§ Earthquakes occur when any of the plates collide at their boundaries. 
§ Scientists now believe that one plate that comprised the landmass from India
   to Australia has broken up into two.  The initial 8.9 eruption happened near the
   location of the meeting point of the Australian, Indian and Burmese plates.
§ Scientists have shown that this is a region of compression as the Australian plate 
   is rotating counterclockwise into the Indian plate.
§ This also means that a region of seismic activity has become active in the
   South Eastern Indian Ocean.
§ The Tsunami originated in a subduction zone, to a length of 1200km and
   a breadth of 100km, over a depth of 20m.
§
Department of Ocean Engineering, IIT Madras, Chennai , India – 600 036
WHY DID IT OCCUR “2004 Tsunami”