Which term describes a combustion reaction that propagates at supersonic velocities?

The term that describes a combustion reaction propagating at supersonic velocities is "detonation." In this context, detonation refers to a type of combustion reaction where the wave of combustion travels through the explosive material at a speed exceeding the speed of sound in that material. This rapid propagation results in a shockwave, leading to a violent explosion characterized by a substantial release of energy in a very short time frame.

Detonation is often associated with high explosives, where the energy release creates a pressure wave that can cause significant damage and destruction. Understanding this concept is crucial for fire investigation professionals, as distinguishing between types of combustion can help in analyzing fire scenarios, identifying potential hazards, and determining the characteristics of the materials involved in an explosion.

In contrast to detonation, "deflagration" refers to a slower combustion process that occurs at subsonic speeds, typically seen in low explosives or combustible gases. "Spontaneous combustion" pertains to a different phenomenon where materials ignite without an external ignition source due to factors like heat buildup, and "flashover" describes a rapid spread of fire through a space where all combustible materials become ignited almost simultaneously due to extreme heat. Each of these terms has its own distinct definition and implications in fire investigation.