The influence of landslide shape and continental shelf on landslide generated tsunamis along a plane beach

Abstract

Abstract. This work proposes an advancement in analytical modelling of landslide tsunamis propagating along a plane beach. It is divided into two parts. In the first one, the analytical two-horizontal-dimension model of Sammarco and Renzi (2008) for tsunamis generated by a Gaussian-shaped landslide on a plane beach is revised and extended to realistic landslide shapes. The influence of finiteness and shape of the slide on the propagating waves is investigated and discussed. In the second part, a new model of landslide tsunamis propagating along a semi-plane beach is devised to analyse the role of the continental platform in attenuating the wave amplitude along the shoreline. With these parameters taken into account, the fit with available experimental data is enhanced and the model completed.

The hydrodynamics of landslide tsunamis: current analytical models and future research directions

“…Nevertheless, quasi-trapped waves are still able to produce enhanced runup around the island. Finally, Renzi and Sammarco (2012) extended the original plane beach model of Sammarco and Renzi (2008) to consider the influence of the landslide shape and the continental shelf on the wave field. Renzi and Sammarco (2012) showed that the presence of irregularities in the shape of the landslide favours the generation of spiky double-crested waves, which carry a more destructive potential.…”

“…Finally, Renzi and Sammarco (2012) extended the original plane beach model of Sammarco and Renzi (2008) to consider the influence of the landslide shape and the continental shelf on the wave field. Renzi and Sammarco (2012) showed that the presence of irregularities in the shape of the landslide favours the generation of spiky double-crested waves, which carry a more destructive potential. On the other hand, the presence of the continental shelf reduces the number of spectral components that are excited by the landslide with respect to an indefinite plane beach and may be beneficial in mitigating the severity of the tsunami.…”

“…Current and future research directions stemming from such models will be further discussed in Section 4. 3 Two-horizontal dimension models 3.1 Plane beach model (Sammarco and Renzi 2008;Renzi and Sammarco 2012) A feature of the plane beach geometry is its ability to trap waves generated on it. This results in energy focussing along the beach, which induces unexpectedly high runups (Kanoglu and Synolakis 2015).…”

“…The numerical results of Lynett and Liu (2005) highlighted the need to develop an appropriate analytical two-horizontal-dimension (2HD) model to explain such dynamics. Following the suggestion of Lynett and Liu (2005), Sammarco and Renzi (2008), Renzi and Sammarco (2010) and Renzi and Sammarco (2012) developed fully 2HD analytical models of landslide tsunami generation and propagation along a plane beach and around a conical island, induced by a sliding solid block. By using the forced linear shallow water equation, Sammarco and Renzi (2008) derived the analytical form of both the offshore component and the transient edge waves travelling along the shoreline of a plane beach.…”

“…Indeed, modelling landslide tsunamis is intrinsically challenging as it involves a time-dependent bottom deformation in the same region where the waves are generated and propagate. In this paper, we shall review the analytical models of Sammarco and Renzi (2008), Renzi and Sammarco (2010) and Renzi and Sammarco (2012), which have become benchmark models for numerical codes (Romano et al 2013;Dias et al 2014;Stefanakis et al 2014) and statistical emulations (Sarri et al 2012) of landslide tsunamis. Analytical models provide an invaluable tool in the science of tsunami modelling, for they allow one to obtain a sound physical understanding of the wave dynamics and to carry out parametric investigations on the influence of the system main parameters on the maximum wave runup.…”