Just take a look at Herrmann package. FYI:

http://www.eas.slu.edu/eqc/eqc_cps/TUTORIAL

You may ask Amin Zahedi, who was a doctorand of mine and used my surface wave analysis some years ago. I never actually used my prediction models for synthetic accelerograms, but think they are suitable as the different wave groups are separately modelled. Amin could still be familiar with the code, he is also here an researchgate.

just had a look after Saeeds links. These are seismologigical codes for long range seismograms (more than 1000km SSD). I refer to near field seismograms (i..e 10-150km SSD depending on magnitude), but unfortunately, cannot provide the codes.

Well, I understand that you want to do some kind of wave front calculations in the far field. I cannot offer help for that, sorry.

But let me wish you freedom and prosperity for the people of Iran. I clearly see a time where a stubborn and intolerant leadership, with its oppressive apparatus and propaganda, have become a short, dark episode in the millenial and great history of Persia, and nobody must fear their spreading of terror all over the world any longer. Iran has far greater problems to solve than the pursuit of nuclear technology, especially in this earthquake prone region.

Take a look at AXITRA: https://www.isterre.fr/annuaire/pages-web-du-personnel/olivier-coutant/article/logiciels-softwares?lang=fr

I did some wave borehole modeling including surface wave but in a fluid solid vertical interface, the subsequent step was to perform get the green function and the make the auto correlation not the cross correlation of the recorded data in order to get some idea of the transfer function of the media and be able to make synthetic sources. Anyway, i could provide my algorithm to you if you are interested in synthetic  surface waves between fluid solid vertical interface.