Powerful earthquakes struck Indonesia for a third day today, terrorising thousands of people who were refusing to return to their homes in fear of tsunami and falling debris.

SCIENTISTS describe the devastating earthquake off the island of Sumatra as a "megathrust" - a grade reserved for the most powerful shifts in the Earth's crust and the equivalent of one million atomic bombs.

Scientists describe the devastating earthquake off the island of Sumatra as a “megathrust” – a grade reserved for the most powerful shifts in the Earth’s crust.