Oedipus' is fulfilling his hamartia is the scene. He is very arrogant to things, like when the Herald told him his father had died and Jocasta realized the prophecy was true, but he still doesn't understand and tries to get Jocasta to tell him.
The story is showing its Hubris when Oedipus is arguing with Tiresias about his fate. His pride and arrogance get in the way of him believing Tiresias.
This is the peripetia of the story. Oedipus tells the Herald of his horrible oracle and the Herald thinks he makes it better by telling Oedipus that that's impossible because Polybus and Meropi aren't really his parents.
This is the Anagnorisis of the story. He finally realizes that he did murder his father and married his mother and now this will lead to his nemesis.
This is the scene where the nemesis or catastrophe is shown. He knows that he has done everything the prophet said and now it's time for his payback. His wife hangs herself and he gouges his eyes out and tears his clothes off just the Tiresias said.
This is the catharsis of the play. Oedipus gets to see his daughters one last time before he is cast out of the city forever.