In a message dated 20/06/2006 15:26:09 GMT Daylight Time,  jonfr500@......... 
writes:

I plan  to move my geophone out, but I need to do it properly. So it
doesn't get  flooded with water and gets damaged because of that.

I want to build  this type of seismic  vault,
http://www.iris.iris.edu/passcal/Manual/rtfm.sa11.2.html (see pdf  file
for picture). There is a lot of water because of a snow during the  winter
that I need to protect my geophone from. If there are any other  types of
seismic vaults that I might consider, please let me  know.
Hi Jon,
 
    This particular vault is NOT WATERPROOF and you can  expect it to flood 
when the snow melts and during heavy rain. Sorry, but I  am near certain that 
it will NOT be satisfactory for your location in  Iceland. The geophone case 
will float if the water level rises.
 
    Your geophones are enclosed in a waterproof plastic  case. It is quite 
easy to seal both the case and the cable glands with silicone  rubber paste. You 
need to buy the sort of silicone rubber which does NOT smell  strongly of 
acetic / formic acid. You could then wrap the case in thin plastic  foam sheet 
and put the whole lot inside polythene bags tied around the  cable, to protect 
it from freezing. You could align the sensor and bury it in  sand at the bottom 
of a hole. You might need to put a weight / bricks / rocks on  top of the 
case to prevent it moving if submerged.
 
    Another alternative might be to use a plastic drain  manifold. These are 
vertical plastic tubes with blanked off connections for  horizontal drain 
pipes. Some of them can be completely sealed - check before you  buy one. At least 
two sizes are available, but they are not cheap. 
    You could fit a tank connector and plastic  water pipe onto one of the 
blanking plates to house the geophone  cable. You could partially fill the main 
case with dry sand and mount the  geophone case on top on a glass or glazed 
ceramic disk.  
    Fit a plastic reducing connector to the end of the  water pipe and seal 
the tube to the cable with black 'Self Amalgamating Tape'.  You stretch the 
tape to tension and thin it and wrap overlapping turns over  the joint. This 
provides an airtight and UV / solar resistant seal. You  should also seal the end 
of the multiway cable with silicone rubber paste. This  prevents air pressure 
changes carrying damp air into the cable and prevents  corrosion
    
 
    There are a number of installations described on  the Guralp website
    See _http://www.guralp.net/general/customers/_ 
(http://www.guralp.net/general/customers/)  and  for a waterlogged site 
    _http://www.guralp.net/articles/20040400-casestudy-eskdalemuir/support_ 
(http://www.guralp.net/articles/20040400-casestudy-eskdalemuir/support) 
    


> Is  Environmental Stability (temperature & humidity) within the vault an  
issue?

I don't think it is going to be a problem inside the vault.  Since I need
to place it at least 2 meters below the surface (if I can even  get that
deep), because of the winter frost where I live.
    I doubt if you will need to go to a depth of 2  m, but it is possible. I 
would have expected 1 m to be adequate. Do you  have any idea of the freezing 
level in your soil? Can you look up the minimum  soil temperatures that you 
can expect at various depths? The Icelandic  Meteorological Service should have 
daily soil temperatures at several depths, if  not at more frequent intervals. 
You might send an EMail to _halldor@......... (mailto:halldor@......... ? The 
company which supplies  your drinking water should also have figures - they 
need to keep the supplies  free of ice in winter.
 
    Regatds,
 
    Chris Chapman







In a message dated 20/06/2006 15:26:09 GMT Daylight Time,=20
jonfr500@......... writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I plan=20
  to move my geophone out, but I need to do it properly. So it
doesn't ge=
t=20
  flooded with water and gets damaged because of that.

I want to buil=
d=20
  this type of seismic=20
  vault,
http://www.iris.iris.edu/passcal/Manual/rtfm.sa11.2.html (see pd=
f=20
  file
for picture). There is a lot of water because of a snow during the=
=20
  winter
that I need to protect my geophone from. If there are any other=20
  types of
seismic vaults that I might consider, please let me=20
know.
Hi Jon,
 
    This particular vault is NOT WATERPROOF and you=
 can=20
expect it to flood when the snow melts and during heavy rain. Sorry, bu=
t I=20
am near certain that it will NOT be satisfactory for your location in=20
Iceland. The geophone case will float if the water level rises.
 
    Your geophones are enclosed in a waterproof pla=
stic=20
case. It is quite easy to seal both the case and the cable glands with silic=
one=20
rubber paste. You need to buy the sort of silicone rubber which does NOT sme=
ll=20
strongly of acetic / formic acid. You could then wrap the case in thin plast=
ic=20
foam sheet and put the whole lot inside polythene bags tied around=
 the=20
cable, to protect it from freezing. You could align the sensor and bury it i=
n=20
sand at the bottom of a hole. You might need to put a weight / bricks / rock=
s on=20
top of the case to prevent it moving if submerged.
 
    Another alternative might be to use a plastic d=
rain=20
manifold. These are vertical plastic tubes with blanked off connections=
 for=20
horizontal drain pipes. Some of them can be completely sealed - check before=
 you=20
buy one. At least two sizes are available, but they are not cheap. 
    You could fit a tank connector and plastic=
=20
water pipe onto one of the blanking plates to house the geophone=20
cable. You could partially fill the main case with dry sand and mount the=20
geophone case on top on a glass or glazed ceramic disk.  
    Fit a plastic reducing connector to the end of=20=
the=20
water pipe and seal the tube to the cable with black 'Self Amalgamating Tape=
'.=20
You stretch the tape to tension and thin it and wrap overlapping turns=20=
over=20
the joint. This provides an airtight and UV / solar resistant seal. You=
=20
should also seal the end of the multiway cable with silicone rubber paste. T=
his=20
prevents air pressure changes carrying damp air into the cable and prevents=20
corrosion
    
 
    There are a number of installations described o=
n=20
the Guralp website
    See http://www.guralp.net/gene=
ral/customers/ and=20
for a waterlogged site 
    http://www.guralp.net/articles/20040400-casestudy-eskdalemuir/support=

    

<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>> Is=20
  Environmental Stability (temperature & humidity) within the vault an=20
  issue?

I don't think it is going to be a problem inside the vault.=20
  Since I need
to place it at least 2 meters below the surface (if I can=20=
even=20
  get that
deep), because of the winter frost where I live.
    I doubt if you will need to go to a depth of 2=20
m, but it is possible. I would have expected 1 m to be adequate. Do you=
=20
have any idea of the freezing level in your soil? Can you look up the minimu=
m=20
soil temperatures that you can expect at various depths? The Icelandic=20
Meteorological Service should have daily soil temperatures at several depths=
, if=20
not at more frequent intervals. You might send an EMail to halldor@........? The company which sup=
plies=20
your drinking water should also have figures - they need to keep the supplie=
s=20
free of ice in winter.
 
    Regatds,
 
    Chris Chapman