Earth Speed Up | Earth Ringing - Earthquake
As seen on the
Earth still ringing
like a bell after Asia quake
MELBOURNE, Jan 9 (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
"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
The magnitude 9.0
earthquake, the strongest for 40 years, struck off the coast of Indonesia's
Sumatra island on Dec. 26. The tsunami it generated claimed more than
\McQueen said the
oscillation was fading and at current levels equated to about a millimeter
of vertical motion of the earth.
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
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 centre during the quake caused the planet
to spin three millionths of a second faster and tilt about 2.5 cm on its
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