Lewotolok

Geography & Climate

Lewotolok is located in Indonesia, within the Sunda Volcanic Arc of the broader Sunda-Banda Volcanic Regions. Situated at 8.27° S, 123.51° E in the Southern Hemisphere, the volcano lies within a tropical climate zone. With a summit elevation of 1,431 meters above sea level, Lewotolok 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

Lewotolok 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 Lewotolok, 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

Lewotolok has 11 recorded eruptions in the geological database, spanning from 1660 CE to 2025 CE. The most powerful recorded event was a severe eruption capable of regional ash fall and pyroclastic flows in 1660 CE, reaching VEI 3 on the Volcanic Explosivity Index. This level of eruptive frequency indicates a persistently active volcanic system that warrants ongoing monitoring. With eruptive activity as recently as 2025 CE, Lewotolok remains an actively monitored volcano.

Significance

With a maximum recorded VEI of 3, Lewotolok 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 11 recorded eruptions, Lewotolok has a substantial eruptive history that provides valuable data for understanding volcanic behavior and assessing future hazards in the Sunda-Banda Volcanic Regions region. Given its recent activity, Lewotolok is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano's high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater.

— Smithsonian Institution, Global Volcanism Program