Physical and Numerical Modelling of Tsunami Run-up on Seawall at Sloping Beach

Abstract

Tsunami run-up on land has a large destructive power. Further studies are deemed necessary to understand the process and characteristics of tsunami run-up in coastal areas. Seawall structures can reduce the run-up of a tsunami depending on the height of the seawall crest. Physical modeling shows that seawall may significantly reduce run-up (𝑅) and inundation (𝑋𝑖). The highest reduction up to 55% where the seawall peak height is 7 cm and the water depth is 15 cm. With the same scenario in numerical modeling, the percentage reduction is 67.53%. The highest inundation (Xi) in the scenario without seawall structure is 6.081 m when the initial water depth (d0) equals to 30 cm. The result of the numerical model for the same scenario is 6.970 m. Seawall as tsunami mitigation structure is only effective when the tsunami wave is relatively low compared to the seawall height (H/ sw). Reduction percentage > 25%, with conditions that H/ sw is < 0.856 (physical model) and < 0.802 (numerical model).