Large-scale volcanic deposit fluidization by dilute pyroclastic density currents - Laboratoire Magmas et Volcans Accéder directement au contenu
Article Dans Une Revue Nature Geoscience Année : 2023

Large-scale volcanic deposit fluidization by dilute pyroclastic density currents

Résumé

There is increasing evidence that fine-grained deposits of pyroclastic density currents can be remobilized on a large scale, resulting in concentrated flows. These flows can be a major hazard: for example, at Soufrière Hills Volcano (Montserrat) in 1997, some travelled beyond the designated danger zone to inhabited areas. Despite their hazard potential, the scale and generation mechanism of these flows are poorly understood. Here we demonstrate using laboratory experiments and numerical modelling that decompression following the passage of dilute pyroclastic density currents can cause rapid deposit fluidization over areas of several square kilometres and to depths of tens of centimetres. The fluidized volume can be substantially greater than that deposited by the triggering pyroclastic density current because of remobilization of previously emplaced deposits, and the fluidized volume can flow even on slopes of a few degrees. The capacity for remobilization of a deposit is limited by its particle cohesion, which rapidly increases with atmospheric humidity. This mechanism of fluidisation should alert us to an under-appreciated volcanic hazard of long–runout pyroclastic flows that can be generated by remobilisation very rapidly and with little warning.

Domaines

Volcanologie
Fichier principal
Vignette du fichier
Kelfoun_Proano_format_HAL.pdf (1.85 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
licence : CC BY - Paternité

Dates et versions

hal-04215005 , version 1 (22-09-2023)

Identifiants

Citer

Karim Kelfoun, Antonio Proaño. Large-scale volcanic deposit fluidization by dilute pyroclastic density currents. Nature Geoscience, 2023, 16 (6), pp.499-504. ⟨10.1038/s41561-023-01190-7⟩. ⟨hal-04215005⟩
37 Consultations
43 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More