The summit of an erupting volcano is one of the most dynamic places on Earth. These natural-color Landsat 8 images of Shiveluch were collected one week apart, on January 24 (top) and January 31, 2014 (lower). The two images show ash and pyroclastic flow deposits accumulating on the Russian volcano’s slopes. The pyroclastic flows are generated by collapses on a new lava dome, that is growing on the northwest face of a dome that had recently been the site of most activity. Turn on the image comparison tool to spot the differences.
Lava domes form when thick lava piles up around the erupting vent, cooling into a mound. Such domes expand from the inside as an eruption continues; eventually the outer crust crumbles, spilling debris down the volcano’s slopes.
A tall ridge—created by a massive, Mount St. Helens-like eruption in 1964—prevents debris from the new dome from flowing northward, instead redirecting it to the southwest. In contrast, many earlier flows traveled to the south-southeast.
Stratovolcanoes like Shiveluch and Mount Saint Helens are constructed by the buildup of different types of lava, debris, and ash. The process takes thousands to hundreds of thousands of years. Analysis of the resulting layers allows geologists to decipher a volcano’s history.
The Kamchatka Peninsula contains 43 stratovolcanoes, including Shiveluch. Of these, Shiveluch is one of the largest and most active. It has an elevation of 3,283 meters (10,768 feet).
NASA Earth Observatory images by Jesse Allen and Robert Simmon, using Landsat data from the USGS Earth Explorer. Caption by Robert Simmon and Holli Riebeek.