01775nas a2200229   4500000000100000008004100001653001900042653002400061653002400085653001300109653001500122100001500137700001700152700001800169700001400187245016900201856006700370300002400437490000700461520106400468022001301532       2013                            d10aCanary Islands10amultistage collapse10asubmarine landslide10asubunits10aturbidites1 aJames Hunt1 aRussell Wynn1 aPeter Talling1 aD. Masson00aMultistage collapse of eight western Canary Island landslides in the last 1.5 Ma: Sedimentological and geochemical evidence from subunits in submarine flow deposits  uhttp://onlinelibrary.wiley.com/doi/10.1002/ggge.20138/abstract  a2159\textendash21810 v143 a<p>Volcaniclastic turbidites in the Madeira Abyssal Plain provide a record of major landslides from the Western Canary Islands in the last 1.5 Ma. These volcaniclastic turbidites are composed of multiple fining-upwards turbidite sands, known as subunits. The subunits indicate that the landslides responsible for the sediment gravity flows occurred in multiple stages. The subunits cannot result from flow reflection or splitting because the compositions of volcanic glasses from each individual subunit in an event bed are subtly different. This indicates that each subunit represents a discrete failure as part of a multistage landslide. This has significant implications for geohazard assessments, as multistage failures reduce the magnitude of the associated tsunami. The multistage failure mechanism reduces individual landslide volumes from up to 350 km3 to less than 100 km3. Thus although multistage failure ultimately reduce the potential landslide and tsunami threat, the landslide events may still generate significant tsunamis close to source.</p>  a15252027