Geoscience Reference
In-Depth Information
Wood, capable of working only in spurts after 1934, produced many
pages of critical notes that never saw publication. In part, he was testing
out various arguments for the value of felt reports in a high-tech age. Many
of these ideas were incomplete, but they revealed the holes where further
research was needed. “In more recent years there has come about a ten-
dency to neglect [noninstrumental] studies, owing to the rapid develop-
ment and utilization of seismometric instruments and methods.” Wood's
experience had convinced him that the public's observations were generally
sound scientific evidence: “the great majority of persons whose occupation
or temperament renders them observant are well qualified to aid in making
observations and reports.” the evaluation of felt reports required scientists'
“critical judgment,” of course, but the public could also be taught to be
more critical: “Although the reporter or observer who cooperates with the
professional seismologist is not immediately concerned with this critical
evaluation of the data it is well that the situation be made clear so that the
information submitted by reporters may be made as objective as possible.”
Wood also reflected on the scientific value of felt reports. even in locations
that were well covered by seismographic stations, noninstrumental studies
“may indicate with greater certainty the place from which the maximum
energy is radiated—as, for example, when the tract of origin of maximum
vibration is not the same as that where the shaking begins.” even reports
of nausea were not to be discounted, since they could be used to mark “the
margin of perceptibility of a large shock, where other effects are few and un-
certain,” and where ground motion itself might not otherwise be perceived.
Observational reports could also help guide field investigations and record
transient effects. Local variations of intensity deserved close study, for they
might shed light on the nature of surface waves; it was possible, for instance,
“that these do not originate at the exact epicenter but rather at a small dis-
tance from it.” Wood turned at this point to questions of basic geophysics;
as the manuscript reflects, his hand could barely keep up with his train of
thought. In these private notes Wood articulated better than anyone else the
moral of seismology's history in Southern California: “Seismologists (and
those who aid them by supplying reports of observations) are, or should
be, interested in both apparent and 'intrinsic' values of intensity, and study
of the distribution of these values geographically will serve more than one
purpose, now and in future as well as in the past.”
199
Byerly, who lived another twenty years after Wood's death in 1958, con-
tinued to argue this point publicly. During the Cold War, while American
seismology was swollen with defense funding and fixated on the problem
of nuclear detection, Byerly dared to suggest that his colleagues were wrong
