Question: how do volcanos erupt

Angela Stevenson answered on 20 Nov 2013:

Hi again Sarah, you ve got some great questions! Excellent 🙂 Volcanoes are beautiful to watch (scary at times)… and very interesting. So lets try to think about how they might erupt. The Earth has three layers: the core (innermost layer), crust (outermost layer), and mantle (the layer just below the Earth’s crust). The core is full of magma, which is actually hot melted rock that we call lava once it has erupted from a volcano. But how does magma manage to escape from the Earth’s crust to cause this volcanic eruption? Well, the mantle is made of up plates that are always moving and shifting. Sometimes the plates separate, which creates heat and causes the mantle to melt into magma. The magma comes up through the crack between the plates. The hot magma collects under the surface of the Earth and if the pressure is high enough or a crack opens in the crust (Earth’s surface), then magma spews out, causing a volcanic eruption! Hope that helps answer your question 🙂