Brennisteinsfjoll

Geography & Climate

Brennisteinsfjoll is located in Iceland, within the Iceland Neovolcanic Rift Volcanic Province of the broader Atlantic Ocean Volcanic Regions. Situated at 63.93° N, 21.78° W in the Northern Hemisphere, the volcano lies within a subarctic climate zone. With a summit elevation of 610 meters above sea level, Brennisteinsfjoll is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a cluster, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Brennisteinsfjoll is situated along a rift zone, where tectonic plates are pulling apart. As the crust thins and fractures, magma rises to fill the gap, creating volcanic activity. Rift volcanism typically produces more fluid lava flows rather than explosive blasts, which means communities near Brennisteinsfjoll in Iceland generally face slower-moving hazards like lava flows and ground fissures rather than sudden pyroclastic events. However, rift volcanoes can still generate significant ash emissions and gas releases that affect local air quality. The dominant rock type is basalt / picro-basalt, 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

Brennisteinsfjoll has 9 recorded eruptions in the geological database, spanning from 9000 BCE to 1341 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1341 CE, reaching VEI 2 on the Volcanic Explosivity Index. This eruption frequency indicates a moderately active volcanic system with periodic reawakenings.

Significance

With 9 recorded eruptions on file, Brennisteinsfjoll has enough documented activity to help scientists identify patterns in its eruptive behavior.

GVP Reference Summary

The Brennisteinsfjöll volcanic system, located east of Kleifarvatn lake, consists of a series of NE-SW-trending crater rows and small shield volcanoes. Postglacial and historical basaltic lavas cover a wide area. An eruption in 1000 CE was dated by its occurrence at the time of a meeting of the Icelandic outdoor parliament at Thingvellier. The most recent eruption took place in the 14th century.

— Smithsonian Institution, Global Volcanism Program