Hi Steve and all,

Ed Cranswick sent me this 1993 article last year on the origins of the  PSN,
may fill in some gaps

 

http://www.rsuw.daleh.id.au/Cranswick_1993_Recording.pdf

Regards

Dale

 

From: psnlist-request@.............. [mailto:psnlist-request@...............
On Behalf Of Stephen Hammond
Sent: Saturday, 28 April 2012 6:17 AM
To: chrisatupw@.......
Cc: psnlist@..............
Subject: RE: Peoples Seismograph Array ---> Public Seismic Network

 

Hi Chris, Thanks for your note and all the references. As for the Lehman's I
currently have, I'm very unhappy with them and they are headed for scrap.
When I was in San Jose I had 40CM booms and they worked very well and had
25-30 second periods. I had to cut the booms down due to space issues on my
small property here in Aptos, after moving  from San Jose and the periods
went from  30 second to 10. I also live uphill from Monterey Bay and the
waves to my west and the main street to the east create lots of noise. So I
have to deal with that a lot of times and when the storms come in the
Lehman's are unusable.  Jan Froom just lent me a  Sprengnether  which is
running after being rebuilt at this point and I'm still testing the lower
pivot I built for it. If you look at AT2 on-line over the last week or two
you will see the Sprengnether at a gain of 210.  I'm still waiting for the
first local event. The period is not too long at this point. I think I need
to pull it apart again and tweak the position of the pivot  as one of the
two cylinder magnets is too close to the coil. When the Springnether gets
going I'm pulling the two Lehman's. The cup / point lower pivot has never
worked that well. I already have three HS10's which were originally in the
old Cal-Net run by the USGS. They work really well. As for the amp and
filter designs, they came from Pete Rowe in 1990 and are on the San Jose PSN
site. Ted Black wrote the original PSN code and we built or own A/D boards
and wrote our own hardware interface drivers in Assembler. Later, after
Larry joined, he developed his hardware data collection  and software and I
continue to us it today. 

 

About the history:  As Ed Cranswick told the story over beers several times
he needed a grant to go to the AGU meeting that year and he published the
"Peoples" Seismic Array paper ( which is listed in the link you provided) so
he could attend the meeting and present his paper. He and Phil (a software
engineer) had been working together on a number of projects and  If I
remember correctly it did have something to do with his work in Turkey or
Russia but I've lost that point and can't recall it. Anyway, Ed got his
funding and went to the AGU meeting with Phil and Ed presented their work.
Like I SAID, IT HAD ABSOLUTLY NOTHING TO DO WITH US. Than in Oct. 1989 the
Loma P event went off in Aptos (Santa Cruz County) and it sparked a lot of
interest in seismology. However, before Oct/89 inside IBM there was a group
of people that had been working on their hobby, not a formal IBM product,
which was seismology instrumentation. Jan From, Ted Blank, Dick and one
outsider, Pete Row had already hooked-up and were sharing information. Jan
was a tools programmer for IBM and wrote the software to float a 3,000 pound
block of granite on streams of air so that master servo tracks could be
written error free on large DASD packs and lived in Gilroy, CA. Ted Blank
was IBM's performance export for the MVS operating system and lived in New
York and worked at the Poughkeepsie, NY plant. Pete Row was a contractor and
worked on secret electronics government projects here in San Jose, CA. Ted
had written his SDAS software for data collection on a PC and had built from
the 1956 plans a Lehmann seismograph. Jan had communicated via IBM's
internal discussion network and gotten the software and info from Ted and
shared it with Pete as they were HAMs on the local 2m radio network and both
had built and operated seismic stations. They would share info and data via
the local 2m network here in San Jose run by Bruce Kenny (W6TED). I (and 250
other people) was working on developing IBM's OSI software product at the
IBM Scientific Center in Palo Alto and lived I lived in south San Jose. Jan
shared his plans and Ted's software with me and I built a Lehman and hooked
it to a PC via an A/D board and amp I built from sample chips I got from
local vendors. Dick Chelberg was an engineer working in the IBM plant
developing DASD in  San Jose and as a side profession operated a complete
machine shop at his home. He had machined a Lehman and was also using Ted's
software and an IBM A/D card to collect seismic data. One Saturday morning
following we got together for coffee and donuts at my home to meet face to
face and talk about seismographs and share info. As we were all using Ted's
software we needed a way to share the datasets so I volunteered to install a
BBS. Within a few weeks it was operational and the IBM Think Magazine folks
got wind of this seismic group operating in San Jose and asked to write an
employee focus item for the Company Think Magazine and they interviewed each
of us and wrote the article. The interesting thing was tha6t totally
unrelated, Ed's AGU paper was discussed in the San Jose Mercury News. And on
that Saturday morning we had kicked around a few names for the BBS and it
ended up being named "THE "PUBLIC" SEISMIC NETWORK" in San Jose. So when we
read about ED I called him at the USGS in Menlo Park and  the next day he
showed up at my house to see what we were doing. From that point on our
relationship grew with lots of support from the USGS and lots of great
advice. John Lahr, Ed and two other's stared to attend our meetings and as
the word about the PSN got around more and more people in the Bay Area
started to join the group. So did the BBS network. Jerry and Dorothy Darby
were part of the 2M radio group in Pasadena and they installed a PSN BBS and
were linked them together with nightly mail runs and file sharing. They also
were operating seismographs at their home as were a number of folks in the
LA area. Charlie Daniels In Memphis, TN had a seismograph and installed the
PSN BBS in Tennessee and link it into our network. The folks at CERI also
supported his site and gave him access to info on New Madrid. Allen Lynn was
the Station Chief at the USGS in Menlo Park and asked me to install a PSN
BBS in his office. Latterly, on top of a filing cabinet in his office, which
I did.  I maintained it via FTP  and later John Lahr took over its
operation. So the original PSN network was a four-node BBS network and the
members could post mail and event files to any of the systems and in turn a
number of elementary schools and high schools started using the systems in
their course work. I helped to install systems and seismographs at MT View
and Los Altos high schools and Anderson Elementary in San Jose. Jan
installed systems at the Gilroy Middle school and today created and
maintains the seismic system and Gilroy Gardens. Pete and Ted are still
active here on the list and the last time I check, Bruce and Dick lived here
in CA. Ed Cranswick was in Australia and we are still arguing over who was
first, the Peoples or Public Seismic Network. I'll have to check the
publication dates to see. 

Regards, Steve Hammond PSN San Jose, Aptos, CA

 

From: chrisatupw@....... [mailto:chrisatupw@........ 
Sent: Thursday, April 26, 2012 5:59 PM
To: shammon1@.............
Subject: Peoples Seismograph Array ---> Public Seismic Network

 

Dear Steve Hammond,

 

**** Edward Cranswick wrote:

http://dominicapsn.freeyellow.com/PSN/PSN_History.html back in 1996 

regarding the PSA / PSN history. But the attached EOS supplement is dated
1990. 

    It looks like the Peoples Seismic Array project was first considered in
1985 ? 

    Larry Cochrane's first PSN Internet file was in the 4th quarter of 1995 

 
     I have spoken to Larry and he suggested contacting you regarding the 
historical development stages of PSA / PSN before 1996. What were the plans
for 
the seismometers, please ? Or were you planning to use extended period
geophones ? 
How did the proposals develop please ?  
 
    I visited your web site and noted that both Lehmans were set at 12 
seconds period. This is much less than the 25 to 30 seconds that we use 
to match the Love waves and I wondered why you had chosen it, please ? 
The boom length of 30 cm is much shorter than we usually use. 
 
Our Seismometer developments  
   Point in a cup and knife edge "bearings" are both fundamentally flawed 
designs. I suspect that the idea of using "knife edge" bearings may have 
originated from chemical balances - but their bearings are ONLY CALLED that
! 
The Agate bar is cut and polished with 60 degree corners, but the bearing 
corner was then carefully lapped to a tiny cylinder to take the rated load 
--- of just 200 gm !! A razor sharp Agate edge would shatter easily. 
 
    Two bearing types which WILL take typical seismometer loads of several
kg 
are a plane rolling on a ball - in my case a section of a SS scalpel blade
on 
a SS ball bearing - and crossed cylinders. These can be hardened EN57 steel
rod, 
or more usually tungsten carbide rods. Tungsten carbide needle roller
bearings are 
produced. You can buy 1/8" OD tungsten carbide drills and use the shank
ends, but 
there are plenty of small WC milling cutters with parallel shanks. I got a
free 
supply of broken cutter shanks from a small engineering business just by
asking ! 
 
    I described the test results of these and of rolling foil and wire very
low 
dynamic loss, high load flexures in a paper in ArchivX. The traditional
crossed 
foil and wire type suspensions show energy loss and noise due to the flexure

being bent very close to the clamped ends. 
  
    Below is a photo of the seismometer that I use
 
http://www.jclahr.com/science/psn/chapman/2008%20lehman/index.html 
    I can set the period to 30 seconds quite easily to sense the Love 
waves at their full amplitude. The principle features are a SS scalpel 
blade rolling on a 1/2" SS ball bearing lower fulcrum. The V cable top 
support prevents the arm from rotating about it's long axis - this can 
produce an undamped peak at 3~8 Hz in the FFT display if it is not 
suppressed. The quad Neodymium magnet damping and sensor blocks are 
highly effective. A 1/16" thick horizontal Copper damping blade is used. 
Soft Aluminum can also be used, but it is significantly diamagnetic and 
has double the resistivity. It is also relatively difficult to buy. One 
advantage of this design is that the magnet block can be slid along the 
base bar to cover just as much of the N/S magnet joint as is required. 
This butted N/S magnet joint develops a much greater damping force than 
a widely spaced poles. The damping force required depends on the period 
of the arm as well as on the seismic mass. The sensor block uses 1.5" 
long magnets and a rectangular coil. This allows the arm to drift +/- 
1/2" without any change in the sensitivity. A relatively few number of 
turns is required on the coil - 1,500 to 2,000. The sensitivity is about 
20x that of a traditional Alnico U magnet + relay coil. 
 
    A Manual for the commercial SEP UK school seismometer is at 
     
http://www.mindsetsonline.co.uk/images/Seismometer.pdf 
    The amplifier band pass is from 0.016 to 5 Hz and the gain can be 
switched x100, x200 or x500. The UK is a crowded noisy island with very 
few local quakes, so a 5 Hz LP filter is optimal. The period is set by 
tilting the base plate and a value of 25 to 30 seconds is usually chosen. 
The suspension is 1/8" OD crossed tungsten carbide needle rollers. The 
mass is brass. The boom is ~56 cm long. The extended period traces enable 
you to pick up at least twice the number of quakes identified by a P&S 
wave trigger. You pick out the often large surface waves and then look 
for the P&S waves.  
    This is a very successful project. Over 400 seismometers have been 
sold since Easter 2007. 
 
    Regards, 
 
    Chris Chapman MA Oxon (Physics-retired)
Hi =
Steve and all,
Ed =
Cranswick sent me this 1993 article last year on the origins of the =
 PSN, may fill in some gaps
 
http://=
www.rsuw.daleh.id.au/Cranswick_1993_Recording.pdf
Regards
Dale
 
From:=
 =
psnlist-request@.............. [mailto:psnlist-request@............... =
On Behalf Of Stephen Hammond
Sent: Saturday, 28 April =
2012 6:17 AM
To: chrisatupw@.......
Cc: =
psnlist@..............
Subject: RE: Peoples Seismograph Array =
---> Public Seismic Network
 
Hi Chris, Thanks for your note and all the references. As for the =
Lehman’s I currently have, I’m very unhappy with them and =
they are headed for scrap. When I was in San Jose I had 40CM booms and =
they worked very well and had 25-30 second periods. I had to cut the =
booms down due to space issues on my small property here in Aptos, after =
moving  from San Jose and the periods went from  30 second to =
10. I also live uphill from Monterey Bay and the waves to my west and =
the main street to the east create lots of noise. So I have to deal with =
that a lot of times and when the storms come in the Lehman’s are =
unusable.  Jan Froom just lent me a  Sprengnether  which =
is running after being rebuilt at this point and I’m still testing =
the lower pivot I built for it. If you look at AT2 on-line over the last =
week or two you will see the Sprengnether at a gain of 210. =
 I’m still waiting for the first local event. The period is =
not too long at this point. I think I need to pull it apart again and =
tweak the position of the pivot  as one of the two cylinder magnets =
is too close to the coil. When the Springnether gets going I’m =
pulling the two Lehman’s. The cup / point lower pivot has never =
worked that well. I already have three HS10’s which were =
originally in the old Cal-Net run by the USGS. They work really well. As =
for the amp and filter designs, they came from Pete Rowe in 1990 and are =
on the San Jose PSN site. Ted Black wrote the original PSN code and we =
built or own A/D boards and wrote our own hardware interface drivers in =
Assembler. Later, after Larry joined, he developed his hardware data =
collection  and software and I continue to us it today. =
 
About the history:  As Ed Cranswick told the story over beers =
several times he needed a grant to go to the AGU meeting that year and =
he published the “Peoples” Seismic Array paper ( which is =
listed in the link you provided) so he could attend the meeting and =
present his paper. He and Phil (a software engineer) had been working =
together on a number of projects and  If I remember correctly it =
did have something to do with his work in Turkey or Russia but =
I’ve lost that point and can’t recall it. Anyway, Ed got his =
funding and went to the AGU meeting with Phil and Ed presented their =
work. Like I SAID, IT HAD ABSOLUTLY NOTHING TO DO WITH US. Than in Oct. =
1989 the Loma P event went off in Aptos (Santa Cruz County) and it =
sparked a lot of interest in seismology. However, before Oct/89 inside =
IBM there was a group of people that had been working on their hobby, =
not a formal IBM product,  which was seismology instrumentation. =
Jan From, Ted Blank, Dick and one outsider, Pete Row had already =
hooked-up and were sharing information. Jan was a tools programmer for =
IBM and wrote the software to float a 3,000 pound block of granite on =
streams of air so that master servo tracks could be written error free =
on large DASD packs and lived in Gilroy, CA. Ted Blank was IBM’s =
performance export for the MVS operating system and lived in New York =
and worked at the Poughkeepsie, NY plant. Pete Row was a contractor and =
worked on secret electronics government projects here in San Jose, CA. =
Ted had written his SDAS software for data collection on a PC and had =
built from the 1956 plans a Lehmann seismograph. Jan had communicated =
via IBM’s internal discussion network and gotten the software and =
info from Ted and shared it with Pete as they were HAMs on the local 2m =
radio network and both had built and operated seismic stations. They =
would share info and data via the local 2m network here in San Jose run =
by Bruce Kenny (W6TED). I (and 250 other people) was working on =
developing IBM’s OSI software product at the IBM Scientific Center =
in Palo Alto and lived I lived in south San Jose. Jan shared his plans =
and Ted’s software with me and I built a Lehman and hooked it to a =
PC via an A/D board and amp I built from sample chips I got from local =
vendors. Dick Chelberg was an engineer working in the IBM plant =
developing DASD in  San Jose and as a side profession operated a =
complete machine shop at his home. He had machined a Lehman and was also =
using Ted’s software and an IBM A/D card to collect seismic data. =
One Saturday morning following we got together for coffee and donuts at =
my home to meet face to face and talk about seismographs and share info. =
As we were all using Ted’s software we needed a way to share the =
datasets so I volunteered to install a BBS. Within a few weeks it was =
operational and the IBM Think Magazine folks got wind of this seismic =
group operating in San Jose and asked to write an employee focus item =
for the Company Think Magazine and they interviewed each of us and wrote =
the article. The interesting thing was tha6t totally unrelated, =
Ed’s AGU paper was discussed in the San Jose Mercury News. And on =
that Saturday morning we had kicked around a few names for the BBS and =
it ended up being named “THE “PUBLIC” SEISMIC =
NETWORK” in San Jose. So when we read about ED I called him at the =
USGS in Menlo Park and  the next day he showed up at my house to =
see what we were doing. From that point on our relationship grew with =
lots of support from the USGS and lots of great advice. John Lahr, Ed =
and two other’s stared to attend our meetings and as the word =
about the PSN got around more and more people in the Bay Area started to =
join the group. So did the BBS network. Jerry and Dorothy Darby were =
part of the 2M radio group in Pasadena and they installed a PSN BBS and =
were linked them together with nightly mail runs and file sharing. They =
also were operating seismographs at their home as were a number of folks =
in the LA area. Charlie Daniels In Memphis, TN had a seismograph and =
installed the PSN BBS in Tennessee and link it into our network. The =
folks at CERI also supported his site and gave him access to info on New =
Madrid. Allen Lynn was the Station Chief at the USGS in Menlo Park and =
asked me to install a PSN BBS in his office. Latterly, on top of a =
filing cabinet in his office, which I did.  I maintained it via FTP =
 and later John Lahr took over its operation. So the original PSN =
network was a four-node BBS network and the members could post mail and =
event files to any of the systems and in turn a number of elementary =
schools and high schools started using the systems in their course work. =
I helped to install systems and seismographs at MT View and Los Altos =
high schools and Anderson Elementary in San Jose. Jan installed systems =
at the Gilroy Middle school and today created and maintains the seismic =
system and Gilroy Gardens. Pete and Ted are still active here on the =
list and the last time I check, Bruce and Dick lived here in CA. Ed =
Cranswick was in Australia and we are still arguing over who was first, =
the Peoples or Public Seismic Network. I’ll have to check the =
publication dates to see. 
Regards, Steve Hammond PSN San Jose, Aptos, =
CA
 
From:=
 =
chrisatupw@....... [mailto:chrisatupw@.......] =

Sent: Thursday, April 26, 2012 5:59 PM
To: shammon1@.............
S=
ubject: Peoples Seismograph Array ---> Public Seismic =
Network
 
Dear Steve =
Hammond,<=
o:p>
 <=
o:p>
**** Edward =
Cranswick wrote: <=
a href=3D"http://dominicapsn.freeyellow.com/PSN/PSN_History.html" =
target=3D"_blank">http://dominicapsn.freeyellow.com/PSN/PSN_Hist=
ory.html back in 1996 =
<=
o:p>
regarding the PSA =
/ PSN history. But the attached EOS supplement is dated =
1990. <=
o:p>
   =
 It looks like the Peoples Seismic Array project was first considered in =
1985 ? <=
o:p>
   =
 Larry Cochrane's first PSN Internet file was in the 4th quarter of =
1995 <=
o:p>
 
     I have =
spoken to Larry and he suggested contacting you regarding the =
historical development stages of =
PSA / PSN before 1996. What were the plans for 
the seismometers, please ? Or =
were you planning to use extended period geophones ? 
How did the proposals develop =
please ?  
 
    I visited =
your web site and noted that both Lehmans were set at 12 =
seconds period. This is much =
less than the 25 to 30 seconds that we use 
to match the Love waves and I =
wondered why you had chosen it, please ? 
The boom length of 30 cm is =
much shorter than we usually use. 
 
=
Our Seismometer =
developments  
=
   Point in a =
cup and knife edge "bearings" are both fundamentally flawed =
designs. I suspect that the idea =
of using "knife edge" bearings may have 
originated from chemical balances =
- but their bearings are ONLY CALLED that ! 
The Agate bar is cut and =
polished with 60 degree corners, but the bearing 
corner was then carefully =
lapped to a tiny cylinder to take the rated load 
--- of just 200 gm !! A razor =
sharp Agate edge would shatter easily. 
 
    Two =
bearing types which WILL take typical seismometer loads of several kg =
are a plane rolling on a ball =
- in my case a section of a SS scalpel blade on 
a SS ball bearing - and =
crossed cylinders. These can be hardened EN57 steel rod, =
or more usually tungsten =
carbide rods. Tungsten carbide needle roller bearings are =
produced. You can buy =
1/8" OD tungsten carbide drills and use the shank ends, but =
there are plenty of small WC =
milling cutters with parallel shanks. I got a free 
supply of broken cutter =
shanks from a small engineering business just by asking ! =
 
=
    I =
described the test results of these and of rolling foil and wire very =
low 
dynamic loss, high load =
flexures in a paper in ArchivX. The traditional crossed =
foil and wire type =
suspensions show energy loss and noise due to the flexure =
being bent very close to the =
clamped ends. 
  
    Below =
is a photo of the seismometer that I use
http://www.jclahr.com/science/psn/chapman/2008=
%20lehman/index.html 
    I can =
set the period to 30 seconds quite easily to sense the Love =
waves at their full =
amplitude. The principle features are a SS scalpel 
blade rolling on a 1/2" =
SS ball bearing lower fulcrum. The V cable top 
support prevents the arm from =
rotating about it's long axis - this can 
produce an undamped peak at =
3~8 Hz in the FFT display if it is not 
suppressed. The quad =
Neodymium magnet damping and sensor blocks are 
highly effective. A =
1/16" thick horizontal Copper damping blade is used. =
Soft Aluminum can also be =
used, but it is significantly diamagnetic and 
has double the resistivity. =
It is also relatively difficult to buy. One 
advantage of this design is =
that the magnet block can be slid along the 
base bar to cover just as =
much of the N/S magnet joint as is required. 
This butted N/S magnet joint =
develops a much greater damping force than 
a widely spaced poles. The =
damping force required depends on the period 
of the arm as well as on the =
seismic mass. The sensor block uses 1.5" 
long magnets and a =
rectangular coil. This allows the arm to drift +/- 
1/2" without any change =
in the sensitivity. A relatively few number of 
turns is required on the coil =
- 1,500 to 2,000. The sensitivity is about 
20x that of a traditional =
Alnico U magnet + relay coil. 
 
=
    A =
Manual for the commercial SEP UK school seismometer is at =
    http://www.mindsetsonline.co.uk/images/Seismom=
eter.pdf 
    The =
amplifier band pass is from 0.016 to 5 Hz and the gain can be =
switched x100, x200 or x500. =
The UK is a crowded noisy island with very 
few local quakes, so a 5 Hz =
LP filter is optimal. The period is set by 
tilting the base plate and a =
value of 25 to 30 seconds is usually chosen. 
The suspension is 1/8" =
OD crossed tungsten carbide needle rollers. The 
mass is brass. The boom is =
~56 cm long. The extended period traces enable 
you to pick up at least twice =
the number of quakes identified by a P&S 
wave trigger. You pick out =
the often large surface waves and then look 
for the P&S waves.  =
    This =
is a very successful project. Over 400 seismometers have been =
sold since Easter 2007. =
 
=
    =
Regards, 
 
=
    =
Chris Chapman MA Oxon (Physics-retired)
=