Countries around the Indian Ocean have learned well from the tsunami that wrought so terrible a toll in 2004. In the wake of Wednesday afternoon's earthquakes off Indonesia, monitoring systems worked largely as intended, warnings and alerts were promptly issued and safety and evacuation measures enacted smoothly. The destructive wave that was feared turned out in most places to be barely a ripple, making the response a trial run rather than an emergency. Doubts that governments had not done enough can be laid to rest, but where nature is concerned, it can never be said that a sufficient effort has been made.

Only the foolhardy could suggest that the hundreds of millions of dollars so far spent on creating an Indian Ocean tsunami warning system is adequate. The inter-government co-ordination, buoys to measure water levels, evacuation centres, coastal sirens and media and mobile phone alerts, although largely absent eight years ago, are only the fundamentals of being prepared. Memories of the giant wave that smashed through communities from Indonesia to Thailand to Sri Lanka to Africa, claiming at least 226,000 lives, are still fresh, as are the images from Japan's huge quake and tsunami little more than a year ago. Nature is unpredictable and the science of forecasting its fickle ways far from exact. Warning and protection measures have to be constantly reviewed, tested and improved.

Governments with budgets and pressing everyday needs can too easily forget about the importance of investing in preparedness. Once the tsunami warning system is completed, they may think that their job is done. But false alarms, inaccurate information and unnecessary evacuations and infrastructure closures can prove costly. Every system has its limitations and there can be glitches, especially if electricity fails.