Curse
When Mira heard the roar and felt the ground shake because of it, she knew something big was happening.
Although she didn't quite understand what caused such a beast to be so angered, she could tell just from the power behind its roar that it was most likely the guardian of the High-Grade Spirit Stone Mine Source and whatever other treasures this place holds.
Just knowing that, Mira could deduce a few possibilities, but the most likely one was that someone either reached the Source of the chasms or did something of similar magnitude.
She felt that her guess was most likely correct because there's simply no other reason for a beast at the caliber of the one that just roared to awaken and make a move by itself unless it was an emergency.