Matthew Island

Geography & Climate

Matthew Island is located in France - claimed by Vanuatu, within the Vanuatu Volcanic Arc of the broader Southwestern Pacific Volcanic Regions. Situated at 22.33° S, 171.32° E in the Southern Hemisphere, the volcano lies within a tropical climate zone. At just 177 meters above sea level, Matthew Island is a relatively low-elevation volcanic feature. Despite its modest height, it remains an active geological formation with the same underlying magmatic processes as its taller counterparts. 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

Matthew Island 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 France - claimed by Vanuatu near Matthew Island, 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

Matthew Island has 7 recorded eruptions in the geological database, spanning from 1828 CE to 1976 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1954 CE, reaching VEI 2 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. The most recent eruption in 1976 CE places this volcano within the modern era of volcanological observation.

Significance

With 7 recorded eruptions on file, Matthew Island has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Matthew Island is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

Matthew Island is composed of two low andesitic-to-dacitic cones separated by a narrow isthmus. The Matthew name originates from an English mariner who sighted the island in 1788. Only the triangular eastern portion of the 0.6 x 1.2 km island was present prior to the 1940s, when construction of the larger western segment began; it consists primarily of lava flows. The western cone contains a crater that is breached to the NW and is filled by a lava flow whose terminus forms the NW coast.

— Smithsonian Institution, Global Volcanism Program