Volcanoes erupt to release pressure built up in the magma chamber by expelling the magma as lava. Along with lava, a volcanic eruption releases ash and greenhouse gases such as sulfur dioxide and carbon dioxide.
The intensity of a volcanic eruption depends on how viscous the magma is. If the magma is very viscous, then the eruption tends to be more explosive, with rocks and ash shooting up several feet. But if the magma is not viscous, the magma may gently flow out of the crater to form lava streams. Some volcanic eruptions are accompanied by pyroclastic flows. A pyroclastic flow is a fast-moving mass of hot gas and rock that flows down the side of the volcano. If ash is released during the eruption, the heavier particles fall back to the ground. The ash is very dense, and if it accumulates on roofs, the weight of the ash can cause the roof to collapse. The lighter particles remain suspended in the air and can block out the sun. People living in areas surrounding a volcano can have difficulty breathing during an eruption due to the ash suspended in the air. Greenhouse gases such as sulfur dioxide and carbon dioxide are released into the atmosphere and can condense as acid rain.Learn More
When magma rises up to the surface of the Earth from a volcanic eruption or through vents, it turns into lava. When this lava stops flowing and cools, it hardens into what is known as igneous rock.Full Answer >
The main features of a volcano include a vent, a summit crater and a magma chamber. The vent is an opening through which volcanic material is erupted. Volcanoes can have more than one vent. The summit crater is the large concave opening that holds the central vent at the top of the volcano. The magma chamber is the large pool-like structure inside the volcano that holds the magma.Full Answer >
The main parts of a volcano include the summit crater, the magma chamber, the central vent and the edifice. While volcanoes vary considerably in terms of size and shape, most land volcanoes have structural similarities.Full Answer >
A fissure volcano, or fissure vent eruption, occurs when lava erupts through an elongated break in the rock at the surface of the earth. Fissure vent eruptions are common in the mid-ocean ranges. Also known as shield volcanoes, they produce pillow basalt formations such as those that make up the Hawaiian Islands.Full Answer >