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Volcanoes can form in three geologic settings, all of which result in the melting of rock in the upper part of the mantle. The rock in the mantle is very hot but is kept solid under immense pressure.
Some volcanoes form at divergent boundaries where two of Earth's tectonic plates pull apart. The crust is thin at these boundaries, reducing pressure on the mantle, allowing some melting to occur, forming molten rock called magma. This rises to the surface, forming volcanoes. This process formed the volcanoes of the East African Rift.
Others form as subduction zones. Here a plate of oceanic crust collides with another plate, sliding under it and into the mantle. With it comes water and other volatiles that seep into the mantle, altering the chemistry and allowing magma to form and rise to the surface, forming volcanoes. This process formed the volcanoes of the Cascades, including Mount St. Helens.
Finally there are hot spots. At these locations extra hot mantle material rises up and partially melts just beneath the crust. The magma then rises up, forming volcanoes. This process formed the volcanoes of Hawaii.
Sometimes fore than one of these settings will line up. The volcanoes of Iceland are the result of a combination of a hot spot and a divergent plate boundary.
What else can I help you with?
Why do volcanos cause more deaths then earthquakes?
Volcanos burn
Are parasitic cone cinder cone the same?
Parasitic cone volcanos and cinder cone volcanos are not the same when classifying. Cinder cone volcanos are the most popular type of volcano, named for its cone shaped formation. Cinder cone volcano are also considered the smallest type of volcanos and can stand alone or grow on the flanks of other volcanos. The parasitic cone volcanos are similar to the cinder cones, however, the volcano is found on the flanks of other volcanos, hence, the name. It is created by flank eruptions of larger volcanos.
Where is the crater in volcanos?
at the top?
What do active volcanos do?
they errupt
What planets and moons have volcanism?
venus - active volcanos injecting sulfate into atmosphere, heat from radioactive decayearth - active volcanos, heat from radioactive decaymars - extinct volcanos, no activity in milllion of years, heat from radioactive decayio - active volcanos, heat from mechanical strain from orbit shapeThere are probably others.
Where does hot melted rock come out of the ground?
Volcanos
Are mud silt and sand in clouds that come out volcanos?
No
Where did the molten rock on the moon come from?
from volcanos that were on the moons surface long ago
Its is not cone what shape is a volcanoe?
A true cone come to a point at the narrow end. Volcanos do not come to sharp points, therefore they are not true cones: however . . . there is a term for a cone that has had its point removed. That term is, "Truncated cone". That is what the mountain-shaped volcanos are.
Why do cinder volcanos have narrow bases and steeper sides than shields volcanos do?
shield volcanoes have cinders that come out then land on it. that's what makes them bigger than cinder cone volcanoes.
What gases come out off volcanos?
carbon dioxide and more don't really care bye
What actors and actresses appeared in Erupting Volcanos - 1990?
The cast of Erupting Volcanos - 1990 includes: Twin Volcanos
Why do volcanos cause more deaths then earthquakes?
Volcanos burn
Where in Asia are active volcanos found?
Where in asia volcanos found
What is vulcanologist?
Volcanologist* -- Volcano = Volcanos Ology= Study of -- It is the study of volcanos
Do volcanos erupt in the grand canyon?
There are no active volcanos in the Grand Canyon
Are parasitic cone cinder cone the same?
Parasitic cone volcanos and cinder cone volcanos are not the same when classifying. Cinder cone volcanos are the most popular type of volcano, named for its cone shaped formation. Cinder cone volcano are also considered the smallest type of volcanos and can stand alone or grow on the flanks of other volcanos. The parasitic cone volcanos are similar to the cinder cones, however, the volcano is found on the flanks of other volcanos, hence, the name. It is created by flank eruptions of larger volcanos.
