Researchers from EPFL and the Weizmann Institute of Science in Israel have made a step forward in assessing earthquake dynamics through a better understanding of how frictional slip – the relative motion of two bodies in contact under shear stress, such as tectonic plates – begins. Their work was published in two complementary parts, in Physical Review X and Earth and Planetary Science Letters. They used high-performance computers to simulate seismic ruptures based on generic laws of friction, which reproduce the change in frictional force depending on the slip velocity measured between different types of materials. Using dynamic rupture theory and applying it to friction, the researchers were able to assess laboratory experiments and ensure that their predictions were correct. “The theoretical models we developed could in the future help us better understand why certain earthquakes in nature are fast and violent, while others propagate slowly and occur over longer periods of time,” explains Fabian Barras, of the Computational Solid Mechanics Laboratory (LSMS) and first author of both articles.