What will happen when magma heats up?

Magma, pretty much by definition, is a hot and semi-fluid material that is found beneath the surface. Once it erupts / flows at or above the surface it is called lava. read more

Magma, pretty much by definition, is a hot and semi-fluid material that is found beneath the surface. Once it erupts / flows at or above the surface it is called lava. The temperature of magma varies, depending on the chemical composition, but if the temperature does increase, the viscosity changes - magma flows more easily the hotter it is, and much more slowly when it is losing heat (and starting to solidify). read more

What happens in a phreatomagmatic eruption is usually the erupting magma is directly introduced into a body of water – possibly a crater lake, meltwater from snow or ice, seawater – and the very large contrast in heat (sometimes upwards of 1100°C between water and basalt) causes an explosion of both the water and magma. read more