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Communications Science

Infrasound, Elephants and Earthquake Detection 34

Posted by timothy from the how-low-can-you-audibly-go dept.
mediareport writes "Science News offers a timely antidote to simplistic mumbo-jumbo about the "mythical power" of animal earthquake detection. Anyone intrigued by reports of possible tsunami-avoidance behavior in Sri Lankan wildlife will enjoy this detailed examination of the latest research into low-frequency sound. Elephant rumblings that produce Rayleigh waves are now under serious study for the first time, while others are designing "highly unusual" experiments to test infrasound sensitivity in humans."
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Infrasound, Elephants and Earthquake Detection More

Infrasound, Elephants and Earthquake Detection

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  • Elephants (Score:2, Interesting)

    by MBCook ( 132727 )
    Elephants know all. There is a story [yahoo.com] about elephants that would give tourists rides that got nervous that day and then grabbed a few tourists and ran for the hills just before the tsunami.

    Weird (and cool) stuff.

  • Animals don't win Darwins (Score:5, Funny)

    by Anonymous Coward on Tuesday January 04, 2005 @01:41AM (#11251625)
    I'm sure there was lots of infra-whats-a-ma-gig going on, but regardless of those factors, what it comes down to is that animals just aren't as stupid as humans.

    When confronted with an unusual, confusing situation, they get the fuck out. Whether it was the vibrations, the noise, or the distant sea swell, doesn't matter, they got the fuck out.

    Humans who feel planet earth is one great big disney park in which they have the right, if not the obligation, to experience *all* the rides, wander down the quickly receding waterline to check it out.

    I suppose it could be valid to think of earth as a disney park, so long as you remember that a large number of the attractions are named "death". If you are too blind to notice that on your way to the shiney new thing..... well.. then I've got a darwin for you.

    (this is mainly directed at the forgein tourists on the (now dry) sea bed starely motionlessly at the wave)
    • (this is mainly directed at the forgein tourists on the (now dry) sea bed starely motionlessly at the wave)
      I love tasteless humor better than the next guy.

      Even your comment might be fun in a week or two when I know if friends died there or not.

      (Some people I like, with their kids, usually goes to Thailand for vacation.)

    • Re:Animals don't win Darwins (Score:5, Interesting)

      by dasunt ( 249686 ) on Tuesday January 04, 2005 @07:07AM (#11252385)

      I'm sure there was lots of infra-whats-a-ma-gig going on, but regardless of those factors, what it comes down to is that animals just aren't as stupid as humans.

      When confronted with an unusual, confusing situation, they get the fuck out. Whether it was the vibrations, the noise, or the distant sea swell, doesn't matter, they got the fuck out.

      That's loser speak. ;)

      What is better for Og: Avoiding the sharp rock that cut him? Or figuring out how to use that sharp rock to cut others?

      Avoid fire like the rest of creation? Or use it to keep him warm and build better spears to kill others?

      Og thinking that, like all other predators, a healthy, adult mammoth shouldn't be messed with? Or scream and taunt the mammoth to the point where, in order to escape this mad creature, the mammoth tries to flee, forgetting about the large cliff...

      Sure, Og's actions lead to a high deathrate amoung Og's kin. But a few Ogs later, the rest of the clan is much better off.

      • There is a difference between constant, repeatable threats, otherwise known as risk, and random, large scale events.

        The first human reaction to danger was always to get out of Dodge. But if the danger was repeatable and comprehendable, it got dealt with. If tsunamis happened on a weekly basis, we'd be surfing on them, not dying by the metric ton.
    • (Warning: non native writer.) Also, most animals can outrun humans. As I understand it, tsunami's can be outrun if you run over 20km per hour. Clearly a lot of big mamals can run faster than that. So that combined with the fact that animals usually do not go investigate how far the sea retracted, makes (bigger) animals byfar more tsunami restistant than humans. I would like to point out however that humans are very successfull multiplying wise. Does anyone know if we outnumber any mamal population (even bef
      • In addition to the modern Homo sapiens' ability to multiply (which I am not too impressed by, if you want to view multiplication just check out some rabbits), we also have the lovely ability to be able to manipulate the environment we live in (which is some of the most varied of larger creatures) to best fit us. And well, often that manipulation may not be the best as far as the long term survival of the species, but who knows about that for certainty. I do not know whether humans out number any large mamm
      • Uh maybe you know of some fancy conversion ratios that make 20km/hour more than 500miles/hour but I sure as hell don't ;). Now if by outrun you mean they realize that shit was about to hit the fan and they got the fuck out of dodge, that's different but if you see the wave and you're not high up on something, doesn't much matter who you are or how fast you are ... you're fucked :)

        • Re:Animals don't win Darwins (Score:1, Interesting)

          by Anonymous Coward
          tsunamis do not hit the shore at 500 mph. The reason it's a big wave in the first place is because it slows down.
      • I am pretty sure we outnumber many other mammels. Maybe thats because they are endangered though (killed off by our actions). Elephants, and giant Pandas come to mind. As far as mammals we havent overhunted, I would hazard a good guess that we outnumber many big cats. There isnt (and never was) room for billions of Lions on this planet. A pride of lions (10, perhaps) takes up many square kms of land, and the amount of land-space in the Lion's habitat is rather small. However in many cities you can hav
      • This is interesting rated but utter nonsense.

        A tsunami has not a speed of merely 20km/h but somewhere between 100km/h and 400km/h.

        Granted when it approaches teh coast it slows down massively, thats why the waves are that high.

        You can play that on your desk by using a sheet of paper. Move it and stop the front edge with your finger while you continue to move it. It waves up.

        The animals did not flew the tsunami, they felt the earthquake and moved BEFORE the tsunami came.

        angel'o'sphere

  • Dead fishes (Score:4, Interesting)

    by helioquake ( 841463 ) on Tuesday January 04, 2005 @03:36AM (#11251950) Journal
    I wondered about those fishes that died ashore after the tsunami...

    The sound wave indeed propagates through water about 1400km/h, much greater than the propagation speed of tsunami wave at this time (~1000km/h). So the fishes most probably have "heard" the low freqency wave. I'm sure no fish can outswim the tsunami, but I'm a tiny bit surprised to see so many of them got stranged in land.

    I know the physics of waves, but have little experience in ocean current under sea. Would tsunami wave actually whirl up and down so fast that deep ocean fishes get dredged up fast and get knocked out before dying ashore? Or do they simply get left behind waves and asphyxiate to death?

    • Re:Dead fishes (Score:5, Insightful)

      by Meetch ( 756616 ) on Tuesday January 04, 2005 @04:19AM (#11252048)
      Hmmm... I would put it down to fish generally not being particularly bright outside of their day-to-day survival instincts, and as they are generally spread out, not needing to respond to such major events as a tsunami for the species to go on. They'd stay in their usual habitat, and if that local habitat goes, then the inhabitants go with it. Occasionally they'd ride a current, especially if given no choice. If they get washed ashore, bad luck.

      What I'd be more interested in is if any, and if so how many, larger sea creatures were dumped ashore. (I believe there were whale beachings in the general vicinity within that general window, but AFAIK it's just coincidental).

      I'm no marine biologist, so anyone with facts that support or shoot down my ideas are quite welcome to do so.

      • I saw on the news that some dolphins were found inland. I think that intelligence is not a decisive factor in a creature's survival when an event of this magnitude comes.
    • The motion of the water under the waves in the deeper part of the ocean would be pretty mild--not too upsetting to the fish. But as the waves got to shore -- becoming steeper and higher, the velocities increased, and then the waves rushed up and over the land. The fish in the nearshore area would be washed inland and then stranded.

  • Could it be ionospheric disturbance? (Score:3, Informative)

    by helioquake ( 841463 ) on Tuesday January 04, 2005 @03:56AM (#11251995) Journal
    Could it be ionospheric disturbance? [nap.edu]

    There is an on-going research to forecast earthquakes via detecting ionospheric disturbances (can't find a good article now...it has to do with the detection of a very-remote FM radio signal that could only be detected when anomalous disturbance occurs in the ionosphere. An initial finding was done while amateur astronomers were monitoring FM radio signal for meteor detection). Maybe animals can detect minute changes in the terrestrial electro-magnetic field, I wonder?
    • It's possible. Until recently, we didn't know a certain kind of squirrel could communicate in very high frequencies, but alas. But I think the easiest explanation is that the animals could hear the deep rumble of the initial earthquake (inaudible frequencies are created) and decided that something must be up and ran away from the source of the sound.

  • Slate's article [slate.com] last week discussed both Raleigh Waves and Infrasound as possible information sources coming from the Tsunami.

  • Feel bad for Pets (Score:3, Insightful)

    by superpulpsicle ( 533373 ) on Tuesday January 04, 2005 @01:38PM (#11255026)
    What about the animals that couldn't leave the house. They must be horrified to know something bad is coming and are trapped in their own house.

  • People are Animals (Score:3, Insightful)

    by radtea ( 464814 ) on Tuesday January 04, 2005 @01:42PM (#11255061)

    Humans are animals.

    All the people saying "No animals were killed, no animal corpses were found" are ignoring this minor fact.

    We're not so very long out of the trees that we have had time to lose any mysterious "sixth sense" that most non-human animals have. The only plausible reason for losing it in such a short time would be if it was strongly selected against.

    So anyone who thinks non-human animals have some ability that humans don't--other than the fairly obvious things like a low panic threshold and the ability to run faster--needs to provide some explanation of why we don't have it when 50,000 years ago we were just another moderately successful social primate.

    --Tom
    • I believe some of us can still hear earthquakes.

      I never lived in an earthquake prone area, but in November 1988, I heard the biggest one felt in Canada a good 30 seconds before everyone. (6.2 on the Richter scale, about 30 km from Chicoutimi, QC). It sounded like a huge invisible semi was coming my way.

      Since then I've always wanted to spend some time in California or Japan to test my earthquake hearing further.
      • Sounds like coincidence to me, unless you are one of the very few people who can hear very low frequency sounds. Most people can hear 20-20,000 Hz, so either you imagined the whole thing after the earthquake or you have better hearing than most people!

        • Actually I noticed I can sense frequencies outside of the audible range. Not with my ears, rather I can 'feel' them. Ive been able to detect powerful low frequency sounds. EVer hear the lowest notes of a pipe organ? Notice that feeling in your gut? Well ultra low frequency sound has that same feeling. Perhaps all the 'furry creatures' out there have a better ability to detect low-level low-frequency sounds than we can.

          I have also 'heard' some 22+khz tones. Not that I could describe what they sounded
          • I and a couple other people I know can hear the horizontal sync frequency on NTSC televisions, around 15 kHz. I know that 20 kHz is often touted as a common upper-bound in young people's hearing, but I've found that most I spoke with had never heard (or perceived, perhaps a significant distinction) that sound.
            • I can definately hear that one and it bothers me to no end. Its a very penetrating sound, I can usually tell if someone in the house has left a TV on upstairs when I walk in the front door and the house is otherwise quiet. Its on the border line between 'hearing' and 'feeling' since I can feel the pressure on my eardrums at the same time as I hear a very high pitched whine. IIRC its closer to 17khz isnt it? In any case its above many people's threshold of hearing.
        • I was actually with other people who thought I was going nuts, "hearing things".

          So no, I didnt imagine it.
    • Good point. I'm wondering how primates in general fared compared to other wildlife. I'm also thinking that our modern lifestyle might contribute to a serious deadening of our senses. Run an elephant through rush hour traffic (or stuff him on an Indian train) for a few years and then see how he does vs. earthquakes. I'm guessing that he'll stop rolling 20's.
  • There was a 4.2 in Illinois on June 28 last year.
    It happened late at night and woke me out of a sound sleep. What really got me up was the noise that my two parrots were making in their cages. They were both clinging to the ceilings of their cages and didn't want to touch down on the ground. It took about 15 minutes to calm them down and go back to bed. It was probably just the shaking of their cages that got them worked up.

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