A resonance wave is an extremely powerful release of energy, capable of destroying a small planet.

A resonance wave was detected emanating from the core of a planetoid in the Delta Quadrant by the crew of the USS Voyager, immediately before the planetoid exploded, trapping the ship in a cloud of metreon gas. Voyager was subsequently ambushed by an Hazari vessel, in an attempt to collect a bounty on the ship. (VOY: "Think Tank")