Soufriere Hills

Geography & Climate

Soufriere Hills is located in United Kingdom, within the Lesser Antilles Volcanic Arc of the broader Middle America-Caribbean Volcanic Regions. Situated at 16.72° N, 62.18° W in the Northern Hemisphere, the volcano lies within a tropical climate zone. With a summit elevation of 915 meters above sea level, Soufriere Hills is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Soufriere Hills sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in United Kingdom near Soufriere Hills, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is andesite / basaltic andesite, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

Soufriere Hills has 9 recorded eruptions in the geological database, spanning from 8050 BCE to 2005 CE. The most powerful recorded event was a severe eruption capable of regional ash fall and pyroclastic flows in 2005 CE, reaching VEI 3 on the Volcanic Explosivity Index. Notable eruptions include 2005 CE (VEI 3), 2004 CE (VEI 3), 1995 CE (VEI 3). This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. With eruptive activity as recently as 2005 CE, Soufriere Hills remains an actively monitored volcano.

Significance

With a maximum recorded VEI of 3, Soufriere Hills has produced eruptions capable of generating pyroclastic flows and significant ash fall in the surrounding area. While not among the largest eruptions globally, VEI 3 events pose serious hazards to local populations and can disrupt regional air travel. With 9 recorded eruptions on file, Soufriere Hills has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Soufriere Hills is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The complex, dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. The volcano is flanked by Pleistocene complexes to the north and south. English's Crater, a 1-km-wide crater breached widely to the east by edifice collapse, was formed about 2000 years ago as a result of the youngest of several collapse events producing submarine debris-avalanche deposits. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits, including those from an eruption that likely preceded the 1632 CE settlement of the island, allowing cultivation on recently devegetated land to near the summit. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but no historical eruptions were recorded until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption.

— Smithsonian Institution, Global Volcanism Program