Re: tsunami impact on animals

Jim Armstrong wrote:

"I think it's a pretty silly assertion that no animals died ..."

You may be right. I'd expect that at least some rodents didn't get sufficiently out of the way. But animals do have special sensitivities, and they're also much closer to the earth than we are. I've missed feeling earthquakes just because I was hiking or otherwise moving (e.g., driving a car) when they hit. But what do many wild land animals do most of the time? They stand still or lie down. The displacements from the quake would be very small in Sri Lanka, but from a quake that large the oscillations could last for several minutes, and at that distance they would have relatively low frequencies--possibly making them easier for animals to detect ( ? ).

There's a different point I'd like to make about tsunamis. Perhaps most of those who monitor this list--as scientists--are already aware of it, but the news media in my monitoring seem oblivious to it. Why are tsunamis so damaging? The media time and again mention wave amplitudes; but amplitude is of secondary importance. Tsunamis are dangerous primarily because their constituent waves have long periods. Ordinary ocean waves as they crash onto shores can have fairly large amplitudes, but they can never push very far inland because their periods are short--maybe 10-30 sec. Troughs rapidly follow peaks. Chris Chapman listed the crest times of the tsunami he observed on Sri Lanka as follows: 9:30 am (precursor wave), 10:10 am (big damage), 11:10 (even higher amplitude), 11:50, 12:35 and 12:55. These very long periods in practice simulate not a water wave but a change in sea level! (Hence "tidal wave"?) The long period enables the water to push far inland (given suitable topography) before the wave amplitude appreciably diminishes. This also explains why none of the videos played on TV showed gigantic waves suitable for surfing, which a lot of people seemed to be expecting.

Don

  ----- Original Message -----
  From: Jim Armstrong<mailto:jarmstro@qwest.net>
  Cc: asa<mailto:asa@calvin.edu>
  Sent: Sunday, January 09, 2005 4:45 PM
  Subject: Re: tsunami impact on animals

  I think it's a pretty silly assertion that no animals died ...as claimed
  by some. There are priorities with respect to who is looking for what in
  the damage area, as well as in the reporting in these early days. I
  expect we will hear in time a complete refutation of the claim, though
  it will not capture the imagination as well as the no-dead-animals
  assertion.

  JimA

  Don Nield wrote:

> Don Winterstein wrote:
>
>> Seismologist Chris Chapman was vacationing at a hotel about 30 km
>> north of Galle, Sri Lanka, when the tsunami hit. Among his comments:
>>
>> "We heard two interesting stories about animals. An Englishman
>> living with a Sri Lankan family near Matara fled to high ground when
>> an alarm about the approaching wave was raised (they must have had a
>> warning wave as we did). When he arrived, he was surprised to find
>> the cattle, which roam freely, already there. Despite the utter
>> devastation, no dead animals have been found in Yala National Park."
>> Apparently the cattle were domesticated--but free.
>> Chapman's "warning wave" was a precursor: "...The sea slowly rose a
>> few metres to the level of the hotel's swimming pool and a small wave
>> gently rolled through the ... hotel lobby." On seeing this he
>> offhandedly remarked to his wife that there must have been an
>> earthquake in the Indian Ocean. When he soon after noted the
>> appreciable retreat of water from the beach, he had the hotel warn
>> everyone to stay off the beach and head for high ground. No lives
>> were lost at their location, and only minor injuries sustained.
>> Although there's considerable anecdotal evidence, controlled studies
>> to evaluate whether animals can sense impending earthquakes so far
>> have proved negative. In this case the animals presumably felt the
>> seismic waves from the earthquake, which would have arrived
>> appreciably before the ocean wave. The animals apparently sought
>> high ground in response. There's no known mechanism that would have
>> allowed them to detect the tsunami itself in advance.
>> Chapman's comments imply he didn't feel the quake himself.
>> Don
>>
>>
>>
>>
>> ----- Original Message -----
>> *From:* Randy Isaac <mailto:rmisaac@bellatlantic.net<mailto:rmisaac@bellatlantic.net>>
>> *To:* asa@calvin.edu<mailto:asa@calvin.edu> <mailto:asa@calvin.edu<mailto:asa@calvin.edu>>
>> *Sent:* Saturday, January 08, 2005 5:06 PM
>> *Subject:* tsunami impact on animals
>>
>> Last night on Larry King Live, Deepak Chandra stated that "....no
>> animals perished in the tsunami. The elephants, rabbits, etc. all
>> fled the coast.......". Presumably he was referring only to
>> undomesticated animals. There seems to be a general
>> public perception that animals can sense a pending earthquake
>> although I don't know of any credible scientific studies
>> confirming it. Do any of you know of any reliable evidence of
>> unique animal behavior wrt the tsunami? If so, is there any
>> insight regarding the mechanism?
>> Randy
>>
> I find Don's comments a very plausibible explanation -- the animals
> deteced seismic waves at frequencies and amplitudes to which humans
> are insensitive. I would guess that the animals would not make an
> explicit connection with the need to go to higher ground. Rather, they
> would merely become disturbed and move away from exposed areas. That
> would mean that they would move away from the coast, and thereby
> automatically move towards higher ground or more dense vegetation that
> would provide protection from a tsumami.
> Incidentally, I read somewhere of a report from East Africa (I think)
> that some hippopotami were swept out to sea. It is understandable that
> because they were in a river they would not have picked up the
> seismic vibrations that are restricted to dry land.
> Don Nield
>
>
>
>
Received on Mon Jan 10 02:45:16 2005