Science of the stick-slip

Scientists have succeeded in modelling what happens when two bodies slide against each other and thereby release the pressure; a discovery that has implications for the understanding of the magnitude of earthquakes. David Kammer from EPFL has developed a digital model that explains what happens at the interface between two materials when they slide against each other; like a book on a table, rubber soles on linoleum, or - more to the point - tectonic plates. Earthquakes occur at the point where two tectonic plates meet. Between each period of sliding, forces accumulate between them up to the point where the friction resistance is released, leading to movement. This displacement of the Earth's crust triggers a shock-wave that is transmitted to the surface of the planet. The scientists ed by Live Science put the physics of earthquakes in the "top ten" of the most interesting scientific mysteries. Accumulation of energy determines the stick-slip - When two materials slide against each other, they don't always react in the same way, according to the prevailing conditions, such as rigidity or the speed of movement. Sometimes the sliding is regular and homogenous; in the case of tectonic plates, the movement is hardly felt, or not at all. At other times, there is a succession of phases of stopping or speeding up, called "stick-slip". Earthquakes are the result of sudden movement. These heterogenous movements systematically trigger a shock-wave at the surface. But what determines the intensity?