Randy:

How long before a submarine is lost the crew knows their unavoidable fate depends on several factors.

If a loss is due to a battery-generated hydrogen explosion, the crew of a diesel submarine dies before
they are aware of the explosion: in 30-40 milliseconds (ms) depending on the length of the pressure-hull.:
(examples:the Soviet K-129 and the ARA SAN JUAN.) Minimum time for human perception 80-100ms.

The special compartmentation associated with the reactor in nuclear-power submsrines may shield those
aft of the reactor from the explosion pressure-pulse and they will survive. In the case of SCORPION, at
least one of her crew escaped. His body was found in the debris field wearing a flotation device. Those
who may have remained in the after spaces survived for 1310s until the pressure-hull collapsed too fast to
be cognitively recognized.

In the case of the Indonesian S402, there is not so far any acoustic data from which to derive values such
as those above. Images of the wreck confirm implosion at great depth. But what caused the S402 to sink
to collapse depth is so far unknown.

I am investigating whether there were seismic detections of the S402 collapse as was the case with the
SAN JUAN but what we need is the bubble-pulse frequency (BPF) as we had with SCORPION, THRESHER
and the SAN JUAN. I don't even know if a BPF can be derived from seismic data but I have gone to a
seismic expert for an answer.

So, we won't know what the S402 crew knew and when they knew it until we know why that submarine
sank to collapse depth. All of this points out the "forensic" value of acoustic data. Without it, we enter
the field of conjecture.

Bruce