I think that this card is too much "elemental hate" towards Earth, the only element capable of burrowing (excluding mutations). An autokill of burrowed creatures would wreck some decks in one shot. I have two suggestions of how to fix the burrowed creatures mechanic of this card:
1) Make the effect just unburrow all burrowed creatures, or
2) Make the effect unburrow all burrowed creatures, but keep their stats the same as when they were burrowed (so a burrowed unupped Shrieker [which is 4|3 burrowed] would become unburrowed and remain 4|3).
I like the other mechanics of the card, though!