PSN-L Email List Message

Subject: Re: book "About Earthquakes" (1956)
From: Steve Hammond Shammon1@.............
Date: Mon, 31 Jul 2000 13:43:54 -0700

Hi Ted, I cannot be specific about the account you describe, whoever, I
can tell you about an effort to digitize the paper records on file at
UCLA in 1971-2. At the time, I was one of the on-campus IBM unit record
CE's, and we had an 047 keypunch (card and paper tape output) connected
to a digitizer board in the Earth Science building. Student would spend
their hours taking paper traces from drum recorders and by using a
crossbar sight and following the ink line,  "Click" the location on the
x/y plotting board as each second tick was reached. The resulting time
series data was then inputted into the IBM 360 model 91 in Engineering
and archived to magnetic tape for further study. 

Regards, Steve Hammond
PSN Aptos, California

ted@.......... wrote:
> I came across a copy of this book by G. Eiby of the Wellington (NZ)
> Seismological Observatory.  Written for the layman, it is easy to
> understand and covers a lot of material.  Does anyone know if Mr. Eiby is
> still around?  The book was published in 1956, so maybe not...
> He begins:  "Earthquakes were among the earliest discoveries to be made in
> New Zealand.  Members of Captain Cook's expeditions felt them in the
> eighteenth century, and within ten years of the founding of Wellington, the
> colonists lost their chimneys."   I greatly enjoyed his style of writing.
> One very interesting quote (in this age of digital everything) concerns
> using analog (electrical) models of buildings to assess their earthquake
> safety.  Here's a quote:
> "Most building codes today lay down some definite value of horizontal
> acceleration which a  building must withstand.  In New Zealand, the value
> varies from 0.08 to almost 0.16 G...  This type of code is gradually being
> replaced by a more elaborate consideration of the dynamic characteristics
> of the building, and use is now made of electrical models or "analogues" of
> the structure.  The analogue is an electrical circuit in which the values
> of the components are arranged to give them a response to electrical
> vibrations that can be compared with the mechanical properties of the
> building.  An ingenious photo-electric device then converts the record of
> an earthquake into a varying electrical current which can be passed through
> the analogue, which is [then] studied by the techniques of electrical
> engineering."
> Would anyone have any idea how this "ingenious photo-electric device" for
> converting paper traces into voltage signals might work?  I'm guessing
> there must be some sort of activity in the field of Seismology to digitize
> old paper seismograms, so maybe there are actual commercial devices to do
> the work now.
> Regards,
> Ted Blank
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Larry Cochrane <cochrane@..............>