About this Event
Dr.Rodrigo Contreras-Arratia will give a wonderful presentation:
Title: Tracking seismicity in an underfunded institution: the case of La Soufriere St Vincent volcanic eruption 2020-2021
Abstract: An unusual volcanic transition was recorded at La Soufriere Volcano in the Lesser Antilles during the 2020-2021 eruptive episode. An initial effusive eruption lasted three months and turned explosive on 9 April 2021. Although the transition was timely recognised and people were promptly evacuated leading to no fatalities, an important question arises; is the monitoring agency capable of replicating this success? To achieve this, the Seismic Research Centre at The University of the West Indies (UWI-SRC) had diversified their methodology toolbox in order to better recognise the detection of subtle geophysical patterns. As a complement to classical location methods applied to VT swarms, the monitoring agency (UWI-SRC) developed new analysis methods including: (1) network analysis of seismic interferometry using cross-correlation functions to locate the sources of tremor and explosions; and (2) use of a fluid-filled crack model to quantify the bulk modulus of magma stored in the system and translate it to gas content. These methods are now available in quasi-real time at UWI-SRC for the interpretation of future unrest episodes and helped to provide a more robust conceptual model of the eruption than the initially proposed with limited seismic analysis. The activation of a preexistent fault (VT swarms), the deepening source of fragmentation during initial stages of the explosive phase and failed explosive transitions are among the most interesting findings. In general, the revised seismological analysis supports and strengthens the conceptual model proposed by Joseph et al., (2022), where a cap sealed the system with a minimal amount of gas exsolved. The system pushed the cap until significant gas exsolution occurred which yielded sufficient energy to initiate the explosive phase.
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