Unknown to his assistant Nikos Spiridakis, Katsoudas was not just trying to predict earthquakes but also to create them. He brought the Third Doctor to his sponsor, Senator Szef, who was actually the Master. The Master had been hypnotising Katsoudas, who in turn hypnotised Spiridakis.
The Master wanted to use the earthquakes to free himself from a time loop, but Katsoudas was more interested in his own research and began to fight the hypnotism. When Spiridakis died trying to stop the Master's temporal machine, Jo Grant brought Katsoudas to the safety of the TARDIS.
Because Katsoudas had knowledge of advanced technology and planned to use it, despite the Doctor's warnings, the Doctor had to remove Katsoudas from his own time to preserve the Web of Time. (PROSE: The Seismologist's Story)