Geoscience Reference
In-Depth Information
Montessus added with a touch of sarcasm that an acceptable international
intensity scale would have only two degrees: felt or not felt.
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in 1900 Charles Davison succeeded in devising a rough conversion
scheme for eleven different scales, including corresponding values of maxi-
mum ground acceleration.
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in 1933, he expanded this to include thirty-nine
scales. By then, however, he had grown pessimistic about the possibility of
settling on a single international scale. As he reflected in 1921, “After an
experience of thirty years in constructing isoseismal lines, i venture there-
fore to suggest that an arbitrary scale of seismic intensity may be of very
considerable service in the study of earthquakes, provided that each degree
of the scale is restricted to one test only, and that personal impressions,
such as those depending on the degree of alarm excited, are excluded. i feel
doubtful, however, whether it would be wise to attempt agreement in the
adoption of one uniform scale in all civilized countries.”
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indeed, a scale with criteria like “chandeliers swing” or “chimneys
thrown down” will not help a seismologist evaluating damage to thatched
huts on Samoa. in Japan, intensity is measured by damage to features of
traditional architecture like stone lanterns and paper-covered sliding doors.
the european Macroseismic intensity Scale of 1998 assumes that for any de-
gree of shaking, the damage will follow a normal distribution: the number
of structures with greater-than-average damage will be roughly the same as
the number that fall at the low end. Such a scale won't work in places where
typical structures (say, California's wooden bungalows) either survive un-
damaged or are wrecked beyond repair. By the same token, in countries
where quakes are typically stronger, scales must be extended at the high
end; in regions of low seismicity, scales must be more finely graded at the
low end. As Davison concluded, “Conditions vary from one country to an-
other, and, so long as those conditions are known and so long as the scale
is expressed in definite terms, it seems to me probable that the gain will
be greater if each seismologist is left free to adopt that scale which is best
adapted to the conditions under which he happens to work.”
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Documenting the Earth
With its information overload, seismology circa 1900 looked poised to be-
come a poster child for the benefits of the “documentation” movement.
in 1895 Paul Otlet founded the international institute of Bibliography in
Brussels for the purpose of “unifying the bibliographic notices relating to
writings of every nature, dealing with all matters, published in every era and
in every country.”
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Otlet's institute was supported by international confer-
