An expert has revealed why a submersible may have suffered a ‘catastrophic implosion’ under the wreckage of the Titantic last week after five people, including two Pakistanis died, an Australian newspaper reported.

The implosion which destroyed the Titan submersible was “a phenomenon where, basically, you are crushing a pressure vessel from the outside”, associate professor Eric Fusil, director of the Shipbuilding Hub at Adelaide University told The Sunday Morning Herald.

“It results in the instantaneous implosion of that vessel, killing everyone within 20 milliseconds,” he added.

By the time it reached the Titanic wreckage, the Titan submersible would have been facing a pressure of between 375 and 400 atmospheres, he said, adding that is equivalent to 4,000 tonnes pushing on an area of one square metre.

Professor Fusil described this pressure as like “crushing a can of soda to the size of a very small marble in your hand”.

The human brain, as Professor Fusil describes, is not able to process information that quickly, so no-one on board would have realised or known what was happening.

OceanGate’s Titan submersible had set off with five divers inside looking to explore the wreckage of the Titanic but it had lost contact with the US coastguard one hour and 45 minutes into the dive.

While officials investigating what happened said it is too early to work out exactly when and how the implosion happened, the conditions on the ocean floor can give some clues as to how such a tragic event occurred.

Why is there so much pressure in deep water?

The story, which was taken as an explainer, said that everyone is exposed to atmospheric pressure and this changes depending on how high up you are and whether you are at ground level or underwater.

This pressure has been described as a long column of air above your head that is reaching to the top of the atmosphere and pressing down on you.

If you go higher, for example, if you climb a mountain, less of that column is pushing down on you, hence the air pressure is lower.

When you get to sea level, the pressure is described as one atmosphere, which is about equivalent to one kilogram of weight pushing down on every square centimetre.

Once you get under the sea, the column pressing down on you increases significantly because you also have to contend with water, which is far heavier than air. The pressure increases by one atmosphere for every 10 metres of ocean depth.