Its ALIENS. They are coming in under cover of darknes and are mining the clay and rock. They need the silicon. Its to restore their reserves. The aliens life system is silicon based.
They are causing the tremors to disguise the blasting.
Its unlikely that an 8 mag earthquake will strike in Aust. Aust lies over a plate. Chile is on the fiery edge of a plate and the Andes are still growing. ie unstable.
Allay your fears, cristian.
Cheers, Marty