My experiments with volcanoesJaggar, Thomas Augustus
Science
My experiments with volcanoes
Jaggar, Thomas Augustus
Geologists -- Biography; Volcanoes
It was evident that hard lava push-ups from the bottom of craters were
characteristic of the Pacific and Carib shores, in contrast to Hawaiian
and Italian flow-downs. The pressure upward breaks a mountain, the slag
and boiling groundwater inside churns up avalanche gravel and dust,
columns of dust-laden steam rush out, the break-up lets up lava, and
according to its frothing gas and heat and the air temperature, it is
capable physically of either foaming out liquid through radial cracks
or pushing up semisolid and piling as an aa heap.
The net effect is flat lava shields for Hawaii, with flows into and
under the ocean, and shapely high cones for the Andes and Japan, with
Italy somewhere in between. The difference in the lavas is a matter of
internal meltability, due to chemistry and gases.
In the first decade of the twentieth century this was new to me as
a geologist, for the books did not explain internal gas in lava.
Geography understood nothing of the relation of a volcano to lines
of cracking earth crust and depth of crust, and gigantic explosions
dominated history as exceptions. Refractory slags were then believed
to be stiff by reason of chemical fusibility, and gas in solution in
a melt is not understood even today. The Japan journey explained the
textbook contrast between oceanic Hawaii and continental Ecuador, both
volcanic, and the further contrast with Yellowstone agglomerates, and
intrusions of the Black Hills of South Dakota. Clearly Hawaii must be
studied, and experimental geology extended to the globe as a laboratory.
On my return to Honolulu, Professor Ralph Hosmer, forester, met me and
reported that Honolulu money was available, if Massachusetts Tech would
send me to Hawaii to found a volcano experiment station. Then and there
the Hawaiian Volcano Research Association formed by business leaders
in Honolulu became a reality, to crystallize later into an educational
corporation.
In 1910, while I was still a professor at Massachusetts Tech, the
United Fruit Company invited me to go in one of their ships to study
the earthquake destruction of Cartago, Costa Rica. I saw an opportunity
to study seismology in the field, as I had studied volcanology in
Martinique. The United Fruit Company owned the railroad and much of
the national debt of Costa Rica. F. R. Hart, treasurer of M. I. T.
and director of the fruit company told me to make my own plans and
the company would pay all expenses. Knowing that engineering is of
first importance in earthquake disaster, I invited Professor Charles
Spofford, head of our Civil Engineering Department, to go with me, and
he promptly accepted.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account