Matthiaas Delescluse, the lead author of the first paper and a geophysicist at the Ecole Normale Superieure in Paris terms these quakes as the most spectacular example of the process of breaking of the sub-plates. He also claims it as the clearest example of newly formed plate boundaries in the Indian Ocean. The pair of massive earthquakes that rocked the Indian Ocean on April 11, 2012 may signal the latest step in the formation of a new plate boundary within the Earth’s surface.
The 9.1 magnitude tremor in 2004 that triggered a massive tsunami across the Indian Ocean and the other one in 2005 may be precursors to the break up of plates happened on April 11 this year by adding to pent-up stresses in the plate’s middle region.
Most large earthquake occurs when two plates collide at their boundaries, and one plate slides beneath the other. By contrast, when plates or portions of plates slip horizontally along a fault line, this usually results in smaller, 'strike-slip' earthquakes. But, the first 1April 11 event defied expectations as the largest strike-slip earthquake on record, and one of the strongest to occur away from any conventional plate boundaries.
According to the previous theories of plate tectonics, the Indo-Australian plate began to deform internally about 10 million years ago. As the plate moved northwards, the region near India crunched against the Eurasian plate, thrusting the Himalayas up and slowing India down. Most scientists think that the Australian portion forged ahead, creating twisting tensions that are splitting the plate apart in the Indian Ocean.