Randall
  It seems that there are two measurements being discussed (horizontal accelerations due to teleseismic events and tilting of the sensor). Accelerometers are designed with a high natural frequency since they are suited to measure displacements below this frequency. Tilting a accelerometer will measure that portion of gravity induced. I think accelerations from a teleseismic events are very very small. I can see how a simple pendulum will act as a tilt meter  if one can remove the possibly changes from temperature, soil moisture gradients ( when sensor is not on bedrock) etc 
  If a pendulum were very long (as you mentioned) I also believe the measurement of displacement relative to the support would measure the earth displacement from a teleseismic event .It seems to me that bodies at rest tend to stay at rest unless an external force is applied to them (like the restoring force of a short period pendulum which is not allowed to tilt). One would have to correct for the drop off in sensitivity by post processing or with real time electronics or math. 
  Regards
  Barry
  

Randall Peters  wrote:
    
  moreover, when monitored with a position rather than velocity sensor, there is no falloff in sensitivity whatsoever when the
frequency is below its natural frequency (unless one stupidly insists on the use of a velocity sensor, which for periods
greater than a few thousand seconds WILL NEVER WORK!).
   
  
   
  The simple
pendulum would be a GREAT candidate for so doing if I had a facility to hold one whose length were 10 m (or even longer). As
compared to the VolksMeter, it would be 100 times more sensitive in every frequency range. (For tide studies it doesn't need
that sensitivity; but for 20 s period teleseisms, it does.)
Randall


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Randall
  
It seems that there are two measurements being discussed (horizontal accelerations due to teleseismic events and tilting of the sensor). Accelerometers are designed with a high natural frequency since they are suited to measure displacements below this frequency. Tilting a accelerometer will measure that portion of gravity induced. I think accelerations from a teleseismic events are very very small. I can see how a simple pendulum will act as a tilt meter  if one can remove the possibly changes from temperature, soil moisture gradients ( when sensor is not on bedrock) etc 
  
If a pendulum were very long (as you mentioned) I also believe the measurement of displacement relative to the support would measure the earth displacement from a teleseismic event .It seems to me that bodies at rest tend to stay at rest unless an external force is applied to them (like the restoring force of a short period pendulum
 which is not allowed to tilt). One would have to correct for the drop off in sensitivity by post processing or with real time electronics or math. 
  
Regards
  
Barry
  


Randall Peters <PETERS_RD@..........> wrote:
  
  
<clip>
  
moreover, when monitored with a position rather than velocity sensor, there is no falloff in sensitivity whatsoever when the
frequency is below its natural frequency (unless one stupidly insists on the use of a velocity sensor, which for periods
greater than a few thousand seconds WILL NEVER WORK!).
  
 
  
<clip>
  
 
  
The simple
pendulum would be a GREAT candidate for so doing if I had a facility to hold one whose length were 10 m (or even longer). As
compared to the VolksMeter, it would be 100