Seconds after the 7.9 Indonesian earthquake was detected by seismographs on Wednesday, Shailesh Nayak, who heads India’s new tsunami warning system in Hyderabad, rushed to the nerve centre to set into motion the drill for what seemed a textbook case for a tsunami build-up. The first bulletin with an alert was out in 30 minutes. But he heaved a sigh of relief only at 8.30 pm when a tsunami wave did hit one of the Andaman islands: as was forecast, it was only 15-20 cm high, a fraction of the high tide. The unit was happy — glitches yes, but their system was working. In the first two bulletins, the 10-15 member team decided to issue only an alert, not a warning. A “red alert” for Andamans meant that both the administration and public had to be in a state of readiness. At that point, the US Government’s National Oceanic and Atmospheric Administration (NOAA) issued ‘warnings’ for the Indian coastline — in other words, evacuate. “There is a reason behind this. It just means that for countries like Japan, there is very little reaction time, hence they find warnings more effective. India had the luxury of waiting and watching,” said Nayak on the discrepancy.In the next 30 minutes, they reduced the alert to orange for Andamans. This was after the tsunami wave had already struck the nearest point on the Indonesian coast — it was only 50 cm high. In the next few minutes, it was the Padang coast, 40 minutes away and a series of four waves, one falling, two and three rising and the fourth falling.“At that time, we knew the danger was not for real. The waves were there but very small,” said Nayak.What was it that made them decide this was different from the killer wave that killed 220,000 people and left 1.5 million homeless across the region in December 2004? Scientists in the control room said that the directivity map showed early on that the earthquake’s energies were focused towards the vast ocean mass south-west from the epicentre. The tsunami would hit but its energy would completely dissipate by the time it strikes the Indian coast.
