It takes place in the direction you're looking. The target also needs to be in the same Y level as the earthbender for it to do damage, if the entity is one level bellow (or above), it won't do anything.
As with all other abilities, there are two choices for Ravine's level IV upgrade.
Fissure: Destroys blocks under it, hit multiple enemies, but costs 1.5x chiFissure is a really good upgrade because it allows the ability to hit more mobs in line (as opposed to one) and to break the blocks beneath your enemies. </p>Shaking earth: Chance to knock armor and weapons off hit enemies</p>This upgrade adds a useful feature to the ability. Shaking earth can disarm enemies that are hit with it. This ability is great against no-bender players and weapon-wielding mobs.</p></p>