The most severe earthquakes worldwide

The strongest earthquakes in the last 2 weeks

► Interactive map

How earthquakes occur

The Earth is not a solid sphere of stone, but consists of different layers with different densities and temperatures. The outermost layer is the Earth's crust and consists of brittle rock masses that float on the Earth's mantle below. Both layers together form the lithosphere. The heat in the Earth's mantle causes a slow but steady movement in which hot and therefore viscous and malleable rock masses slowly rise from the Earth's interior, cool down again and sink once more. These movements are transferred to the continental plates that make up the Earth's outer crust. In the course of many millions of years, our continents drift further and further apart.

If two tectonic plates move towards each other, they fold up at the edges and whole mountain ranges are formed over a long period of time. However, most of these plate boundaries do not run on land, but under water in the oceans. Such huge continental plates do not move at a constant speed. Unlike the deeper layers of the Earth, they are much cooler and therefore firmer. This creates great stresses, which at some point become so great that massive layers of rock break. The resulting jerky discharge of stress generates seismic waves over many kilometers. This is known as earthquakes at the surface.

While the Earth's crust is between 8 and 70 kilometers thick, most earthquakes occur at a depth of 20 to 50 kilometers. That is, where the rock plates are no longer hot enough to deform. The place where the Earth's crust first breaks open is called the hypocenter. The travel time of the seismic waves to different measuring stations often makes it possible to determine this very precisely. The term epicenter describes the location on the Earth's surface above the hypocenter.

The map on the right (source: NASA, DTAM project team) shows the most frequent epicenters of earthquakes, regardless of their magnitude, and thus illustrates the boundaries of the continental plates. In particular, earthquakes occur with striking frequency along the U.S. West Coast and along the Pacific Ring of Fire.

The most severe earthquakes since 1950

Chile, Alaska (USA) and Indonesia appear several times in the list of the most severe earthquakes over the last 60 years. The total damage column includes destroyed homes and financial losses. It does not include victims and damage from tsunamis possibly triggered by the quakes.