Geoscience Reference
In-Depth Information
years,” Wood wrote, “though places of residence in this part of the country
were not numerous and were separated widely for the most part, yet the
local earthquakes which were felt in those years were put on record about
as well as could have been expected. In the last few decades, however, these
happenings have not been recorded adequately. this is true especially of
very weakly felt shocks which are, perhaps, more significant and interesting
for serious seismologic studies than many of the shocks of greater energy.
they tell us more definitely what they have to tell.”
146
Felt reports could
do more than supplement and corroborate other forms of data; they also
held “practical value of their own which in some respects possesses
more
immediate importance
than much of the more fundamental data of survey
and measurement.” Wood urged the formation of “permanent groups of
cooperative observers, comprising from one person to a half-dozen per-
sons in a given place . . . made up of people who will agree to make report
upon
all earthquakes
which come to their notice in their vicinity, whether
felt by themselves or by others.” Of the utmost importance, Wood stressed,
was that each and every shock be reported: “those who make use of the
assembled reports must feel confident that, on any given occasion, no
earthquake came to notice in the locality of the observer, if no report is re-
ceived from him.”
147
What was needed was a permanent network of vigilant
citizen-observers.
As Wood complained to his Berkeley colleague Perry Byerly in Septem-
ber of 1927, he had “at present no mechanism for obtaining reports effi-
ciently.”
148
At that time Wood was relying on the Coast Survey to distribute
questionnaires following shocks. that november the survey's director Lester
Jones telegraphed Wood: “not ready to obtain reports on recent earth-
quakes. Hope to have plan organized soon.” As Wood admitted to Byerly,
“I have no machinery for gathering reports other than this.”
149
It turned out
that Byerly was already in the habit of sending out questionnaires after each
shock in northern California. He had “learned that speed is essential.”
150
Wood's own stock of questionnaires from 1924 had unfortunately been
“destroyed.” He asked for Byerly's advice on designing a new form.
151
Wood
thought it best that they share a standard questionnaire. Over the next three
years, the two men frequently traded ideas for improving their reporting
forms. Wood sent Byerly a draft in March of 1928 with the request to “criti-
cize it as savagely as you please.”
152
they agreed that brief postcards should
be used for assessing intensities and epicenters. Full-length questionnaires,
on the other hand, would ask for more detailed information, such as ac-
companying sounds and the direction of shaking (if felt outdoors, to avoid
the distorting effects of buildings). they sought the aid of ordinary citizens
