Tsunami Research is Modelling Forces in the Laboratory

How a Tsunami is created is well understood and, whilst the devastation they cause is all too familiar, there has been little reliable data available to guide the design of coastal defences. This deficiency is now being addressed by UCL (University College London) and HR Wallingford, the world leading, specialist hydraulic research and consultancy organisation, in a collaboration which has constructed the largest specialist tsunami simulator in Europe; 70 m long and 4 m wide.

One of the principal aims of the simulation project is to develop an understanding of how coastal defences might amplify the destructive effects of the tsunami by causing waves to build up until they suddenly fail causing devastation to be increased on the landside, even in areas previously considered safe. To simulate this effect, the team constructed a ‘wall’ that can be made to fail under control. The point at which the wall can be made to fail was originally equipped with several pressure sensors to monitor the build-up of force of the wave but this proved to be too simplistic as the forces acting on the wall were three dimensional. To solve this problem, the wall was fitted with a Kistler Type 9327 force link which accurately measures the forces at work in three, perpendicular directions. This data, together with that from the pressure sensors, provides a clear model of all the forces acting on the wall as the wave builds up and the wall is overtopped or fails.

The tsunamis created in the simulator at a scale of 50:1 have been compared with data from actual events showing a very close match. The data that will be produced from the collaboration should provide a reliable guide to the design of future coastal defences to deliver better protection for areas currently at risk.