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Hi David,<br><br>
Here is link from Dupont on its Corian product that discusses its
product. See page 62 in the document: <br>
<a href="http://www2.dupont.com/Corian/en_IT/assets/downloads/pdfs/technical/english_2005_dupont_corian_book_techknowhow.pdf" eudora="autourl">
http://www2.dupont.com/Corian/en_IT/assets/downloads/pdfs/technical/english_2005_dupont_corian_book_techknowhow.pdf<br>
</a>and
<a href="http://www2.dupont.com/Surfaces_Commercial/en_US/assets/downloads/pdfs/Corian_Technical_Bulletins/Performance_Properties_of_Corian.pdf" eudora="autourl">
http://www2.dupont.com/Surfaces_Commercial/en_US/assets/downloads/pdfs/Corian_Technical_Bulletins/Performance_Properties_of_Corian.pdf</a>
.<br><br>
<font size=2 color="#262824"><b>Thermal expansion<br>
</b>The coefficient of linear thermal expansion for
Corian</font><font size=1 color="#262824">®
</font><font size=2 color="#262824">is 1 mm per meter. Link
to thermal characteristics that includes concrete & glass:
<a href="http://www.hukseflux.com/thermalScience/thermalConductivity.html" eudora="autourl">
http://www.hukseflux.com/thermalScience/thermalConductivity.html</a>.<br>
<br>
Thus, this is why we have chosen Corian for our portable vault
bases: good thermal stability, light weight (over glass or tile),
less prone to breakage during shipping and dropping accidentally, easily
machinable, provides isolation from ground currents similar to glass,
provide flat base to install the small C_Trill, and is durable (used over
& over again). <br><br>
Once we duct seal the 2 gallon bucket (bottom cut out) to the vault base,
we do have a water tight seal; and the bucket is tethered to the base w/
3 tethers (tension of tethers is slight) to insure bucket is not detached
from duct seal during burial. Bucket has a screw lid with a
O-ring; buckets are food buckets for storing and freezing food.
Buckets are also lightweight and reusable. <br><br>
We use a bulkhead fitting (designed by Greg Steiner) to water-tight the
cable entry into the bucket. <br><br>
When we install, we usually put a small layer of playsand in the hole
first to help level and couple the base in the hole; then pack a
bit of sand around the bucket and base to help anchor the bucket before
packing in the native dirt around the bucket up to the base of the
lid. Next, install the seismometer, insulate with fiberglass, add
dessicant just below lid where condensation usually forms, then screw on
lid tightly; then finish burying the system with at least 6 inches
but try to do a foot if possible for temporary, portable sites.<br><br>
So far, we have used these vault systems in Arkansas which CERI
installed, in New Madrid, MO, during the National Level Exercise where it
rained much, in Reno, NV, where we installed 16 stations for a month (but
most vaults were duct sealed to a garage floor or outside concrete patio
w/o trouble, 8 stations along the Calaveras Fault in mtns for next 6
months to a year (outcome not known yet), and I tested one for 2.5 months
in satellite dish compound at USGS Golden office (no water
contamination).<br><br>
Attached is a ML3.0 (really 2.98; NCSN) within 15 km of the stations for
the Z and N components to scale, no filtering, for perusal.
<br><br>
Thinking of doing AGU poster on the vault system; better get on the
stick.<br><br>
Best Regards,<br>
Mark<br><br>
<br>
</font>At 18:16 7/20/2011, David S. Croker wrote:<br>
<blockquote type=cite class=cite cite="">Thanks Mark (and others).
All good comments. Looks like we will always have to trade ease and
cost of installation and maintenance with data quality. And
accessibility (ie, how long does it take to uncover the vault when you
need to and can you get the lid off after its been sitting in the soil
for 3 years). <br><br>
Paul Bodin shared a couple thoughts:<br>
"That said, based on my previous experiences and not ever having
used a Tcompact, I nevertheless think that direct burial is the most
likely to be successful. i.e., narrow borehole as deep as you can
conveniently get (1-2 m?), packed in sand. If you put them in a tube, I'd
argue for a fairly compliant material - i.e. pvc rather than steel---and
something with a low coefficient of thermal expansivity."<br>
He also included a rough draft of a paper he wrote and submitted to BSSA
on "some of the sad facts we've learned about long period
seismometry and vault design over the past year." With his
permission, I can forward it to everyone.<br><br>
Dave Drobeck chimed in with similar thoughts as Mark and I, and similar
concerns that maybe our vaults have not been as thoroughly tested as they
perhaps should be. Sounds like a perfect task for Bob. Part
of the problem is that no one vault is appropriate, or even possible, at
all locations.<br><br>
The difficult thing the NCSN is facing for this summer is how to install
a C-Trill (or is it Tcompact, or Trilco?) in a location where metamorphic
quartzite bedrock is right on the surface and the Forest Service needs us
to be as discreet and low-profile as possible (forget a backhoe).
<br><br>
Mark, that's a cute little vault you have in the attachments. Can
you point me to a link that shows me what it is? I assume it's
water tight? Is the bottom removed?<br><br>
Thanks again,<br>
Dave<br><br>
At 09:58 PM 7/19/2011, Mark E. Meremonte wrote:<br>
<blockquote type=cite class=cite cite="">Hi Dave,<br><br>
For 6 months to a year we use the small vault systems we developed for
portable systems: see attachments. For the portables we try
to install insulated vaults at least 6 inches below the
surface. However, for permanent install I would not install
less than a foot below the surface; or, if necessary, we mound at least a
foot of soil over top of vault if less than a foot below
surface.<br><br>
For permanent I will probably be using a smaller version of our regional
vaults with sandblasted glass bases and using insulation. See
<a href="ftp://ftpext.usgs.gov/pub/cr/co/golden/hazards/Eq_Effects/Vaults/Regional/5_Vault_CMG3-MEMS.jpg" eudora="autourl">
ftp://ftpext.usgs.gov/pub/cr/co/golden/hazards/Eq_Effects/Vaults/Regional/5_Vault_CMG3-MEMS.jpg</a>
<br>
<br>
Yes, I believe some tests should be done on temperature effects.
Similar to other BBs, they should be insulated to stabilize temps.
Sounds like an experiment for Bob Hutt at ASL.<br><br>
Some thoughts and Regards,<br>
Mark<br><br>
At 15:20 7/19/2011, David S. Croker wrote:<br>
<blockquote type=cite class=cite cite="">Hi All,<br><br>
Simple question with a potentially longwinded answer (simple answer
preferred): What kind of vault installation do you do for permanent
Trillium Compact sites? Full-blown vaults with lots of insulation,
slightly reduced scale vaults with a little less insulation, or simple
small scale tubes buried a couple feet down with minor insulation?
How do they respond to temperature changes?<br><br>
Thanks for any insight you might have.<br><br>
Dave<br><br>
__________________________________________________________<br>
USGS - Earthquake Science Center - NCSN Field Operations Manager<br>
David S.
Croker
office (650) 329-4697<br>
345 Middlefield Rd, MS
977
fax (650) 329-4732<br>
Menlo Park, CA
94025
cell (650) 465-4334<br>
email: croker@usgs.gov<br>
Quake info:
<a href="http://earthquake.usgs.gov/" eudora="autourl">
http://earthquake.usgs.gov/</a><br>
USGS URL:
<a href="http://www.usgs.gov/" eudora="autourl">http://www.usgs.gov/</a>
<br><br>
_______________________________________________<br>
ANSS-netops mailing list<br>
ANSS-netops@geohazards.usgs.gov<br>
<a href="https://geohazards.usgs.gov/mailman/listinfo/anss-netops" eudora="autourl">
https://geohazards.usgs.gov/mailman/listinfo/anss-netops</a></blockquote>
<br><br>
<font face="Times New Roman, Times">
*********************************************************<br>
Mark E. Meremonte
Geophysicist USGS/ANSS/NEIC<br><br>
U.S. Geological Survey Work:
303-273-8670 Cell: 303-478-5766<br>
MS 966, Box 25046
Email: meremonte@usgs.gov<br>
Denver, CO
80225
Web:
<a href="http://geohazards.cr.usgs.gov/" eudora="autourl">
http://geohazards.cr.usgs.gov</a><br>
<br>
Ship: U.S. Geological Survey, 1711 Illinois St., Golden, CO
80401<br>
**********************************************************<br>
</font><br>
</blockquote><br>
<font face="Times New Roman, Times">
*********************************************************<br>
Mark E. Meremonte
Geophysicist USGS/ANSS/NEIC<br><br>
U.S. Geological Survey Work:
303-273-8670 Cell: 303-478-5766<br>
MS 966, Box 25046
Email: meremonte@usgs.gov<br>
Denver, CO
80225
Web:
<a href="http://geohazards.cr.usgs.gov/" eudora="autourl">
http://geohazards.cr.usgs.gov</a><br>
<br>
Ship: U.S. Geological Survey, 1711 Illinois St., Golden, CO
80401<br>
**********************************************************<br>
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