Editing Volcano (section)

===Stratovolcanoes (composite volcanoes)===
[[File:Volcano scheme.svg|thumb|upright=1.4|'''Cross-section through a [[stratovolcano]] (vertical scale is exaggerated)''': {{Div col|colwidth=30em}}{{ordered list
    |1=Large magma chamber
    |2=Bedrock
    |3=Conduit (pipe)
    |4=Base
    |5=Sill
    |6=Dike
    |7=Layers of ash emitted by the volcano
    |8=Flank
    |9=Layers of lava emitted by the volcano
    |10=Throat
    |11=Parasitic cone
    |12=Lava flow
    |13=Vent
    |14=Crater
    |15=Ash cloud
}}{{div col end}}]]
{{Main|Stratovolcano}}
Stratovolcanoes are tall conical mountains composed of lava flows and [[tephra]] in alternate layers, the [[strata]] that gives rise to the name. They are also known as ''composite volcanoes'' because they are created from multiple structures during different kinds of eruptions; the main conduit bringing magma to the surface branches into multiple secondary conduits and occasional [[laccolith]]s or [[Sill (geology)|sill]]s, the branching conduits may form [[parasitic cone]]s on the flanks of the main cone.<ref name=dkp/> Classic examples include [[Mount Fuji]] in Japan, [[Mayon Volcano]] in the Philippines, and [[Mount Vesuvius]] and [[Stromboli]] in Italy.
[[File:Mount Vesuvius Araucaria.jpg|thumb|left|Mt. Vesuvius, a stratovolcano, [[Gulf of Naples]].]]

[[volcanic ash|Ash]] produced by the [[explosive eruption]] of stratovolcanoes has [[recorded history|historically]] posed the greatest volcanic hazard to civilizations. The lavas of stratovolcanoes are higher in silica, and therefore much more viscous, than lavas from shield volcanoes. High-silica lavas also tend to contain more dissolved gas. The combination is deadly, promoting [[explosive eruption]]s that produce great quantities of ash, as well as [[pyroclastic surge]]s like the one that destroyed the city of Saint-Pierre in Martinique in 1902. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose [[tephra]] are material for dangerous [[lahar]]s.<ref>{{Cite book|url=https://books.google.com/books?id=eJopFDVRgYMC&pg=PA115|title=Volcanoes: Global Perspectives|first1=John P.|last1=Lockwood|first2=Richard W.|last2=Hazlett|year=2010|isbn=978-1-4051-6250-0|page=552|publisher=Wiley}}</ref> Large pieces of tephra are called [[volcanic bomb]]s. Big bombs can measure more than {{convert|4|ft|m|order=flip}} across and weigh several tons.<ref>Berger, Melvin, Gilda Berger, and Higgins Bond. "Volcanoes-why and how ." Why do volcanoes blow their tops?: Questions and answers about volcanoes and earthquakes. New York: Scholastic, 1999. 7. Print.</ref>