A Python program for plotting the focal sphere of seismic sources, both pure double couple and non DC sources described with the moment tensor. The program is made by Krieger and Heimann  and available at http://www.larskrieger.de/mopad/. The program is included with SEISAN and started with command mopad. The program has many options for plotting and manipulating seismic sources using either the moment tensor or the strike, dip rake as input. For examples see http://www.larskrieger.de/mopad/. To see the options type mopad -h. MOPAD is the only program in SEISAN that can plot moment tensor solutions. It is implemented in EEV (command fm) with the only option of plotting the moment tensor solution as given in the S-file.
See Figure 23.7 for an example. The corresponding S-file is
1976 1 1 129 53.4 D -29.250-176.960 47.8 HRV 7.3WHRV 6.2bHRV 1 ACTION:SPL 17-06-02 19:06 OP:ff STATUS: ID:19760101012953 I 202. 30. 93. HRV HARVAR A F 1976 1 1 129 53.4 -29.250-176.960 47.8 HRV 7.3WHRV GlobCMT M MT 7.680 0.090 -7.770 1.390 4.520 -3.260HRVS19 0.956E+20 GlobCMT M