PHYSICAL MODELLING OF SOLITARY WAVE OVERTOPPING IN THE PRESENCE OF A COASTAL DUNE

Abstract

Oceanic underwater disturbances are associated with submarine landslides, volcano eruptions, or seismic activity occurring below or near the ocean basin, which can produce tsunami, which have a small amplitude in deep water with a very long wavelength, so they generally pass unnoticed offshore (Robke and Vott, 2017). These types of tsunami waves can cause massive damage or failures to coastal structures (Kato et al., 2007). From the field surveys after the 2004 Indian Ocean and 2011 Japanese tsunami, it was revealed that natural coastal features such as dunes, dense vegetation, and a combination of dunes with vegetation, acted as natural buffers and provided protection to infrastructure and communities further landward (Fritz and Borrero, 2006; Wijetunge, 2006; Murthy et al., 2012; Wijetunge, 2012). The role of coastal forests, such as mangrove vegetation, on tsunami run-up and inundation reduction, have been extensively studied by many researchers with physical and numerical modeling (Husrin et al., 2012; Yao et al., 2015; Esteban et al., 2017), but not the influence of coastal dunes in offering direct protection. Hence, the present research aims to investigate the mitigation of tsunami run-up and overtopping by coastal dunes.