Agung

Geography & Climate

Agung is located in Indonesia, within the Sunda Volcanic Arc of the broader Sunda-Banda Volcanic Regions. Situated at 8.34° S, 115.51° E in the Southern Hemisphere, the volcano lies within a tropical climate zone. At 2,997 meters above sea level, Agung rises above the surrounding terrain into montane or subalpine conditions. The elevation creates distinct ecological zones along its flanks, from forested lower slopes to exposed rocky terrain near the summit. 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

Agung 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 Agung, 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

Agung has 7 recorded eruptions in the geological database, spanning from 1808 CE to 2022 CE. The most powerful recorded event was a paroxysmal eruption with devastating regional consequences in 1963 CE, reaching VEI 5 on the Volcanic Explosivity Index. Notable eruptions include 2017 CE (VEI 3), 1963 CE (VEI 5), 1843 CE (VEI 5). This eruption frequency indicates a moderately active volcanic system with periodic reawakenings. With eruptive activity as recently as 2022 CE, Agung remains an actively monitored volcano.

Significance

With a maximum recorded VEI of 5, Agung has demonstrated the capacity for paroxysmal eruptions comparable to the 1980 eruption of Mount St. Helens. Eruptions of this scale can devastate areas within 20-30 kilometers and produce ash fall that disrupts aviation and agriculture across hundreds of kilometers. With 7 recorded eruptions on file, Agung has enough documented activity to help scientists identify patterns in its eruptive behavior. Given its recent activity, Agung is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

Symmetrical Agung stratovolcano, Bali's highest and most sacred mountain, towers over the eastern end of the island. The volcano, whose name means "Paramount," rises above the SE rim of the Batur caldera, and the northern and southern flanks extend to the coast. The summit area extends 1.5 km E-W, with the high point on the W and a steep-walled 800-m-wide crater on the E. The Pawon cone is located low on the SE flank. Only a few eruptions dating back to the early 19th century have been recorded in historical time. The 1963-64 eruption, one of the largest in the 20th century, produced voluminous ashfall along with devastating pyroclastic flows and lahars that caused extensive damage and many fatalities.

— Smithsonian Institution, Global Volcanism Program