Iditarod pioneer. (Iditarod, Alaska) 1910-19??, 1912-06-15
Volcanoes and Earthquakes:
Their Relation and Attendant Phenomena

The causes of volcanic action are
still much obscured, though various
explanatory theories have been nd.
vanced. The view now most generally
accepted is that internal heat. which
increases towards the earth's center,
causes the evolution of q great body of
elastic vapor, which expanding and
seeking an outlet where there is the
least resistance, manifests itself in the
upheavals and explosions of an erup-
ton. The body Of vapOr is thought to
be derived from the snperti :ial mass of
the earth, become hydrated, or com
bined with water. Such action as well
as the presence Of the molten rock
known as lava, is accounted for by vast
internal displacements. bringing the
inner crust, with its high temperature,
nearer TO the surface. Volcanoes are.
in general, to be found in areas where
the earths crust is of an inferior
strength, These areas are naturally
ocean basins, the territory bordering
on such basins, or the ranges of noun
tains marking or Ranking the outlines
Of the continents. With the possible
exception of Wrangell, Alaska (having
reference to the mountain, lt,00g feet
high, east of Copper river, near lai-
tude " deg, J, no active volcano exists
far inland save in a district which is
either the scene of a comparatively
recent displacement or is marked by
an instability in the earth's crust. One
of the chief lines Of distribution sur
rounds the Pacific ocean, running along
the western coast of South, Central
and North America: the Aleutian
islands. Kamchatka and The Kurile
group; Japan, Formosa, the Philip
pines. the Mo!uccas, the North Heb
rides, New Zealand and South Victoria
Land. Numerous phenomena are ac-
cessory to volcanic Disturbances, nota-
bly, earthquakes, electric, magnetic
and various acoustic manifestations, Of
the latter a very marked instance be-
ing on the night of the It'll of the
present month, when for nearly two
hours at short intervals explosive
sounds were heard in Iditarod--a dis
lance Of at least 800 miles in a straight
line from the scene of volcanic activity
the Ou1d5 at the time being generally
attributed TO blasting operations, but
in reality more closely resembling the
detonations from heavy gunnery a mile
or two distant.
The relation of volcanic action to
earthquakes has been recognized since
the days of Aristotle, Strabo and Piiny,
but it is only in recent times that in
such relation with considerable fidelity
to detail. Ii is found that active yolca-
noes are confined TO The margins of the
seas or to the seas themselves, from
which it is argued that leakage of sea
water into the hot interior Of the earth
causes the generation of great quanti
of this steam pushes masses Of molten
lava far back under the earth away
IRON The vicinity where the force orig
mates. and this causes earthquakes
distance away from The sea to which
volcanoes DO not approach. The erup-
ton of volcanoes always relieves the
pressure and such earthquakes cease.
On the other hand earthquakes 50
caused are not always followed by VOL
car ic eruptions, because the steam
pressure is relieved by the formation
and movement of faults in the earGh's
crust, or escape through ifs ureS, most
commonly in the floor of the sea. where,
upon abatement of the pressure be-
meath, the assures would close. AS
Witnessing one effect of volcanic pres
sure, it is noted that in the great
earthquake of September 1918, 1899,
the coast Of Yakutat bay, Alaska, was
elevated II feet inches, and the ele-
walton extended for more than 100
miles, with small depressions in few
places. Moreover, Prof. H. d. Curtis,
of the D. O. Mills expedition of Lick
Observatory, at Santiago, Chile, re-
ports that the late Valparaiso earth
quake raised the coast 10 feet. Similar
known instances are quite numerous.
The seat Of the disturbance felt and
heard in the Iditarod last week may be
the Hanna volcano. l2,066 feet high,
on the west coast of Cook inlet. 1t is
known to be "alive.'
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