More than 20 further tremors ranging in intensity from 4.9 to 7.8 repeatedly set off tsunami warnings in Indian Ocean countries throughout Thursday.
 
However, there were no reports of major ocean surges hitting coastlines.
 
"There was a tsunami created by the earthquake, it just travelled in a southwest direction away from land," said Mike Turnbull at Central Queensland University in Australia.
 
Homes destroyed
 
Susilo Bambang Yudhoyono, the Indonesian president, said on Thursday that the damage from the initial quake was "relatively less" than feared.
 
Late on Thursday the roads in north Bengkulu were still lined with tents as residents who feared more quakes and stayed away from their damaged homes.
 
People huddled by fires outdoors to keep warm in the drizzling rain.
 
Erfan Riyanto, a driver, said: "When the first quake struck, we ran out of our house. Then we returned to the house to sleep but another big quake hit, so we ran out again. Since then we have been afraid."
 
Rustam Pakaya, head of the Indonesian health ministry's crisis centre in Jakarta, said 51 people had been injured across the region.
 
In Bengkulu, nearly 800 houses collapsed and many more were damaged, but the full extent of the quake was still unknown because of the difficulty of reaching or contacting some areas.
 
"However, we still have to do a thorough assessment. People are better at responding to disasters than in previous years."
 
Off-shore tremors
 
The worst destruction on Thursday was caused by the jolts along the coast, especially in the Sumatran city of Padang.
 
Almost all the tremors were less than 200km from the shore and around 20km deep, the US Geological Survey said.
 
The mayor of Padang, the capital of West Sumatra, said many people were trapped under collapsed buildings.
 
Indonesia suffers frequent earthquakes, lying on an active seismic belt on the so-called Pacific "Ring of Fire".