[buildbot]

The math is really that hard? I have no idea what the soil or rock is, what happens when the first bomb hits it, the second, and then the third? Does the timing matter? Does the timing matter if it's 5 minutes between? 1 hour between? Seconds between? Does the type of soil or rock compact or loosen when bombed? What's the variation in explosive yield? Does the ground transfer force from a shockwave well or poorly? Does that change after the first one?

I really doubt this is very linear.

[cjbgkagh]

For it to be super-linear an additional meter of concrete / earth / whatever must be easier to penetrate than the one before it which I would classify as a physical impossibility. This is why linear is the ideal case.

[ethbr1]

Not with regard to multiple bombs.

> Does the type of soil or rock compact or loosen when bombed?

Is the most relevant question.

It seems reasonable that fractured rock may be easier for subsequent bombs to penetrate.

[cjbgkagh]

Even if I were to accept the dubious premise that there is enough fractured rock to make a difference and there is no hampering with rocks falling into the void and that it's possible to hit the exact same spot repeatedly without touching the sides, all that would do in big O notation would be increase the constant factor. It would not be super linear after the second bomb.

If your are talking about bombs that hit side by side then clearly that is sub-linear as no matter how fractured the rock it’s not easier to push through than air.

[ethbr1]

An explosion creates a pressure wave. A pressure wave fractures rock. Fractured rock may be easier to pierce than solid rock.

Ergo, if first bunker buster penetrates to maximum depth -20m and then explodes, fracturing rock within a __ radius, then second bunker buster travels through that fractured rock, the second (and so on) may be able to penetrate deeper.

I have no idea about the physics of penetrating fractured vs non-fractured rock, but it's a physically plausible mechanism.

Furthermore, given the multi-minute timeline reported, there's enough time for the bombs to be deployed sequentially.

[cjbgkagh]

In the linear case a bomb twice the size goes twice as deep.

Take a bomb, cut it in half and drop each half separately, one after another into the same hole, would you except the cumulative depth to be greater than the whole bomb or less? Consider that in the case of the whole bomb it is equivalent to two halves arriving at the exact same time.

[ethbr1]

It's not about bomb size.

It's about bomb quantity and sequential effects.