Multistage collapse of eight western Canary Island landslides in the last 1.5 Ma: Sedimentological and geochemical evidence from subunits in submarine flow deposits

摘要: Volcaniclastic turbidites in the Madeira Abyssal Plain provide a record of major landslides from Western Canary Islands last 1.5 Ma. These volcaniclastic are composed multiple fining-upward turbidite sands, known as subunits. The subunits indicate that responsible for sediment gravity flows occurred stages. cannot result flow reflection or splitting because compositions volcanic glasses each individual subunit an event bed subtly different. This indicates represents discrete failure part multistage landslide. has significant implications geohazard assessments, failures reduce magnitude associated tsunami. mechanism reduces landslide volumes up to 350 km3 less than 100 km3. Thus although ultimately potential and tsunami threat, events may still generate tsunamis close source.