The Incineration Cannon fires five streams of explosive particles in a tight spread which release in four different directions upon detonation. The explosive particles then detonate again individually, increasing the effective radius of the initial explosion.
Because there are multiple explosive particles, it is very easy to kill multiple players with one shot.
It does enough damage to the Scorpion, the Wraith, and the Mantis to destroy them in one hit, but only if all the explosive particles hit the vehicle. A Warthog can survive one shot from an Incineration Cannon because not all explosive particles will hit it.