Volcano

Depending on the type of volcano, layers can differ in lava/ash content. (Plummer et al., 2000) For example, some strato and composite volcanoes have alternating ash and lava flow layers. Others have more lava than ash, or more ash than lava; some may consist of 50% ash and 50% lava flow layers. There is a reservoir inside the earth filled with melted rock called magma. (Scarth, 1994) At the top of the reservoir is a tunnel that the magma climbs through to the top. Shapes of volcanoes" cone are described in the next paragraph. The magma and other volcanic material come out of the cone when the volcano erupts. (Scarth, 1994) An eruption will actually occur when the magma is subjected to pressure. (Rittman, 1976) The magma begins to rise and may overflow in the form of lava. It may also begin to move downwards along the sides of the mountain. Several shapes of volcanoes are found throughout the world.
             There are several different types of volcanoes. After reviewing many of them, I decided to write on three major ones. These consist of the shield volcanoes, strato (composite) volcanoes, and caldera complex volcanoes. Like the ones you may see in Hawaii, shield volcanoes are in the shape of wide plateau mounds. The eruption frequency tends to be very high. These volcanoes have low-explosivity. The lava from .
             Ziehm 3.
             shield volcanoes is liquid and flows from the crater and the sides of the volcano. (http://www.volcano.und.nodak.edu) Strato volcanoes, also known as composite volcanoes, tend to have violent eruptions and have an intermediate eruption style. These flanks usually are fairly steep and they have layered lava/pyroclastic material. (http://www.volcano.und.nodak.edu). Caldera complexes are usually the most explosive of the Earth's volcanoes. They may not look like a volcano, but their eruption style is so intense that they can end up collapsing on themselves. Yellowstone is probably the most popular of these in the United States.