Earthquake in Chile.

[Dragonelf68]

Holy shit!

[Ḷëģöläš]

I also saw that on Yahoo! news. Quite interesting.

[NiteStryker]

The 2004 quake shortened the day as well....to shorten the day, you have to have the earth spin faster....so the quake just threw everything off?

[Nittany Tiger]

Nah. You can also make the Earth smaller or give it more angular momentum.

According to the article, the mass distribution of the planet was altered, which altered the axis of rotation. That redistribution probably took place in the mantle (or below). I can't say for sure, and this article isn't detailed enough for me to begin with. If it was, I could draw a better conclusion.

And apparently slip-strikes don't cause mass-distribution changes (Haiti was a slip-strike). Apparently, it takes vertical movements in the crust to alter the mass distribution of the planet. Knowing how thrust fault events happen, though, it would seem like the earth should actually slow down.

Again, not enough info.

[NiteStryker]

So it changed the weight distribution? How does the shifting of the crust of the Earth shift trillions and trillions of tons of magma and iron below enough to alter it?