from : http://spectregroup.wordpress.com/2010/03/05/did-you-feel-that/

Days Now Slightly Shorter
http://jpl.nasa.gov/news/news.cfm?release=2010-071
http://bloomberg.com/apps/news?pid=20601124&sid=aLAUn4Gy92ss
“The earthquake that killed more than 700 people in Chile on Feb. 27 probably shifted the Earth’s axis and shortened the day, a NASA scientist has said. Earthquakes can involve shifting hundreds of kilometers of rock by several meters, changing the distribution of mass on the planet. This affects the Earth’s rotation, said Richard Gross, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who uses a computer model to calculate the effects. “The length of the day should have gotten shorter by 1.26 microseconds (millionths of a second),” Gross said. “It’s what we call the ice-skater effect,” said David Kerridge, head of Earth hazards and systems at the British Geological Survey. “As the ice skater’s going around in a circle, and she pulls her arms in, she gets faster and faster. It’s the same idea with the Earth going around if you change the distribution of mass, the rotation rate changes.” The magnitude 9.1 Sumatran in 2004 that generated an Indian Ocean tsunami shortened the day by 6.8 microseconds and shifted the axis by about 2.3 milliarcseconds, Gross has said.”

(Rotation Affected Much More by Wind)
http://www.scientificamerican.com/article.cfm?id=did-the-earthquake-that-s

Core Flux
http://www.phy6.org/earthmag/dynamos2.htm
http://news.nationalgeographic.com/news/2009/12/091224-north-pole-magnetic-russia-earth-core.html
“The magnetic north pole moved little from the time scientists first located it in 1831. Then in 1904, the pole began shifting northeastward at a steady pace of about 9 miles (15 kilometers) a year. In 1989 it sped up again, and in 2007 scientists confirmed that the pole is now galloping toward Siberia at 34 to 37 miles (55 to 60 kilometers) a year. A rapidly shifting magnetic pole means that magnetic-field maps need to be updated more often to allow compass users to make the crucial adjustment from magnetic north to true North. Geologists think Earth has a magnetic field because the core is made up of a solid iron center surrounded by rapidly spinning liquid metal. This creates a “dynamo” that drives our magnetic field. Scientists had long suspected that, since the molten core is constantly moving, changes in its magnetism might be affecting the surface location of magnetic north. Nobody knows when another change in the core might pop up elsewhere, sending magnetic north wandering in a new direction.”

Earth’s Inconstant Magnetic Field
http://pubs.usgs.gov/gip/dynamic/dynamic.html
http://science.nasa.gov/headlines/Y2003/29dec_magneticfield.htm
“Every few years, scientist Larry Newitt of the Geological Survey of Canada goes hunting. He grabs his gloves, parka, a fancy compass, hops on a plane and flies out over the Canadian arctic. Not much stirs among the scattered islands and sea ice, but Newitt’s prey is there–always moving, shifting, elusive. His quarry is Earth’s north magnetic pole. Keeping track of the north magnetic pole is Newitt’s job. “We usually go out and check its location once every few years,” he says. “We’ll have to make more trips now that it is moving so quickly.” Earth’s magnetic field is changing in other ways, too: Compass needles in Africa, for instance, are drifting about 1 degree per decade. And globally the magnetic field has weakened 10% since the 19th century. They’ve also learned what happens during a magnetic flip. Reversals take a few thousand years to complete, and during that time–contrary to popular belief–the magnetic field does not vanish. “It just gets more complicated,” says Glatzmaier. Magnetic lines of force near Earth’s surface become twisted and tangled, and magnetic poles pop up in unaccustomed places. A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti. Weird. But it’s still a planetary magnetic field, and it still protects us from space radiation and solar storms. And, as a bonus, Tahiti could be a great place to see the Northern Lights…”

North Magnetic Pole Shifting Rapidly Toward Russia
http://news.nationalgeographic.com/news/2005/12/1215_051215_north_pole.html
“New research shows the pole moving at rapid clip—25 miles (40 kilometers) a year. Over the past century the pole has moved 685 miles (1,100 kilometers) from Arctic Canada toward Siberia, says Joe Stoner, a paleomagnetist at Oregon State. At its current rate the pole could move to Siberia within the next half-century. “It’s moving really fast,” he said. “We’re seeing something that hasn’t happened for at least 500 years.” The shift is likely a normal oscillation of the Earth’s magnetic field, Stoner said, and not the beginning of a flip-flop of the north and south magnetic poles, a phenomenon that last occurred 780,000 years ago. Such reversals have taken place 400 times in the last 330 million years, according to magnetic clues sealed in rocks around the world. Each reversal takes a thousand years or more to complete. “People like to think something special is happening in their lifetimes, but despite the dramatic changes, I don’t see any evidence of it,” Stoner said. “It’s probably just a normal wandering of the pole.” The north magnetic pole shifts constantly, in loops up to 80 kilometers (50 miles) wide each day. The recorded location of the pole is really an average of its daily treks, which are driven by fluctuations in solar radiation. The pole is currently at about 80º north latitude and 104º west longitude, in the Canadian territory of Nunavut.”

Build Yr Own
http://www.npr.org/templates/story/story.php?storyId=90947943
“The compass has been around since at least the 12th century, but scientists still don’t know exactly how the Earth generates the magnetic field that keeps a compass needle pointing north. But geophysicist Dan Lathrop is trying to find out — by building his own planet. Later this year he plans to fill it with molten metal and set the whole 26-ton ball spinning. At top speed the equator will whirl by at 80 miles an hour. “It was a little scary the first time we spun it up,” he says. Lathrop figures it can’t be too hard to get a magnetic field — after all, most planets in our solar system have one. But while nature has an easy time making magnetic fields, scientists do not. This is Lathrop’s third attempt.

If you could dig a deep hole, about 2,000 miles down, you would hit the outer core, which is probably made of liquid iron. That iron can conduct electricity. And if it flows in the right way, it can turn the Earth into what scientists call a dynamo, generating a self-sustaining magnetic field — in Earth’s case, producing one pole up in Canada and another down in Antarctica. Iron only melts at high temperatures, though, so Lathrop’s team will fill his sphere with a different metal — sodium. Sodium becomes liquid at stovetop temperatures and conducts electricity well, but it’s flammable. A sodium fire can’t just be put out with water. Water can actually make things worse — so Lathrop’s team has disabled the sprinkler system…”