A blast radius is the distance from the source that will be affected when an explosion

Explosion

An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...

 occurs. A blast radius is often associated with, but not limited to, bomb

Bomb

A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...

s, mines

Land mine

A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....

, explosive projectiles (propelled grenades

40 mm grenade

The 40mm grenade is a military grenade caliber for grenade launchers in service with many armed forces. There are two main types in service: the 40×46mm, which is a low-velocity round used in hand-held grenade launchers; and the high-velocity 40×53mm, used in mounted and crew-served weapons. The...

), and other weapons with an explosive charge.

For instance, a 2000 pounds Mk-84 bomb has a blast radius of 400 yards (365 metres).