Did The Chilean Quake Shift Earth's Axis

Terra Daily ^ | 3/12/2010 | Dr. Tony Phillips

[ErnstStavroBlofeld]

Pictures of widespread devastation leave no doubt: Last month's 8.8 magnitude earthquake in coastal Chile was extremely strong. Indeed, say NASA scientists, it might have shifted the axis of Earth itself. "According to our calculations, the quake moved Earth's figure axis by about 3 inches (8 cm)," says geophysicist Richard Gross of the Jet Propulsion Laboratory in Pasadena, California.

If the Earth tilted over 3 inches, you probably think you would have noticed. But that's not how the "figure axis" works. "The figure axis defines not how Earth is tilted, but rather how it is balanced," says Gross.

Consider the following:

Earth is not a perfect sphere. Continents and oceans are distributed unevenly around the planet. There's more land in the north, more water in the south, a great ocean in the west, and so on. As a result of these asymmetries, Earth slowly wobbles as it spins. The figure axis is Earth's axis of mass balance, and the spin axis wobbles around it.

"The Chilean quake shifted enough material to change the mass balance of our entire planet," Gross says.

A shifting figure axis is nothing new. On its own, the figure axis moves about 10 centimeters per year as a result of "Ice Age rebound." After the last great glacial period some 11,000 years ago, many heavy ice sheets disappeared. This unloaded the crust and mantle of the Earth, allowing the planet to relax or "rebound" back into a more spherical shape. The rebounding process is still underway and so the figure axis naturally moves.

[seawolf101]

"According to our calculations, the quake moved Earth's figure axis by about 3 inches (8 cm)," says geophysicist Richard Gross of the Jet Propulsion Laboratory in Pasadena, California.

WE'RE DOOMED!!!

We need to send Al Gore more money, or at leasty give him more awards.

[ErnstStavroBlofeld]

I glad I ditched my ex-fiancee.

[ErnstStavroBlofeld]

It did affect GPS

[AussieJoe]

we all need to go over the other side of the earth and push it back up

[ETL]

It did affect GPS

Do you have any sources for that? Although I found something on space craft communications, I couldn't find anything on GPS.

[Irenic]

This unloaded the crust and mantle of the Earth, allowing the planet to relax or “rebound” back into a more spherical shape.
____________________________________________________________
OOoooh! So that’s how the Earth stopped being flat! =P

Yeah, I’m a ‘flat Earther’, Mr Gore...

[ErnstStavroBlofeld]

I just remember reading it. It may be in the article

[bunkerhill7]

Yes, evidently it did. All the sidehill wampuses here are running straight instead of in circles.

[ErnstStavroBlofeld]

The key is GPS1. "Using a global network of GPS receivers, we can monitor the rotation of Earth with high precision," he says. "Changes in Earth's spin and the orientation of Earth's axes affect [the phase and timing of] signals we get from the satellites in Earth orbit." GPS is already used to monitor seasonal changes in Earth's spin. It turns out that tides, winds, ocean currents, and circulation patterns in Earth's molten core modulate Earth's rotation on a regular basis. For instance, a typical day in January is about 1 millisecond longer than a typical day in June. The roughly six-month variation is driven mainly by seasonal winds; there are also changes on time scales of weeks, years, decades and centuries. Earthquakes throw a "spike" into GPS signals, which Gross believes he can find

Its in the article if you read it.

[bubman]

Why its George W Bush’s fault. Where have you been? /s

[ETL]

I had only read your excerpt. But I checked just now and saw it there. I was going to post the same paragraph that you just did which mentions it. Sorry for not checking the article first.

[EBH]

Actually the disturbed axis is just a bit more than the disturbed axis from earlier this decade.

http://www.theage.com.au/articles/2004/12/28/1103996533891.html

[ETL]

It’s interesting the way they describe the mechanics of it. They say that when a tectonic plate moves beneath another to a significant degree, it causes the earth to contract a little and therefore spin faster (like a figure skater pulling her arms in and spinning faster). But the Earth also pulls apart at rift centers such as the mid-oceanic spreading centers. I wonder how that affects the spin rate?

[SoldierDad]

You realize, of course, there are a couple ways to interpret your comment ;-)

[villagerjoel]

“Yeah, but whose FAULT is it??? /s”

Watching the local news a day or so after the quake, they were showing a woman who’s car was buried under a brick wall. She commented that the worst of all of it was that there was nobody to hold responsible for it!

(On a side note, I’m sure a good American lawyer could sue the person who put up the wall, the people who made the bricks, the people who made the car, etc)

[HiTech RedNeck]

They’re also talking about changing the balance axis too?

[Beowulf9]

“we all need to go over the other side of the earth and push it back up”

Maybe Atlas shrugged again.

[Minn]

I’ve been wondering why I missed that putt.

[ETL]

I don’t know. Would that cause a slight wobble in addition to a faster spin?

[JRios1968]

"According to our calculations, the quake moved Earth's figure axis by about 3 inches (8 cm)," says geophysicist Richard Gross of the Jet Propulsion Laboratory in Pasadena, California.

Rove, you magnificent bastard!