This section describes the volcanic features and phenomena generated by volcanic eruptions. The eruptive products are highly variaible and largely dependent on the composition, viscosity, and gas content of the erupting magma. Lava flows, for example, are more common in relatively non-explosive basaltic eruptions associated with shield volcanoes, scoria cones, and fissures. On the other hand, pyroclastic flows, lahars and voluminous tephra deposits are more common in explosive andesitic-to-rhyolitic eruptions associated with stratovolcanoes. Gaseous emissions are also examined, as are their harmful effects on both local and global scales.
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