Vernon County censor. [volume] (Viroqua, Wis.) 1865-1955, 1906-07-18

There have been not few uniusti.
fed sneers at science because of the
widely discrepant theories evoked in
newspaper interviews with experts as
70 the cause of the earthquake. Seis
raology is a young science, with much
yet to accomplish, but it is not so en-
tirely chaotic as compilation of these
incompatible views would indicate.
Vesuvius the cause? Certainly. Ger
tainly not! l am not prepared to say.
The cause was a fault It was sim
ply combination Of an earthquake
and a seaquake. 1t was caused by
sunspots. 1t was due to the shrinking
of the earth's crust.
And as it goes; there is no limit to
the variety of opinion that can be ex.
tracted by he simple process Of ring
| ing doorbeIls. The methods of science
are more deliberat , and in the course
of time more will be known. That
there are so many shades of opinion is
due to the fact that there are various
types Of earthquakes. The results are
essentially similar whether the Initial
shock comes from volcanic action or
from the sudden fall of a large area OF
earth, and the seat of the disturbance
is ordinarily so far removed from d.
rect observation that 1t can be discov.
cred only by scientific inference.
II is to be noted, however, that the
/ nV4F ~ IL N.
Perrey's celebrated tidal theory, by
which the cause was the action of the
moon upon the hypothetical liquiu
mass of a molten interior. His laws
as deduced from statistics, are Cd
that earthquakes are more frequent at
new and full moon, ~ when the moon
is approaching its least distance from
the earth, (3) when the moon is near
the meridian. His statistics showed
that rather more than half of an OBJ
served series of quakes occurred when
the moon was within As degrees Of the
meridian. At San Francisco the moon
must have passed the meridian by
rather more than so degrees when th5
shock occurred. The discrepancy
would not be very serious If the other
laws were observed, but as a matter
of fact the moon approached apogee
april 24) and not perigee april 81,
and lacked five days of being new.
Thus the earthquake does not conform
In any particular to Perrey's so
called laws. which have received from
scientists more laborious investigation
than they perhaps merited, because OF
rather striking table of percentages
which more extended observation has
discredited
Many references have been made to
the gcgde of the earthquake, and some
misapprehension has been shown as TO
the nature of such scale Costly ana
delicate as are the instruments of the
laboratory, they do not as yet serve
for measuring intensities. Just as Il
is still necessary to depend on the eye
for measuring the magnitudes of stars,
the magnitude of earthquakes must be
estimated in merely popular way,
and the efforts of scientists thus FAR
have been to find some clear tests
that can be generally applied with
minimum of ambiguity. The standard
scale is that devised 80 years ago by
Trof. di Rossi of Rome and Prof Forel
Of Geneva. The ten grades are as
follows
~ Microseismic; felt only by deli
cate instruments.
(2) Extremely feeble; felt by a
few persons at rest.
(3) Very feeble; direction or dura-
ton appreciate.
a. Feeble. felt by persons in mo
ton; doors and windows rattle.
(5) Moderately intense; felt by all:
furniture shaken.
(6) Fairly strong; sIeepers wake;
small bells ring; clocks stop; trees
are agitated; some persons leave their
dwellings.
% Strong; plaster falls; church
bells ring; general panic, without dam
age to buildings.
90 Very strong; chimneys fall;
walls are cracked.
(9) Extremely strong; some build
ings destroyed.
(10) Extremely intense; great dis
aster; assures in the ground; rock
falls from mountains
The Rossi-Forel scale has been crit
icised on the score that it overrefnes
in the case of feeble shocks, and does
not grade closely enough the destruc-
tive earthquakes Several scales
have been prepared 10 correct this de.
feet. among them being the MeTcalnI
scale which is used in Italy The
seventh degree nearly corresponds
with the eighth above, and the remain
ing three are
(S) Ruinous; fell with great alarm.
partial ruin of some houses, with lit.
tie or no loss Of life.
90 Disastrous, with complete orI
nearly complete ruin Of some houses
and serious cracks in others; a few
lives lost.
(10J Very disastrous, with ruin oil
many buildings and great loss Of life,
cracks in the ground landslips FROM
mountains, etc.
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