Savannah morning news. [volume] (Savannah) 1868-1887, 1886-09-03
wILLET ON EARTHQUAKES.
He Gives His Opinion as to TleiI
Nature and Various Causes.
From the Macon (GG.) Telegraph.


Nature and Various Causes.
From the Macon (Gd.) Telegraph.
In compliance with your request l sub
nit the following hasty lines on the NJ
ture and causes of earthquakes. TIE
subject is somewhat obscure, but muh
systematic observation and study are nv
given to the subject, and we may son
have more satisfactory informatia.
Causes of earthquakes were formerly l.
tributed to volcanic agency alone. Mar, |
doubtless, proceed from volcanic cause, |
whatever they are. The younger Pin,
in his account of the violent death or b
uncle, by beng overwhelmed with a ston |
Of ashes from Vesuvius, which covers |
Pompeii for many centuries, descrlhS
the awful earthquake that acc0mpanid
it. It|
Etna has been the centre ofmany earth
quakes, one notable one within few
months past. The States of Chill, Pen
and Venezuela, surrounding their great
volcanoes, have almost constant trem
blings, with occasional outbursts OF ter
rible violence.
But earthquakes sometimes cannot be
traced to any volcanic explosion. An eX-
ample is the earthquake of New Madrid,
Mo-, which occurred in 1911, and is refer
red to in your extra of to-day. This was
remote from all volcanic disturbance,
and the huge assures in the earth, with
upheaval and sinking of the surface,
point to a local cause. As this is regard
ed as the probable explanation of most
earthquakes, l will illustrate it. We are
apt to think the body of the earth as solid
and finished, so to speak. The great vol
umes of matter that gush out from volca-
noes, however, prove the interior of the
earth to be not all solid. The slow rising
of our Atlantic coast, the slow sinking
OF Greenland, ETC., etc., show the body
of the earth not to be finished. Our partly
liquid and partly solid globe is slowly
cooling, faster may be at some places
than at others, and adjustments are TAX
ing place within all the while. These
crackings, pendings, ETC., of the rocks
below, when large enough, may make
themselves known to us by vibration or
Observation-Disclosures small or large.
Another fact: The coal miner follows his
bed of coal along, say horizontally, under
the earth for months. Suddenly his bed
of coal gives out; ne finds nothing but
rock. If he has experience he does not
stop here, but drives his shaft up or down,
and, in many cases, comes on his lost bed
of coal, and then follows on again. The
rock and coal had vertical crack to take
place, and one side sunk down. or rose
up. 10, so or 100 feet. The miners call this
"fault." This slipping of great masses
of rock could hardly occur quietly and
without vibrations.
Such adjustments, some miles within
the earth, become centres from which
great waves of vibrations radiate in
every direction. The disturbance is
greatest at the centre, and becomes less
at the points more and more distant.
These faults, slips, cracks, ETC., in the
h hn x~tlIa xuff n
miner and geologlst meet them every
where. There are perhaps thousands in
the granite here in Bib county. These
crackings and slippings up ana down are
thought to be the cause OF many earth
quakes.
We do not know the origin of our earth.
quake. 1t may be the far-of effect Of
some Central American volcano. But
the incomplete and terrible news just in
from Charleston this evening seems to
point to a centre OF disturbance in that
direction-either ON land or out in the At
lantlc. Some cracking and sliding of the
rocks within the earth produced terrible
shock in the earth above, and the waves
radiating from that as centre sent an
earthquake over all the States east Of the
Mississippi. This is ventured only as a
con lecture with our present amount OF in
formation.
A WORD as 10 no" Iney sIuuy earIn-
quakes. The observations are made
mostly by pendulum, swung very dell
cately. They terminate in sharp point
or pencil below, and this point just
touches a piece OF paper covered with
lampblack, or white paper Is sufficient
when a pencil is used. This pendulum
swings under the swaying OF the building,
and the point traces out devious set OF
curved lines, showing the direction
whence the wave came. A watch shows
the time. Tracing out on a map the dl-
rections OF the sweeps OF the pendulums
at many places, we get map OF the
earthquake. Prof. Newcomb, of the OBJ
servatory at Washington, timed the
shocks last night at hours 90 minutes
20 seconds-9 :54:3O; and lasted TIL 9:o9 TO
the second. BE will probably make out
map in few days.