Randall Peters wrote:
 
Notice, Bob, what I said about the matter.  If the 'purity' of the  events is 
not what you are most interested in, then give it a try.  The  'carrier' (a 
misnomer) you mention is not 20 Hz but 50 mHz (much lower frequency  than body 
wave values).  There is useful information concerning the energy  of the 
earthquake by doing the power spectral density (corrected for the  transfer 
function of the instrument; i.e., the transient, or 'ringing'  features)-- 
independent of the 'events'.  My guess is that most people  don't really use the details 
of the event
information quantitatively  anyway.
 
Hi Randall,
 
  I guess I am not like "most people". I try very hard to keep my  sensors 
calibrated and as broadbanded as required to accurately sense and  reproduce all 
phases, and my timing within a fraction of a second. I am not  particularly 
interested in the L phases, except for estimating direction. If you  look at my 
Molucca Sea event file, 070121.114300.rem.psn, you will not find the  extra 
hour it took to receive the L waves.
 
  Sorry, but I will not even think of trying what you suggest.
 
  Nor am I interested in displacement sensing. I tried that a long  time ago, 
and all my dynamic range was used up by uncontrollable tilts and  drift. If I 
want to see displacement, I integrate my velocity data after high  pass 
filtering it with my own design zero lag filter to exclude signals  lower than 
0.025 Hz.
 
Bob





Randall Peters wrote:
 
Notice, Bob, what I said about the matter.  If the 'purity' of the=
=20
events is not what you are most interested in, then give it a try.  The=
=20
'carrier' (a misnomer) you mention is not 20 Hz but 50 mHz (much lower frequ=
ency=20
than body wave values).  There is useful information concerning the ene=
rgy=20
of the earthquake by doing the power spectral density (corrected for the=20
transfer function of the instrument; i.e., the transient, or 'ringing'=20
features)-- independent of the 'events'.  My guess is that most people=20
don't really use the details of the event
information quantitatively=20
anyway.
 
Hi Randall,
 
  I guess I am not like "most people". I try very hard to keep my=20
sensors calibrated and as broadbanded as required to accurately sense and=20
reproduce all phases, and my timing within a fraction of a second. I am=
 not=20
particularly interested in the L phases, except for estimating direction. If=
 you=20
look at my Molucca Sea event file, 070121.114300.rem.psn, you will not find=20=
the=20
extra hour it took to receive the L waves.
 
  Sorry, but I will not even think of trying what you suggest.
 
  Nor am I interested in displacement sensing. I tried that a long=
=20
time ago, and all my dynamic range was used up by uncontrollable tilts=20=
and=20
drift. If I want to see displacement, I integrate my velocity data after hig=
h=20
pass filtering it with my own design zero lag filter to exclude signals=
=20
lower than 0.025 Hz.
 
Bob