Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1892-10-21
CAUSES or EARTHQUAKES.
Are They Produced Through the shrini
are lof the Surface of tha ciry,.Y

are Ihoy Proauced Through the Shrink
age nj the Surface of the Globe9
} Without doubt the consensus OF judy
ment among physicists is that earthquakes
result from the shrinkage of the surface OF
. the earth from the ceaseless dissipation OF
its heat into the cold of space As this
loss of heat progresses strains are inaugu-
rated throughout the surface Of the earth.
and on account Of that surface being of TIM
equal strength there arrives moment
when breakage of a portion of the sur
lace takes place along the weakest portion
thereof Every miner is familiar with the
faults" which he encounters in the line
OF bis drifts, and rarely can he tell whether
| the continuation Of his vein is above or be-
low him when he comes to bare wall at
the abrupt end of his vein II Is we'll
known to biologists that the faults are Of
extraordinary depths, AS shown in the
region cut through by the canyon OF the
/ Colorado
The phenomena attending these great
descriptions are weakly exhibited In the
earthquakes of today, when small tlisloca-
lions occasion comparatively great results.
In the great earthquakes In Japan, nota-
piy In that or 1881, and In great earth
qnakes along the Andean coast Of South
America, there have been relatively small
but little change OF the surface Of the
earth. Nor has there been any exhibition
Of forces in these earthquakes that cannot
be explained en- the theory OF the rupture
OF g relatively very small area Of the earth's
surface.
In the great earthquake OF Krakatoa. a
lew years since. there was an unusual ex-
Intuition OF explosive forces accom- panvinv
the disruption of the surface, when vol |
canic Agencies blew up half OF high
rocky isiet and left great depression be- I
low the surface Of the water. There bn4
been no such other exhibition ia mod, ru |
times. for the material of the islet and the !
submarine material was projected into /
The higher atmosphere in very minute !
particles, and gave rise to the extraordi- 1
pary exhibition OF the beautiful red skies
Visible near sunset. This matter WINS car
Red around the whole earth in the higher
The mechanical theory Of heat will read
hy explain how great disruption Of tbs
earths surface may produce all the phe-
nomena OF volcanic action when the condi-
tions of the material and the extent OF the
rupture are invariable. Imagine what
must have been the intensity OF heat de-
veloped when faults OF one mile deep were
formed, and the terrible friction Of two
surfaces OF such great extent were in
vowed we can only approach the SUBJ
lect ny the mathematics of the theory of
heat, and certainly not by any experience.
Along this coast the lines of rupture of
the weak parts OF the earth's crust are
shown In the depression Of the plateau of
the Pacific ocean bed and the parallelism
of at least four lines OF coast mountains
and the great backbone of the Sierra Ne
vada and Cascade range. And these lines
and the closely adjacent country must be
The seat OF seismic changes, as the earth
loses its heat. We have the
evidence clearly before us that along the
line OF rupture OF these ranges there have
been many overfiows OF lava forming the
basaitic layers visible in the Sierra Nevada
In certain localities. and especially In the
many overflows along the northern part of
the Cascade range
The dynamical theory accounts for these
resultant exhibitions, and il is easy To
imagine that there must have been many
other concenitant exhibitions of electrical
aud volcanic forces. In the great chain of
the Aieutian Islands, where so many ex.
Sinct and active volcanoes exist. everv
earthquake along this weak line in the
sarth's surface IL accompanied by renewed
ictivity IN the living volcanoes, and IL NAV
De safely assumed that all the phenomena
nay be traced to the contraction and rnn-
iure OF some part Of the surface or ernst
rom the ceaseless but slow cooling of our
planet. Professor George Davidson in San
Examiner