i don't actually know that's y im askin plz answer if u know
It happened on December 26, 2004.
Please see the related questions.
you can't prevent a Tsunami because it's a big waves so you will die
It occured in the Indian Ocean (the epicentre was just off the northern tip of the island of Sumatra) on the plate boundary where the Indo-Australian Plate is subducted under the Eurasian plate.