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Texas Size KILL ZONE

From some boat guys:

http://www.boatdesign.net/forums/showthread.php?t=9354

Quote:

The U.S. Navy has developed an extremely powerful (low frequency) sonar to detect "quiet" submarines, and it has applied for a permit from the National Marine Fisheries Service (NMFS) to deploy it. However, based on newly available scientific information, we know that this low frequency sonar emits a shock wave that at 150 to 160 decibels can kill whales, other marine mammals and marine fish by rupturing the membranes surrounding their lungs, swim bladder, brain and auditory air spaces. The second lethal effect of the shock wave involves the activation of supersaturated gas in marine animals' blood and in their cells to form small bubbles which, like the "bends" can block the flow of blood to the brain (causing stroke) and can rupture the cell walls. This effect will be greatest in deep-diving animals (such as bluefin tuna, swordfish, bigeye tuna and deep-diving whales) that will have the highest levels of supersaturated gasses in their blood and cells.

The source level of this sonar is 240 decibels (equivalent to the intensity of a Saturn rocket). But, because low frequency underwater sound can travel hundreds of miles with little loss of power, it will actually create a "kill zone" several hundred miles in diameter. NATO naval exercises using low frequency sonar conducted off Greece in 1996 killed whales that were more than 100 km away. In the final EIS for its sonar system, the Navy admits that an intensity of 160 decibels (a lethal level) will be felt several hundred miles away from the source. This will create a "Kill Zone" the size of Texas.

The Navy says it wants to deploy this sonar in 80% of the world's oceans (omitting only the Arctic and Antarctic). It has already been, or is to be used in many areas that are prime habitat of marlin, swordfish, bluefin tuna, mako sharks, bigeye tuna, sailfish, spearfish, wahoo, yellowfin tuna and many other premiere game fish (and their prey species). Such areas include the Bahamas, the continental shelf off New Jersey, North Carolina, the Azores, Canary Islands, California, Hawaii, etc. During the spring-early summer, the deep channels between the Bahamas and the larger Caribbean Islands are the center of spawning for swordfish, white marlin and blue marlin of the North Atlantic Ocean. As also described on our website (see below), these species' prime summer-fall feeding grounds include (1) the edge of the continental shelf (between the 100 and 1000 fathom lines) from just below Cape Hatteras, North Carolina, to the eastern tip of Georges Bank off Massachusetts; (2) similar areas along the edge of the continental shelf in the northern Gulf of Mexico; and (3) the Azores, Madeira and the Canary Islands (following the extension of the Gulf Stream as the Azores Current and then the Canary Current). The Navy has not evaluated the consequences of its sonar on marine fish.

The Navy can not proceed unless it is given a permit issued by NMFS, which must consider the sonar's effects under authority of the Marine Mammal Protection Act and the Endangered Species Act. NMFS is in the final stages of making its determination, so time is of the essence. For more detailed information on the worldwide effects of high intensity sonar on whales and other marine mammals, visit the website of the Ocean Mammal Institute (www.oceanmammalinst.org).

The Biodiversity Legal Foundation and James Chambers submitted an analysis of the new scientific information on April 4, 2002. It describes the real severity of the effects of low frequency sonar on not only marine mammals but also most species of fish. Of particular concern is its effects on the world's large pelagic species - billfish, tunas, sharks and their prey. A copy of the BLF letter to NMFS' Director can be found HERE:

http://www.bigmarinefish.com/sonar_effects.htm

What can YOU do?

Express your concern in a letter to NMFS' Director (and send copies to your representatives in Congress and members of the Bush administration). And pass this alert on to others so they can act, too.

"Democracy is not a spectator sport.

I know that it will make you and your cronies very happy when the day comes when Red China or Iran puts a sub somewhere in an ocean around us and lobs several nukes over and takes care of America for good. The fishes will have been saved from a terrible death by the dreaded American military.

Then all the fishes in the sea will be caught by the country who wins and be eaten. Thats a lot better than a few possibly being killed by a weapon that might protect the country.

Thanks for the article, makes me remember that I have not had any good fish lately. Time for some swordfish tonight!

JoeA

(Member of PETA, aka people eating tasty animals)

Thanks for being so open minded.:rolleyes:

From Snopes :

http://www.snopes.com/critters/crusader/sonar.htm

From 2001................Status: Undetermined.

I suggest you at least read it, and make up your own mind.

Whenever environmentalists have a movement or petition or lawsuit to "ban" something, there's a simple test to determine if they are yahoos or not: Just ask them how many whales/spotted owls/little furry kittens/monkeys in cages it's acceptable to kill given various other benefits to society.

If they say "none" then say "thanks for coming" and move on, since you're dealing with a wacko fringe group. If they've actually done an analysis and their argument is that a proposed action will impose an excessive burden on an ecosystem, species, etc, then--just maybe--you're dealing with reponsible, thoughful scientists who have a valid point.

Quote:

Originally posted by RallyJon
wacko fringe group...........reponsible, thoughful scientists

I'm affraid it will take some digging or diving on this one to determine the facts. It's been five years since first reported, if this program is not on Rumsfeld's wish list I don't think we have much to worry about.

Quote:

Originally posted by RallyJon
If they've actually done an analysis and their argument is that a proposed action will impose an excessive burden on an ecosystem, species, etc, then--just maybe--you're dealing with reponsible, thoughful scientists who have a valid point.

The problem then becomes that no one knows just what constitutes an 'excessive' impact to the ecosystem. For all we know, that fringe group who says that losing one more blue whale will upset the balance could be right. We just might not be able to recognize that for a hundred years or so. Greenies tend to err on the cautious side.

How does an ever expanding circle/sphere not lower it's energy? Or is it directional? The description does not work with classical laws of physics.

Quote:

Originally posted by red-beard
How does an ever expanding circle/sphere not lower it's energy? Or is it directional? The description does not work with classical laws of physics.

Water is a lot more dense than air (100 times). I think in air it's the square of the distance the db level goes down.

I have read that the very low frequency of whale singing can travel very far - Artic Circle to Antarctic Circle.

EDIT: got rid of my post. I'm clueless too. Time for more research when workload permits.

Part of my job in the Navy has been to hunt submarines from the air. There are two ways to track a sub, passively (you try and listen for tell-tale sounds with sensors in the water) or you use active methods, basically emit energy in the water and hope for a return echo from the submarine (in very simple terms, it is like radar in the water.)

As submarines have become increasingly more quiet (US subs are amazingly quiet) active sonar tecnologies have been improved, usually by increasing the power out of the sensor (more power increases range of detection) or moving to low frequency spectrums, which travel farther in water than higher frequencies.

The impact of these sensors on marine mammals and fish has been an issue for years...when I was doing flight test, we had to get specific environmental clearances to test our airborne, low-frequency sonars we were developing for the H-60. In addition, employment of the sensors are often very restricted.

There are some sub guys on the board who are no doubt experts, but this has been, and will continue to be an important issue.

Quote:

Originally posted by wludavid
From wikipedia:
http://en.wikipedia.org/math/e/b/f/e...db3c3c8057.png

I'm wondering if the Navy took into account the temperature of the water and how that affects it's natural resonate frequency, found a way to ride this and bent a few rules along the way.

Maybe they just used UFO's.:D

I did not read all the papers linked to, will have to do this later.;)

Quote:

Originally posted by kach22i
I'm wondering if the Navy took into account the temperature of the water and how that affects it's natural resonate frequency, found a way to ride this and bent a few rules along the way.

Maybe they just used UFO's.:D

I did not read all the papers linked to, will have to do this later.;)

Trust me, the various acoustic environments in the world's oceans and seas and the effects of temperature, salinity, depth, etc. is taken into account. Again, the sub guys live there and are better qualified...all I can say is that the chess match played out above, on and below the water is a facinating 3-D game and the sub bubbas rule it.

One last thing: I have listened to whales sing on my passive sensors, very beautiful and eerie.

With a statement like that, it's not the water that is dense. The inverse square rule applies no matter what. Unless it's focused like a laser. In that case, it is a tight beam, and then it's not indescriminate.

So, you can't have it both ways.

Here's a better approach:

http://en.wikipedia.org/math/a/e/5/a...149909f046.png

where p is sound pressure (N/m^2), ρ is medium density, c is speed of sound in medium and ξ is particle displacement. I suspect particle displacement as a lot to do with the strength of the initial sound. So lets plug in some numbers while keeping ξ = 1; ω = 314 rad/s or 50 hertz; ρ(air) = 1; ρ(water) = 800; c(air) = 331; c(water) = 1450.

In air,
p = (1)(331)(314)(1) = 103934 N/m^2

In water,
p = (800)(1450)(314)(1) = 364240000 N/m^2

In water, the sound pressure exerted (force per units squared) will be about 3500 times greater than in the air. Of course it will take a lot more energy to create this sound in the water than in the air...

Now lets look at the pressure/distance relationship which is actually 1/r. Since it's simply an inverse relationship, the pain (or in this case, death) threshold will be 3500 times further away in the water than in the air.

Someone please check my math and my assumptions. I am not an acousitcal engineer. :)

Yes, but it would take 3500 times the energy. So what? And the inverse square rule still applies.

This all "sounds" like junk science to me.

Quote:

Originally posted by red-beard
Yes, but it would take 3500 times the energy. So what? And the inverse square rule still applies.

Not necessarily 3500 times the energy to create it, and it's an inverse, not an inverse-square relationship. That's beside the point anyway. Because sound travels further and faster underwater, we need to be careful that the things we put in the ocean. We already know that there are sound pressures that will burst the human eardrum. A whale's lungs act as a tympanic membrane when enough pressure is exerted - and those can be burst too - with more lethal consequence for the whale than the human concert-goer with the burst eardrum.

IT IS AN INVERSE SQUARE. Has to be. That is how it works. You are talking about a "wave" which is focused, like the laser. When things "radiate" they follow the inverse square rule. You can have one, or the other, but not both.

I read a few of the articles linked, seems to me that no one knows exactly what this does. That being the case, it would appear that more research is needed before deployment

How many species do we really need, anyway?