The 70m by 4m simulator at HR Wallingford near Oxford creates 50:1 scale tsunamis by sucking water into a pressure chamber. The water is then released, smashing into model walls fitted with force and pressure sensors to measure the wave’s impact on coastal defences.
Huge earthquake-generated waves devastate coastal communities when they hit land, said water engineer David McGovern. “Tsunamis don’t happen very often, and when they do happen they tend to destroy everything – that is the nature of tsunamis.”
In 2004, the Boxing Day tsunami in the Indian Ocean killed more than 230,000 people and made 1.7m homeless after a 9.2 magnitude earthquake. Hitting 14 countries, the tsunami reportedly killed more than 70% of villagers in some coastal communities.
The destructive power of the seismic waves makes studying them very difficult, said former University College London professor McGovern, who is now publishing research at London South Bank University.
“We are very limited in what we can actually understand about how they can interact with the built environment, because any measurements you have in the field would be reading a maximum value or it is just completely destroyed,” he said. “Recreating it in a lab is really important, and we haven’t been able to do that until recently.”
One of the main aims of the simulator – said to be the largest in Europe and the only one of its design in the world – is to understand how coastal defences can actually amplify destruction by causing waves to build up before collapsing, sending water inland and hitting previously safe areas.
To simulate this effect, the team built a wall which made to fail under control. It was fitted with a Kistler force link to accurately measure forces in three perpendicular directions, creating a clear model of all the forces as waves build up and go over the top or the wall collapses.
McGovern and colleagues will use research based on the data to help inform a first international tsunami-oriented design code for construction, helping to protect lives, infrastructure and properties in coastal communities around the world.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.