A mindquake is an advanced form of mindburst, signified by a local kinetic agitation caused by a telekinetic losing control of their abilities. It causes a local, free-form vibration of the surrounding area, similar to an earthquake.
In 2258, after his abilities had been enhanced by the Psi Corps, Jason Ironheart's mindbursts rapidly progressed into full-on mindquakes. When ships from the Corps attacked his, Ironheart's mindquake was strong enough to extend hundreds of meters out from his ship and vaporized the incoming fighters. After arriving on Babylon 5, Ironheart chose a stateroom well off the beaten path so that his mindquakes would cause less damage to the station. Eventually, these mindquakes got worse - especially after being agitated by the Psi Cops - until finally they tore apart his physical body, and Ironheart transcended to a form of pure energy.