Tremor

The ground around you in a 15-foot Emanation begins to shake violently. You are unaffected by the tremors. The ground is considered Difficult Terrain and whenever the Emanation enters a creature’s space, a creature enters the Emanation, or the creature ends its turn there, the creature makes a Dexterity saving throw. On a failed save, the creature takes 1d6 Bludgeoning damage and has the Prone condition. A creature makes this save only once per turn.

Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 1.