There is no doubt that sound from seismic sound sources is a strong sound impulse, but it is not unique in its strength. Natural sounds like lightning striking into the water, ice bergs calving and even sound from marine mammals can have similar, or even higher, amplitudes. Like with noise in air, noise in water will weaken with distance to the sound source.
During our seismic operations offshore Argentina, we will have dedicated mammal observers onboard the seismic vessel to monitor and record marine life, such as whales and dolphins. Their task is to ensure that animals sensitive to low frequency sounds are not nearby prior to starting the sound source. Once the sound source is started, the sound output is increased slowly to give animals time to move away.
If animals are observed nearby during the seismic acquisition, the sound output will be paused until they are well outside the exclusion zone defined by the Argentinian authorities.