The National Environment Agency (NEA) commissioned the National University of Singapore (NUS) and the Nanyang Technological University (NTU) to conduct a study to ascertain Singapore's vulnerability to the effects of giant tidal waves caused by underground earth movements in 2006.

The study found that two regions near Singapore had the potential to cause earthquakes - the Sunda Arc fringing Indonesia, and the Manila Trench bordering the Philippines. Using computer simulation, the researchers found that it would take an earthquake measuring about 9 on the Richter scale for a tsunami to be generated that could reach Singapore. And it would take at least 10 hours for the tsunami to hit Singapore's shores.

The study also found that if this happened, Singapore's waves of no more than 0.7 metres above the average sea level would hit beaches of no more than 50 metres from the shoreline.

Six unprotected beaches here were also identified as potential vulnerable areas - West Coast Park, Labrador Park, Sentosa, the Southern Islands, East Coast Park and Pasir Ris Park.

But the NEA said that this still posed limited threat because the nearest residential area from the coastline in Singapore was 80m inland and any built up area was constructed at least 1.25m above the highest tide level of about 1.5m above the average sea level.

Still, the NEA said it had put in place a system involving various agencies to alert the public and evacuate vulnerable beaches. And the lead time of 10 hours before any tsunami hit Singapore was enough to do all this, said the director-general of NEA's meteorological services, Mr Foong Chee Leong.

The study had been commissioned in response to the devastating Indian Ocean tsunami on Dec 26 four years ago (04), which killed more than 225,000 people. That tsunami, triggered by an undersea earthquake off the Indonesian island of Sumatra measuring about 9.2 on the Richter scale, did not record any rise in sea level in Singapore, said Mr Foong.