Estimating Volcanic Risk in the Lesser Antilles

Type Report
Title Estimating Volcanic Risk in the Lesser Antilles
Publication (Day/Month/Year) 2013
Publisher The University of the West Indies Seismic Research Centre
The potential catastrophic effects of future volcanic eruptions in the Lesser Antilles can be
decreased by the utilisation of effective risk quantification measures and their subsequent
incorporation into disaster risk reduction strategies. A volcanic risk study conducted by the
Norwegian Geotechnical Institute (NGI) in collaboration with Bristol Environment Risk
Research Centre (BRISK) on priority countries of the Global Facility for Disaster Risk
Reduction (GFDRR) of the World Bank provides a possible way for this to be achieved. The
study produced a simple estimate of the risk posed to any one country by combining numerically
assigned hazard levels and their related uncertainty with population exposure indices for each
volcano. Our study applied this methodology to countries in the Lesser Antilles to establish risk
levels and assess its usefulness for preparing for the threat of upcoming eruptions.
A database of past eruptions and their characteristics was compiled using data from the Volcanic
Hazard Atlas of the Lesser Antilles, Smithsonian Global Volcanism Program, Global Database
of Large Magnitude Explosive Eruptions (LaMEVE) and other published literature for the
region. This, together with population distribution data was used to calculate risk levels (ranging
1 to 3) for volcanoes of the English-speaking islands of the Eastern Caribbean. The results
assigned more than 60% of the volcanoes to Risk Level 2 and 25% to Risk Level 3. However,
applying the risk estimation method has its limitations. The hazard component of the method was
found to be heavily dependent on the quality and quantity of eruptive data. The paucity of
eruption records for this region made it easy for the hazard level to be underestimated. To
account for this, future eruption scenarios were used in tandem with past eruption details to
determine volcano hazard levels. Also, the exposure component only considered the physical
threat to the surrounding population. It is recommended that other exposed human elements such
as infrastructure and communication routes be incorporated into the estimation.

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