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in italian but not in French. Degree 6 specified in French that “a few fearful
people leave their houses”; in italian that people exited “due to fear or pru-
dence”; the italian alone further specified that in describing the shock people
would mention “that fortunately there were no damages.” Not surprisingly,
the French version was the one most often cited as “
the
Rossi-Forel scale,”
thanks to the language's cosmopolitan status. Charles Davison judged it
superior to the italian scale, but that was probably beside the point. in 1903
the iSA resolved to develop an international scale of seismic intensity, but
candidates emerged slowly.
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Few members had acquired as much expertise with the international
measurement of intensity as August Sieberg, secretary of gerland's Stras-
bourg observatory. By virtue of “processing a vast amount of macroseismic
observations, collected from people of the most varied education levels
throughout the world,” combined with on-site inspections of earthquake
damage in italy, Sieberg felt ready to propose a new scale for international
use in 1912. One drawback of earlier scales, in his view, was the brevity
of their descriptions of observable effects. “i cannot fathom the considera-
tions behind this terseness; in any case it has proved in practice to be the
greatest obstacle to an effective use of intensity scales.”
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he also called for
more detail in the questions posed to observers. the questionnaire should
suggest typical, recognizable earthquake effects; otherwise novice observers
answered the bare question “effects?” with “None.”
Sieberg cautioned against including human injuries or emotional ef-
fects as criteria, but he could not dispense with them. indeed, his scale is
remarkable for the care with which it describes psychological and socio-
logical phenomena. For example, degree 1 stipulates a shock not felt by
people, “however once the registration becomes known, individual people
report that they purportedly felt the quake.” Degree 2 notes, in keeping
with Davison's research on “the effects of observers' conditions”: “Only a
few people finding themselves completely at rest, specifically those with
sensitive nerves, noticeably feel the quake in the higher stories of houses,
while on the ground barely anyone is conscious of it. the quiet of the night
is also more favorable to perceptibility, if the observer is awake.” Degree 3
specifies: “many only recognize afterwards, through the mutual exchange of
ideas, that they were dealing with an earthquake.” And degrees 4 through 6
distinguish among different levels of panic:
4: “this movement almost never induces terror, only if the residents have al-
ready been made nervous and fearful by other earthquakes.”
5: “in isolated cases the inhabitants flee their dwellings.”
