The earthquake made the Earth wobble on its axis by an inch or so, altered regional geography by a few metres and cut the length of the day by a few millionths of a second.
It struck where one plate corresponding to the Indian Ocean floor is being pushed under another, Eurasia, along a long fault line known as a subduction zone.
At the fault, which stretches from the seabed to a few miles beneath the ocean floor, the two plates slipped violently and abruptly over a 700-mile stretch.
Based on calculations by Dr Chen Ji at Caltech, the 9.0-magnitude quake may have caused movement around the fault by 20-30 metres, according to Dr Ken Hudnut of the US Geological Survey, who added: "That is a lot of slip."
In turn, this will affect the local geography, notably subsidence that led to inundation along the coastline. "That earthquake has changed the map," he said.
"It is the permanent vertical movement along the coastline that may have had a serious human impact in this case, in that some harbours and port facilities may have been raised, lowered, or damaged such that they cannot readily be used in relief efforts."
He added: "The small islands that lie off the coast of Sumatra itself, such as Simeulue, and even possibly the Nicobar and Andaman Islands, may have moved by several tens of centimetres up to possibly several metres."
Dr Hudnut, of the Southern California Earthquake Hazards Assessment Project, said his colleagues planned to visit the area to examine the effects with the aid of the global positioning survey.
"That will take weeks or months to complete." The energy released as the two sides of the fault slipped against each other made the Earth wobble on its axis, he said. "A piece of the Earth's crust is in a different place, though relative to the mass of the Earth it is tiny and the effects, though potentially just barely observable, will be small."
Dr Ben Chao, of Nasa's Goddard Space Flight Centre, said one calculation suggested that the quake would cut the length of day by three millionths of a second and cause a pole shift of around an inch.
Another USGS research geophysicist, Dr Stuart Sipkin, agreed that the Earth would have received a "little jog", but said the islands off Sumatra would have been moved higher by the quake.
• The Richter scale, known for decades as the measure of earthquakes, is now seen as out of date and the term is no longer used by scientists among themselves.
Seismologists prefer the moment magnitude scale developed by Dr Hiroo Kanamori of Caltech. This is derived from the energy released during the ground movements that generate the earthquake.
Bron: http://www.telegraph.co.uk/
ROME, Dec. 28 (Xinhuanet) -- Italian space researchers said on Tuesday that the earthquake in Asia two days ago was so powerful that it shifted the axis around which the earth revolves.
"It was so violent that it modified in a considerable way the inclination of the axis of terrestrial rotation," said scientists at an Italian Space Agency centre in the southern town of Matera.
According to Giuseppe Bianco, one of the geological experts whospecialize in finding the exact position of geographical points, the axis moved by about five or six centimetres.
"The variation observed is very small and I don't think it could have any repercussions on the climate," he said.
On Sunday, huge tidal waves killed more than 50,000 people in some Asian countries including Sri Lanka, India, Indonesia, Thailand, Malaysia the Maldives and Myanmar. Enditem
Bron: www.chinaview.cn
It struck where one plate corresponding to the Indian Ocean floor is being pushed under another, Eurasia, along a long fault line known as a subduction zone.
At the fault, which stretches from the seabed to a few miles beneath the ocean floor, the two plates slipped violently and abruptly over a 700-mile stretch.
Based on calculations by Dr Chen Ji at Caltech, the 9.0-magnitude quake may have caused movement around the fault by 20-30 metres, according to Dr Ken Hudnut of the US Geological Survey, who added: "That is a lot of slip."
In turn, this will affect the local geography, notably subsidence that led to inundation along the coastline. "That earthquake has changed the map," he said.
"It is the permanent vertical movement along the coastline that may have had a serious human impact in this case, in that some harbours and port facilities may have been raised, lowered, or damaged such that they cannot readily be used in relief efforts."
He added: "The small islands that lie off the coast of Sumatra itself, such as Simeulue, and even possibly the Nicobar and Andaman Islands, may have moved by several tens of centimetres up to possibly several metres."
Dr Hudnut, of the Southern California Earthquake Hazards Assessment Project, said his colleagues planned to visit the area to examine the effects with the aid of the global positioning survey.
"That will take weeks or months to complete." The energy released as the two sides of the fault slipped against each other made the Earth wobble on its axis, he said. "A piece of the Earth's crust is in a different place, though relative to the mass of the Earth it is tiny and the effects, though potentially just barely observable, will be small."
Dr Ben Chao, of Nasa's Goddard Space Flight Centre, said one calculation suggested that the quake would cut the length of day by three millionths of a second and cause a pole shift of around an inch.
Another USGS research geophysicist, Dr Stuart Sipkin, agreed that the Earth would have received a "little jog", but said the islands off Sumatra would have been moved higher by the quake.
• The Richter scale, known for decades as the measure of earthquakes, is now seen as out of date and the term is no longer used by scientists among themselves.
Seismologists prefer the moment magnitude scale developed by Dr Hiroo Kanamori of Caltech. This is derived from the energy released during the ground movements that generate the earthquake.
Bron: http://www.telegraph.co.uk/
ROME, Dec. 28 (Xinhuanet) -- Italian space researchers said on Tuesday that the earthquake in Asia two days ago was so powerful that it shifted the axis around which the earth revolves.
"It was so violent that it modified in a considerable way the inclination of the axis of terrestrial rotation," said scientists at an Italian Space Agency centre in the southern town of Matera.
According to Giuseppe Bianco, one of the geological experts whospecialize in finding the exact position of geographical points, the axis moved by about five or six centimetres.
"The variation observed is very small and I don't think it could have any repercussions on the climate," he said.
On Sunday, huge tidal waves killed more than 50,000 people in some Asian countries including Sri Lanka, India, Indonesia, Thailand, Malaysia the Maldives and Myanmar. Enditem
Bron: www.chinaview.cn
