Simbo

Geography & Climate

Simbo is located in Solomon Islands, within the Solomon Volcanic Province of the broader Southwestern Pacific Volcanic Regions. Situated at 8.29° S, 156.52° E in the Southern Hemisphere, the volcano lies within a tropical climate zone. At just 335 meters above sea level, Simbo 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

Simbo 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 Solomon Islands near Simbo, 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

Simbo has 1 recorded eruption in the geological database, spanning from 1910 CE to 1910 CE. The most recent eruption in 1910 CE places this volcano within the modern era of volcanological observation.

GVP Reference Summary

Simbo is a small island in the western Solomons with three truncated andesitic volcanic centers. The only Potassium-Argon date (2.3 +/- 1 million years ago from Mount Patukio) suggests a Pliocene-to-Pleistocene age for the island (Solomon Islands Geological Survey, 1982). The southern half of the island is thermally active. It contains fault-related fumarolic areas and hot springs near saltwater Lake Ove along the western coast and along the eastern coast near Mount Patukio, which has a steep-walled summit crater. Grover (1955) noted native accounts of the explosive enlargement of the Ngusunu explosion crater along the SW coast of the island one to two generations prior to 1955, probably after a visit by Guppy in 1882. Press reports mentioned an eruption in the early 1900s that forced the evacuation of villages beside Lake Ove, immediately adjacent to Ngusunu crater.

— Smithsonian Institution, Global Volcanism Program