Giant Squid Killed by Sound?

http://news.nationalgeographic.com/news/2011/05/110503-giant-squid-octopus-sonar-acoustic-tests-science-whales-sound/

something doesn’t smell right here. And it aint the rotting squid. Sound energy, like radiation, gravity and most other point sources, obeys the inverse square law. When we talk of 175 decibels, we need to know at what distance we’re measuring the pressure. Typically the headline reading is the measurement within a couple of metres. Double the distance and you quarter the volume. In the case of logarithmic units like decibels, that means you knock 6 units off the score, so a 175 db source at 2 metres drops to 169 at 4, 163 at 8 and so on. The damage reported here is caused by the 175 source maintained for 2 hours AT 2 METRES. (or thereabouts). In what conceivable circumstances would a giant squid in the wild remain within 2 metres of a 175 db sound source??? More realistically, they’ll have been tens or hundreds of metres from the source and would have bolted as the noise began. So in the real world their exposure would have started at 120-140 db (if they were unlucky) and they’d have swum out of danger range within a few seconds.

Advertisements

About Harry Stottle
Refugee from the Stumbleupon Blogicide of October 2011 Here you will find my "kneejerk" responses to the world and what I happen to bump into. For my more detailed considerations and proposals, please visit my website or my previous main blogging site.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: