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Paul Hovnanian P.E.
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 Posted: Fri Aug 01, 2008 3:48 am Post subject: Re: OT: Seismographs |
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qrk wrote:
[quote]
On Tue, 29 Jul 2008 18:00:09 -0700, "Paul Hovnanian P.E."
paul@hovnanian.com> wrote:
I>ve got a question about the state of the art in seismographs (if any
of you in So Cal are still alive). After the latest shaker down there,
the news cut over to the USGS HQ to show the obligatory drum style pen
recorders with the squiggly line.
A few years back, a few people in the area of Indonesia were discussing
a major event and posted a couple of traces of their accelerometer
readings. IIRC, these things had time resolutions of milliseconds. No
paper and pen, it was all digital. Various views of the transient were
available, including frequency domain traces (from sub Hz to 100 Hz at
least). I>m guessing that, given an accurate time base (probably sync>d
to GPS), some valuable geological information can be gleaned from
distributed networks of sensors of this sort.
This is a third world country. But we still have paper tape. What is the
state of the art? If we>ve got it, why show everyone the pen and paper
stuff on the news?
http://pasadena.wr.usgs.gov/eqview/cgi-bin/makePublicView.php?EVID=14383980
Looks like digital data to me. This data gets posted minutes after an
event. The poor USGS servers were instantly bogged down right after
the quake.
They probably have drum data as backup or a show & tell for the news
dweebs.
[/quote]
The labor to maintain and operate pen recorders could be put to better
use elsewhere.
Backup? Wouldn>t the money be spent more wisely on RAID storage? Same
for show and tell. Even more, people are used to PC displays, computers,
etc. Seeing the USGS using out of date technology makes me wonder if
they really know what they>re doing anymore.
--
Paul Hovnanian mailto:Paul@Hovnanian.com
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Life is like a buffet. Its not very good but there>s plenty of it. |
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Paul Hovnanian P.E.
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| Posted: Fri Aug 01, 2008 7:05 am Post subject: Re: OT: Seismographs |
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mpm wrote:
[quote]
On Jul 31, 6:48�pm, "Paul Hovnanian P.E." <p...@hovnanian.com> wrote:
qrk wrote:
Backup? Wouldn>t the money be spent more wisely on RAID storage? Same
for show and tell. Even more, people are used to PC displays, computers,
etc. Seeing the USGS using out of date technology makes me wonder if
they really know what they>re doing anymore.
Agreed, but there is something to be said for "low-tech".
Especially if you consider these chart recorders may be installed out
in the boonies, off-grid, etc... I for one could not in good
conscience recommend Vista for such applications. :)
-mpm
[/quote]
Doubtful that these would be installed "in the boonies". Most of the
ones shown on TV are at some sort of USGS HQ (or university lab). The
pen and paper requires a conditioned environment and frequent
pen/ink/paper replacement. Not conducive to remote installation. I>d
venture a guess that solid state event recorders are quite a bit more
robust (and cheaper).
--
Paul Hovnanian mailto:Paul@Hovnanian.com
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Paul Hovnanian P.E.
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| Posted: Fri Aug 01, 2008 7:05 am Post subject: Re: OT: Seismographs |
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Phil Hobbs wrote:
[quote]
Paul Hovnanian P.E. wrote:
qrk wrote:
http://pasadena.wr.usgs.gov/eqview/cgi-bin/makePublicView.php?EVID=14383980
Looks like digital data to me. This data gets posted minutes after an
event. The poor USGS servers were instantly bogged down right after
the quake.
They probably have drum data as backup or a show & tell for the news
dweebs.
The labor to maintain and operate pen recorders could be put to better
use elsewhere.
Backup? Wouldn>t the money be spent more wisely on RAID storage? Same
for show and tell. Even more, people are used to PC displays, computers,
etc. Seeing the USGS using out of date technology makes me wonder if
they really know what they>re doing anymore.
Chart recorders make *way* better theatre. That pen wiggling back and
forth looks like a frustrated child scribbling on a drawing that didn>t
come out. Perfect.
[/quote]
Probably true. But on the other hand, think about the ability to 'play
back' digital data for the news crew.
[quote]Part of the problem is that definitions of earthquake magnitude depend
on the frequency passband, which depends on the design of seismographs
and probably on pen recorders too. One way to keep the numbers
comparable is to keep the hardware the same.
[/quote]
I>m sure that the response of a pen recorder could be modeled in a
digital data acquisition system.
[quote]
The 'Richter' scale quoted by reporters is not the original Richter
scale, but a modified one with a wider passband (and some low-frequency
boost, iirc).
Cheers,
Phil Hobbs
[/quote]
--
Paul Hovnanian mailto:Paul@Hovnanian.com
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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.
-- Etaoin Shrdlu |
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Paul Hovnanian P.E.
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| Posted: Fri Aug 01, 2008 7:05 am Post subject: Re: OT: Seismographs |
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It depends on the characteristics of the ground as well.
I went through the Nisqually 'quake in 2001. A couple of buildings
(including the one I worked in) were nearly destroyed. When I finally
made it back home, nothing had moved, in spite of the fact that my
workshop, shelves, book cases, etc. are an avalanche of junk waiting to
happen. My house is built on rock strata, not very deep, whereas the
Boeing Renton plant is built on river bottom.
They tore down a couple of the damaged buildings, but the one I worked
in was the office of a couple of geezers that they didn>t want to move
(think about the stress caused by changing the schedule at the old folks
home). So we had to put up the dilapidated wreck until they retired.
--
Paul Hovnanian mailto:Paul@Hovnanian.com
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Bloody typical, they>ve gone back to metric without telling us. |
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