Tremor

Evocation [earth]
Tier: 3
Components: Verbal, Somatic
Casting Time: 1 major action
Range: 120 ft
Area: 40 ft radius spread
Duration: Instantaneous
Saving Throw: Reflex negates
You touch the ground, and speak the words. The others scream as dust and stones rain from the ceiling.

Stone shifts and shakes in the target area. Each creature in the area must make a Reflex save or be knocked prone. Structures, trees, and other natural formations may be damaged by this spell, depending on how stable they are:

Unstable structures are very likely to collapse.

Stable structures will take damage, but will probably remain standing.

Very stable structures will definitely survive, but may suffer some damage.

This spell works by manipulating stone in the target area; it is ineffective where there is no underlying stone, or structures made of stone.