Magma and Erupted Materials
viscosity lava pahoehoe aa pillow lava pyroclastic flow pyroclastic material
Types of Magma
No matter what type of magma you have, silica
main ingredient. What determines the type of magma is the percentages of
silica and present. Magmas with high silica content have a high viscosity
(resistance to flow) and are generally more explosive when eruptions
occur. All magmas also contain some degree of trapped gasses (CO2
& H2O ). The more trapped gas the more violent the
). The more trapped gas the more violent the explosion.
/ Granitic Magma
All magma that reaches the surface can be classified as Lava.
Basaltic lava is classified according to its texture.
Ash and Rock Fragments
Solid fragments that are thrown from volcanoes are called pyroclastic materials. They are ejected by the trapped gases within the volcanoe and are classified according to their size.
Forms of tephra
Last modified: October 17, 2003