Preface: Thematic issue “Landslide-generated tsunami waves”

Abstract

Landslide-generated tsunami waves (LGTWs) are gravity waves generated by impulsive impacts of the submarine or subaerial landslides into a water body. Large-scale LGTWs are extreme natural hazards with devastating and fatal consequences on infrastructures and communities. The study of LGTW processes, e.g. slides initiation (or triggering), motion, interaction with water and air, impulsive wave generation, propagation, run-up, overtopping, and inundation, is a multidisciplinary challenge and is an essential task to acquire an informed assessment and to manage the LGTW risks. Landslide-generated waves and the interactions between landslide and water body are the topics of this thematic issue of Landslides. The objective of this issue is to increase awareness and to extend knowledge, about this important theme, among the Landslides readers, both practitioners and researchers. Laboratory experiments are an indispensable component of obtaining a comprehensive understanding of the LGTW event complexities. Alessandro Romano, Marcello Di Risio, Giorgio Bellotti, Matteo Molfetta, Leonardo Damiani and Paolo De Girolamo provide a dataset of three-dimensional experiments for subaerial LGTWs triggered by slide at the edge of a conical island. The high spatial resolution of the dataset can be used for the benchmarking of analytical and numerical models. A series of experimental data in a wave basin with flexible mesh-packed slides is presented by Frederic Evers and Willi Hager. They examine the existing prediction methods for wave height in comparison with the test data. Modelling the interactions of the landslide and water body is a demanding and an elegant task and it is required for an intuitive understanding of the related phenomena and the risk assessment of LGTWs. There are two review articles in this issue with the focuses on the analytical and numerical modelling of LGTWs. An extensive review of the conceptual, mathematical and numerical aspects of the landslide-generated waves modelling for both submarine and subaerial is presented by Saeedeh Yavari-Ramsheh and Behzad Ataie-Ashtiani. They also scrutinise the shortcomings and the future challenges for the numerical modelling of LGTWs. Emiliano Renzi and Paolo Sammarco provide an overview of analytical models for the dynamics of landslide tsunami generation and propagation along beaches and around islands. The analytical modelling is in the framework of shallow-water wave theory. They also suggest directions for the future research of analytical modelling in this field. The application of numerical modelling in association with field measurements and investigations of recent events and case studies, as well as data analysis of historic events are key sources for an enhanced insight into the landslide-generated wave impacts. James Kirby, Fengyan Shi, Dmitry Nicolsky and Shubhra Misra present the numerical simulations for tsunami waves generated by the 27 April 1975 Kitimat, British Columbia submarine landslide. Slide motion is modelled using two approaches by assuming a solid sliding mass or a highly viscous Newtonian fluid lower layer. They show both approaches can resemble the observations. Kyoji Sassa, Khang Dang, Hideaki Yanagisawa and Bin He introduce a new model for the numerical simulation of the landslide-induced tsunami. The underwater landslide initiation and motion, as well as tsunami wave due to the landslide, are simulated. They applied the model to the largest landslide-induced tsunami disaster occurred in Japan and their numerical simulations successfully reproduce the historical tsunami heights, recorded for the 1792 Unzen-Mayuyama event. Sylfest Glimsdal, Jean-Sebastien L’Heureux, Carl B. Harbitz and Finn Lovholt present the results of the post-tsunami field survey and the numerical modelling of the 29th January 2014 submarine landslide at Statland, Norway. By comparing the simulated tsunami run-up for different scenarios with observations, they reconstruct the landslide dynamics, tsunami generation and wave runup. James Goff and James Terry discuss tsunamigenic slope failures as a possible source of the tsunami hazard for Pacific Island Countries and Territories. They suggest a range of indicators such as geological, oral tradition and archaeological components to identify evidence of past tsunamis. Jersain Gomez, Moises Berezowsky, Alejandro Lara and Elizabeth Gonzalez present a study of the water waves generated due a possible semi-submerged landslide in La Yesca Reservoir, Mexico. A physical model of the reservoir and numerical model based on shallow water equations are employed. The Guest Editor hopes that the thematic issue encourages further researches and publications in Landslides on various aspects of LGTW hazards including; warning procedures, understanding of related phenomena, and mitigation measures. I gratefully acknowledge the international experts who reviewed the manuscripts and in particular the support of Editor-in-Chief Professor Kyoji Sassa that made the publication of this thematic issue possible.