Tsunami escape: Scientists hope modelling will help save lives

Friday, 11 October 2019

GNS scientist Dr William Power is aiming to save lives by developing computer modelling on how people flee a tsunami.

Scientists hope to save lives by modelling how people in three high-risk New Zealand cities will flee a tsunami.

GNS scientist Dr William Power has produced modelling for Lower Hutt, Napier and Christchurch that predicts how people will evacuate.

His research will help identify safer and quicker evacuation routes for communities in tsunami-prone areas.

The ultimate aim was to produce a model that will help evacuate the capital, he said. 'Wellington's CBD is challenging because there are so many people in such a small space.'

Dr William Power is aiming to save lives by developing computer modelling predicting how people escape a tsunami.

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Although he acknowledged it was not a precise science, Power said the models, created by researchers and scientists from GNS Science, Massey University, East Coast LAB (Life at the Boundary) and the University of Canterbury, would help planners who needed to know where people were likely to flee to.

The modelling simulates the movement of people who have self-evacuated on foot and shows likely congestion areas during the daytime and at night.

In the harbourside Lower Hutt suburb of Petone, Power said the modelling showed residents in the east would head towards Moera, at the foot of Wainuiomata Hill. That involved crossing a narrow pipe bridge, an issue, planners would have to address.

Hawke's Bay Civil Defence team leader Lisa Pearse said predicting how people behaved when a tsunami was coming could be a life saver.

'It helps inform us where the pinch points are and what we can do to improve those and help people evacuate quicker.'

Japan and Chile, two other earthquake-prone countries, are doing similar modelling but the technology behind it is still being refined.

A message is displayed on the screen during the Rugby World Cup Pool D match between Fiji and Uruguay in Kamaishi, northeastern Japan, on September 25. Nearly nine years ago the northeastern Japanese town of Kamaishi was devastated by a magnitude-9 earthquake and a tsunami that killed just over 1000.people.

Power would like to do a model that predicts how people in cars will respond but his next challenge is central Wellington. It presents a major headache because of its narrow streets, apartments and high-rise buildings.

Power will have to work out how long it takes to evacuate large apartment blocks and also predict how people in tall buildings will react to the threat of tsunami.

'What advice do we give people in high-rise buildings? Should they stay or evacuate?'

There is also the problem of working out how many people will walk, ride or drive to safety in Wellington and the impact on travel time for those on foot.

The modelling uses household and population data to predict how long people will take to walk to their nearest designated safe point.

Everyone should know where their tsunami safe zone is and how to get there.

Japan and Chile, two other earthquake-prone countries, are doing similar modelling but the technology behind it is still being refined.

Power believed that we are generally complacent about the threat tsunamis posed. The Christchurch and Kaikōura shakes helped raise awareness and he said modelling was another step in giving people the information they needed to respond appropriately.

Lower Hutt installed blue hazard lines in 2017 to identify areas that are safe after a big shake.

In the 2016 Kaikōura Earthquake there was confusion in Petone with residents causing massive congestion by driving to the Western Hills and Wainuiomata, rather than heading in-land on foot up the valley towards higher ground.

Power said the installation of blue lines, designating how far inland a tsunami was likely to travel, would change how people reacted over time.

Civil Defence advice for a tsunami

Everyone living and working in tsunami evacuation zones should know how to evacuate quickly and safely following a long or strong earthquake.

* For a local source tsunami, which could arrive in minutes, there won't be time for an official warning. It is important to recognise the natural warning signs and act quickly.

* If you are near a shore do not wait for official warnings if you feel a strong earthquake that makes it hard to stand or a earthquake that lasts more than a minute. If you a sudden rise or fall in the sea that is a sign that a tsunami is coming.

* Drop, cover and hold during the shaking. As soon as the shaking stops, move immediately to the nearest high ground, out of all tsunami evacuation zones, or as far inland as you can.

* Walk, run or cycle if at all possible to reduce the chances of getting stuck in traffic congestion.

* Take your animals with you only if it will not delay you. Do not spend time looking for them and if you are not at home, do not return to get them.

* While evacuating, avoid hazards caused by earthquake damage, especially fallen power lines.

* Do not return until an official all-clear message is given by Civil Defence.