The Wonder Book of Volcanoes and EarthquakesHouston, Edwin J. (Edwin James)
Science
The Wonder Book of Volcanoes and Earthquakes
Houston, Edwin J. (Edwin James)
Earthquakes; Volcanoes
These waves reach a distant point in the following order: the sound
wave through the earth and the great earthquake or shake which
produces the damage. Then a smaller sea wave called the forced sea
wave. This is followed almost immediately by the sound wave through
the sea. Next come the air sound wave and finally the great sea wave;
which, rushing in on the shore, sweeps nearly everything before it.
In other words, the disturbances produced by the great earthquake
follow in this order of sequence. If, therefore, the great earthquake
wave proper transmitted through the earth should for any reason be
delayed in reaching a distant place, the great sound waves should be
able to give warning of the coming disturbances.
Again, as we have already seen, the earthquake wave is preceded by a
number of preliminary tremors, and is followed by a number of after
tremors or _earthquake echoes_. Since, therefore, the preliminary
waves reach a place first, it would seem that the approach of an
earthquake must be heralded by the preliminary tremors. These,
perhaps, at least in part, enable the lower animals to detect its
coming.
Again, in almost all instances there are a number of preliminary
shocks that precede the great earthquake shock. Some of these
preliminary shocks continue at intervals for several days or even
longer. Sometimes, indeed, these subterranean sounds fail to be
followed by earthquakes. Milne thinks that these sounds are caused
by the preliminary tremors which precede the principal shock of the
earthquake and that they reach the place first. Here again then it
is evident that, were we able to interpret properly these sounds, we
would probably be able to foretell the coming quake with a fair degree
of certainty.
There would appear to be no reasonable doubt that in some manner
which we have not yet been able to discover, but probably along some
of the lines indicated above, animals are capable of recognizing a
coming earthquake. Long before the coming of the catastrophe they are
said to exhibit extreme terror, and in many cases appear to seek the
companionship of man, as if for protection.
That the senses of smell and hearing are far more acute in the lower
animals than in man no one can reasonably doubt. The manner in which
a trained dog can follow a scent, for a long time after the animal
or thing producing it has passed, far exceeds the power of scent
possessed by man, and it is more than likely that this same power is
possessed by all animals who live upon or prey upon other animals. It
is probable that faintly odorous vapors or gases escape from the crust
shortly before the great shock occurs, and that these faint odors are
warnings to the animals of the approaching calamity. The sense of
hearing also is much more acute in the lower animals.
Daubeny is evidently of this belief, as will be seen from the
following:
Public-domain text, read in full here on John Shaqi.
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