Jerry,
=20
Here is a useful site that contains some instrument prices (but mostly =
specs) in a convenient matrix. Some info is a year or two old, but its =
an eye opener. Professional seismic instrumentation is certainly not =
cheap. Please go to:
=20
http://sismic.am.ub.es/jvila/instrumentation/
=20
Click on any of the four different links for listings.
=20
Regards,
=20
Allan

-----Original Message-----
From: psn-l-request@.............. =
[mailto:psn-l-request@................. Behalf Of ChrisAtUpw@.......
Sent: Sunday, December 03, 2006 2:08 PM
To: psn-l@..............
Subject: Re: Technicial Terms


In a message dated 2006/12/03, gpayton880@....... writes:



Another technical term that I am not familiar with has popped up: =
EIGENFREQUENCY.  Is that synonymous with "natural period" (for our =
purposes)?



Hi Jerry,

       This refers to fixed period responses, due to physical =
characteristics. For instance, the Earth has a wide range of possible =
oscillatory modes in the millihertz region commonly lumped together as =
Eigen Modes, with various suffixes. The frequencies are fixed, but the =
amplitude of the oscillations varies with the exciting source and with =
time. The huge quake in Sumatra excited many modes some of which took =
months to die away.

       The term was first applied to characteristic optical responses of =
atoms.

       I am too embarrassed to ask the manufacturer.  Do you know the =
cost for the Lennartz seismometers?  Or, any other mfg.?  I'm just =
curious........

       Not off hand, but I can enquire if you like? Was there any =
particular model that you are interested in? Single axis vertical models =
and triaxial models are usually marketed. Would this be for just the =
sensor, or for a system complete with an ADC, datalogger and timing?

       New prices of 4.5 Hz geophones are about $60, 2 Hz geophones =
about $450 and 1 Hz geophones $1,000 to $2,500 depending on the model. =
There may be considerable price reductions for 2 and 1 Hz units, if you =
want a quantity.=20

       The cost of the Guralp PEPP single vertical sensor for schools =
CMG EDU was about $4,000 when I last looked - response 30 Hz to 30 =
seconds. This is for the sensor, the ADC + electronics and GPS timing. =
You have to supply a PC computer + monitor. We can buy them at a reduced =
price since we do not need GPS timing - DCF77 timing at E10 per receiver =
works just fine!=20

       My severe cold flu? seems to be slowly clearing up, but I am =
still feeling tired and achy.=20

       Regards,

       Chris=20








Jerry,
 
Here=20
is a useful site that contains some instrument prices (but=20
mostly specs) in a convenient matrix. Some info is a year or =
two old,=20
but its an eye opener. Professional seismic instrumentation is certainly =
not=20
cheap. Please go to:
 
http://sismic.am.u=
b.es/jvila/instrumentation/
 
Click=20
on any of the four different links for listings.
 
Regards,
 
Allan

  
-----Original Message-----
From: =
psn-l-request@.................
  [mailto:psn-l-request@...............On Behalf Of=20
  ChrisAtUpw@.......
Sent: Sunday, December 03, 2006 2:08=20
  PM
To: psn-l@..............
Subject: Re: =
Technicial=20
  Terms

In a message dated 2006/12/03, gpayton880@....... =
writes:


  Another technical term that I am not familiar with has =
popped=20
    up: EIGENFREQUENCY.  Is that synonymous with "natural period" =
(for our=20
    purposes)?


Hi=20
  Jerry,

       This refers to =
fixed period=20
  responses, due to physical characteristics. For instance, the Earth =
has a wide=20
  range of possible oscillatory modes in the millihertz region commonly =
lumped=20
  together as Eigen Modes, with various suffixes. The frequencies are =
fixed, but=20
  the amplitude of the oscillations varies with the exciting source and =
with=20
  time. The huge quake in Sumatra excited many modes some of which took =
months=20
  to die away.

       The term was =
first=20
  applied to characteristic optical responses of=20
  atoms.

       I am too =
embarrassed to ask=20
  the manufacturer.  Do you know the cost for the Lennartz=20
  seismometers?  Or, any other mfg.?  I'm just=20
  curious........

       Not off =
hand, but=20
  I can enquire if you like? Was there any particular model that you are =

  interested in? Single axis vertical models and triaxial models are =
usually=20
  marketed. Would this be for just the sensor, or for a system complete =
with an=20
  ADC, datalogger and =
timing?

       New=20
  prices of 4.5 Hz geophones are about $60, 2 Hz geophones about $450 =
and 1 Hz=20
  geophones $1,000 to $2,500 depending on the model. There may be =
considerable=20
  price reductions for 2 and 1 Hz units, if you want a quantity.=20
  

       The cost of the Guralp =
PEPP=20
  single vertical sensor for schools CMG EDU was about $4,000 when I =
last looked=20
  - response 30 Hz to 30 seconds. This is for the sensor, the ADC + =
electronics=20
  and GPS timing. You have to supply a PC computer + monitor. We can buy =
them at=20
  a reduced price since we do not need GPS timing - DCF77 timing at E10 =
per=20
  receiver works just fine! 

       =
My=20
  severe cold flu? seems to be slowly clearing up, but I am still =
feeling tired=20
  and achy. 

      =20
  Regards,

       Chris=20