Integrated geophysical and geological investi-gations of volcanic flank collapses at the southern Cape Verdes archipelago: Origin, magnitude and tsunami potential

佛得角群岛南部火山侧翼塌陷的综合地球物理和地质调查：起源、震级和海啸可能性

• 批准号: 507049253
• 负责人: Privatdozent Dr. Andreas Klügel
• 金额: --
• 依托单位: School of Earth and Environmental Sciences
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/507049253?language=en
• 关键词: Integrated; geophysical; geological; investi; gations

The tsunamigenic potential of large volcanic island flank collapses has long been recognized, yet the scale of risks associated with these events as well as their frequency are still poorly constrained and heavily debated. The recent discovery of tsunamigenic deposits in the Cape Verdes showed that Fogo - one of the most active oceanic volcanoes in the world - collapsed catastrophically at ~73 ka, resulting in a megatsunami with a near-source tsunami amplitude in excess of 250 m. The corresponding debris avalanche deposits, however, had only been mapped by medium resolution bathymetric data. Based on this shortage in knowledge, a cruise for a detailed geological and geophysical characterization of the flank collapse deposits was realized in summer 2019; an extensive data set consisting of hydroacoustic and seismic data as well as sediment samples was collected during the cruise. The combined geophysical and geological analysis of the new data in this proposal will address two major aspects of mass transport deposits from the southern Cape Verdes archipelago: i) the distribution, size and volume of mass transport deposits in the entire volcaniclastic apron based on acoustic data, and ii) their respective compositional variability and provenance within the upper 10 meters of cored sediments. Specific objectives include i) the reconstruction of a comprehensive stratigraphic framework for the southern Cape Verdes, ii) the development of a compositional database for event layers with respect to their origin at the volcanic edifices and/or the slope as well as their lateral and distal variability, and iii) the development of an integrated model for origin, emplacement, and triggers of recurrent mass transport deposits off the southern Cape Verde archipelago, and its implications for oceanic islands and tsunami modelling in general. The study of combined geological and geophysical parameters provides a unique opportunity to reconstruct the generation and impact of a megatsunami, directly linked to a study of its trigger mechanism. The results will put us at a critical juncture where the latest developments in tsunami modelling can be integrated with both offshore and onshore evidence, to produce a forecast model more robust than any currently available. This is particularly timely and relevant given the recent unrest at Fogo volcano.

长期以来，大型火山岛侧面崩溃的海藻型潜力已被认可，但是与这些事件以及它们的频率相关的风险规模仍然受到限制较差，并且有严重的争论。最近发现，佛得角（Cape Verdes）在海角中发现的海啸沉积物表明，世界上最活跃的海洋火山之一的福戈（Fogo）在约73 ka时崩溃了，导致巨大的巨木纳米（Megatsunami），其巨大的海啸幅度接近250 m。但是，相应的杂物雪崩沉积物仅通过中等分辨率的测深数据映射。基于知识的短缺，2019年夏季实现了侧面塌陷沉积物的详细地质和地球物理特征的巡游。在巡航过程中收集了包括氢声和地震数据以及沉积物样品的广泛数据集。该提案中对新数据的地球物理和地质分析的综合将介绍来自南部角verdes群岛的大众传输沉积物的两个主要方面：i）基于声学数据的整个火山层围裙中大规模运输沉积物的分布，大小和数量，以及ii）它们的各自的组成性可变性和燃料的固定物中的各自的成分可变性和出处。具体目标包括i）重建南方角verdes的全面地层框架，ii）事件层的组成数据库的开发在火山层面和/或坡度和/或斜坡上的起源以及横向和远程的偏差以及它们的横向变异性以及iii的开发，以实现的质量，empleceles和emplecement，emplecers of Emplagers and emplagers offirt，emplagers和iii）的开发群岛及其对海洋岛和海啸建模的影响。对地质和地球物理参数组合的研究为重建巨木纳米的产生和影响提供了独特的机会，这与对其触发机制的研究直接相关。结果将使我们处于一个关键关键时刻，在该关键时刻，可以将海啸建模的最新发展与海上和陆上证据集成在一起，从而产生比当前可用的任何可用的预测模型。考虑到最近在Fogo火山的动荡，这尤其及时且相关。