Graphite lubricates fault zones



Graphite is known to be a low-friction material, and rocks rich in graphite are often found in fault zones. Oohashi et al. conducted laboratory studies to determine how much graphite is needed to reduce the frictional strength of a fault. Their experiments included samples with various mixtures of graphite and quartz, as well as pure quartz and pure graphite, and they covered large displacements (up to 100 meters), a range of slip rates (from 200 micrometers per second to 1.3 meters per second), and a range of shear strains (up to several tens of thousands).