Slow growth of a lava dome characterizes the current eruption of Russia’s Shiveluch Volcano. Lava domes are formed when magma is too thick to flow. Instead it builds a rounded mound. According to Denison University volcanologist Erik Klemetti, eruption rates also play a role, with low rates likely to create lava domes and higher rates favoring lava flows. (The expansion of the lava dome on Mount St. Helens from 2003–04 illustrates how lava domes grow from within.)
This false-color satellite image of Shiveluch was collected by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard Terra on February 2, 2012. The dome itself is shrouded in a plume of steam and other volcanic gases. Light brown ash covers snow downwind of the lava dome to the southeast. The northern slopes of Shiveluch are in deep shadow, and the surrounding forests are red/brown.