Lava dome

In volcanology, a lava dome or plug dome is an approximately circular mound-shaped projection resulting from the sluggish eruption of felsic lava from a volcano, or from multiple lava episodes of dissimilar magma types. The characteristic dome shape is credited to high levels of silica in the magma, causing the magma to be fairly viscous and thick. The viscosity of the lava prevents it from graceful distant from the vent that it extrudes from, causing it to solidify rapidly and build on preceding volcanic extrusions, creating a dome-like shape.

Domes may arrive at heights of several hundred meters, and can grow gradually and steadily for months or years. The sides of these structures are calm of unstable rock debris. Due to the option of the building up of gas pressure, the dome can experience additional explosive eruptions over time. When part of a lava dome collapses while it still contains molten rock and gases, it can create a pyroclastic flow, one of the most lethal forms of a volcanic event. Other hazards linked with lava domes are the obliteration of property, forest fires, and lahars triggered by pyroclastic flows close to snow and ice. Lava domes are one of the main structural features of many stratovolcanoes universal.