Geoscience Reference
In-Depth Information
Conclusion
By the second decade of the twentieth century, international seismologists
were announcing the arrival of the “new” seismology, ushered in by the
latest seismographs. The Swiss, by contrast, insisted that instruments could
never furnish complete knowledge of an earthquake. As the director of the
Swiss earthquake service argued in 1914, “In and of themselves instruments
do not give the complete picture of earthquakes as a natural phenomenon.”
By then, the observational network, human and instrumental, had out-
grown the capacities of the Swiss Natural Scientific Society. Between 1912
and 1914, it was transferred to the federal meteorological institute in Zurich,
but every effort was made to maintain continuity—to ensure, in particular,
“that also in the future full attention will be paid to the macroseismic data,
for which the original instructions and questionnaires of the Earthquake
Commission today still contain all essential points of view and guidelines.”
Scientists would still need to recognize and accommodate the uncertainty
and cultural specificity of human observations: “It must be remembered
that the earthquake map, which must be constructed essentially according
to individual perceptions, will display an anthropogenic character—that is,
it is in many respects a representation of the population density and of the
culture of the inhabitants. . . . Therefore it is best in the descriptions to re-
place certainty and confidence with possibility and probability.”
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A decade
later, the next director of the earthquake service was still arguing the same
point: “one must still begin with the careful collection and analysis of the
observations that have been made directly by man. . . . They will need to be
tended to in the future as well.”
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far from disqualifying human observations, the development of seis-
mography revealed new layers of meaning. It allowed Swiss researchers to
trace “parallels between the results of the instruments and those of the ob-
servers,” above all in the telltale sequence of longitudinal and transverse
waves. Close comparison of observers' descriptions and seismographic
curves showed “that in the subjective observations these facts have always
found expression. It seems that relatively close to the area of greatest shak-
ing in our land both waves are often felt as temporally separated and dis-
tinct shocks.” If, as experience suggested, observers could indeed count the
seconds between the arrival of the “vertical” and the “horizontal” shocks,
this figure could be used to calculate the depth of the focus. “As evidence for
the manner in which the different types of wave in the epicentral region are
actually perceived by observers at rest, I quote deliberately a very old obser-
vation, that of Pastor Studer during the great Visp earthquake: he writes: 'I
