It will be years before tsunami warnings can be accurate enough to avoid unnecessary evacuations, an earthquake expert says.
A tsunami watch around the Indian Ocean was lifted hours after two earthquakes struck off Sumatra in Indonesia on Wednesday.
University of Queensland earthquake warning expert Huilin Xing said the 8.6 magnitude tremor and aftershock sounded a tsunami alarm causing thousands to flee coastal and low-lying areas for higher ground.
Wednesday's earthquake was felt as far afield as Thailand, where skyscrapers in the capital Bangkok swayed. Indonesia, Malaysia, Burma, Thailand, India, Sri Lanka, Kenya and Reunion all issued alerts or evacuation orders that were later lifted.
Dr Xing said the tsunami system was better than nothing but had its limitations and there was still a lot of work to do.
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"The problem is, there are a lot of false alarms because not all large earthquakes will generate a tsunami," Dr Xing said.
"Australia is years away from perfecting the system and how quickly that is done depends on the level of investment in research and development."
Dr Xing said while earthquakes larger than 6.5 magnitude can generate a tsunami, no single model can predict what kind of earthquake will generate tsunamis and how big they might be.
"Researchers need to study the details of the earthquake, its triggered sea floor motion and interaction with water," he said in a statement on Thursday.
But Professor James Goff, director of the Australia-Pacific Tsunami Research Centre in Sydney, said the tsunami-warning system had worked well.
Locals were better prepared than before the 9.1 magnitude Boxing Day earthquake and Indian Ocean tsunami that killed 220,000 people in 2004.
"Many people self-evacuated and fortunately, because of the incredible amount of tsunami-related work in the region," Prof Goff said after the warning was put in place.
British volcanologist Dr David Rothery from Open University said Wednesday's earthquake was about 10 times less energetic than in 2004 and of a different nature.
It happened on the bending Indian Ocean floor as it approached the Sunda Trench, and not as a megathrust quake in the trench itself.
