On the characteristics of landslide tsunamis

Abstract

This review presents modelling techniques and processes that govern landslide tsunami generation, with emphasis on tsunamis induced by fully submerged landslides. The analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths. Scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed. It is found that the landslide acceleration determines the initial tsunami elevation for translational landslides, while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides. Retrogressive effects stretch the tsunami, and in certain cases produce enlarged amplitudes due to positive interference. In an example involving a deformable landslide, it is found that the landslide deformation has only a weak influence on tsunamigenesis. However, more research is needed to determine how landslide flow processes that involve strong deformation and long run-out determine tsunami generation.

Tsunamis: bridging science, engineering and society

“…Løvholt et al [12] review the effects of submarine landslide kinematic parameters such as velocity, Froude number and acceleration on the tsunamigenesis. A novel aspect in their review is the distinction between translational landslides with slow acceleration and rapid slumps.…”

“…The data provide breakthrough information to identify and solve challenging problems in tsunami hydrodynamics. One application has been in documenting the effects of dispersion, which according to Løvholt et al [12], An & Liu [73] and Okal & Synolakis [74], appear quite limited, as all tsunameter records appear to be modelled with linear or nonlinear shallow water wave theory, in the far field.…”

Rheological considerations for the modelling of submarine sliding at Rockall Bank, NE Atlantic Ocean

“…17 have combined a turbulent term with the granular model introduced by Savage and Hutter 13 to incorporate the water drag in their submarine landslide simulations. The turbulent term results from the empirical formula first described by Voellmy for the rheology of snow avalanches.…”

Assessment of GNSS-based height data of multiple ships for measuring and forecasting great tsunamis

“…This is because the source time function of greater earthquakes is relatively longer than that of smaller earthquakes, and thus source estimation of greater earthquakes requires longer-period seismic wave analysis (up to a couple of hundreds of seconds) than smaller ones (Katsumata et al 2013). In addition, greater earthquakes may involve tsunami earthquakes (Satake 1994;Dutykh et al 2012) and seafloor failures due to strong seafloor shaking which can generate additional tsunamis (Kawamura et al 2014;Løvholt et al 2015).…”