Do explosions travel at a specific speed?

Question

Lets say that you have two different devices that when exploded cover 10 square miles. Also you could set them off in a perfect environment with no obstacles to hinder the explosion. Would the explosions expand to cover the 10 sq miles in the same amount of time?

Or, if you have a 10kT bomb and a 20kT bomb (I know the explosion would be bigger from the 20kT). Say you set them off at the same time again in a perfect environment. Would the explosions reach one mile from the core in the same exact amount of time?

Answer 1

the pressure waves of both bombs would travel at the speed of sound and reach the mile mark at the same time

on the other hand

the particles in the 20kT explosion, on average, would travel anywhere up to √2 ≈ 1.41 times faster than a bomb with half the energy ie 10kT,

so the particles from the 10 kT bomb would take anywhere up to √2 times as long, on average, to reach the mile mark.

the √2 comes from the relation that kinetic energy is proportional to the square of the velocity

this is an approximation when applied to many particles and makes the √2 an absolute maximum that could never occur in reality especially once you also consider the energy loss due to air resistance

nevertheless, the particles in an explosion with more energy will travel faster, on average, and cross the mile mark quicker

,.,.,

Answer 2

Whatever the speed, rules state that it shall be slower than the protagonist in a movie as they will always be able to outrun and jump out of the way of an explosion into safety.  

Answer 3

Of course, the electromagnetic energy (heat, light, gamma radiation, etc) will travel outwards at the speed of light, so there is no difference there.

As far as I know, the shock wave from the explosion will travel at the speed of sound, so again there would be no difference between the two explosions, only in intensity.

With a nuclear explosion, the physical material ejected from the explosion will just be a ball of gas from the vapourised bomb which will be diffused in the atmosphere quite quickly.

So the answer to the last part of your question is yes, the explosion will reach one mile from the core in the same time.