Earthquake

Increase the damage dealt to structures by 10 points of damage per tier. Increase the damage dealt by cave-ins and landslides to 10d8 points of damage. Increase the damage dealt to those pinned beneath rubble to 1d10 points per minute. Add your tier to the DC of concentration checks and Constitution checks attempted as a consequence of this spell.

Augmented (8th): If you expend two uses of mythic power, the spell lasts for an additional round and the spread's radius increases by 20 feet. Each round this spell is in effect, on your turn you may expend one use of mythic power to continue its duration for 1 round and increase its radius by another 20 feet.