Shiveluch on Russia's Kamchatka Peninsula is one of the most active volcanoes on the planet. Usually its eruptions are dramatic explosions, but over the last few weeks, it has started erupting ... a thing. It looks like an alien structure rising out of the ground, but a what we call a whaleback is a special kind of lava dome made by a volcanic eruption.
Whalebacks are the volcanic equivalent of squeezing old toothpaste out of the tube. The lava erupting is dacite, a relatively high silica magma that can be very sticky. If that dacite is especially cool after sitting and crystallizing inside the volcano, it can erupt nearly as a solid. This style of eruption produces smooth or grooved spines, or domes of lava that eventually crumble ... sometimes leading to violent eruptions (but not always).
The Mount St. Helens whaleback dome that formed in the 1980 crater during ...
