Lava erupts from the Arenal Volcano in Mexico

Where it occurs: Volcanoes, or through deep cracks in the Earth’s surface

Speed: Between a few inches per day to 24kmph (15mph)

Max speed: 56kmph (35mph)

Max temperature: Fresh lava is 700°C (1,300°F) to 1,200°C (2,200°F)

Casualties: Difficult to estimate deaths caused by lava flows alone, most casualties occur because of the accompanying effects of a volcanic eruption, like gas and falling debris.

Lava is red to white-hot molten rock (magma), which escapes from deep below the surface of the Earth. Some of the world’s islands - like Hawaii - were formed by lava slowly escaping through cracks in the seabed.

The speed at which lava travels depends on the type of lava, the gradient of the Earth’s surface and whether the lava is escaping through a channel, or over a large area. Unlike the destruction caused by other natural disasters, lava flow damage is permanent - it buries everything in its path beneath hardened rock, changing the landscape forever.