RAYPS

First Step

Before you proceed to the example below, you should have read another article on RAYPP to understand the earth model to be used.

Procedure

To run the program RAYPS you have to go through the steps below :

• Install Scilab on your computer.
• Download the program, and keep it in a directory of your choice. Let us assume that you put the file in directory /home/yourname/seislib.
  The size of the program is approximately 5.4 Kb.
• Write an ASCII file that contains commands to create the earth model, do ray tracing, and plot the travel-time curve. You can then modify the file to create new earth models to produce new travel-time curves. As an example, call the text editor, type the following lines, and save the lines in a file named exam1.sci in the directory you like.

  // Linking
  nps = link('rayps.o','rayps','f');
  
  // Model
  vp = [1000 2000 2500]';
  vs = [500 1000 1250]';
  d  = [100 200 250]';
  x  = [0:50:500]';
  
  // Ray tracing
  nl = mini([length(vp) length(vs) length(d)]);
  ns = length(x);
  tm = fort("rayps",vp,1,"r",vs,2,"r",d,3,"r",nl,4,"i",x,5,"r",ns,6,"i",...
       "out",[nl,ns],7,"r")
  
  // Plotting
  st = ones(1,nl);
  xbasc();
  plot2d1("onn",x,tm',st,"021");
  xtitle('P-S reflections','Offset (meter)','Waktu (detik)');
  xend();
  

• Go to directory that contains file exam1.sci and call Scilab by typing scilab in xterm.
• Type the following command in the Scilab command window :

  exec('exam1.sci')
  

• You'll be given the travel-times (matrice tm) and the figure below :