Like the other second tier Ancient Magic spells, Quake II is learnable at level 75. Its scroll can be bought from Susu in Lower Jeuno for 129,180 gil.
When used, Quake II deals massive earth damage to a single enemy and lowers its magic resistance against the wind element for a period of 15 seconds. Due to the latter effect, Quake II can be easily be followed up with a wind-elemental spell such as Aeroja, Aero V, or Aero VI.
Through Merit Points, Quake II's Magic Burst potency can be increased by 3%, while its magic accuracy can be increased by 5. In addition, its potency can be further increased through Job Points.
Behind the scenes
Prior to its implementation as a Black Mage spell, Quake II appeared as an enemy exclusive spell during the Chains of Promathia expansion, being usable by the Jailer of Faith Notorious Monster found inside the Garden of Ru'Hmet.
When initially introduced into the game, Quake II could only be learned by Black Mages level 75 and higher by spending 3 Merit Points on the merit menu. Following the June 2019 patch update, Quake II was changed to become a purchasable spell in Lower Jueno.