Earthquake

Earthquake (地震, Jishin), also known as Crack and Quake, is a recurring enemy ability in the series, and is usually a powerful Earth-elemental attack that affects the entire party. In the original Final Fantasy, it instead attempted to inflict Instant Death to the party. It can also be utilized by the player party, and is usually an ability used by the Geomancer class. On other occasions however, the equivalent spell usable by the player is Quake.

Final Fantasy
Earthquake, originally called Crack, attempts to inflict Instant Death on the party. It is used by Sand Worm, Omega, Echidna, Ahriman, and Chaos.

Final Fantasy II
Earthquake was used by the Sand Worm and inflicts 50 - 200 Matter-elemental damage to the entire party. The party could use the ability, called Earthquake IX, by using the Gaia Drum item.

Final Fantasy III
Earthquake is an ability used by the Geomancer job by using the Terrain command. It deals Earth-elemental damage to all enemies, and can only be used on Plains.

Final Fantasy IV
Earthquake, called Quake in the SNES version, is simply a weaker version of the spell Quake, dealing less Earth-elemental damage to the entire party, though it could be avoided by casting Float. It is used by T-Rex, Zeromus EG, and Lunar Titan.

Final Fantasy IV: The After Years
Earthquake retains the same properties as it did in Final Fantasy IV. It is once again used by Titan, as well as other enemies.

Final Fantasy V
Earthquake comes in two forms; the traditional Earthquake, used by the more deadlier enemies such as Gil Turtle, Omega, and Neo Shinryu, and Earth Shaker, which does slightly less damage than Earthquake to the entire party and is used only by Bahamut, Catastrophe, Titan, and the Crystal of Earth. The party can also use Earthquake through the Geomancer's Gaia command, and can only be used if the party is fighting on the Plains, Fire-Powered Ship, Drakenvale, or North Mountain. Again, Earthquake can be avoided by casting Float.

Final Fantasy VII
Earthquake is a weak Earth-elemental attack used by Land Worm and Sea Worm. It inflicts damage on the entire party.

Final Fantasy VIII
Earthquake is an Earth-elemental attack used by Armadodo as a final attack, or by Ochu. It can be avoided by junctioning Quake or magic that raises Earth resistance to a character's Elemental Defense slot, or simply by casting Float. Abyss Worm has a similar ability called Sand Shake.

Final Fantasy IX
Earthquake again appears as an enemy ability used by Hilgigars, Jabberwock, Lich, and the Crystal World version of Lich. It inflicts Earth-elemental damage to the party, but can be avoided by casting Float or wearing Earth-absorbing equipment. Quina has a similar ability called Earth Shake. The similar Earth Power, used by Ralvuimago, inflicts moderate Earth-elemental damage to the party.

Final Fantasy X
Earthquake is used by several enemies in the game. When it is used by Lord Ochu, it inflicts Gravity-elemental damage equal to half the party's max HP. When used by any other enemy, it inflicts non-elemental damage and Delay Buster on the entire party.

Final Fantasy X-2
Earthquake is only used by the Sand Worm and Earth Worm, and it inflicts major non-elemental damage to the party.

Final Fantasy XIII
Earthquake is used by the Eidolon Alexander.

Dissidia Final Fantasy
Earthquake is one of Garland's HP Attacks that can only be used while on the ground.

Final Fantasy: The 4 Heroes of Light
Earthquake is used by the second and third forms of Chaos. When the ability is used it causes a giant earthquake to attack all members of the opposing party, inflicting moderate earth elemental damage and causing blind.