BANDA ACEH, Indonesia - 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.
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.
"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.
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.
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.
"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.
"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."
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 southern India when the waves hit.
System activated in June 2006
Made up of seismographic stations and deep-ocean sensors, the Indian Ocean Tsunami Warning System was activated in June 2006 after being agreed 17 months earlier at a United Nations conference in Japan.
When an quake hits, data is sent to the Pacific Tsunami Warning Centre in Hawaii and the Japan Meteorological Agency, which coordinate with national tsunami centres in the region.