SU).

example 1: readsegy ../segy oke699_1 ..

example 2: readsegy /cdrom/99asr01/segy oke699_1 /usr/seismic/okeedata

Step 4. Run boom. boom wants the following information in this order on one line separated by spaces

1= tmin (time minimum for this data set is 0)
2= tmax (time maximum, for this data set is .200 or .300)
3= directory location of the SU formatted data (minus the /SU)
4= the SU file name (without the .su extension).
5= the height of the plot in inches (try 8)
6= the pclip value (try 95).

example 1: boom 0 .200 .. oke699_1 8 95

example 2: boom 0 .200 /usr/seismic/okeedata oke699_1 8 95

Repeat steps 3 and 4 for each data file.

Step 5. View the seismic profile using a web browser or kview for GIF formatted files, or ghostview for Postscript files.

The following list of files are produced or called by the SU scripts (readsegy and boom). These should also be extracted from the boom.tar file:

aldenseismic - used if plotting to an alden plotter.

binary - stores the binary portion of the SEG-Y header when the file is converted to SU format.

header - stores the stripped ascii header information when the SEG-Y file is converted into SU format.

gsgifscript - needed by makegif2 to convert the postscript image to GIF format.

gsscript - needed if you run aldenseismic to produce an alden formatted plot.

landscape.ps - converts the postscript plot into a landscape display direction.

makegif2 - converts the postscript image to a gif image.

print_alden - prints the alden formatted plot.

printhead_alden - prints a header file for an alden plot.

proc_history - records the data processed and parameters used.

Note: These are c-shell scripts. Make sure that your .cshrc file has been modified as per the SU installation intructions. For example on our system you must add the location of /opt/cdp/bin to the set path statement. Also a setenv statement must also read setenv CWPROOT/opt/cwp .

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