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A review on the current knowledge of tephra remobilization from scoria cone eruptions

Natalia Isabel Villalba1 , Marie-Noëlle Guilbaud2

  • Affiliations:  1Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad de México, México; 2Departamento de Vulcanología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad de México, México 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 178

  • Programme No: 3.5.37

  • Theme 3 > Session 5

Abstract

Tephra remobilization has proven to be an important hazard during several recent eruptions at stratovolcanoes, causing significant impact on health, environment and infrastructure. As scoria cone eruptions differ from those of stratovolcanoes in several key parameters (e.g. volume, explosivity, duration, composition, etc.), we believe that a specific study on tephra remobilization processes at these volcanoes is needed, in order to understand erosive phenomenon and related hazards in monogenetic fields. To assess the current body of knowledge on this topic, we conducted a review of the scientific literature. We found 36 articles, yet most of them focus on cone morphology, which has limited implications for hazards. The Paricutin volcano stands out for being the one case for which syn- and post-eruptive processes are thoroughly described, while studies on other volcanoes are restricted on specific aspects or only include brief mentions. The erosive mechanisms commonly identified are rill and sheet erosion and channel widening for water-related erosion, and deflation and re-suspension for wind-related erosion. The type of erosive agent (water, wind, gravity) is determined by external factors, such as climate, slope, topography, soil and vegetation. The presence of lava flows or other topographic obstacles highly promotes the accumulation of remobilized tephra. Deposits vary from massive to parallel- and cross-stratified. They tend to be well sorted and dominated by fine-ash particles that consist of scoria mixed with sediments or soils incorporated during transport. So far, there is little information available on the distribution of the deposits and the duration of the remobilization process.