My first attempt is going to be a Lehman.  I am not afraid to tackle =
anything however.  As soon as I get an amp, filter, A/D converter and =
the PC software going I thing it is going to be fun expermiting with =
different sensors.

Jan D. Marshall
Nampa, Idaho
jandmarshall@............

  ----- Original Message -----=20
  From: meredith lamb=20
  To: psn-l@.................
  Sent: Friday, October 05, 2001 12:41 AM
  Subject: Re: What type of foundation


  Hi Jan,=20
  Perhaps.....the most important aspect is,....what kind of=20
  terrain and/or space do you have available....i.e, city/country,=20
  to place any seismo on.  Any house crawlspace available, or=20
  garage, shed, or least disturbed area of land around?  One=20
  will have to make "do" with what they have for placement.=20
  If you do indeed have bedrock, that would be a plus....if...its=20
  convenient and adaptable for a seismic "vault".  If you have=20
  loose soil, the best remote and least watered/susceptible=20
  area would be best.=20

  The best material seems to be a "pier" of concrete, that can=20
  be inside/outside weather enclosed and somewhat isolated from=20
  domestic seismic sources of "noise"......or....if not possible=20
  to do so, one would have to live with the noise it generates;=20
  which is usually easy to denote with time/experience.  The=20
  pier usually needs to "fit" the area required by the sensor/s=20
  anticipated.  The thickness of the concrete slab can be=20
  debated I suppose, but I'd try for whatever depth/thickness=20
  you can squeeze in the spot you chose.  I use about a 7-8"=20
  thickness of my three piers....which are in reality cast concrete=20
  pavers stacked together but layered in the joints and surfaces=20
  with real concrete.  I chose this as it was near impossible to=20
  mix massive concrete on my knees under the house, let alone=20
  move all the sand/concrete therein.  For myself, I elected to=20
  also use thick mylar sheet under the piers, to limit water=20
  absorbion into the piers.  I even used a water repellent paint=20
  on the pier/s to limit water absorbtion.  Even after completion,=20
  you can expect a period of time before the piers stabilize from=20
  curing....perhaps acouple months.  If you can make the pier=20
  thickness even greater than say...6 inches thick, I'd do so.  Do=20
  not use iron, steel in the pier.=20

  Personally I live in Denver, and in a city lot.....so, I use my=20
  house soil crawlspace for pier/seismometer placements.  I=20
  also enclosed the piers with walls and insulation to somewhat=20
  limit temperature excursion that do occur.  Among the PSN=20
  members....we kind of all utilize whats available.....=20

  So....in a way....everything gets back to what space you=20
  have now that could be utilized.  Next, the physical size of=20
  your anticipated seismos you're planning on building/using.=20

  I think you're right to get into the seismo housing/piers aspect=20
  right off the bat.....if one doesn't; than they will get into alot of=20
  soil tilt, water, weather, temperature  related problems that will=20
  make any consistent seismic monitoring rather useless otherwise.=20
  Suggest that any pier/containment is well built and temperature=20
  insulated; this can take time, but it would pay off in the long=20
  run.=20

  Outside of the above,.....what kind of seismic sensors are you=20
  planning on using.....the instrumentation sensor aspect is always=20
  interesting.=20

  Take care, Meredith Lamb=20

  "Jan D. Marshall" wrote:=20

    I am starting to design my sensors and electronics and have decided =
that I understand the requirments there pretty well -- what I don't have =
a very good understanding on is what do I need for a base or foundation =
to set the sensors on.  What type of mass does it need? does it need to =
set on bedrock?  I do not have any cement slab floors. Thanks Jan D. =
Marshall=20
    Nampa, Idaho=20
    jandmarshall@...............






My first attempt is going to be a =
Lehman.  I=20
am not afraid to tackle anything however.  As soon as I get an amp, =
filter,=20
A/D converter and the PC software going I thing it is going to be fun=20
expermiting with different sensors.
 
Jan D. Marshall
Nampa, Idaho
jandmarshall@............

  
----- Original Message ----- 
  From:=20
  meredith =
lamb=20
  
  
To: psn-l@.............. 
  
Sent: Friday, October 05, 2001 =
12:41=20
  AM
  
Subject: Re: What type of=20
foundation
  

Hi Jan,=20
  
Perhaps.....the most important aspect is,....what kind of =

terrain=20
  and/or space do you have available....i.e, city/country, 
to place =
any=20
  seismo on.  Any house crawlspace available, or 
garage, shed, =
or least=20
  disturbed area of land around?  One 
will have to make "do" =
with what=20
  they have for placement. 
If you do indeed have bedrock, that would =
be a=20
  plus....if...its 
convenient and adaptable for a seismic =
"vault".  If=20
  you have 
loose soil, the best remote and least watered/susceptible =

  
area would be best.=20
  
The best material seems to be a "pier" of concrete, that can 
be =

  inside/outside weather enclosed and somewhat isolated from =

domestic=20
  seismic sources of "noise"......or....if not possible 
to do so, =
one would=20
  have to live with the noise it generates; 
which is usually easy to =
denote=20
  with time/experience.  The 
pier usually needs to "fit" the =
area=20
  required by the sensor/s 
anticipated.  The thickness of the =
concrete=20
  slab can be 
debated I suppose, but I'd try for whatever =
depth/thickness=20
  
you can squeeze in the spot you chose.  I use about a 7-8"=20
  
thickness of my three piers....which are in reality cast concrete=20
  
pavers stacked together but layered in the joints and surfaces =

with=20
  real concrete.  I chose this as it was near impossible to 
mix =
massive=20
  concrete on my knees under the house, let alone 
move all the =
sand/concrete=20
  therein.  For myself, I elected to 
also use thick mylar sheet =
under=20
  the piers, to limit water 
absorbion into the piers.  I even =
used a=20
  water repellent paint 
on the pier/s to limit water =
absorbtion.  Even=20
  after completion, 
you can expect a period of time before the piers =

  stabilize from 
curing....perhaps acouple months.  If you can =
make the=20
  pier 
thickness even greater than say...6 inches thick, I'd do =
so.  Do=20
  
not use iron, steel in the pier.=20
  
Personally I live in Denver, and in a city lot.....so, I use my =

house=20
  soil crawlspace for pier/seismometer placements.  I 
also =
enclosed the=20
  piers with walls and insulation to somewhat 
limit temperature =
excursion=20
  that do occur.  Among the PSN 
members....we kind of all =
utilize whats=20
  available.....=20
  
So....in a way....everything gets back to what space you 
have =
now that=20
  could be utilized.  Next, the physical size of 
your =
anticipated=20
  seismos you're planning on building/using.=20
  
I think you're right to get into the seismo housing/piers aspect =

right=20
  off the bat.....if one doesn't; than they will get into alot of =

soil tilt,=20
  water, weather, temperature  related problems that will 
make =
any=20
  consistent seismic monitoring rather useless otherwise. 
Suggest =
that any=20
  pier/containment is well built and temperature 
insulated; this can =
take=20
  time, but it would pay off in the long 
run.=20
  
Outside of the above,.....what kind of seismic sensors are you =

planning=20
  on using.....the instrumentation sensor aspect is always =

interesting.=20
  
Take care, Meredith Lamb=20
  
"Jan D. Marshall" wrote:=20
  

    
    I am starting to design my =
sensors and=20
    electronics and have decided that I understand the requirments there =
pretty=20
    well -- what I don't have a very good understanding on is what do I =
need for=20
    a base or foundation to set the sensors on.  What type of mass =
does it=20
    need? does it need to set on bedrock?  I do not have any cement =
slab=20
    floors. Thanks=20
    Jan D. Marshall 
Nampa, Idaho 
jandmarshall@............=20