How long does it take a volcano to explode?

Answer 1

A common explosive that people ask this question about is the military explosive C-4 (cyclotrimethylene-trinitramine (C3H6N6O6)).

C-4 expands when detonated at 26,400 feet per second (about 95 million miles an hour). By comparison the speed of sound is 1,126 feet per second, meaning that a C-4 explosion travels at almost 23½ times the speed of sound.

Other explosive expansion rates:

• Mercury fulminate has an expansion rate of 13,943.57 fps.
• Ammonium nitrate has an expansion rate of 17,290.03 fps
• TNT has an expansion rate of 22,637.79 fps.
• Nitroglycerin has an expansion rate of 25,362.47 fps
• Octanitrocubane has an expansion rate of 33,136.48 fps. theoretically the highest of any known standard chemical explosive.
• The speed of the blast winds from nuclear detonations are measured in hundreds of kilometers per hour.

Answer 2

from the exact time the bomb hits the ground to the exact time the bomb blows? less than one billionth of a second

One "shake" (a single generation of nuclear fission) is 10 nanoseconds (billionths of a second) and it takes roughly 100 to 200 "shakes" for a nuclear fission explosion to complete (1 to 2 microseconds). So the answer to this question is 1 to 2 microseconds.

However the previous answer brings up a totally separate question with a totally different answer: fusing, the type of fuse on an atomic bomb. Very few atomic bombs are fused for surface burst, some options are:

• Airburst, used against cities. An altimeter detonates the bomb a few thousand feet in the air for maximum damage radius on soft target.
• Surface burst, used against hardened targets like missile silos. An accelerometer detonates the bomb when it hits the ground.
• Ground penetrating, used against hardened underground targets. Penetrates as much as a couple hundred feet into ground before detonating.
• Laydown, used against military airbases. Dropped very slowly and softly by parachute, lays down on runway. An accelerometer starts a timer that may run anywhere from a few minutes (to let a low altitude bomber escape) to a few hours (to destroy crews attempting emergency runway repair after damage by earlier bombs). The bomb detonates when the timer runs out.
• Underwater, used in antisubmarine depth bombs and anti-ship torpedoes.
• Highaltitude, used in ionosphere (to cause EMP) and in space to destroy satellites or ICBMs.
• etc.

Answer 3

There is no time for this It just happens!

Answer 4

about the same amount of time it takes the fuse to contact the gun powder

Answer 5

There is no set time. A volcano will erupt when all the conditions for an eruption are right.