Hi Geoff,
=20
Curiously enough I was interested at one time in a omni directional =20
seismometer but also wanted directional information. What I ended up with w=
as a =20
pendulum with 2 degrees of freedom which via a quadrant photo cell  resolve=
d =20
the N-S,  E-W  component independently.=20

As my wife=E2=80=99s family is in Japan I am on permanent earthquake watch =
for =20
anything from there.  If the first responses are identical in amplitude and=
 =20
both of the same polarity I know the quake  is on the N-E  S-W axis.  The t=
ime=20
interval between the P and the S give of course the distance and being =20
based in England,  I have a choice of ether the middle of South America or =
 of=20
the east coast of Japan. Any thing over M6.5 and my wife is straight on the=
 =20
phone to Japan.

Regards Martin
=20
=20





Hi Geoff,
 
Curiously enough I was interested at one time in a omni directional=20
seismometer but also wanted directional information. What I ended up with w=
as a=20
pendulum with 2 degrees of freedom which via a quadrant photo cell=20
resolved  the N-S,  E-W  component independently. 

As my wife=E2=80=99s family is in Japan I am on permanent earthquake w=
atch for=20
anything from there.  If the first responses are identical in amplitud=
e and=20
both of the same polarity I know the quake  is on the N-E  S-W ax=
is.=20
The time interval between the P and the S give of course the distance and b=
eing=20
based in England,  I have a choice of ether the middle of South Americ=
a or=20
of the east coast of Japan. Any thing over M6.5 and my wife is straight on =
the=20
phone to Japan.

Regards Martin