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intensity' in a technical sense throughout this report.” “Intensity” as used
in the report was “arrived at by applying
literally
the criteria of the Rossi-
Forel scale,” a remark echoed later in the discussion of the plotting of iso-
seismals.
31
Clearly, the investigators did not appreciate that the Rossi-Forel
scale and its relatives exist solely in order to be applied
literally;
their criteria
derive from the reports of ordinary observers, as codifications of typical ver-
nacular reports. One researcher was even assigned by Lawson to determine
a coefficient for converting “apparent intensity,” as reported on alluvial sur-
faces, to a “real intensity” corresponding to some ideal terra firma.32
32
It was a
quest that California's seismologists would pursue fitfully for the next three
decades.
Despite such hesitations, the commission's final report consists in large
part of the stories of survivors. It is two volumes and over six hundred
pages of field observations, eyewitness testimony, photographic plates, and
theoretical synthesis. As the British seismologist Charles Davison noted in
1925, “no report on any previous earthquake has been issued on so liberal
a scale.” the first volume, all 450 pages, is sold as a paperback today with
a full-color cover view of sailboats on a rocky bay. the report synthesized
observations from no fewer than three hundred individuals. As Davison ob-
served, “Whenever possible, they have been allowed to speak for themselves
in short notes and papers, so neatly worked into the text that, in reading
it, there seems to be no breach of continuity.” In this way, the report was
able to follow the effects of the quake all along the San Andreas fault from
the Mexican border to the Pacific. As Perry Byerly would note years later,
“the earthquake itself had a certain simplicity—one unbelievably long fault
which over much of its length was a single surface break.”
33
the Lawson
report has since acquired iconic status. It is perhaps the single best instantia-
tion of ernst Mach's ideal of complete knowledge of an earthquake.
Rebuilding a City and a Science
Lawson's commission had every right to expect that their massive research
effort and meticulous survey of structural damage would lead once and for
all to a reform of construction practices in the Bay Area. What they didn't
foresee was the continuing strength of the boosters. In the logic of capital-
ism, destruction was conceived as an opportunity for modernization, not
for pausing to take stock.
34
the policies of the insurance industry also pro-
moted the continued denial of seismic risk. Insurers refused to pay claims
for damage resulting from the earthquake, defined as an “act of God.” Prop-
erty owners therefore claimed that damage was the result of fire. Already
