Earlier quoted context omitted.
If you have pressures above 3,000psi any sudden leak or hole will be pretty catastrophic. Not an explosion like a fire explosion, something more like explosive decompression in a plane. Anyway I think they Swedes have pinned it down to an explosion, as in a bomb, based on seismometers.
Water pressure at 80 meters would be about 130 psi, so the pipe is 2800 psi over "ambient" which gives it a certain amount of "pop" should it do so. But it's also designed to not pop (and do we have any examples of a catastrophic pipe failure vs a leak?).
I could be wrong.