8.6 magnitude earthquake hits Indian Ocean

Indonesia, Sri Lanka and India among those countries threatened by possible Tsunami

It was nothing like December 2004. Sirens wailed, warnings blared and police moved people away from coastlines around the Indian Ocean as a powerful earthquake off northern Indonesia sparked fears of another devastating tsunami. (AFP/Getty Images)

Damage was light and big waves never came in the wake of Wednesday's quake, not like nearly eight years ago when walls of water roared across the Indian Ocean and ploughed into coastal communities in 13 countries without warning. (AFP/Getty Images)

"The reports were of people panicking but there was little damage. We need to check for sure directly though," Eko Budiman, the deputy head of emergency mitigation, said at Medan airport in northern Sumatra, struggling to reach Simeulu island near the epicenter. (AFP/Getty Images)

The alerts and evacuations mean a regional system passed a major test since it was set up after the massive quake and tsunami of 2004 that killed 230,000 people around the Indian Ocean, including 170,000 in northern Indonesia alone. (AFP/Getty Images)

But luck may have helped avert disaster this time as much as the warning system, especially in Indonesia's Aceh province, where roads were jammed with residents trying to flee. (AFP/Getty Images)

"The simple message is that in any critical condition like this, it's impossible to get everyone out in time," said Keith Loveard, chief risk analyst at Jakarta-based security firm Concord Consulting. (AFP/Getty Images)

"The tsunami alert system worked to a degree ... While awareness has improved, reinforced by 2004, it still needs to get better through public education and government campaigns."(AFP/Getty Images)

The 2004 disaster swept in with sudden ferocity. Thailand's southwestern beaches and hotels were packed with tourists on their Christmas vacations and people were out for a stroll on Chennai's Marina Beach in eastern India when the waves hit.(AFP/Getty Images)