John-
    This is a very interesting email.
-Edward

"John R. Evans" wrote:

> Doug,
>
> Thank you for your enthusiastic and thoughtful response to
> my e-mails on the ICS-3028 accelerometer design.  By Cc: of
> this e-mail, I'm soliciting key colleagues' thoughts on the
> issues.
>
> YES, the thought of gillions of strong-motion sensors on-line
> is extremely interesting to us.  Indeed, we've been nurturing such
> fantasies for some time, and are in the process of working toward
> a "big science" solution (well, big for us anyway).  But we would
> also be very interested in a good small-science/amateur solution,
> to augment any array we might eventually build.  PSN and similarly
> interested folks could make a truly valuable contribution, given
> the extreme spatial variability of shaking strength, the need for
> detailed data to test models and improve building codes, and the
> skills and dedication shown by you folks over the years.
>
> A suggestion:  I could try to get some official "outreach"
> money or even a little internal "Team" money (we're talking
> small dollars and moderate staff time) to create a 3-accel
> redesign and make a large purchase of these boards possible.
> USGS could buy that bunch of boards and make them available
> to those showing serious interest (PSN, high-school science
> teachers, etc.).  As you point out, the board is the hardest
> bit to do in small quantities.  I'm sure between you and other
> PSN members, the appropriate software will follow shortly.
>
> (Also, there may be a commercial solution not too far off, I'd
> guess for in the neighborhood of $1000, but nothing is firm.)
>
> You and like minded folks could then make a group purchase of
> the other parts.  (ICS is in Milpitas, and they sell through an
> EG&G building in Santa Clara.  They take Visa and doubtless other
> forms of green.)  The only other hard parts to find are the low-
> value trimming resistors (must be metal film, should be low Ct,
> should be low wattage to fit the board and keep leads short, as
> must be).  I have the start of a comprehensive collection here
> and we might find a way to help each other make a more extensive
> central stash for all to draw from.  There may be a significant
> advantage in buying the Op Amps and thermistors in bulk too, and
> you might want to buy a bunch of mounting blocks from a machinist
> somewhere.
>
> Yes, that's three acceleration channels and one temperature.
> The design does not compensate for temperature variation of
> sensitivity (too noisy), which is done digitally in the data
> collection system (ICS supplies the needed, serial-number-
> specific coefficients).  I have software to help select pairs
> of compensating resistors from any pool, by the way.
>
> We would offer guidance on siting to get "free field" sites.
> Basically, anyone with a one- or two-story wood-frame house
> and a garage, utility room, or outbuilding with a grade-level
> slab (and no basement beneath) has a nearly ideal spot--one
> we've had our eyes on for several years.  Such structures are
> light and have little effect on the seismic signal (i.e., they
> have minimal "soil-structure interaction").  The accelerometers
> need to be rigidly affixed to the slab, preferably away from
> large noise sources like washing machines.  They also need some
> insulation to keep air circulation down and slow the temperature
> changes.  Any decent chunk of urethane foam will do the trick.
>
> My schedule these days is totally nuts, but this is something
> I could probably fit in over the next year.  Alternatively, I
> could give guidance and let someone else do the legwork of the
> board re-design.  Indeed, the notion of making kits available
> might get PSN's interest?  (Anyone out there interested in
> making a single-board with 18-bit ADCs on it too?)  In any
> case, someone else will have to do any resistor pulling from
> the central stash (I can't afford to offer my time for that,
> but we could at least build upon my existing $1200 stash).
>
> We already accept Internet reports of MMI (Modified Mercalli
> Intensity--observations of local earthquake effects/damage) so
> adding a semi-secure port for shaking metrics would probably be
> straightforward.  We would be interested in shaking metrics (peak
> accelerations, peak velocities, etc.--we can help with software)
> in the first minutes after an event to help build our ShakeMap
> images.  We would be extremely interested in the waveforms too
> (after a few hours or days) and could be a good release route
> for those data, if you desire.  That availability could make the
> waveforms very valuable for the structural engineering community
> as well, though they are a very conservative lot (since they can
> be sued if they goof).  Appropriate caveats would have to be
> attached to the waveforms ("amateur generated--use at your own
> risk" or something like that).  I think it would be worth our
> investment in software if there were hundreds or more of sites.
>
> Realize that I'm not yet able to offer an "official" proposal.
> This is part of the discussion that could lead to a proposal
> within the USGS to do some or all of what I suggest here.  It
> would help for that process if you got some firm measure of the
> number of folks with serious, immediate interest, at least in
> PSN.  Given our various experiences with asking for help siting
> our own instruments, I suspect there would be lots of interest,
> with the main negative the need to build and maintain it
> yourself.
>
> I don't know why Guralp is non-responsive.  For PEPP, contact
> Prof. Robert Phinney (rphinney@...............  Bob can point
> you to the right person to answer your questions.  (Bob:  any
> thoughts on bringing PEPP into this to make strong-motion
> available to science teachers?)
>
> Best wishes,
> John
> jrevans@........
>
> -----------------------------------------------------------
>
> Doug wrote:
> >
> > On Thu, 26 Aug 1999, you wrote:
> >
> > > I have a design for a good but relatively inexpensive (ca.
> > > $500 parts for three components) strong-motion sensor.
> >
> > This is excellent. Thank you for the information.
> >
> > I took a look at the report and component listing, and it
> > looks really interesting.  But I am wondering how hard it
> > will be to source parts in single quantities, and also
> > the production of the PCB board would be very difficult
> > for me.  I am very interested in getting a strong motion
> > sensor set up like the one you outlined, and the cost is
> > not a problem.  But do I have to build it from scratch?
> > Any ideas on how I might get an assembled one, or at
> > least a PCB board for it?  It appears to be exactly what
> > I am looking for but I'm a software guy and I'm not sure
> > I'm up to the task of putting it together from scratch.
> > Any ideas or suggestions?  I'd sure like to try hooking
> > up ethernet to this 3028-based sensor.
> >
> > > You will need four channels (the fourth for temperature)
> > > if you use it.
> >
> > Is that three ICS-3028s and one thermistor?
> >
> > > PEPP would be interesting and useful too (Susan Schwartz at
> > > UCSC would like some teleseismic records, I'm sure, to look
> > > at anisotropy) but strong-motion is my passion (and bias!).
> >
> > I am very interested in the PEPP system also, and intend
> > to get one. Strangely though I can't seem to get a reply
> > from the people at Guralp. I sent two emails to their
> > north american sales rep asking for pricing and how to
> > order, but no reply so far. Any idea who I might talk to
> > to get one the CMG-PEPP units?
> >
> > Thanks,
> > Doug
> >
> > PS. It would be really interesting to put together a fairly
> >     low cost yet useful strong motion sensor that could be
> >     plug-and-play on the internet, automatically joining a
> >     "federation" of other sensors.  It would be cool to
> >     have a station that anyone can use, with software that
> >     automatically sends event data to a site on the net
> >     that USGS could use for analysis.  One could imagine
> >     1000s of these sensors plugged into everyday networks
> >     all around the san andreas, imagine how much data
> >     could be gathered!

--
Edward Cranswick                Tel: 303-273-8609
US Geological Survey, MS 966    Fax: 303-273-8600
PO Box 25046, Federal Center    cranswick@........
Denver, CO 80225-0046  USA      E.M. Forster said, "Only connect".




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