Geol 492/692 - Getting JRG, VIewmat, and Data for the Refraction Exercise

Create a new folder on your computer for this exercise. On a PC, you might call it ``c:\jrg''. Download the jrg.jar (<300 kbytes) into this folder. Make sure you are getting this binary file out of your web browser without it being converted to text. If you have put everything together in one folder and followed the commands below, and you still get java running but reporting ``class not found: Viewmat'', this could be the problem. In Netscape, point at the link here and hold down the right mouse button, then select ``Save Link As...'' and make sure it is type ``All Files''. If you have trouble, download the jrg+src.zip (<500 kb) zipped archive to the folder, then double-click on it to unzip it, and you should see the jrg.jar file. Or get the jar and data files on a cd from the instructor.

Getting the Seismic Data

The seismic refraction data you will pick is contained in a 1.0 Mbyte binary SEG-Y format file. SEG-Y is a standard defined by the Society of Exploration Geophysicists for the interchange of seismic survey data. The SEG-2 format is commonly written by engineering seismic recorders, and the data has to be converted to SEG-Y.

Download the dixie-refr.sgy data file. This SEG-Y file is also a binary file that should not be saved as ``text.'' You can download the picklab.zip zipped file if you have trouble. You will also want to download the text file of source and receiver station locations dixie-med-vp.txt. These data were obtained in southern Dixie Valley, Nevada, by the Spring 1998 Geol 453/653 class.

If your data transfer involves using FTP over a network, make sure that you use the binary file-transfer mode. ASCII-mode transfers will corrupt any seismic data file. Any files of picks, plots, or parameters that you write out of Viewmat, however, are in plain text and will transfer fine in ASCII mode.