Recently I saw reference to an article on the parameters of "Earth =
Hum"---Real long period waves of 4 to 5 minutes.  This translated to a =
frequency 16 octives below (256 Hz) middle C.  These waveforms are =
detectable seemingly anywhere on the Earth's surface.
   The article can be found in the Sept. 30th '04 issue of Nature =
magazine, but didn't give much help in the recording mechanics of such =
long waveforms. Can anyone simplify an explanation of how these waves =
are detected????  These low frequency oscillations seem to be caused by =
winter storms over oceans, and are quite detached from common =
microseisms we are familiar with.
                            Jim Lehman







Recently I saw reference to an =
article on=20
the parameters of "Earth Hum"---Real long period waves of 4 to 5 =
minutes. =20
This translated to a frequency 16 octives below (256 Hz) middle C.  =
These=20
waveforms are detectable seemingly anywhere on the Earth's=20
surface.
   The =
article can be found=20
in the Sept. 30th '04 issue of Nature magazine, but =
didn't give=20
much help in the recording mechanics of such long waveforms. Can =
anyone=20
simplify an explanation of how these waves are detected????  These =
low=20
frequency oscillations seem to be caused by winter storms over oceans, =
and are=20
quite detached from common microseisms we are familiar=20
with.
          &nbs=
p;            =
;    =20
Jim Lehman