These 5 images show how the Earth is built and why volcanoes form

In Iceland, there have been repeated earthquakes on the Reykjanes Peninsula in recent weeks. Now there was a volcanic eruption late Monday evening. The eruption created a four kilometer long fissure from which approximately 100 to 200 cubic meters of lava flowed per second. Here you can discover how such natural phenomena arise.

In everyday life we ​​are hardly aware of what is under our feet. Until now we could not see the center of the earth. It is approximately 6,378 kilometers to the Earth’s core. For comparison, this is roughly equivalent to the distance from Switzerland to New York (6326 km). The deepest drilling only reached 12 kilometers into the ground. With the help of seismographs, measuring devices that detect earthquake waves, researchers were able to discover that the Earth consists of three different shells: the Earth’s crust, the Earth’s mantle and the Earth’s core.

Within these layers, further subdivisions can be made based on temperature and pressure. The Earth’s inner core can reach temperatures as hot as the surface of the Sun – up to 5700°C. The Earth’s outer core reaches temperatures of 3000°C to 5000°C.

There are also differences in the Earth’s crust: there is the oceanic and the continental crust. They differ in that the layer on the seabed is thinner than in the mountains. The Earth’s crust is the thinnest layer of the Earth and is up to 80 kilometers thick.

Below the Earth’s crust is the mantle. Both layers are sturdy. Together, the two layers of the Earth are called the lithosphere, which means something like a rock shell. The lithosphere is divided into plates that move on the viscous asthenosphere. The lower mantle is solid and the pressure there is very high. The Earth’s core can be imagined as a hot, rotating metal ball: unlike the outer core, the Earth’s inner core is solid.

As already explained, the upper layer of the Earth is divided into several plates, which move on the viscous mantle (asthenosphere). They can move towards or away from each other. Over millions of years, the shifting plates have created mountains, volcanoes and islands.

So-called convection currents ensure that the plates can move at all. The following happens: Magma rises from deeper layers of the Earth, cools and sinks back into the deeper layers. This process creates currents that set the upper plates in motion. This can lead to a collision or separation of the Earth’s plates.

Volcanoes are formed by the shifting of the Earth’s plates. Two earth plates must move towards each other. Here too there is a difference between oceanic and continental plates:

When an oceanic and continental plate meet, the oceanic plate slides beneath the continental plate. The part at the bottom partially melts and this causes hot magma to rise at this point. This creates a volcano.

When two continental plates collide, mountains are formed. Since both plates have approximately the same weight, neither sinks downward and one plate must move upward. This is how, for example, the Alps were created.

When two oceanic plates meet, one slides downward. This is usually the older one, which is heavier. Ultimately, volcanoes also form here.

Plates moving away from each other tear the ground apart. When a crack forms, the hot rock slides to the surface. On land these cracks are called ‘rifts’ and in the ocean they are called ‘ocean ridges’.