Moving Earth

The Earth has shifted on its axis!!!
Can you believe that an earthquake would be able to do that?!
I guess if you seriously think about it, it would, wouldn't it?

With the earthquake, the land mass has shifted and now Japan is a little closer to the US.
This has started me thinking of the fact that land masses don't move all the time.
Aren't all islands floating islands?
The giant oceans don't have the power to move countries.
I don't believe the islands are stuck to the center of the Earth, right?
If you dive into the sea, at some point in time, you'll be able to hit the end of the island, right?
So why is it that land masses move only when earthquakes happen?

Not only that, this particular earthquake has shortened time.
How interesting is that?!
I wonder if the same thing happened during the Boxing Day earthquake in 2004.
Nothing was mentioned about Sumatra moving from its position or shortening time...