this post was submitted on 08 Jan 2025
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NonCredibleDefense

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They're probably fine... right? (lemmy.world)
submitted 3 days ago by [email protected] to c/[email protected]
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[–] [email protected] 46 points 3 days ago* (last edited 3 days ago) (2 children)

Sonar systems[...]generate slow-rolling sound waves topping out at around 235 decibels[...]. These sound waves can travel for hundreds of miles under water, and can retain an intensity of 140 decibels as far as 300 miles from their source.

140 dB is a gunshot at the source. About 190 in air pressure will cause an explosive shockwave that can kill a person. 235 dB in dense water pressure is...somewhat more violent, as we understand how the decibal curve works and molecular pressure at depth.

[–] JohnDClay 1 points 13 hours ago

Every 10dB is twice as much energy, so 235 dB is pretty scary.

[–] [email protected] 37 points 3 days ago* (last edited 3 days ago) (1 children)

But that means that a person would be killed even if they are miles away? Maybe tens of miles.

Found it: Based on sonar guidelines and studies on sound propagation, a diver exposed to 235 dB low-frequency sonar would likely need to be more than 1.5–2 kilometers (1–1.2 miles) away to ensure safety.

However, pings are conical and the strongest sonar is at the bow. So you could literally be safe if you were diving behind it.

[–] [email protected] 20 points 3 days ago

This R*ddit comment suggests that it's only close-range that it's reliably lethal.