Alma record. (Alma, Mich.) 1878-1928, 1886-10-22
SEISMIC DISTURBANCES.
a Subject that Has Been Care
fully Studied Only During the
Last Thirty Years.
Duration md Velocity of Earthquake
Shocks Their Relation to VOL
canic Eruptions.
Unreliable signs.

SIX hours ut the south, especially in the
stricken city of Charleston, :. c., is the
severest that has been felt on the east
crn coast of America during the present
century, writes w. lie Contc Stevens in
The hc,O York World, and scarcely, if
st all. surpassed in violence by any on
the Pacific coast of our continent Its
elect seems to have been felt over
nearly the whole area of the United
States east of the Rocky mountains.
The intense popular interest just now
excited in phenomena of this class
makes It important that brief general
discussion of earthquakes be given in
connection with the recital of these ter
rible events, that will be remembered
throughout the lifetime of all whose
homes have been desolated or whose
friends have been exposed to peril.
An earthquake is commotion pro-
pogatcd through the earth's crust in
all directions from some source Of dis
turbance. in waves that outcrop on the
surface and are man tested in percepti-
bic motion of the ground. They vary
in intensity from gentle tremblings. re-
curing delicate instruments for their
detection, TO commissions of terrific vi
olence. capable of destroying the most
substantial products of human labor.
During the last thirtyyears the study
of earthquakes has been developed
into a special branch of science, TO which
the name seiSmology has been given.
The first man who gave the world any
reliable scientific discussion Of such
Phenomena was Mr.. Robert Mailct. of
England who visited Naples immcdi-
ately after the earthquake which de-
vaNtatcd southern Italy in 1851 In his
subsequent labors he received impor-
tant aid from his son, DR.. John w.
Mallet. whose name has since become
prominently associated with the pro-
gresS of chemical science in America.
The number of investigat ons in recent
years has been greatly multiplied. In
strumcntS have been devised for meas
uring the intensity Of shocks and Of re-
cordIng the direction and res STEERING
the time of transit. In regions where
earthquakes are of frequent occurrence
such seismomctcrs are distributed at
many points and kept in constant read
mess. Ii is from systematic records
\ from these that we derive our most I'M
portant information today.
America is fortunately not often
shaken. and the number of eismomc-
tiers kept in readiness in our country is
too small 10 assure Us of accurate
knowledge regarding the recent shock.
Earthquakes occur in all parts of tho
world, but are most frequent in noun
famous regions, and especially those of
volcanic activity. In many cases the
shocks are directly the consequence Of
volcanic eruption. bat they occur also
in places and under circumstances that
indicate not the least connection with
volcanocs. Tbs seem, to be true Of
the recent Charleston earthquake.
The Andes region Of South America
and the southern part OF Italy include
some Of the worst shaken districts in
the world, and some of the most active
volcanoes. But among them earth
quakcs often occur without the exhibi-
ton Of any unusual volcanic activity.
The earthquake which was so destruc-
tive to life and property 4 few days
ago in Greece and Italy was imme-
diately followed by commotion in the
crater Of Ncsuyius. 1t is safe TO say
that the same cause may give rise to
both volcanoes and earthquakes, but
neither of these implies the other nee
essarily. The Iimalayas and table
lands of Central A,ia are subject TO vi
olent earthquakes. but almost free
from volcanoes. The Alps and Pyre-
nec' arc f EN- 81 aien, but include no
volcanoes that are not extinct. The
same is true Of the American Pacific
coast range south Of the Columbia river.
Non-volcan G basins, such rs the val
ley Of the Mississippi and the basin of
the Baltic sea, have been roughly sha-
ken. Earthquakes are most rare in
Russia. which consists mostly of low
plain free from mountains.
The region most shaken within the
past two days is near the southern ex-
tremity of the Allegheny range. 1t is
too early yet to foru any reliable esti-
mate of the point where the disturbance
originated.
Mr.. Mallet collected catalogue of
between 5000 and 1000 earthquakes
recorded between the periods b. G.
-S606 and A. ID. 1850. This is obviously
mere fraction of the number that oc-
Cured between those dates. Since
1850 the number of earthquakes record
ed has greatly increased, though there
Is no reason to believe that there is any
increase in actual frequency of shocks.
By the use of sesmometers in Italy,
Japan. and elsewhere it has been prov
cd that in such regions scarcely day