Geoscience Reference
In-Depth Information
Dutton had stumbled into a hole that would ensnare many more Amer-
ican seismologists in the future. He had failed to appreciate that felt re-
ports contain more than just geophysical information; they are not mere
substitutes for instrumental observations. Oldham was right to fault Dut-
ton for “misusing words.” exploiting felt reports required attention to the
observers' own language. it depended on the consistent use of a scientific
vernacular.
“The Trouble with Holden”
Among the small number of scientists who shaped the development of seis-
mology in California, astronomers were remarkably well represented. They
brought with them an expertise with measuring instruments, a distrust of
naked-eye observation, and a disinclination for field research. These individ-
uals included George Davidson, W. W. Campbell, Charles Burckhalter, and
A. O. Leuschner and, last but not least, edward Singleton Holden. Holden
was a Saint Louis-born astronomer with no background at all in geology. in
1885, at the age of thirty-nine, he moved to California to become president
of the University of California, and in 1888 he became the first director of
the Lick Observatory, near San Jose. it was astronomy that piqued Holden's
interest in earthquakes because of their tendency to disturb his telescopes.
(in much the same way, astronomers were led to study meteorology in or-
der to foretell favorable observing conditions.) At the Lick, Holden decided
that it was essential “to keep a register of all earthquake shocks in order to
be able to control the positions of the astronomical instruments.”
72
To do
so, he furnished the Lick and several other locations in the San Francisco
area with ewing duplex seismometers—an apparatus held stationary by two
coupled pendulums, relative to which horizontal ground motion was au-
tomatically recorded on a smoked glass plate. He also began to compile
a list of California earthquakes reaching back to the eighteenth century.
He drew not only on newspapers and published catalogs (including those
of Rockwood and Trask), but also on informers like the California state
mineralogist H. G. Hanks, the San Francisco instrument maker Thomas
Tennent, and the historian H. H. Bancroft,
and on “verbal accounts from
various gentlemen.”
73
Like several of these predecessors, Holden seems to
have embarked on his research already convinced that California's earth-
quakes were nothing to be feared. “When we take into account the whole
damage to life and property produced by all the California earthquakes, it is
clear that the earthquakes of California have been less destructive than the
tornadoes or the floods of a single year in less favored regions.”
74
Holden,
