Nick and all...
Many have argued that the seaquake theory is
questionable because undersea earthquakes are common along the mid
ocean ridge system where pods of deep diving whales feed on
squid. Their logic is similar to yours: "One can
always find several underwater earthquakes for every mass
stranding." One scientist, using the
same reasoning, told me 30 years ago that he thought mass stranding were
caused by car wrecks in New York City because every time whales stranded there
was a car wreck.
I disagree. In my opinion, the occurrence
of several suspicious earthquakes along a segment of mid-ocean ridge ~30
days prior to a mass stranding is strong supportive evidence that my
theory is valid especially when coupled with the fact that mass beachings DO
NOT occur in a given area when there are no upstream
earthquakes of significance.
Another point is that we do not look for "causal"
earthquakes in a broad area along a ridge axis. We select events that
are upstream from the beaching site. If the earthquake is located in an
area where the current would carry the injured whales in a different direction,
then we rule out this event. We are careful in selecting a
suspicious quake. I recall 20 years ago that we often had 10 or more
earthquake to considered. But lessons learned over time, along with
advancement is seismic instruments, has taught us how to weed out many
earthquakes. We are at the point now where only one event stands out as a
likely source of barotrauma. We are also finding that ~10% of the ridge
axis produces 90% of the dangerous seaquakes. We think this is associated
with magma chambers below a particular segment. There is something
special happening to create danger for diving whales but we have not yet
found what that might be.
Too might also consider these other
facts:
(1) Submarine earthquakes have been occurring
in the backyard of pelagic whales since long before the beginning of recorded
history.
(2) Pod strandings of pelagic
whales predate recorded history.
(3) Sea bottom earthquakes with a
strong vertical component can generate a series of pressure changes in
the water column estimated by Navy seismologists to exceed 14,500 pounds per
square inch (280 db re 1 microPa) one meter off the seafloor. The
largest estimate ever place on a shockwave above the epicenter of an
undersea earthquake was 100,000 pounds per square inch (298 db re 1 microPa) by
scientists with Goddard Space Flight Center.
(4) Rapid and excessive changes in
ambient pressure presents a serious danger to any air-breathing
animal who dive under the surface, including baleen whales, seals,
walruses, and etc.
(5) Undersea earthquakes have never been
investigated as a possible cause of mass strandings.
(6) The mystery of why whales mass
strand remains unsolved.
It would be relatively easy to proved
the seaquake theory. If mass strandings can be predicted with reasonable
accuracy using earthquake data three weeks in advance, then
the seaquake theory should be received as the leading hypothesis
to explain mass strandings. Accurate prediction can
be made with a little help from the scientific community. The
major stumbling block lies in the interpretation of the satellite data on
ocean currents. Another important factor in predicting strandings is
to including the help of experts on the location of habitats of
various species. You got to know where the pods are
located in order to predict the likelihood of an earthquake
encounter. Another big boost to predicting stranding would be to
secure spectrographs of various earthquakes as recorded by hydrographic
listening stations. Records from T-wave stations would also be a
value.
Many thanks for your probing
questions.
Warm Regards,
Dave Williams
----- Original Message -----
Sent: Thursday, January 07, 2010 7:10
AM
Subject: Re: [ECS-TALK] Comments on recent pilot
whale strandings on eastern coast of Canada
> Dear David,
>
> No, I'm looking for evidence of a
causal association. It doesn't matter
> if there are one or several
quakes, but as you present the evidence
> it's unconvincing because
quakes may be so common that mostly you will
> find one that fits your
theory.
>
> It's like me explaining my cat's epileptic fits as due
to lorries
> passing in up to 10 minutes beforehand. Actually there
are so many
> lorries there will often be an association even though it
is not causal.
>
> So the data you present is interesting, but
raises this question that
> you don't address, and the theory is not
accepted, although it could be
> right. The test I proposed was
designed to avoid subjective evaluation
> of any data on the part of the
person looking for causal quakes.
>
> v best
>
>
Nick
>
>
>
>
>