Hi Ted, George is sadly no longer with us. He worked at the Institute of Geophysics here in Wellington as I recall. He has published a number of books, many aimed at laymen, Earthquakes was published in a revised edition in the 80s. And Volcanoes was published about the time George died which is a while ago now. George was a keen actor, enjoying Shakepearian roles. No idea about the ingenious photoelectric device, but I would suspect some kind of flying spot scanner, with a ramp in sync with the spot being sampled when black paper was seen. A fax machine would be a good start these days. The analogue computer sounds like a work of art. I will endeavour to turn it up. Mark 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 > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>