The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1886-07-13
Origin Of Earthquakes.


Extracts from paper " On the probable origin
OF earthquakes" read before the Paris ACADEMY
OF Sciences, 22nd of March, 1885, by NJ. Oh. LalIe-
mand, lngenienr de L'Ecole des Mines, Paris.)
TRANSLATION.
All these facts, which have given rise to nu-
merous theories, indicate incontestibIy the exist
ence of an interior permanent and universal force
This can hardly be explained without calling in
the old hypothesis of a central fluid nucleus
which has been upheld In France, especially by
Ellie de Beaumont
In the course of mission in Italy, directed by
Nd. de Chaucourtas, for the study of chronological
questions, have considered the possibility of
connecting seismic phenomena with recent and
ingenious theory of the form of the earth, due to
NJ. Lowthian Green,+ according to which the ter
restrIal globe should have taken, in cooling, a
general form derived from the tetrahedron This
hypothesis is justified in my opinion, by this fact
that of all the regular solids, the tetrahedron is
that which embraces the smallest volume under a
given surface and which, consequently required q
minimum of contraction for the crust. "
" The four grand depressions occupied by the
Indian, Atlantic, Pacific and Arctic oceans would
form the faces OF this tetrahedron, of which the
three angles Tor edges directed towards the south
would be represented with sufficient correctness by
the African, Australian and Southern Continents
which, all three, terminated by point to-
wards the south.
Just as the tetrahedral figure developes ITSELF
the three projections of the northern hemisphere
became removed from the line of the poles, the
axes Oh rotation, whist the regions towards Inc
south approach 1t the first are thus found to
have had speed of rotation smaller than the cor
responding points of the primitive sphere and
would remain Ell TetGrd In the movement of rota-
ton of the EARTH whilst the lands of the southern
hemisphere, preserving an excess of velocity,
would take a position IN advance, or towards the
east.
Such would be- according to Mr.. Green, the rea-
son why the lands of the southern hemisphere are
all thrown towards the east compared to the
northern continents, of which they form the pro-
longations.
Another result of this species of torsion of the
tetrahedral solid about its axis would have been
the production in the neighborhood of the equator
of set of depressions occupied to-day by the
Mediterranean, the Red Sea, the Persian Gulf, the
Eastern Archipelago and the Gulf of Mexico
which seperate the northern reliefs from their
prolongations towards the south.
According to Mr.. Green, the tetrahedral figure
would still continue to be produced the mountains
would be raised more and more, whilst the oceans
would increase every day, a fact which the most
recent geological observations seem to confirm.
Earthquakes seem to me to be explained quite
naturally, if we admit this theory.
The contraction resulting from cooling would
have had in fact, results, at first foldings mas
much as the crust was then plastic; then, later,
fractures, when it became more resistant.
The regions adjoining the edges and above all
the submits of the tetrahedron, those where the
crust has suffered the greatest deformations-
would have been, with the grand intercontinental
depression, the principal regions of those fractures
of least resistance, ready to yield to the first
effort.
With the progress of the cooling the old frac-
lures would open and be thus heightened farther
away.
Earthquakes, like volcanoes, would then be
only secondary phenomenon, indicative of the
incessant work which is going on under the crust.
They would thus have as their principal foci,
the continental masses of the northern hemisphere
with their southern prolongations, and above all
the zone occupied by the Mediterranean, the Per-
sian Gulf, the Eastern Archipelago and the Gulf
of Mexico; which seems to accord well with the
realitvs
We may easily conceive besides, that in the
neighborhood of the equator and in all the tropi-
cal zones, the existence of interior luni-solar
tide might become, at certain moments, the de-
termining cause of the rupture of equilibrium.
Thus are explained the greater frequence of earth
quakes in equatorial regions, and their increase
clearly observed the approach of the equinoxes,
in accordance with the great tides of the ocean,"
*Yestiges of the molten globe, London 1875 This
theory has been explained by M. de Lapparent in
article entitled The symmetry of the terrestrial globe
Brussels, 1882.
- have obtained an experimental Yerifcaton by
producing gradually vacuum in rubber balloons -