Savannah morning news. [volume] (Savannah) 1868-1887, 1884-08-30
WHY THE EARTH ouAKEs.
Forces that are Pent Up Under Us and
would Smash Us if they Got I,oose.

4
would Smash Us if they Got Loose.
Prof. George II. Merriman. of Rutgers
College, New Brunswick, has made the
crust of the earth a study, and has writ
ten on the subject. He said a few DAYS
ago:
Nv lille facts enough regarding the ex-
tent OF the recent earthquake have not
come to hand to enable me to sneak
on the direction of the earth wave or its
peculiar features as compared with other
earthquakes, yet something may be said
as 10 the latest convictions of students of
science on the nature of the earth below
the point any man can penetrate. That
may lead us to guess inteIHgently at the
cause of earthquakes.
You know the long received theory of
the nature Of the interior Of the earth was
that 1t is molten mass, and that we
move around on a crust enveIoping the
earth and caused by the cooling off OF this
mass ON the outside. 1t is undoubtedly
true that about 80 miles below the
earth's surface the temperature is so high
that everything is in melted condition.
We know this, because we have learned
that every 90 feet we penetrate into the
earth there is an increase of temperature
OF about degree, and at a distance of 80
miles the heat is so great that any sub
stance we know of would melt. Perhaps
the melted mass is in the form of a LIQUID
That would be certain but for the immense
pressure omit. The pressure is estimated
at 10000 tons on square foot. Of course
sclentlnc men cannot experiment with
matter at high temperature with a pres
sure OF 10000 tons to a square foot so we
can only guess what may be it's condition.
In talking about this melted mass 80
miles under us the term water substance
is used by biologists.
"HoW great is the distance through
this water substance we do not know,
but it is certain that its density increases
more and more, gradually, until the in
terror OF the earth is solid, probably, from
the uncomfortable pressure 1000, 2.000 or
1900 miles from the surface. Sir William
thompson has demonstrated that the
earth must have core much denser than
the land and water we 1--we on. He points
out the fact that if a shell only thirty
miles thick surrounded a molten LIQUID
mass extending from one side of the earth
through the centre to the other side. then
the moon, through the law of gravitation,
would displace the liquid or gas in the
interior of the earth to such an extent
that the earth's crust would bulge out in
the direction of the moon, making a tide
in the solid crust of the earth, as certainly
| as the skin of an orange buIges out when
you squeeze the fruit between the palms
of you hands. And this would be evident
to us because the ocean tides would be
almost, if not quite, imperceptible to us.
To Withstand the attraction of the moon,
the earth, Sir William says, must be as
rigid as steel.
$50 we have the theory that the crust
OF the earth floats on and imposes an i'm
mense weight on a water substance,
which is inconceivably hot. Now, as to
the way an earthquake may be caused.
suppose moisture trickled gradually, year
after year, through this crust into the
heated mass. In our atmosphere steam
would be produced. Thirty miles below
us the pressure is so great that it is not
likely that steam could be generated.
One thing, though; the pressure of 10000
tons TO the square foot, pressure eXerted
IN every direction, would be increased.
Some effect must be produced down there.
and 1t is easy to see that if one place in
the earthS crust IS weaker than another
near the region where the water trickled
In then the weakest place must stand the
strain 1t is not unreasonable to suppose
that this pressure below might be so great
that the earth'S covering was shifted a
little to adapt itself to the pressure from
below. This shifting of the crust is, in
fact, the earthquake.
Il believe this theory has the greater
reason on It's side, because earthquakes
are almost always in the region of volca-
noes, and volcanoes are almost always in
or near the ocean.
''Another theory of earthquakes is that
as the earth is very gradually cooling off
the crust is thickening on the under side,
and cracks or assures on the under side
of the crust many miles deep may occur
in consequence of the enormous pressure,
so that the water substance rushes into
new position with force that would
knock continent out of shape if it took
place on the earth's surface. That motion
would be sufficient to produce a vibration
thirty miles distant.