Physical Geology 101
Landforms which develop from the eruption of magma and are built of volcanic materials (lava, ash, etc.)
Volcanic landforms include more than just volcanoes
Volcanic materials can be divided into two main categories:
Pyroclastic deposits - welded, cemented or unconsolidated pyroclasts
Tuff, ignimbrite, ash fall, ash flow deposits are all terms used to describe pyroclastic deposits
Lahars and Mudflows (Example 1, Example 2)
Non-violent, effusive eruptions of lava which flows along the surface
Basalt is the most common lava rock type
The type of flow is controlled by the composition of the lava
Lava Flow Types
Pahoehoe - very fluid flows - low viscosity; ropy surface appearance; basalt.
Aa - higher viscosity than pahoehoe; surface consists of spiny, angular clinkers; basalt, andesite.
Block flows - surface consists of angular blocks; andesite, rhyolite, obsidian