The vehicle presumably still had a lot of propellant in it when the engine cut off and it fell back on the reef, presumably in flames from the fire that caused the problem, and wouldn't be shut down by the cutoff valve. Why wasn't there an earth-shattering kaboom?

Fuel by itself doesn't explode -- you need to mix it with oxidizer. Presumably the tankage ruptured in such a way (assuming the tanks failed) that the LOX and RP-1 didn't efficiently mix.

I wonder what happens if you pour LOX on seawater, btw. It's denser than water, but will be rapidly heated, so there will be lots of vapor present.

Fuel by itself doesn't explode

I know that, Paul--it wasn't intended to be that dumb of a question. That's why I used the word "propellants."

It just struck me as surprising that it managed to land in such a way, with an available combustion source, that they didn't mix and combust. After all, "our rockets always blow up." Though I guess if you've ever seen the Corporal Story, there are many instance of entertaining and quite energetic launch failures that didn't result in explosions.

score one for flight termination that doesn't end in pyro-caused explosion

Paul, I've poured LOX into fresh water, anyway- it does a very odd seething, with the LOX on top of the water, supported by boiling vapor... but tendrils of LOX reach down into the water, pinch off into blobs, shrink & sink until the upward drag of the bubbles pull the blobs back to the interface.

Very cool looking, sorta like a blue-in-clear lava lamp in reverse.

I suspect that a large LOX spill in water would rapidly sink, break up (like low-speed rain) and boil VERY rapidly.

When a rocket blows up in flight or it hits the ground, the propellants are free to mix. But hitting water means that the water will get in the way and to some large degree prevent good mixing. Plus, a cloud of kerosene blobs and droplets in the air has *far* more surface area than a slick of the stuff on water.

What happened to my kaboom? There was supposed to be an earth-shattering kaboom!

Man, it would stink to be a fish swimming around, happy as can be, and all the sudden have a blob of LOX drop on you!

Anyone want a photo of lox boiling in water?

Gee, A Marvin Martian reference. Rand, you are more literate than I thought!