Local tsunami run-up depending on initial localization of the landslide body at submarine slope
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Leopold Lobkovsky I Raissa Mazova I Ilya Remizov I Natalia Baranova
Local tsunami run-up depending on initial localization of the landslide body at submarine slope
Abstract The numerical simulation of tsunami induced by layer-bylayer sliding of submarine slope with various initial location of landslide body is performed. For the landslide body, an elastoplastic model with layered sediments taking into account the porosity and deconsolidation of the landslide mass, resting on a relatively rigid base, is used. The characteristic parameters of the above model correspond to those of the landslide and tsunami event in the Corinth Bay on February 7, 1963 modeled by the authors (Papadopoulos et al. 2007). To numerically represent the dynamics of landslide motion numerical code FLAC is used, which in contrast to the finite element method implements an explicit finite-difference scheme for solving three-dimensional problems of continuum mechanics, and allows simulation of the nonlinear behavior of poroussaturated grounds under conditions of plastic flow above the yield stress. Because of plane slope conditions, the nonlinear system of shallow water equations is used for the numerical simulation of tsunami. The results demonstrate that at each time moment, the tsunami runup occurs at novel surface of the coastal slope that leads to complex repositioning of the shoreline point that depends on initial location of the landslide volume. Such an observation is absent in conventional (e.g. rigid block, viscoplastic etc.) models The results of the work demonstrate a rather physical picture of the process under consideration. More importantly modeling results of this work may help in identifying the generating mechanism of historical or future landslide tsunamis. Keywords Local tsunami . Submarine landslide localization . Elastic-plastic landslide model . Numerical simulation Introduction In recent decades, anomalously strong tsunamis from sources located on the shelf (local tsunamis) have been observed: earthquake of moderate strength has led to a large runup magnitude (Gonzalez 1999; Kanamori and Kikuchi 1993; Pelinovsky and Poplavsky 1996; Мazova 2003; Watts et al. 2003). In some cases, these tsunamis were not accompanied by seismic events. As one explanation for this phenomenon, an underwater (or partially localized above water) landslide of sufficiently high power can be suggested, which generates a wave on the water surface and leads to a large runup in the landslide origin area (see, e.g., Garder et al. 1993; Jiang and LeBlond 1993, 1994; Rabinovich et al. 2003; Fine et al. 2005). The problem of tsunami wave runup onto the coast during sliding of the coastal slope, or during landslide motion on a submarine slope, is one of the most important and most challenging in this field, since in the coastal zone, it is necessary to take into account the nonlinear character of the runup, dissipation, and wave breaking, as well as the complex geometry of the shelf zone, etc. (see, e.g., Murty 1977; Pelinovsky and Mazova 1992). The compl
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