Earthquakes and volcanoes

In short: Earthquakes occur when stresses in the Earth’s crust are suddenly released. Volcanoes are openings through which magma, ash and gases reach the surface.

In more detail: Both occur mainly at the edges of the Earth’s plates (plattentektonik).

In detail

• Hypocentre and epicentre: The hypocentre is the source inside the Earth, the epicentre the point above it on the surface.
• Strength: Magnitude (formerly the Richter scale) measures the energy released. Each step means about 32 times more energy.
• Tsunami: Undersea quakes can trigger huge waves.
• Volcano types: Shield volcanoes (flat, runny lava) and stratovolcanoes (steep, explosive).
• Behaviour in an earthquake: Under a sturdy table or in a doorway, stay away from windows, go outside after the quake. Build earthquake-resistant buildings.