Earthquake (Elemental prince)

The Earthquake (Elemental prince) spell was introduced as part of the Baldur's Gate II: Throne of Bhaal game expansion.
This spell isn't castable by any party member in the game and is provided to the elemental "princes" Sunnis and Ogremoch only.
==Gameplay==
For a player who casts the High-level class ability spell Elemental Summoning or Greater Elemental Summoning and via a random d100 probability calls forth Sunnis the 'good' aligned prince/princess of Earth, then while Sunnis is available the creature can be directed to cast the Earthquake spell up to twice during the summoning period - Sunnis won't use it unless ordered to do so by the controlling player.
If the evil aligned Prince of Earth, Ogremoch, is encountered in the game, the creature's assigned AI script will probably use this spell early in any battle with the party.
This spell is a near clone of the priest spell Earthquake, with a few changes made to it.
The most apparent change is that this particular Elemental prince version is changed to be "friendly" to the caster's party affiliation, rather than affecting all creatures in the area of effect.
The other change is that this spell initiates almost instantly, rather than having a casting time of 9.
When Sunnis casts the spell, it won't affect the player's party - and when Ogremoch casts it, it won't affect anyone except the player's party and affiliated creatures.
Any affected creature in the initial spell AoE will be exposed to the spell's effects, as described below:
* Affected creatures are made Unconscious for 24 seconds unless resisted with a Saving throw versus Spells (with a 6-point penalty).
* Three separate applications of Crushing damage are applied: 
** 6d6 initial damage, halved with a successful save vs. spells with a 6-point penalty.
** 3d6 damage 12 seconds later, halved with a successful save vs. spells with a 2-point penalty.
** 2d6 damage 24 seconds later, halved with a successful save vs. spells.
During the spell's duration, there will be a series of "screen shake" effects and sound effects audibled.
The spell will halt all operations when all the initial affected creature(s) are killed, if that isn't the case the spell's total duration is 24 seconds.
This entire spell can be negated with a Spell Immunity: Alteration.
The spell's unconsciousness effect can potentially be blocked by Magic resistance - the damage is unaffected by MR.
There is a 2% chance that a hostile Greater Earth Elemental appears, spawned by this earthquake event after an 18-second delay. 
This spell is flagged as "hostile" and will harm any creature and will elicit a hostile reaction from innocent/neutral creatures, and possibly others in the vicinity.