Earth Tremor

Transmutation [earth]
Level: Artificer * 3, Bloodrager * 3, Druid * 3, Hunter * 3, Magus * 3, Shaman * 3, Sorcerer */Wizard * 3, Warlock * 3
Components: V, S
Casting Time: 1 Standard Action
Range: up to 30 ft. (see text)
Area: 30-ft. line, 20-ft. cone-shaped spread, or 10-ft.-radius spread (see text)
Duration: instantaneous
Saving Throw: Reflex half, see text
Spell Resistance: no
  You strike the ground and unleash a tremor of seismic force, hurling up earth, rock, and sand. You choose whether the earth tremor affects a 30-foot line, a 20-foot cone-shaped spread, or a 10-foot-radius spread centered on you. The space you occupy is not affected by earth tremor. The area you choose becomes dense rubble that costs 2 squares of movement to enter. Dense rubble adds 5 to the DC of Acrobatics checks and adds 2 to the DC of Stealth checks. Creatures on the ground in the area take 1d4 points of bludgeoning damage per Caster Level you have (maximum 10d4) or half damage on a successful save. Medium or smaller creatures that fail their saves are knocked Prone.
  This spell can be cast only on a surface of earth, sand, or stone. It has no effect if you are in a wooden or metal structure or if you are not touching the ground.