Re: crawl space under houseGary, Yes your wine cellar on concrete =
noise, looks similar to my "walk up to noise" in my basement with =
concrete floor. I too get only small temp changes in this room, summer =
or winter.
Thanks, Ted
----- Original Message -----=20
From: Gary Lindgren=20
To: psn-l@.................
Sent: Saturday, August 30, 2008 4:38 PM
Subject: RE: crawl space under house
Hi Ted,
I'm glad you are getting lots of ideas for your new seismometer =
location. I have mine in the wine cellar, on the concrete floor. =
Temperature is very stable. No real changes during the day. Over the =
seasons, it may change 10 degrees F. However when we visit the wine =
cellar, the alarms go off. Walking by will give quite a jolt, at least =
on the screen. But quickly settles down. I see traffic noise from 6AM to =
11PM (freeway 2 miles away) and freight trains in the middle of the =
night (1 mile away) and of course the washer/dryer. It's only 15 feet =
away but with 6" framed wall with insulation between. Let us know what =
you decide to do.
Gary
See http://www.blue-eagle-technologies.com/images/ch1.gif If you are =
quick, the red signal in upper right is the last wine cellar visit.
=20
=20
From: psn-l-request@.............. =
[mailto:psn-l-request@............... On Behalf Of =
tchannel1@............
Sent: Saturday, August 30, 2008 2:39 PM
To: psn-l@..............
Subject: Re: crawl space under house
=20
Hi Bob, Thanks for sharing...........Presently my sensors are in the =
basement on a concrete floor. Yes I do see people walking upstairs, =
but mostly if I place the sensor close to a vertical wall.
My new house set on a new foundation, so as you point out I may get a =
lot of noise as the house settles. We shall see. All your =
information is good to know.
=20
Ted
----- Original Message -----=20
From: Bob Hancock=20
To: psn-l@.................
Sent: Saturday, August 30, 2008 12:40 PM
Subject: Re: crawl space under house
=20
Hi Ted -
When we lived in NJ, I operated a 3 channel MET seismometer in the =
crawl space under my apartment. I had the instrument sitting on a =
hexagonal cement block of 12 inches across and 2 inches thick, all =
covered with a Styrofoam bucket. The building design included =
foundation walls that were placed several feet in the soil, including =
individual foundations walls between each apartment. Although I had the =
instrument more or less in the middle of the area, I found that as I =
walked on the floor above, I could see that motion on the instrument. =
Depending upon your foundation, you may find that walking around your =
house will cause deflections of the instruments. I have heard similar =
comments from individuals who have placed instruments in basements or on =
garage floors.
When we moved to Arizona, I tried a variety of locations including =
under my house, in a nearby storage shed and in my workshop. None were =
adequate. I finally placed the instrument in the ground, first about 75 =
feet away and I could always tell when the washing machine when into the =
spin cycle. I finally moved the instrument about 250 feet from the =
house where I get a minimum of wind and cultural noise. The road is =
about 400 feet from the instrument and I can see vehicles striking =
potholes in the road. I find that if I drive my garden tractor within =
50 feet of my vault, I can see movement on the instrument. =20
Depending upon your yard size, you might consider a subsurface vault =
in a quiet area, away from trees and any buildings. It is very =
difficult to remove cultural noise as I have found. However, you should =
be careful and do not disturb any more dirt than you need. Dirt once =
disturbed is difficult to re-compact and will be a source of noise for a =
long time to come as it settles. I have found that after 1 1/2 years, I =
still get occasional ground noise from settling dirt.
Another thought to consider is insulating your instrument from wind =
currents. Seismometers are extremely sensitive to any wind flow and =
temperature change. In my setup, I first covered my instrument with =
sand bags, and that did a good job of insulating the instrument from =
thermal variation and wind flow. However, they were hard to remove from =
the hole, and I settled on a large bucket lined with fiberglass which =
sits on top of the instrument and covers it down to its base. I have =
found this to be very effective and the bucket protects the instrument =
from both wind flow and thermal variations. Even in a sealed seismic =
vault you need to protect against errant wind currents caused by uneven =
thermal heating of the vault as the sun moves across the sky.
The key for a quiet instrument is reduction of cultural noise and =
wind noise. Things to consider is under a house you will most likely =
pick up movement of people in the house, and tilt from the house in =
times of high and possibly even moderate winds. You proximity to trees =
is another consideration as the root structure causes ground tilt for a =
considerable distance. Railroad tracks can transmit vibrations for =
miles. The worst rail noise comes from diamonds where one set tracks =
crosses another set of tracks. Major roads that are in poor repair with =
potholes and lots of semi-trailers are another source of cultural =
noise.......Just some thoughts to consider.
Good luck on your location wherever you choose it.
Bob Hancock
=20
----- Original Message -----=20
=20
From: Gary Lindgren =20
=20
To: psn-l@.................
=20
Sent: Thursday, August 28, 2008 9:59 AM
=20
Subject: craw space under house
Hi All, I am building a new house. This house has no =
basement, but has a 24"? crawlspace under the house. I have lots of =
time, to create a space for my three sensors, under the house. I =
could also place them in the garage on the concrete floor. My thought =
was to enter the crawlspace, and dig a small pit large enough to allow =
for elbow room, then line the pit with concrete blocks to keep dirt =
away. Perhaps covering the floor area similarly. Concrete may not be =
the best material. I could also pour a pad or small footing using =
cement.
=20
Please any thoughts on preparing this space?
=20
=20
=20
=20
Thanks, Ted
=20
=20
Re: crawl =
space under house
Gary, Yes your wine cellar on =
concrete noise,=20
looks similar to my "walk up to noise" in my basement with =
concrete=20
floor. I too get only small temp changes in this room, =
summer or=20
winter.
Thanks, Ted
----- Original Message -----
From:=20
Gary=20
Lindgren
Sent: Saturday, August 30, 2008 =
4:38=20
PM
Subject: RE: crawl space under=20
house
Hi=20
Ted,
I=92m=20
glad you are getting lots of ideas for your new seismometer location. =
I have=20
mine in the wine cellar, on the concrete floor. Temperature is very =
stable. No=20
real changes during the day. Over the seasons, it may change 10 =
degrees F.=20
However when we visit the wine cellar, the alarms go off. Walking by =
will give=20
quite a jolt, at least on the screen. But quickly settles down. I see =
traffic=20
noise from 6AM to 11PM (freeway 2 miles away) and freight trains in =
the middle=20
of the night (1 mile away) and of course the washer/dryer. It=92s only =
15 feet=20
away but with 6=94 framed wall with insulation between. Let us know =
what you=20
decide to do.
Gary
See=20
http://www=
..blue-eagle-technologies.com/images/ch1.gif =20
If you are quick, the red signal in upper right is the last wine =
cellar=20
visit.
From: =20
psn-l-request@.............. [mailto:psn-l-request@............... =
On=20
Behalf Of tchannel1@............
Sent: Saturday, August =
30, 2008=20
2:39 PM
To: psn-l@..............
Subject: Re: =
crawl space=20
under house
Hi =
Bob, =20
Thanks for sharing...........Presently my sensors are in the basement =
on a=20
concrete floor. Yes I do see people walking upstairs, but =
mostly=20
if I place the sensor close to a vertical =
wall.
My new =
house set on=20
a new foundation, so as you point out I may get a lot of noise as the =
house=20
settles. We shall see. All your information is =
good to=20
know.
Ted
----- =
Original=20
Message -----
From: Bob=20
Hancock
To: psn-l@..............=20
Sent: =
Saturday, August=20
30, 2008 12:40 PM
Subject: Re: =
crawl space=20
under house
Hi Ted =
-
When we lived in NJ, I operated a 3 channel MET seismometer =
in the=20
crawl space under my apartment. I had the instrument =
sitting on=20
a hexagonal cement block of 12 inches across and 2 inches thick, all =
covered=20
with a Styrofoam bucket. The building design included =
foundation walls=20
that were placed several feet in the soil, including individual =
foundations=20
walls between each apartment. Although I had the instrument =
more or=20
less in the middle of the area, I found that as I walked on the =
floor above,=20
I could see that motion on the instrument. Depending upon your =
foundation, you may find that walking around your house will cause=20
deflections of the instruments. I have heard similar comments =
from=20
individuals who have placed instruments in basements or on garage=20
floors.
When we moved to Arizona, I tried a variety of =
locations=20
including under my house, in a nearby storage shed and in my =
workshop.=20
None were adequate. I finally placed the instrument in =
the=20
ground, first about 75 feet away and I could always tell when the =
washing=20
machine when into the spin cycle. I finally moved the =
instrument about=20
250 feet from the house where I get a minimum of wind and cultural =
noise.=20
The road is about 400 feet from the instrument and I can see =
vehicles=20
striking potholes in the road. I find that if I drive my =
garden=20
tractor within 50 feet of my vault, I can see movement on the =
instrument.=20
Depending upon your yard size, you might consider a =
subsurface=20
vault in a quiet area, away from trees and any buildings. It =
is very=20
difficult to remove cultural noise as I have found. However, =
you=20
should be careful and do not disturb any more dirt than you need. =
Dirt=20
once disturbed is difficult to re-compact and will be a source of =
noise for=20
a long time to come as it settles. I have found that after 1 =
1/2=20
years, I still get occasional ground noise from settling=20
dirt.
Another thought to consider is insulating your =
instrument from=20
wind currents. Seismometers are extremely sensitive to any =
wind flow=20
and temperature change. In my setup, I first covered my =
instrument=20
with sand bags, and that did a good job of insulating the instrument =
from=20
thermal variation and wind flow. However, they were hard to =
remove=20
from the hole, and I settled on a large bucket lined with fiberglass =
which=20
sits on top of the instrument and covers it down to its base. =
I have=20
found this to be very effective and the bucket protects the =
instrument from=20
both wind flow and thermal variations. Even in a sealed =
seismic vault=20
you need to protect against errant wind currents caused by uneven =
thermal=20
heating of the vault as the sun moves across the sky.
The key =
for a=20
quiet instrument is reduction of cultural noise and wind noise. =
Things=20
to consider is under a house you will most likely pick up movement =
of people=20
in the house, and tilt from the house in times of high and possibly =
even=20
moderate winds. You proximity to trees is another =
consideration as the=20
root structure causes ground tilt for a considerable distance.=20
Railroad tracks can transmit vibrations for miles. The =
worst=20
rail noise comes from diamonds where one set tracks crosses another =
set of=20
tracks. Major roads that are in poor repair with potholes and =
lots of=20
semi-trailers are another source of cultural noise.......Just some =
thoughts=20
to consider.
Good luck on your location wherever you choose=20
it.
Bob Hancock
-----=20
Original Message -----
From: Gary=20
Lindgren <mailto:gel@.................>=
;=20
To: psn-l@.................
Sent: Thursday, August 28, 2008 9:59=20
AM
Subject: craw space under=20
house
Hi =
All,=20
I am building a new house. This =
house has no=20
basement, but has a 24"? crawlspace under the house. =
I=20
have lots of time, to create a space for my three sensors, =
under the=20
house. I could also place them in the garage on =
the=20
concrete floor. My thought was to enter the =
crawlspace,=20
and dig a small pit large enough to allow for elbow room, then =
line=20
the pit with concrete blocks to keep dirt away. Perhaps=20
covering the floor area similarly. Concrete may not be =
the=20
best material. I could also pour a pad or small =
footing=20
using cement.
Please any=20
thoughts on preparing this space?
<=
BR>Thanks,=20
Ted