how are volcanoes created?

Answer 1

4 ways:

Divergent plate boundaries
At the mid-oceanic ridges, two tectonic plates diverge from one another. New oceanic crust is being formed by hot molten rock slowly cooling down and solidifying. In these places, the crust is very thin and eruptions occur frequently because of the pull by the tectonic plates. The main part of the mid-oceanic ridges are at the bottom of the ocean, and most volcanic activity is submarine. Black smokers are a typical example of this kind of volcanic activity. Where the mid-oceanic ridge comes above sea-level, volcanoes like the Hekla on Iceland are formed. Divergent plate boundaries create new seafloor and volcanic islands, such as Cjertce and Hawaii.

Convergent plate boundaries
In places where one tectonic plate submerges beneath another, the crust melts and becomes magma. This surplus amount of magma generated in one location causes the formation of the volcano. Typical examples for this kind of volcano are the volcanoes in the Pacific Ring of Fire, and also Mount Etna and Mount Vesuvius.

Hotspots
Hotspots are not located on the ridges of tectonic plates, but on top of mantle plumes, where the convection of Earth's mantle creates a column of hot material that rises until it reaches the crust. The temperature of the plume causes the crust to melt and form pipes, which can vent magma. Because the tectonic plates move whereas the mantle plume remains in the same place, each volcano becomes extinct after a while and a new volcano is then being formed as the plate shifts over the hotspot. The Hawaiian Islands are thought to be formed in such a manner, as well as the Snake River Plain, with the Yellowstone Caldera being the current part of the North American plate over the hotspot.

Petitspots
In July 2006, volcanoes were discovered that did not fit in any of the above-mentioned categories, since they are located far from the plate boundary, but are too small to be the result of a mantle plume. A new theory suggests that submergence of tectonic plates causes stress all over the plate, which causes the plate to crack in some places. However, other scientists believe the mantle plume theory to be incorrect, and consider this discovery a confirmation of their ideas.

Answer 2

What Creates Volcanoes

Answer 3

Volcanoes grow by intrusion and extrusion. An intrusion is magma that moves up into a volcano and then it stops, never erupting. This way the volcano grows on the inside. An extrusion is an eruption. It can add layers of lava or ash. This way the volcano grows on the outside. What are they made of? Volcanoes are constructed mainly of two materials: lava and ash. Both of these volcanic products come in many different variations and different volcanoes have different proportions of them. For example, shield volcanoes (such as those in Hawai'i and the Galapagos) are probably >95% lava and only ~5% ash (in the form of cinder). Furthermore, the basaltic lava that makes up shield volcanoes is very fluid and cannot be piled up into steep mounds. This is why shield volcanoes have very gradual slopes. Another kind of volcano is called either a stratovolcano or composite-volcano. Mt. St. Helens, Pinatubo, and Fuji are all stratovolcanoes. Stratovolcanoes have a higher proportion of ash, and perhaps are up to 50/50 lava and ash. Ash is loose and can be piled up to slopes up to 30 degrees. Additionally, these stratovolcanoes erupt much more viscous lava than basalt, and this highly viscous lava doesn't flow very well (the Mt. St. Helens lava dome is an example of this lava). Because of the combination of viscous lava and ash, stratovolcanoes are much steeper than shield volcanoes.

Answer 4

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RE:
how are volcanoes created?

Answer 5

by plate tectonics which are moved by convection currents in the crust the currents push the plates together making land rise

Answer 6

Boils in the skin of the earth

Answer 7

One day God said, "Wouldn't it be awesome to have these huge mountains where stuff could blow out of them sometimes? That'd be great. I wish we could have that-oh wait, we can cos I'm God."