School of Civil, Environmental and Mining Engineering

What the Boxing Day tsunami taught us

Chari

Professor Chari Pattiaratchi

Professor of Coastal Oceanography

October 2014

The University of Western Australia's coastal engineering expert Chari Pattiaratchi has vivid memories of the Boxing Day tsunami in 2004 that killed some 250,000 people—he nearly became one of its casualties.

Pattiaratchi is the Professor of Coastal Oceanography within the School of Civil, Environmental and Mining Engineering at the University of Western Australia.

Ten years ago, when the tsunami hit, he was in Sri Lanka with his son and his son’s girlfriend driving along a road blocked by a fishing boat dumped by the tsunami.

He recalls people saying: “The sea has come ashore!”

“I said: ‘Don’t worry, there’s no other wave coming, they’ve come and gone’,”  says Professor Pattiaratchi.

It turns out that wasn’t quite right.

Like millions of other people around the world, Professor Pattiaratchi was about to gain a new understanding of tsunamis.
The initial set of waves had come and gone through Sri Lanka. But still to come were the giant waves that were reflected from other countries.

Having driven to another part of the coast, Professor Pattiaratchi noticed water reversing in a drain and rising around his feet – the second set of big waves was on its way back and about to hit.

They scrambled into the car and raced off.

“Two or three days later when we came back, that’s when I got scared, my knees were shaking because when I first went to that place, everything was intact,” Professor Pattiaratchi recalls.

“And now, there were no walls, no houses.

“Where the boat was, was my mother’s village.

“Her grandfather had built the nearby railway station, but now there was no railway station left.

“From where I was standing, the reflected wave had gone seven metres high.”

Professor Pattiaratchi has since devoted much of his professional life helping scientists develop a better understanding of tsunamis. He was the chair of an international working group which helped set up the Indian Ocean tsunami warning system.

On 28 October, he presented a public lecture, A Decade of Developments in Tsunami Science and Warning Systems Since the 2004 Sumatra Event, at UWA.

“Ten years ago, the majority of people in the world didn’t know what a tsunami was,” he says. “They didn’t know how to respond and there was no warning system. Now, there is a warning system.”

A lot of work has been done since 2004 to avoid a repeat of the devastating effects of a tsunami in the Indian Ocean.
That includes the detection system consisting of an array of seismometers to detect where the earthquake happens and the tide gauges to see where a tsunami has been generated and how big it could be.

Just as important is the communications system devised to alert people around the Indian Ocean rim that a tsunami is coming – and to evacuate if necessary.

“Now, this is being rehearsed all the time,” he says. “So every year, they have a system they test, all the communications go through what we call ‘down to the last mile’, the part that actually reaches people and communities in danger.”

The research into tsunami behaviour is still continuing.

“In WA in 2004, the biggest waves initially happened at Geraldton, which coincided with high water,” he says. “But in fact the biggest wave hit Bunbury 18 hours later, almost a day later, but it happened at low tide, so there was no damage.

“That wave was reflected from the Mascarine ridge and Madagascar.

“Now I’m running some simulations showing that some of the waves that hit Thailand and Malaysia in the 2004 tsunami were reflected from Sri Lanka.”

Tony Malkovic

 

School of Civil, Environmental and Mining Engineering

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Last updated:
Tuesday, 8 March, 2016 9:36 AM

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