The Warner weekly sun. (Warner, Brown Co., Dakota [S.D.]) 1883-1885, 1884-10-17
WHY THE EARTH oUAKEs
rhs Forces Supposed TO be at work rb,v..
Miles Beneath us.

rrolessor george IA. Merrlman. q
Rutgers college, New Brunswick. has
made the crust ofthe earth a study. ans
has written on the subject. He saws.
while facts enough regarding liz
extent of the earthquake of Sundas
have not come to hand to enable ma +
speak on the direction Of the eartl
wave OF it's peculiar features as com.
pared with other earthquakes, yet some.
thing may be said as to the latest Con
victions of students of science on III.
nature of the earth below the point a.,
man can penetrate. That may lead Is
to guess intelligently at the CAUSE al
earthquakes.
"You know the long received theorv
of the nature of the interior ofthe earth
was that it is a molten mass, and thai
we move around on a crust enyelopinp
the earth and caused by the cooling IA
of this mass on the inside. It Is III.
doubtedly true that about thirty miles
below the earth's surface the tempera.
ture is so high that everything is In
melted condition. We know this, Be.
cause we have learned that every ffty
feet we penetrate into the earth there's
an increase of temperature Of about one
degree, and at a distance of thirty miles
the heat is so great that any substance
we know of would melt.
Perhaps the melted mass is in The
form of a liquid. That who'd be Ger.
tain but for the immense pressure On ii
The pressure is estimated at 10000 tons
on a square foot. OF course scientific
men cannot experiment with matter IL
a high temperature with a pressure q
10, 200 tons to a square foot, so we caf
only guess what may be its condition.
In talking about this melted mass THIRTY
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 It's destiny increase
more and more, gradually, until the in
terror of the earth is solid, probably,
from the inconceivable pressure 1900,
1900 OF 5000 miles from the surface.
Sir William Thompson has demonstrate
ed hat the earth must have a core much
denser than the land and water We live
or He points out the fact that ifs
shell only thirty miles thick SURROUNDED
a molten liquid mass extending from
one side of the earth through the CEN
tire to the other side, then the moor,
through law of gravitation, would dis
place the liquid or gas in the interior
of the earth to such an extent that ths
earth's crust would bulge out in the di-
rectiGn of the moon, making q tide u
the solid crust of the earth, as certainly
as the skin of an orange hHlges out Wihen
you squeeze the fruit between the palms
3f your hands. And this would be eyi.
dent tous because the ocean tides would
be almost, if not quite, imperceptible
to us. To withstand the attraction o
the moon, the earth, Sir William SAYS,
must be rigid as steel.
So we have the theory that the crust
Of the earth floats on and imposes amin
mense weight on a water substance,
which is inconceivably hot. Now, as g
the way an earthquake may be caused.
Suppose moisture trickied gradually
year after year, through this crust into
d heated mass. In our atmospdeft
steam would be produced Thlrts
miles below us the pressure Is 50 greas
that it is not likely that steam could %
generated. One thing, though; the
pressure of 10000 tons to the square
foot, a pressure exerted in every dlrec.
ton, would be increased. Some efieei
must be propuced down there, and lth
easy to see that il one place IN tht
earth's crust is weaker than another r.
gion where the water trickled IN, then
the weakest place must stand ts
strain It is not unreasonable to sup
pose that this pressure below might ~
so great that the earth's covering was
shifted a little to adapt itself to the pres
sure from below. This shifting OF tns
crust is, in fact, the earthquake.
IT believe this theory has the gre1Iel
reason on It's side, because earthquakes
are almost always in the region o. yo1'
canoes, and volcanoes are almost AWAY
in or near the ocean.
another theory Of earthquakes !
that as the earth is very gradually coor
ing off the crust is thickaning on lns
under side and cracks or assures on. tn'
under side of the crust many miles deel
may occur in consequence Of the enoL
nous pressure, 50 that the water sa9
stances rushes into q new position WIZ
a force that would knock q eentanen
out OF shapei il ittook place on the cartn \
surface. That motion would be sun
cient to produce a viabration thlft
miles distant.
Whatever the cause Of the eartn
quake on Sunday added Professo
Norman, "I think the earth in the =
glon where it took place has either se'
tied into a new position on Is forcs
back into an old position from which
was pushed by former earthquakes.