Soputan

Geography & Climate

Soputan is located in Indonesia, within the Sangihe Volcanic Arc of the broader Western Pacific Volcanic Regions. Situated at 1.11° N, 124.74° E in the Northern Hemisphere, the volcano lies within a tropical climate zone. With a summit elevation of 1,785 meters above sea level, Soputan 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

Soputan 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 Indonesia near Soputan, 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

Soputan has 20 recorded eruptions in the geological database, spanning from 1971 CE to 2020 CE. The most powerful recorded event was a severe eruption capable of regional ash fall and pyroclastic flows in 2018 CE, reaching VEI 3 on the Volcanic Explosivity Index. Notable eruptions include 2018 CE (VEI 3), 2016 CE (VEI 3), 2015 CE (VEI 3). With an average interval of roughly 2 years between eruptions over a span of 49 years, this is one of the more frequently active volcanoes in the database. This persistent activity suggests a robust and well-supplied magma system beneath the volcano. With eruptive activity as recently as 2020 CE, Soputan remains an actively monitored volcano.

Significance

With a maximum recorded VEI of 3, Soputan 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. Its 20 recorded eruptions make it one of the most prolific volcanoes in our database, reflecting a persistent and well-documented eruptive history that has provided volcanologists with extensive data for understanding eruption patterns and forecasting future activity. Given its recent activity, Soputan is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano is the only active cone in the Sempu-Soputan volcanic complex, which includes the Soputan caldera, Rindengan, and Manimporok (3.5 km ESE). Kawah Masem maar was formed in the W part of the caldera and contains a crater lake; sulfur has been extracted from fumarolic areas in the maar since 1938. Recent eruptions have originated at both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.

— Smithsonian Institution, Global Volcanism Program