18 Jun 2013

Computer model highlight tsunami threat in Tonga

4:28 pm on 18 June 2013

A new computer model has been developed to help Tonga prepare for the effect a tsunami would have on the capital, Nuku'alofa.

The model, developed by the Secretariat for the Pacific Community, shows that an 8.7 earthquake in the Tonga Trench would create a wave that would inundate most of the kingdoms only city.

The Director of the Tonga National Emergency Management Office, Leveni Aho, told Jamie Tahana the models give the government a clearer picture of how to prepare the city for a major earthquake and tsunami.

LEVENI AHO: The risk has always been there, but I think with this new information available now, it'll be easier for us to demonstrate, particularly with the modelling, The support that we can from sobac enables us to run a tsunami simulation from the various locations and various scenarios and what-not. And we can look at the outcome of that in a computer model.

JAMIE TAHANA: What do these graphics show us?

LA: What we're taking is we're taking the worst-case scenario because we've got the Tonga Trench to our east, which is only about 200km to 300km east of us, and these are the areas where scientists always predict seismic activity appears. And, if anything, it will probably generate a tsunami from that particular location.

JT: So how do we prepare now we know all this information?

LA: We're currently working with our other partners on developing public awareness. We are leading them to high grounds and we try to find evacuation centres and evacuation routes to these areas, and also the early warning system, 'cause I think the biggest issue here is we don't have much time. It's only 200km away. We will be receiving the wave if it's coming from this particular location in 7 to 20 minutes, so time is very critical. It's very important that we can get the early warning out. Also, another important thing is to educate people. Once they can feel a major earthquake they can always be ready to self-evacuate.

JT: All this was known before these graphics came out, though. How do these graphics directly contribute to your planning for a natural disaster?

LA: I don't know whether you've been in Nuku'alofa before, but it's a very flat, low-lying area. But that's where the density of our population is sitting, and we've got something in the order of 40,000 people in this particular area. When we evacuate out to other areas in the south it's quite congested, the roads and that. But we have identified about four areas within Nuku'alofa which are about 10-to-12 metres high as a possible area for people to move into.