Geoscience Reference
In-Depth Information
the seven-degree scale that Volger had used to classify damage from the
1855 earthquake. forel only intended his scale to be used “while awaiting
more precise observation by standardized recorders,” but it would form the
basis of scales used in Switzerland and elsewhere into the 1960s.
70
Modified
in collaboration with an Italian colleague, the “rossi-forel” scale was by
far the most widely used circa 1900.
71
As part of a carefully constructed sci-
entific vernacular, the rossi-forel scale bears comparison to the scales and
idioms that emerged in the nineteenth century for the observation of winds
and clouds.
72
Cloud taxonomies and the Beaufort wind scale were scientific
tools based on the experiences of laypeople—artists, farmers, fishermen,
and sailors. unlike seismological intensity scales, however, they were not
designed to register the subjective effects of geophysical phenomena on hu-
mans. This peculiarity of earthquake science was decisive.
“The Relationship of Man to Earthquakes”
The rossi-forel scale committed seismology to a culture-bound perspective
on earthquakes. Intensity measures the
felt
effects of shaking and is assessed
primarily with respect to humans and their habitations. It can be used both
to compare seismic events and to identify regions of seismic hazard, but
it is not possible to measure intensity in uninhabited areas.
73
forel's scale
confirmed seismology's dependence on lay participation. In fact, the scale
operated in part by calibrating the reactions of the general public. for in-
stance, degree 6, “Some frightened people leave their dwellings,” versus de-
gree 7, “general panic.” In the Italian version of the scale, degree 3 tremors
were “felt by people who are not concerned with seismology.” By contrast,
a degree 1 quake would be noted only by a “practiced observer” [
exercé,
geubten
]. Word choice was telling: the relevant criterion for such sensitivity
was not expertise but practice. The commission found that weak tremors
were more frequently reported in the wake of a widely felt one, an effect that
seemed too robust to attribute to suggestion. Indeed, the public
could
learn
to observe earthquakes. And scientists could learn to work with their obser-
vations. Hence forel's comment that “this scale will be able to be corrected
once we have more experience in this line of research.”
74
forel's scale reflected the ambiguous status of eyewitness reporters: they
were both scientific observers and objects of observation. Certain construc-
tions suggested that the witness's role was passive. Thus, for instance, the
parallel constructions of “shocks registered by different seismographs” and
“shocks reported by persons at rest” or “by active persons.” other phrases
attributed a degree of discernment to the witness. only a shock of degree
