> They have known about this for years; they have either finished the testing OR they have completed their purpose with regards to the weapon.
Sonar is not a weapon; it's a sensor system intended to discover enemy submarines.
Sonar is not a weapon; it's a sensor system intended to discover enemy submarines.
Sonar is really all you have to see underwater, and is used heavily for scientific purposes, not only military purposes. Ocean-floor mapping is done with sonar. Active sonar of the kind that hurts whales is not in frequent use by deployed military vessels on military or surveillance missions because, while it gets you a good picture, it also announces "HERE I AM!!!" to the entire world.
https://en.m.wikipedia.org/wiki/Cetacean_stranding
I read somewhere it's about 240db. For reference, a jackhammer at about 1m (3.3ft away) is 130db and is classified as Painful for humans,
http://www.asha.org/public/hearing/Noise/
I am not knowledgeable on acoustics, let alone acoustic dissipation or acoustics in water - but I can see logic behind the argument that LFA sonar causes a problem for whales.
So 240dB is 10^(2.4-1.3) times as much sound power as 130dB.
y = 10 * log(x)
and the conversion back is
x = 10 ^ (y/10)
Every change of 3dB is a doubling or halving of power. Every change of 10dB is an order-of-magnitude change in power.
I'm not sure if it's even possible to get to 240 dB in air... Ah, an article on wikipedia sort of backs me up: [1] says that, at 1 atmosphere of pressure in air, the maximum loudness for undistorted sound is around 194 dB. Anything louder would be a shockwave.
[0]: http://news.nationalgeographic.com/news/2003/11/1103_031103_...
When a friend was working on sonar software they had extremely rigorous safety controls in place when working in the same room as a test rig. Pings could kill you. At a minimum you would shatter your ear drum.
Sound in water is a more effective weapon. The ping of a sonar is a weapon within the medium of water. A quick search: "There are no noise-cancelling headphones to stop the U.S. Navy's 235-decibel pressure waves of unbearable pinging and metallic shrieking. At 200 Db, the vibrations can rupture your lungs, and above 210 Db, the lethal noise can bore straight through your brain until it haemorrhages that delicate tissue. If you're not deaf after this devastating sonar blast, you're dead."