The official GemStone IV encyclopedia.
An Elemental Wave is a forceful wave of energy which emanates from its caster. Casting this spell will cause a disruptive physical pulse to travel throughout the caster's immediate area, potentially knocking down all creatures and characters not joined to the caster. In addition to becoming prone, targets which fail to out-maneuver this pulse are "buffeted" by the waves, and can suffer roundtimes up to 20 sec, depending upon the severity of their failure. The combination of these two states effectively "pins" its targets down for a period of time, making them vulnerable to follow-up attacks (especially susequent maneuver attacks).
The primary success factor of this spell is a level comparison of the caster vesus its targets. Minor Elemental ranks are also factored in.