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Old January 11th 05, 03:42 PM posted to uk.sci.weather
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Default (Was) "Has the tsunami changed world weather forever?"

I Remember something from uni and some documentaries that if the axis
shifts beyond a threshold it flips now that wood be fun... Tsunami
itsself will not effect weather/climate but what the article below
says my just have some impact however difficult to quantify or
qualify:


========================================
MELBOURNE, Australia (Reuters) -- Two weeks on, the Earth is still
vibrating from the massive undersea earthquake off Indonesia that
triggered the tsunami, Australian researchers said on Sunday.
The Australian National University (ANU) said the reverberations were
similar in form to the ringing of a bell, though without the sound,
and were picked up by gravity monitoring instruments.
"These are not things that are going to throw you off your chair, but
they are things that the kinds of instruments that are in place around
the world can now routinely measure," said ANU Earth Sciences
researcher Herb McQueen.
"It is certainly above the background level of vibrations that the
earth is normally accustomed to experiencing."
The magnitude 9.0 earthquake, the strongest for 40 years, struck off
the coast of Indonesia's Sumatra island on December 26. The tsunami it
generated claimed more than 156,000 lives.
McQueen said the oscillation was fading and at current levels equated
to about a millimeter of vertical motion of the earth.
Immediately after the quake the oscillation was probably in the 20 to
30 cm motion range that is typically generated in the earth by the
movements of the sun and moon.
"This particular earthquake because it was 10 times larger than most
of the recent large earthquakes is continuing to reverberate," McQueen
said.
"We can still see a steady signal of the earth vibrating as a result
of that earthquake two weeks later. From what it looks like, it
appears it will probably continue to oscillate for several more
weeks."
The ANU's gravity meter is housed in a fireproof basement at the Mount
Stromlo Observatory near the capital Canberra and is part of a global
geodynamics project established after major earthquakes in the 1960s.
U.S. scientists said just after the quake that it may have permanently
accelerated the Earth's rotation shortening days by a fraction of a
second and caused the planet to wobble on its axis.
Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in
California, theorized that a shift of mass towards the Earth's center
during the quake caused the planet to spin three millionths of a
second faster and tilt about 2.5 cm on its axis

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Old January 11th 05, 04:49 PM posted to uk.sci.weather
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Posts: 103
Default (Was) "Has the tsunami changed world weather forever?"

It did have some effects!
http://www.mercopress.com/Detalle.asp?NUM=4951

Simon S wrote:
I Remember something from uni and some documentaries that if the axis
shifts beyond a threshold it flips now that wood be fun... Tsunami
itsself will not effect weather/climate but what the article below
says my just have some impact however difficult to quantify or
qualify:


========================================
MELBOURNE, Australia (Reuters) -- Two weeks on, the Earth is still
vibrating from the massive undersea earthquake off Indonesia that
triggered the tsunami, Australian researchers said on Sunday.
The Australian National University (ANU) said the reverberations were
similar in form to the ringing of a bell, though without the sound,
and were picked up by gravity monitoring instruments.
"These are not things that are going to throw you off your chair, but
they are things that the kinds of instruments that are in place around
the world can now routinely measure," said ANU Earth Sciences
researcher Herb McQueen.
"It is certainly above the background level of vibrations that the
earth is normally accustomed to experiencing."
The magnitude 9.0 earthquake, the strongest for 40 years, struck off
the coast of Indonesia's Sumatra island on December 26. The tsunami it
generated claimed more than 156,000 lives.
McQueen said the oscillation was fading and at current levels equated
to about a millimeter of vertical motion of the earth.
Immediately after the quake the oscillation was probably in the 20 to
30 cm motion range that is typically generated in the earth by the
movements of the sun and moon.
"This particular earthquake because it was 10 times larger than most
of the recent large earthquakes is continuing to reverberate," McQueen
said.
"We can still see a steady signal of the earth vibrating as a result
of that earthquake two weeks later. From what it looks like, it
appears it will probably continue to oscillate for several more
weeks."
The ANU's gravity meter is housed in a fireproof basement at the Mount
Stromlo Observatory near the capital Canberra and is part of a global
geodynamics project established after major earthquakes in the 1960s.
U.S. scientists said just after the quake that it may have permanently
accelerated the Earth's rotation shortening days by a fraction of a
second and caused the planet to wobble on its axis.
Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in
California, theorized that a shift of mass towards the Earth's center
during the quake caused the planet to spin three millionths of a
second faster and tilt about 2.5 cm on its axis

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Old January 11th 05, 07:03 PM posted to uk.sci.weather
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Default (Was) "Has the tsunami changed world weather forever?"

Simon S wrote:
The ANU's gravity meter is housed in a fireproof basement at the Mount
Stromlo Observatory near the capital Canberra and is part of a global
geodynamics project established after major earthquakes in the 1960s.
U.S. scientists said just after the quake that it may have permanently
accelerated the Earth's rotation shortening days by a fraction of a
second and caused the planet to wobble on its axis.
Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in
California, theorized that a shift of mass towards the Earth's center
during the quake caused the planet to spin three millionths of a
second faster and tilt about 2.5 cm on its axis


Eh? This stuff was already earlier mentioned on different newsgroups.
One specific response caught my attention. It seems that the Earth's
rotation because of the gravitational pull of the Moon slows every year.
Now this was already known. The poster also said that by this every day
is lengthened by 15ms on a yearly basis. Sooo .. how can this 3ms
speedup then be permanent? Within approx 2.5 months there should be no
effects left.
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Old January 11th 05, 07:22 PM posted to uk.sci.weather
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Posts: 489
Default (Was) "Has the tsunami changed world weather forever?"

Richard wrote:
Simon S wrote:

The ANU's gravity meter snip ...




Eh? This stuff was already earlier mentioned on different newsgroups.
One specific response caught my attention. It seems that the Earth's
rotation because of the gravitational pull of the Moon slows every year.
Now this was already known. The poster also said that by this every day
is lengthened by 15ms on a yearly basis. Sooo .. how can this 3ms
speedup then be permanent? Within approx 2.5 months there should be no
effects left.


You are cheating now (:
You are not allowed to use your ability to count ... just believe (look
deep into NASA's eyes) ... the foam hitting the heat shield had no
effect ... no effect ... ooops ... wrong NASA page.

--
Gianna Stefani

www.buchan-meteo.org.uk
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Old January 11th 05, 07:22 PM posted to uk.sci.weather
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First recorded activity by Weather-Banter: Sep 2004
Posts: 85
Default (Was) "Has the tsunami changed world weather forever?"

Richard wrote:
during the quake caused the planet to spin three millionths of a
second faster and tilt about 2.5 cm on its axis



Eh? This stuff was already earlier mentioned on different newsgroups.
One specific response caught my attention. It seems that the Earth's
rotation because of the gravitational pull of the Moon slows every year.
Now this was already known. The poster also said that by this every day
is lengthened by 15ms on a yearly basis. Sooo .. how can this 3ms
speedup then be permanent? Within approx 2.5 months there should be no
effects left.


And to follow up on that, the following link had some nice info:
http://www.iers.org/iers/earth/rotat...od/ut1lod.html.

"Universal time and length of day are subject to variations due to the
zonal tides (smaller than 2.5 ms in absolute value), to oceanic tides
(smaller than 0.03 ms in absolute value), to atmospheric circulation, to
internal effects and to transfer of angular momentum to the Moon orbital
motion."

The 3 ms of the Sumatra quake therefore is slightly larger than the
variations due to zonal tides. Not really something to write home about.


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