Tsunami: Their characteristics and effects on buildings
The Tsunami Generator in action
Tsunami waves travel across oceans with quite small vertical displacements, but shoal up dramatically in coastal and nearshore depths, and can cause extensive loss of life and infrastructure. Propagation of tsunami waves in the nearshore, across the shoreline, and then inland is not well modelled by many current techniques.
Physical modelling can be used to study flow and force processes, but correct generation of the tsunami wave(s) is essential and conventional wave paddles simply do not have adequate stroke to reproduce the required wavelength.
This weakness is being addressed within the EPICENTRE research initiative through collaboration between UCL and HR Wallingford (HRW). HRW are constructing the first Tsunami Generator that will be capable of generating a complete Tsunami wave within a hydrodynamic model by adapting the principles of HRW’s pneumatic tide generators, to generate multiple waves (viz. the 3-4 peaks in the Boxing Day Tsunami), and ensure realistic wavelengths. The Tsunami Generator is being mounted within a conventional (45m long) wave flume equipped to measure coastal processes, inundation and wave forces. It will generate tsunami waves which have been previously transformed from deeper water (approx -200m) to shallow water (approx -20 to -50m) using a suitable numerical model. Bathymetry in the wave flume will further shoal the tsunami waves over a representative coastal slope though the shoreline and inland, covering a suitable inland inundation area. Measurements of tsunami transformations through the nearshore region will test / validate existing numerical models. UCL and HRW researchers will then examine interactions of the tsunami with representative buildings, and investigate the characteristics of tsunami loading on structures. The vulnerability of structures to tsunami loading will then be researched with the aim of providing guidance on the assessment and design of structures for tsunami.
Ingrid Charvet, an EPICentre PhD student at H R Wallingford
The Tsunami Generator at H R Wallingford