smudge13
Registered
I just retired form the Navy in 2014. I was a sonar technician and spent my career tracking submarines. I can tell you that low frequency sound can travel enormous distances underwater. It's though that humpback whales communicate at transoceanic distances.
Diving La Jolla Canyon you can also experience a phenomenon called "upslope enhancement" where the contour of the sea floor will enhance sounds of certain wavelengths as they propagate towards shallower water.
That being said, what you heard with your human ears was not likely a military submarine especially if you're describing it as a high pitched whine. More likely a boat whose noise was trapped in a surface layer propagation path and was therefor well with in hearing range underwater but beyond your visual horizon on the surface. Also, because of the tremendous difference in the speed of sound in water vs the speed of sound in air, your ears are not calibrated to pick out the direction that a sound is coming from in water. You cannot accurately tell which direction a noise is coming from underwater.
Diving La Jolla Canyon you can also experience a phenomenon called "upslope enhancement" where the contour of the sea floor will enhance sounds of certain wavelengths as they propagate towards shallower water.
That being said, what you heard with your human ears was not likely a military submarine especially if you're describing it as a high pitched whine. More likely a boat whose noise was trapped in a surface layer propagation path and was therefor well with in hearing range underwater but beyond your visual horizon on the surface. Also, because of the tremendous difference in the speed of sound in water vs the speed of sound in air, your ears are not calibrated to pick out the direction that a sound is coming from in water. You cannot accurately tell which direction a noise is coming from underwater.