Savannah morning news. [volume] (Savannah) 1868-1887, 1886-09-04

loSAo Washington it is only 0 O'Clock
"' StPuis or Chicago.
H"t 1uaSes, especially when occur
.lnH lplcanic regions, are often not limi-
teu To 70 or three shocks in quick sue
oessloIput come in periods or groups.
Ourllthe twenty-four hours following
the deslction of Lima in l746 as many
as zVo SEEKS were counted, and within
the neXtur months $50 more were felt.
AZ pan aYador, in Central America, in
the nelgArhoOd Of Lake Hopango, more
tuhn oUO RrtnQuake shocks we're felt
Wllhln tnlast ten days of 1879. The
water OF q lake was thrown into COM
motlon, thSound was broken into net
WORK OF cnks, and in January, 1880, a
new volcanrose in the centre of the lake.
inese ear9uakes were obviously pro-
aucts OF volnic energy. After the New
Zealand eabquake of 1848, the shocks
continued + nearly five months, and
during mucof the time at the rate of at
least ] 200 shks per day. By comnari-
son with Is, the afflicted people of
Charleston ay call themselves blessed,
even thoughthe earth shocks did not
cease there ltil twelve hours after the
nrst one had assed.
NATURE & EARTHQUAKE WAVES.
The naturef earth waves is best I'M
derstood by fsuming single point as
focus OF distJbance. From this wave
proceeds outsphericslly as she'll of
compression, ach particle traversed by
IL receiving forward and then back
ward motion. II body be Immediately
over the focust is thrown vertically up.
ward. Elsewere the motion is both up
ward and sitMard, the upward c0mpo-
nent becomin less IN comparison with
the other as ne horizontal distance is
increased. 1.-The focus be long assure,
as is generally the case, the motion be-
comes ratheItmore complex. In some
cases whining effect is produced. IS IN
the Calabrhn earthquake of 1888, in
which 0lo0s of stone forming square
columns wee twisted at various angles.
vIOLENG OF EARTHQUAKE SHOCKS.
In 1891 anearthquake occurred in the
Andes. its tcus being almost under the
village of Robamba. The ground was
shattered in many places; the bodies Of
men were thown upward fully 100 feet
into the air aid found afterward on hill
across a smalTiyer. Graves are said to
have been renbpen and corpses hurled
out of them.
In 1912 Caraas, the capital of Vene-
zuela, WAS Destroyed by an earthquake,
and 10000 ofits Inhabitants persisted
within two miutes.
Despite sue violence the extent Of
swing imposed upon the ground by an
earth wave is seldom more than a few
inches. By tn use of seismOmeters in
Japan the verttomponent has been found
rarely to eXceeI One-nftieth of an inch,
and when the OriZOntal component eX-
ceeds fourth # an inch buildings begin
to be shattered This limit was evidently
exceeded at Charleston. In
New York chandeliers aud doors were
made TO swing trough considerable arcs,
but the extent d swing depends more on
the violence tan the amplitude OF the
initial impulse.
After the Ne9Oitan earthquake Of 1857
Mr.. Mallett, by careful examination of
the cracks produced in buildings and the
direction in which bodies were thrown,
estimated the ocus to be fissure nine
miles long, the point Of greatest commO-
ton being nearone end of it and not more
than ten miles below the surface. By the
use of seismOmeters the direction of mo-
ton and angle o. emergence may be reg
stered at many different places around
he same focus. BY comparing these
ana noting the Tune at which the shock
at hseismometer the position
If the focus and the rate oftransit through
L
8 rarely more tAan twenty miles.
VELOCITY OF TRANSMISSION.
Japan is continually shaken by earth
Iuakes, and from observations on seis.
nometers in that country the following
esulrs have been deduced:
l. Different earthquakes across the
anne country may travel with different
varying from few hundreds
If feet to two miles or more per second.
2. The same earthquake travels more
apidly near It's focus than across regions
emOte from IT.
3. The greater the intensity of the shock
he greater is the velocity Of transmission.
have been artihcially pro-
'nced by the explosion of gunpowder or
dynamite under ground. The rate of
ransit for shocks produced by gunpOw-
Ter was found by Mir. MalletC to be S25
eet per second in sand, and 1866 feet in
granite. Dynamite explosions are more
udden and violent than those Of gun
powder. An explosion Of 10000 pounds
# dynamite was effected at Halletts
Point IN 1876. Through the neiRhbOring
country the rate of transit of the shock
yaried from 5000 to 5000 feet per second.
About 100000 pounds Of dynamite were
at Flood Rock in October OF last
nv varied from 5000 to 90, 900 feet per
second, or say. from one mile to four
niles per second, being fastest where the
yround is hard rock and slowest where it
8 sandy.
1t is scarcely possible at the present
moment to estimate the velocity of prOpa-
ration of the earthquake wave Of Tuesday
light from the accounts thus far tele-
,rapbed and published in the morning
,aners. Nor are we yet furnished with
data TO estimate the position OF
be focus. COnjectures have been already
but careful comparison OF
many observations is Indispensable.
EFFECTS OF EARTHQUAKES ON SAND.
The effect of an earthquake shcck is
sually far more disastrous on beds of
and or clay than on solid rock. The re-
ent shock has been most violent In re-
ions OF alluvial deposit. Charleston and
avanDah are built on beds OF low, fiat,
andy country, hundreds of miles away
rom the rocky regions OF the Alleghanles.
lost. If not all, of the cities that have
cen destroyed by earthquakes have been
ituated on soft ground.
In 1855 the most disastrous earthquake
n record passed under Lisbon. Toe
over part Of the city, built on ciay. was
tterly destroyed. All OF the buildings in
he upper part, resting on a foundation
t bssaItic rock and bard limestone, es-
aped enure!y.
In soft ground q violent earthquake
early always produces cracks, which
ften close just after the passage OF the
7ave. In many ca9es they are left as
pen chasms of great size. In an earth