Why is lava so hot?

Answer 1

The source of the heat is from the interior of the Earth; from radioactive decay, gravitationally created friction, and residual heat from Earth's creation. Magma forms when hot (very hot) rocks experience a drop in surrounding pressure, or when subducted wet lithosphere is introduced into the mantle and melts. When it "breaks out" onto the surface of the earth, we call it lava.

Answer 2

The volcano itself is not necessarily hot: I could have stood on Mt St Helens quite happily before it erupted. When it erupted, of course, I would not have been so willing to stand on its cone. When inactive, a volcano is no different from any other mountain, bar the fact that it has a magma chamber beneath it and a vent rising through the middle of it, and so it may be that it is freezing at a high altitude, or boiling when it is erupting. Just to get that out of the way: volcanoes are not necessarily hot.

During an eruption, material is ejected from a volcano. An effusive eruption will involve a lava flow, and little else. This lava may travel several kilometres however before it cools and stops. This lava is very hot, perhaps more than 1100 degrees Celsius. This is the hotter, less viscous lava (basaltic lava). In an explosive eruption, there is likely to be an ash cloud, pyroclastic flow, lahars and other minor features, including volcanic bombs. Lava of this type (granitic lava) is cooler, if erupted, and is typically erupted at a lower temperature of perhaps 700 degrees Celsius.

The heat creating magma and lava is derived from the interior of the Earth, from factors like radioactive decay, the retention of heat from Earth's formation, and friction from gravitational processes. Heat in the Earth increases with the depth from the surface.

Answer 3

When a volcano is erupting, it is pumping out molten rock from deep within the Earth. The interior of Earth has always been extremely hot; first heated by massive collisions that formed the Earth and kept hot by the crystallization of minerals and radioactive decay.

Answer 4

Lava is molten rock that is formed deep within the Earth's mantle. It is extremely hot because of the high temperatures in the Earth's interior that cause rocks to melt. When a volcano erupts, this molten rock, or lava, is expelled onto the Earth's surface, where it cools and solidifies.

Answer 5

its like an incubator, the lava is hot because its been in the earths core which has all the heat trapped inside to keep the planet moving

Answer 6

Magma is hot because it is formed deep within the Earth. Magma is formed by rocks melting in an area of extreme heat and pressure. This keeps the magma hot.

Answer 7

Lava is molten rock, made a liquid by the heat of the interior of the Earth, continental collisions, or decompression melting.

Answer 8

The material erupted from volcanoes consists of molten rock and pyroclastic material formed from it. This originates deep inside the earth where temperatures have always been extremely high.

Answer 9

Lava originates deep below the Earth's surface where it is still extremely hot.