=20
In a message dated 17/10/2009, _gel@.....................
(mailto:gel@..................  writes:=20

After the big quakes in the South Pacific a  couple weeks ago it seems to=
=20
me that the background noise was very high after  the events and stayed th=
at=20
way for many days. But now things are back to normal  and low noise and I=
=20
can crank up the gain again. There is always a chance that  that the noise=
 is=20
from the ocean, but I don=E2=80=99t think so. Did you noticed a jump  in=
 noise after=20
the recent Big Ones. If so, is there any rule as to how long  things take=
=20
to cool off.

Hi Gary,=20

These are almost certainly deep ocean  microseisms, but you also get highe=
r=20
signals when a storm system crosses the  coast and when a cold front passe=
s=20
through. You see signals like this world  wide. There is a centre south of=
=20
Greenland and another east of Japan. Waves on  the west coast are likely=
 to=20
show up.
    See wave heights at _http://www.oceanweather.com/data/index.html_=20
(http://www.oceanweather.com/data/index.html)=20

With two Lehmans, you can estimate the  direction.

The rise and fall is likely to be several days  minimum, similar to storm=
=20
systems.=20
=20
    Regards,
=20
    Chris







In a message dated 17/10/2009, gel@................. writes: 

    After the big quakes in the South Pacific=
 a=20
couple weeks ago it seems to me that the background noise was very high af=
ter=20
the events and stayed that way for many days. But now things are back to=
 normal=20
and low noise and I can crank up the gain again. There is always a chance=
 that=20
that the noise is from the ocean, but I don=E2=80=99t think so. Did you no=
ticed a jump=20
in noise after the recent Big Ones. If so, is there any rule as to how lon=
g=20
things take to cool off.

Hi Gary, 

    These are almost certainly deep ocean=20
microseisms, but you also get higher signals when a storm system crosses=
 the=20
coast and when a cold front passes through. You see signals like this worl=
d=20
wide. There is a centre south of Greenland and another east of Japan. Wave=
s on=20
the west coast are likely to show up.
    See wave heights at http://www.oceanweath=
er.com/data/index.html

    With two Lehmans, you can estimate the=20
direction.

    The rise and fall is likely to be several=
 days=20
minimum, similar to storm systems. 
 
    Regards,
 
    Chris