This is how Te Kā starts to erupt goes in The Great Forest Rescue.
Tahu: If she's dormant, why would she suddenly start erupting?
Umarak the Hunter: She is supposed to be that way. And the Great Prince told me if something upsets the balance of nature, Te Kā will get angry.
Gali: What makes her angry?
Umarak the Hunter: Mostly people cutting down trees.
Pohatu: Cutting down trees isn't gonna make a forest guardian erupt.
Umarak the Hunter: Maybe not by cutting them, but anything harms the animals she gets really mad.
Lewa: Like that would ever happen.
Umarak the Hunter: But what enrages Te Kā the most is if Man and other hunters shoot and kill animals.
Onua: Then we have to stop them.
Kopaka: We must drive Man out.