Explosive sequence of La Soufrière St Vincent April 2021: Insights into drivers and consequences via eruptive products

P. D. Cole, J. Barclay, R. E. A. Robertson, S. Mitchell, B. V. Davies, R. Constantinescu, R. J. S. Sparks, W. Aspinall, A. Stinton

Research output: Chapter in Book/Report/Conference proceedingChapter (peer-reviewed)peer-review

12 Citations (Scopus)
1 Downloads (Pure)

Abstract

This paper forensically reconstructs the timings, impacts and processes that drove the sequence of explosive eruptions of La Soufrière, St Vincent in April 2021 using a combination of field-based stratigraphy and textural dissection of the deposit character together with contemporary visual observations. Explosive activity on 9 April and early on 10 April involved destruction of almost all of the 2020/2021 lava dome, c. 60% of the 1979 dome and formation of a 600 m diameter crater by 2pm UTC on 10 April. Following the initial explosion, plumes rose to altitudes of c. 15 km and pyroclastic density currents (PDCs), formed by column collapse, first occurred on 10 April, only after .24 h of explosive activity. Dense PDCs reached the sea only in the Larikai and Roseau valleys, and dilute PDCs were restricted to within 2.5 km of the Summit Crater rim. The tephra fallout deposits are stratified, composed of numerous layers of both lapilli-rich and ash-rich layers, which we have grouped into at least 7 units, based on their common characteristics (Units 1 to 7). Volume estimates, using a range of techniques to constrain uncertainties, indicate that the bulk volume of tephra (fallout and PDC) is 1.19 × 10 8 m 3 + 20% making this a VEI 4 eruption.

Original languageEnglish
Title of host publicationThe 2020-21 Eruption of La Soufriere Volcano, St. Vincent
EditorsR. E. A. Robertson, E. P. Joseph, J. Barclay, R. S. J. Sparks
PublisherGeological Society of London
Pages81-106
Number of pages26
Volume539
DOIs
Publication statusPublished - 1 Apr 2024

Publication series

NameGeological Society Special Publications
PublisherGeological Society of London

Cite this