The weekly register. [volume] (Point Pleasant, Va. [W. Va.]) 1862-1909, 1886-09-08
Blu. .he present geological spocb

present epoch, Us indeed 10 t0fmer
epochs, biologists attribute to the
slipping Of great assures 10 the
ear!b's crust. The severe earth.
quake that shook the Mississippi
Valley in1Sll was dueto this cause
! 10 the region about The mouth of
the Ohio liver large tracts q land
we're sunk several feet aud have
been covered with water ever since.
Theone that occnredi in India about
the mouth Of the Indus river, in
1878, was also due TO this cause.
There 1000 square miles Of land
on one side Of the assure slipped
down and became covered with wa.
ter, while shout OOsqaate miles
on the other side was elevated ten
feet
But these slipsare Insignificant
compared with those oftormer geol.
ogiCal epochs. For example, there
were once slips of2O,OOOfeet in the
strata in Pennsylvania, 10000 feet
10 the Uinlah mountains Of the
west, 10000 feetin1 the Wahsatch
range, and from 5000 to 10000 feet
in the Appalachian chain, but
most Of the slips that occur do not
extend to the surface aud only pro
duce an earthquake shock.
But the theory generally advan.
ced as accounting for most earth
quakes is the formation and con.
,fnement Of steam or gas beneath
1.-THE earth's crust. In volcanic re.
gions earthquakes and volcanic
eruptions are closely connected.
when the vent of an active yolca.
no becomes closed an earthquake
generally follows. Thegreat earth
quake that DESTROYED Rhiobamba
and 10000 people in 1877 occurred
just after a neighbOring volcano
ceased ernpting. The terrible
earthquake in Calabria in 1883 &C,
cured just as slromboli ceased
erupting. The peopleof QuitOex.
pect an earthquake whenever the
smoke disappears from Cotopoxi.
Also where regions have frequent.
Fly been visited by earthquake
shocks, the disturbance generally
ceases when the gases burst forth
ina volcanic eruption. The shocks
that destroyed Caracas and nearly
all its inhabitants in 1912, ceased
as soon as st. Vincent, volcano
800 miles distant erupted.
Ifthe theory Of confinement Of
gases is a true one, while eartb
quakes are most likely to originate
in volcanic regions, they may also
have their source in regions not
considered volcanic. From the re
ports received so far, from South
Carolina, the earthquake must
have had its origin from this cause
The focus, or center Of the disturb
ance must have been beneath the
crust somewhere near Charleston,
as the vibrations Of the earth
seemed to extend in every direct.
ion like waves from a pebble
thrown into lake. Also the mo.
tion Of the earth was more nearly
perpendicular in South Carolina
than in other regions. The motion
of the earth directly over the ori'
gin Of a shock Of this kind, is per.
pendicular. In the great earth,
quake Of Rhiobamba, men and OBJ.
jects on the ground were hurled
several hundred feet into the air.
Butoutward from the point where
the surface is first reached the
waves become more aud more hori,
zontal as they emerge, This seems
to have been the case in the late
earthquake These waves travel
at the rate Of about twenty miles
per minute, depending upon the
density of the medium through
which they pass, Their velocity
in The granite axes Of great noun.
tain ranges es greater than in any
other medium. 1t is a noticeable
feature that in most earthquakes
in this country tho waves take the
direction Of great mountain ranges,
The wave phenomena from an
earthquake caused by a Slipping
f'snreare in mostrespects idenLi'
cal with the last mentioned.
While igneous agencies are the
ptimarycause Of earthquakes, there
are doubtless other things that
have soBe influence, Earth.
qnakes are more frequent when
The moon is in perigree or nearest
the earth, and more frequent in
new thau'full moon. More occur
in July than in any other month.
They are more frequent after long