How does a volcano erupt?

Answer 1

A volcano erupts because all fluids (magma) move from areas of high pressure to areas of low pressure and also light density magmas try to move up in high density rock.
Anyhow, depending on the composition and temperature of the magma, it can erupt and flow easily (basalts in Hawaii), or it can be explosive (when the viscosity is high and the temperature is low, like in rhyolites in south America).

Answer 2

Explosive eruptions are caused when lava in the vents hardens into rock. Steam and lava build up under the rocks. When the pressure of the steam and new lava becomes great, a violent explosion occurs. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Volcano eruptions have been known to knock down entire forests. An erupting volcano can trigger tsunamis, flashfloods, earthquakes, mudflows and rockfalls.

Fresh volcanic ash, made of pulverized rock, can be harsh, acidic, gritty, glassy and smelly.

Answer 3

Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually some of the magma pushes through vents and fissures in the Earth's surface. A volcanic eruption occurs! Magma that has erupted is called lava.

I hope this has answered your question

Answer 4

im learning this in science it erupts because its under a hot spot and lava is coming up into the dome it can sometimes erupt just by a little earthquake

Answer 5

Lying over a hot spot, and the magma is constantly boiling underneath earths surface and then it pops