🚀 go-pugleaf

>I am quite concerned that the following issue has not received the
>necessary publicity to lend itself to healthy dialog about this matter.
>I am referring to two extremely loud sound sources that are starting
>operation this month and next month, off 1) Kauai, Hawaii and 2) Pt. Sur,
>California, which is an especially productive area rich in marine mammal
>life.  The speakers are to be placed at a depth of about 700-800 m just off
>the coast of these two locations.  The intensity of these sound sources will
>be about 195 dB.  This is about 10,000,000 times 120 dB (dB is a logarithmic
>scale).  120 dB is the level of intensity at which even the comparatively
>acoustically insensitive grey whale avoids noise.  120 dB is also the threshold
>of pain for humans for airborne sound.  The sound sources will be broadcasting
>a fairly low-pitched sound, 70 Hz in frequency (human hearing extends down to
>20 Hz).  The sounds will remain on for a duration of 20 min, off for 4 hrs,


	Although I am not a great fan of this experiment, I think
	that some other numbers would help put things in
	perspective.  The source level chosen is a consequence
	of objections raised by marine mammal specialists
	during the process of obtaining the environmental
	permits.  Thus, at about 1 km from the source the sound
	level will have dropped to the mar. mam. noise avoidance
	level, ie, around 120dB.

	Moreover, a typical oil tanker will radiate in the same
	frequency range at levels ABOVE 200 dB, significatively
	louder than the experiments source. And as you all know
	as long the ship is cruising it will be blasting this
	noise continuously.  Thus compared to the shipping noise
	along the coast of California, the source for the
	above experiment is a barely perceptible nuissance
	from the point of view (or hearing ...) of mar. mams.

	Finally, whales themselves produce sounds in this
	low-frequency range at levels between 160 and 190 dB.