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

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