Tsunamis are water waves triggered by impulsive geologic events such as sea floor deformation, landslides, slumps, subsidence, volcanic eruptions and bolide impacts. Tsunamis can inflict significant damage and casualties both nearfield and after evolving over long propagation distances and impacting distant coastlines. Tsunamis can also effect geomorphologic changes along the coast. Understanding tsunami generation and evolution is of paramount importance for protecting coastal population at risk, coastal structures and the natural environment. Accurately and reliably predicting the initial waveform and the associated coastal effects of tsunamis remains one of the most vexing problems in geophysics, and -with few exceptions- has resisted routine numerical computation or data collection solutions. While ten years ago, it was believed that the generation problem was adequately understood for useful predictions, it is now clear that it is not, especially nearfield. By contrast, the runup problem earlier believed intractable is now well understood for all but the most extreme breaking wave events.

Tsunamis are water waves triggered by impulsive geologic events such as sea floor deformation, landslides, slumps, subsidence, volcanic eruptions and bolide impacts. Tsunamis can inflict significant damage and casualties both nearfield and after evolving over long propagation distances and impacting distant coastlines. Tsunamis can also effect geomorphologic changes along the coast. Understanding tsunami generation and evolution is of paramount importance for protecting coastal population at risk, coastal structures and the natural environment. Accurately and reliably predicting the initial waveform and the associated coastal effects of tsunamis remains one of the most vexing problems in geophysics, and -with few exceptions- has resisted routine numerical computation or data collection solutions. While ten years ago, it was believed that the generation problem was adequately understood for useful predictions, it is now clear that it is not, especially nearfield. By contrast, the runup problem earlier believed intractable is now well understood for all but the most extreme breaking wave events.

In the wake of the disastrous tsunami which struck Papua New Guinea in 1998, this volume presents 20 state-of-the-art contributions on landslide tsunamis, including earthquake characteristics and ground motions, modeling of landslides in geotechnical engineering, field surveys on land and at sea, simulations of past, present, and potential future tsunamis, and theoretical studies of tsunami generation by landslides.

This book is a part of ICL new book series “ICL Contribution to Landslide Disaster Risk Reduction” founded in 2019. Peer-reviewed papers submitted to the Fifth World Landslide Forum were published in six volumes of this book series. This book contains the followings: • Four Forum lectures and one award paper • Sendai Landslide Partnerships, Kyoto Landslide Commitment, and International Programme on Landslides. • Landslide-induced tsunamis • Landslides at UNESCO designates sites and contribution from WMO, FAO, and IRDR • Education and Capacity Development for Risk Management and Risk Governance Prof. Kyoji Sassa is the Founding President and the Secretary-General of International Consortium on Landslides (ICL). He has been the Editor-in-Chief of International Journal Landslides since its foundation in 2004. Prof. Matjaž Mikoš is the Vice President of International Consortium on Landslides and Vice President of Slovenian Academy of Engineering. He is a Professor and Dean of Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia. Dr. Shinji Sassa is Head of Soil Dynamics Group and Research Director of International Research Center for Coastal Disasters, Port and Airport Research Institute, National Institute of Maritime, Port and Aviation Technology, Japan. Prof. Peter Bobrowsky is the President of International Consortium on Landslides. He is a Senior Scientist of Geological Survey of Canada, Ottawa, Canada. Prof. Kaoru Takara is the Executive Director of International Consortium on Landslides. He is a Professor and Dean of Graduate School of Advanced Integrated Studies (GSAIS) in Human Survivability (Shishu-Kan), Kyoto University. Dr. Khang Dang is the Secretary General of the Fifth World Landslide Forum. He also serves as the Research Promotion Officer of ICL and a Lecturer at the University of Science, Vietnam National University, Hanoi.

This book presents selected articles from the International Conference on Asian and Pacific Coasts (APAC 2019), an event intended to promote academic and technical exchange on coastal related studies, including coastal engineering and coastal environmental problems, among Asian and Pacific countries/regions. APAC is jointly supported by the Chinese Ocean Engineering Society (COES), the Coastal Engineering Committee of the Japan Society of Civil Engineers (JSCE), and the Korean Society of Coastal and Ocean Engineers (KSCOE). APAC is jointly supported by the Chinese Ocean Engineering Society (COES), the Coastal Engineering Committee of the Japan Society of Civil Engineers (JSCE), and the Korean Society of Coastal and Ocean Engineers (KSCOE).

This book is a comprehensive collection of state-of-the-art studies of seafloor slope instability and their societal implications. The volume captures the most recent and exciting scientific progress made in this research field. As the world’s climate and energy needs change, the conditions under which slope instability occurs and needs to be considered, are also changing. The science and engineering of submarine – or more widely subaqueous – mass movements is greatly benefiting from advances in seafloor and sub-seafloor surveying technologies. Ultra-high-resolution seafloor mapping and 3D seismic reflection cubes are becoming commonly available datasets that are dramatically increasing our knowledge of the mechanisms and controls of subaqueous slope failure. Monitoring of slope deformation, repeat surveying and deep drilling, on the other hand, are emerging as important new techniques for understanding the temporal scales of slope instability. In essence, rapid advances in technology are being readily incorporated into scientific research and as a result, our understanding of submarine mass movements is increasing at a very fast rate. The volume also marks the beginning of the third IGCP project for the submarine mass movement research community, IGCP-640 S4SLIDE (Significance of Modern and Ancient Submarine Slope LandSLIDEs). The Submarine Mass Movements and Their Consequences symposium is the biannual meeting under the IGCP umbrella.

Submarine mass movements represent major offshore geohazards due to their destructive and tsunami-generation potential. This potential poses a threat to human life as well as to coastal, nearshore and offshore engineering structures. Recent examples of catastrophic submarine landslide events that affected human populations (including tsunamis) are numerous; e.g., Nice airport in 1979, Papua-New Guinea in 1998, Stromboli in 2002, Finneidfjord in 1996, and the 2006 and 2009 failures in the submarine cable network around Taiwan. The Great East Japan Earthquake in March 2011 also generated submarine landslides that may have amplified effects of the devastating tsunami. Given that 30% of the World’s population live within 60 km of the coast, the hazard posed by submarine landslides is expected to grow as global sea level rises. This elevated awareness of the need for better understanding of submarine landslides is coupled with great advances in submarine mapping, sampling and monitoring technologies. Laboratory analogue and numerical modeling capabilities have also developed significantly of late. Multibeam sonar, 3D seismic reflection, and remote and autonomous underwater vehicle technologies provide hitherto unparalleled imagery of the geology beneath the oceans, permitting investigation of submarine landslide deposits in great detail. Increased and new access to drilling, coring, in situ measurements and monitoring devices allows for ground-thruth of geophysical data and provides access to samples for geotechnical laboratory experiments and information on in situ strength and effective stress conditions of underwater slopes susceptible to fail. Great advances in numerical simulation techniques of submarine landslide kinematics and tsunami propagation, particularly since the 2004 Sumatra tsunami, have also lead to increased understanding and predictability of submarine landslide consequences. This volume consists of the latest scientific research by international experts in geological, geophysical, engineering and environmental aspects of submarine mass failure, focused on understanding the full spectrum of challenges presented by submarine mass movements and their consequences.