What is the purpose in the plays action of the soothsayers warning the strange sightings and the earthquake in Rome?

The soothsayer's warning and the strange sightings, along with the earthquake in Rome, serve to foreshadow impending chaos and the fragility of the social and political order. They highlight the theme of fate versus free will, suggesting that the characters' actions may be influenced by forces beyond their control. These omens create an atmosphere of foreboding, emphasizing the consequences of ambition and betrayal, particularly in the context of Julius Caesar's impending assassination. Together, they set the stage for the tragic events that unfold, underscoring the tension between human agency and destiny.