Kinds of Volcanic Materials

When volcanoes erupt, lava, gas and solid materials are ejected into the air. The material that erupts depends on how sticky or fluid a volcano's magma is.

Lava is the name for magma that is ejected onto the earth's surface. There are two kinds of lava: the acid lava and basic lava.

The gas that is emitted during eruptions is hot. It includes steam, carbon dioxide, sulphur dioxide, and nitrogen. When these gases rush down the volcano, it is called a nuée ardente.

The solid materials spewed out of the volcano include ash, dust, cinders and volcanic bombs. They are called pyroclasts. The dust, which can be carried great distances by winds, affect the world's climate by reducing the amount of sunlight reaching the earth. The ash, which may combine with water in a stream, forms a boiling mudflow known as lahars. These lahars may reach high speeds or 100km per hour and flow down the volcanoes. They are extremely dangerous and can bury towns such as Armero and remove trees and houses, which lie in their way. Volcanic bombs are large fragments of rocks and are generally called cinders.

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