Illustrated Volcano Glossary
- VolcanologyLava flows are almost self-explanatory. When magma is erupted in molten or a partially molten state it often has the ability to flow. This is typically the case for basaltic volcanoes such as Hawaii and Etna whose lavas are relatively fluid. Lava flows might form either as primary flows directly flowing out of a vent from the vent or by rapid aggregation of hot fluid spatter that fall back from lava fountains to form a flow.The appearance of lava flows can vary greatly with chemistry, flow rate, strain rate, temperature, viscosity and other factors. The most simple division can be made between aa lava that usually has a blocky appearance, since the surface of the flow breaks into spiny or blocky pieces, and pahoehoe lava flows, which form a smooth surface and often produce spectacular ropy textures.