Submarine Landslides and Their Tsunami Hazard

Abstract

Most tsunamis are generated by earthquakes, but in 1998, a seabed slump offshore of northern Papua New Guinea (PNG) generated a tsunami up to 15 m high that killed more than 2,200 people. The event changed our understanding of tsunami mechanisms and was forerunner to two decades of major tsunamis that included those in Turkey, the Indian Ocean, Japan, and Sulawesi and Anak Krakatau in Indonesia. PNG provided a context to better understand these tsunamis as well as older submarine landslide events, such as Storegga (8150 BP); Alika 2 in Hawaii (120,000 BP), and Grand Banks, Canada (1929), together with those from dual earthquake/landslide mechanisms, such as Messina (1908), Puerto Rico (1928), and Japan (2011). PNG proved that submarine landslides generate devastating tsunamis from failure mechanisms that can be very different, whether singly or in combination with earthquakes. It demonstrated the critical importance of seabed mapping to identify these mechanisms as well as stimulated the development of new numerical tsunami modeling methodologies. In combination with other recent tsunamis, PNG demonstrated the critical importance of these events in advancing our understanding of tsunami hazard and risk. This review recounts how, since 1998, understanding of the tsunami hazard from submarine landslides has progressed far beyond anything considered possible at that time. ▪ For submarine landslide tsunamis, advances in understanding take place incrementally, usually in response to major, sometimes catastrophic, events. ▪ The Papua New Guinea tsunami in 1998, when more than 2,200 people perished, was a turning point in first recognizing the significant tsunami hazard from submarine landslides. ▪ Over the past 2 to 3 years advances have also been made mainly because of improvements in numerical modeling based on older tsunamis such as Grand Banks in 1929, Messina in 1908, and Storegga at 8150 BP. ▪ Two recent tsunamis in late 2018, in Sulawesi and Anak Krakatau, Indonesia, where several hundred people died, were from very unusual landslide mechanisms—dual (strike-slip and landslide) and volcanic collapse—and provide new motivations for understanding these tsunami mechanisms. ▪ This is a timely, state of the art review of landslide tsunamis based on recent well-studied events and new research on older ones, which provide an important context for the recent tsunamis in Indonesia in 2018. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 49 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Frontal wedge variations and controls of submarine landslides in the Negros–Sulu Trench System, Philippines

“…In the past, submarine landslides were overlooked to cause damaging tsunamis until the 1998 Papua New Guinea submarine slump. This event caused a 15 m wave height leading to more than 2,200 fatalities that reshaped the perspective on the impacts of submarine landslides (Heinrich et al, 2001;Tappin 2021). Advancements in seafloor mapping and tsunami modeling have also led to revisiting past tsunamis that were once attributed only to earthquakes.…”

Dating submarine landslides using the transient response of gas hydrate stability

“…Although submarine slides have never been observed directly, sea oor scars and mass transport deposits (MTDs) from the slope failures are detectable through seismic networks, seabed bathymetry and 3D seismic surveys 9,10 .…”

Instability simulation of the submerged anti-dip slope based on the CFD-DEM coupling method

“…These engineering constructions will make evident disturbances to the stratum structure and have a significant impact on the stability of water-related slopes, like 1) the Three Gorges Reservoir, 2) the exploitation of oil and gas resources in the Yellow River Delta, and 3) the exploitation of combustible ice. The instability of these slopes not only poses a great threat to people's lives and artificial facilities but also leads to some catastrophic disasters (like tsunami and earthquake), which are also thought to be associated with these slopes (Ten Brink et al, 2009;Goff and Terry, 2016;Yavari-Ramshe and Ataie-Ashtiani, 2017;Tappin, 2021). The seepage can carry away different kinds of particles in the soil, causing gradual destabilization of the submerged soil structure (Bai et al, 2021a;Bai et al, 2021b).…”