Edifice Sector Failure at Soufriere Hills Volcano, Montserrat: Documenting the Failure Dynamics of a Hydrothermally-Altered Edifice in Three-Dimensions

9909673

Voight and Elsworth

The potential for catastrophic structural failure of volcanoes and related hazards implications are now well recognized, but apart from a study at Mount St Helens, the mechanisms of collapse are poorly understood. The major edifice failure on Montserrat in December 1997 provides an unusual opportunity for a comprehensive analysis of collapse. The failure occurred on the altered south flank of Soufriere Hills volcano, generated a debris avalanche that reached the coast, and triggered a volcanic blast. The failure has been well documented, and abundant volcano monitoring data have been collected by Montserrat Volcano Observatory; one of us, BV, is a member of this organization. We propose to analyze the deformation and stability of this volcano, using powerful computer-modeling tools not used previously in volcano analyses. The study will evaluate realistic models representing gradual to sudden collapse, examine the effects of earthquake loading in a rigorous fashion, and consider the potential for collapse prediction from monitored data. The results of this study are likely to have a significant impact on evaluations of potential structural failure at other volcanoes, with an important bearing on volcano hazard management.