Here is an excerpt from an article I found on Wired News. I heard about this sonar a while back, but had hoped that it would not come to this. As a person who values his ears I cannot imagine blowing other beings eardrums out…

The US Government is letting the Navy use a powerful low-frequency sonar that can detect enemy submarines but which environmentalists fear will harm whales, dolphins and other marine mammals.
Whales are particularly susceptible to sonar interference because they rely on sound for communication, feeding, mating and migration. According to the Navy, each of the sonar’s 18 speakers transmits signals as loud as 215 decibels, equivalent underwater to standing next to a twin-engine F-15 fighter jet at takeoff.
Environmentalists say, however, that with the convergence of sound waves from each of the speakers, the intense effects of the system would reach farther, as if the signals were 235 decibels.
The intense low-frequency sonar can travel several hundred miles, and the transmissions are on the same frequency used for communication by many large whales, including humpbacks.
Some biologists believe whales are irritated by sounds louder than 110 decibels and that a whale’s eardrums could explode at 180 decibels.
Environmentalists’ fears are partly based on the Navy’s deployment of a powerful mid-range sonar in March 2000 during a submarine detection exercise in the deep water canyons of the Bahamas.
At least 16 whales and two dolphins beached themselves on the islands of Abaco, Grand Bahama and North Eleuthera within hours. Eight whales died. Scientists found hemorrhaging around the brain and ear bones, injuries consistent with exposure to loud sounds.
Twelve Cuvier beaked whales beached themselves in Greece during NATO exercises in 1996 using the low-frequency sonar, but the whales decomposed before scientists could investigate.