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The hypothetical scenario of a 7m tsunami hitting Fremantle has been used by scientists to demonstrate how advances in flood modelling technology can more accurately predict disaster damage.

CSIRO fluids modeller Dr Mahesh Prakash said traditional flood modelling programs only showed water levels rising, but a new method of modelling being used by the scientific organisation showed the path of destruction of flood waters and resulting forces on different structures.

“Most flood modelling that has been done recently has been in what is called bath-tub models, so essentially what you are looking at is just water filling up,” he said. “If you let the water hit the bricks the forces can be quite significant and this type of modelling captures those forces really well.”

He said the animation, which shows flood waters hitting the West side of Rottnest at high speed before inundating port-side Fremantle was a simplified version of what could be simulated using new modelling techniques.

“If we were commissioned (to do a wider study) we would be able to start looking at forces that you could actually expect on specific high-value buildings and infrastructure,” he said.

Dr Prakash said Fremantle was used because of its proximity to the ocean and the potential for tsunami damage.

“The chances of the Fremantle harbour being hit by a real tsunami is actually quite high because you can actually get an earthquake related tsunami coming from Sumatra,” he said.

This video illustrates how complex CSIRO computer models can visualise the effects of tsunamis and storm surges.

The first clip shows a hypothetical tsunami flooding the coastline off Fremantle and Rottnest Island. The speed of the water is shown in different colours (red is fastest, blue is slowest).

Key buildings in Fremantle are shown at their actual locations and elevations in the second clip to visualise the path of the 7m wave.

The third clip is a hypothetical street scene from no specific location. It shows a surge of water flooding the street and lifting objects like cars, which themselves can cause further damage.