How did tectonic plate movement cause the Indian ocean tsunami?

Two plates, the Indian plate and the burma plate (a section of the eurasian plate), slipped, forcing the Indian plate underneath the burma plate, as the Indian plate had a thiner crust and less buoyancy (floatation) than the burma plate. This caused the burma plate to move upward pushing vast amounts of water up, causing the tsunami.

=P hope this helps - make sure u check somewhere else as well incase i am wrong