Final answer:
Parzival survives the Cataclyst's explosion in 'Ready Player One' due to an invincibility power-up known as the Extra Life Coin.
Step-by-step explanation:
In the context of the book 'Ready Player One' by Ernest Cline, Parzival manages to survive the detonation of the Cataclyst because he possesses an invincibility power-up in the virtual world called the OASIS. This power-up is known as the Extra Life Coin, which he received earlier in the story for being the first avatar to discover a certain easter egg. This special item grants him a second chance, allowing him to survive events that would normally result in the death of his avatar, including the widespread destruction caused by the Cataclyst artifact's explosion.