As an action, a tremor ripples out from you along the ground. Each creature other than you on the ground in a sphere centered on you must make a Reflex saving throw.
On a failure, it takes 1d8 bludgeoning damage and is knocked prone.
On a critical failure, it takes twice as much damage.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
If the ground in that area is loose earth or stone, it becomes difficult terrain until cleared, with each 1-meter diameter portion requiring at least 1 minute to clear by hand.
You can increase the damage by 1d8 for each additional mana expended.
Tremors. You can expend 2 additional mana so it deals no damage, but the tremors around you are continuous. The duration changes to 1 minute/mana, concentration and the tremors erupt around you in an aura shaped as a sphere. Until the spell ends, the aura moves with you, centered on you.