Tsunami-causing quake has astounded scientists
While the world has focused on the deadly tsunami it triggered, researchers have been unearthing the stunning facts behind December's Sumatra-Andaman earthquake.
It lasted longer than any quake ever recorded -- up to three hours. It ripped along more than 800 miles of fault, creating the longest known fault rupture.
Some researchers think the quake's official magnitude should be raised from 9.0 to 9.3, which would make it the second most powerful quake ever recorded on seismometers.
It released up to three times more energy than previously thought -- as much energy as the United States uses in six months, the equivalent of a 100-gigaton bomb.
Yet strangely enough, only one-third of that energy was released during the first 10 minutes of the quake, as the fault unzipped at speeds of up to 6,700 mph.
After the violent shaking stopped, the fault kept slipping, but much more slowly, sending out very long, slow seismic waves that people could not feel.
"The fault was sort of oozing along,'' said Thorne Lay, a seismologist with the University of California-Santa Cruz.
No part of the Earth was unaffected by the great quake. At every point on the globe, the ground rose and fell by at least a fraction of an inch, said Michael West, a seismologist with the Alaska Volcano Observatory in Fairbanks.
"The Sumatra earthquake is just a different kind of event,'' he said. "We're not used to dealing with earthquakes like this.''
Edmonton Journal: Our North loses the Pole
If the pole continues its current course, it will shoot across the top of Earth and end up in Siberia by mid-century.
But the pole's movements are difficult to forecast, since its location depends on a terrestrial magnetic field that is produced by extremely complex forces deep inside Earth. Those forces, at their simplest, drive a churning mass of molten iron that rises and falls on convective currents more than 3,000 kilometres below the planet's surface. The movement of that iron conducts and produces the magnetic field, whose poles are located fairly close, although still often thousands of kilometres away from, the geographic poles.
Curiously, the speed with which the pole moves could be related to dramatic events like the massive earthquake that caused last December's devastating tsunami. That quake was big enough to alter the shape of Earth and jar the planet into a slightly different axis of rotation. It also had enough power to jolt the molten iron that powers the magnetic field, and could be partly responsible for magnetic "jerks" that are propelling the magnetic North Pole
A bit creepy that, seeing as I was reading about it the other day, the hollow earth stuff that is...
