Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France.
Instituto Volcanológico de Canarias (INVOLCAN), Antiguo Hotel Taoro, Parque Taoro s/n, 38400 Puerto de la Cruz, Spain.
Nat Commun. 2017 May 15;8:15246. doi: 10.1038/ncomms15246.
Giant mass failures of oceanic shield volcanoes that generate tsunamis potentially represent a high-magnitude but low-frequency hazard, and it is actually difficult to infer the mechanisms and dynamics controlling them. Here we document tsunami deposits at high elevation (up to 132 m) on the north-western slopes of Tenerife, Canary Islands, as a new evidence of megatsunami generated by volcano flank failure. Analyses of the tsunami deposits demonstrate that two main tsunamis impacted the coasts of Tenerife 170 kyr ago. The first tsunami was generated during the submarine stage of a retrogressive failure of the northern flank of the island, whereas the second one followed the debris avalanche of the subaerial edifice and incorporated pumices from an on-going ignimbrite-forming eruption. Coupling between a massive retrogressive flank failure and a large explosive eruption represents a new type of volcano-tectonic event on oceanic shield volcanoes and a new hazard scenario.
大洋盾状火山的大规模山体滑坡会引发海啸，这种潜在的灾害虽然规模大，但发生频率低，其作用机制和动力学特征也难以推断。本文记录了特内里费岛西北坡高处（高达 132 米）的海啸沉积物，为火山侧翼滑坡引发特大海啸提供了新证据。对海啸沉积物的分析表明，17 万年前曾有两次主要海啸袭击了特内里费岛的海岸。第一次海啸是由岛屿北部侧翼后退式滑坡引发的，而第二次海啸则是在山体崩塌形成的碎屑流之后发生的，并裹挟了正在喷发的火山灰流中的浮石。大规模后退式侧翼滑坡与大型爆发式喷发的相互作用，代表了大洋盾状火山上新的火山-构造事件类型和新的灾害情景。
