Global Volcanism Program | Image GVP-02369
The currently active Troitsky crater of Maly Semiachik formed during an explosive eruption about 400 years ago. The eastern crater wall shows light-colored hydrothermally altered rocks of the vent complex that are overlain by darker lava flows and fall deposits from eruptions that followed formation of the crater. A hot, acidic lake now fills the crater, which has been the source of historical eruptions.
Photo by Oleg Volynets (Institute of Volcanology, Petropavlovsk).
This image is made available under the Creative Commons BY-NC 4.0 license terms.