Indonesia escaped being hit by a devastating tsunami after an earthquake off Sumatra because the wave it triggered was forced away from the coast and out into the Indian Ocean, an Australian expert said on Thursday.
Seismologist Mike Turnbull, at the Central Queensland University, said the earthquake on Wednesday created the opposite effect to the massive 2004 quake that caused an Indian Ocean-wide tsunami that killed 2,83,106 people.
"It was certainly big enough to cause a devastating tsunami and close enough to shore," Turnbull told Reuters.
He said the "earthquake mechanism" -- the way the seabed ruptured -- caused the 2004 tsunami to head towards Sumatra, while Wednesday's quake saw a tsunami travel southwest, away from land.
"In this case the plate bodies that cause the earthquake ruptured in a way that saw the water thrown forward to move away from Sumatra. It was totally different to the Boxing Day 2004 mechanism," said Turnbull.
"As a result Sumatra did not suffer from a devastating tsunami. There was a tsunami created by the earthquake, it just travelled in a southwest direction away from land."
The quake hit 130 km (80 miles) southwest of Bengkulu, on Sumatra island, killed at least six people and buried many more under buildings. The quake was caused as result of thrust faulting at the boundary of two tectonic plates -- the Australian plate and the Sunda plate.
Sumatra was pounded by aftershocks on Thursday after the world's most powerful earthquake this year.
Turnbull said aftershocks could result in a different type of rupture that could send a tsunami towards land, but this was unlikely.