When a deep-sea submarine implodes, it does not necessarily make a loud noise that can be heard by human ears. Implosions in deep-sea environments occur due to immense pressure exerted by the surrounding water on the structure of the submarine. The extreme pressure difference between the inside and outside of the submarine causes it to collapse inward, which can be catastrophic for the vessel.
In deep-sea environments, the pressure can reach several hundred times that of atmospheric pressure at sea level. During an implosion, the structural integrity of the submarine is compromised, leading to the collapse of the hull. While this event generates intense forces and can be destructive, the noise produced is likely to be muffled and absorbed by the surrounding water.
Additionally, the sound propagation properties in deep-sea environments differ from those in the air. Water is denser than air, and sound travels more efficiently through water. However, the sound of an implosion is unlikely to reach the same decibel levels as, for example, an explosion in the air or a sonic boom. The noise generated would likely be localized and not easily detectable from a distance.
It's important to note that deep-sea submarines are designed to withstand the extreme pressures of the deep ocean, and extensive engineering goes into ensuring their structural integrity. Implosions are rare and generally only occur if the submarine exceeds its operational depth limits or experiences a catastrophic failure.