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Landslides and Tsunamis: Multi-Geohazards

2023; Springer Science+Business Media; Volume: 20; Issue: 7 Linguagem: Inglês

10.1007/s10346-023-02084-w

1612-5118

Shinji SASSA,

Seismology and Earthquake Studies

The Virtual Thematic Issue titled "Landslides and Tsunamis: Multi-Geohazards" presents a global collection of papers on landslides and tsunamis as multi-geohazards published in the journal Landslides from America, Europe, Asia, and Oceania.The landslides that trigger tsunamis represent coastal and submarine landslides, river landslides, reservoir landslides, lake landslides, as well as fjord landslides.The origins range widely from earthquakes to volcanoes, rainfalls, rising water levels, and others.This Virtual Thematic Issue includes the most cited papers on landslide and tsunami events as multi-geohazards, such as the 2018 Indonesia Sulawesi earthquake and tsunami disasters and the Three Gorges Reservoir landslides and tsunamis in the twenty-first century.An overview and a concise summary of a total of seventeen papers presented in this Virtual Thematic Issue can be described as follows.On 28 September 2018, on the island of Sulawesi, Indonesia, a strong strike-slip fault earthquake induced extensive liquefaction along coastal land, generating multiple coastal and submarine landslides that caused multiple tsunamis (e.g., Fig. 1).This cascading earthquake-liquefaction-coastal and submarine landslides-tsunamis event (Sassa and Takagawa 2019) resulted in more than 2000 fatalities.The total areas of collapse were about ten times greater than that in the 2010 Haiti earthquake, which shared the same basic mechanisms involving a strike-slip fault earthquake, liquefaction, coastal and submarine landslide, and tsunami, emphasizing the multi-phased physics of the multi-geohazards.A cascading rainfall-landslide-tsunami event occurred on 29 June 2022 in a lake in Southern Chile after 4 days of heavy rains with a maximum intensity of 62 mm/day during an extratropical cyclone (Aránguiz et al. 2023).The landslide with a total volume of 10,500 m 3 that occurred in a steep hillslope subjected to weathering and fracturing generated a tsunami with an initial tsunami amplitude of ~1 m.This small landslide-induced tsunami resulted in the collapse of a pedestrian bridge and overturning other mooring facilities in the lake and the coast (Fig. 2).Landslide tsunami uncertainty was addressed by Løvholt et al. (2020).They presented a probabilistic tsunami hazard analysis framework for analyzing uncertainties emerging from landslide source processes, with reference to large rockslides in Lyngen fjord, Norway.Comparing tsunami inundation maps considering three different levels of magnitude frequency distributions (MFDs, Fig. 3) showed that the tsunami runup height was highly sensitive to the uncertain landslide parameters pertaining to landslide dynamics.A heavy rainfall induced-landslide along the bedrock of weathered granite generated a tsunami-like wave in the Truong River in Vietnam on 5 November 2017 (Minh Duc et al. 2020).This landslide and landslide-induced tsunami caused a fatality.They destroyed houses in a residential area (Fig. 4).The results of the numerical analysis combined with the observations of the landslide scarp,