This fault model is a variation of one invented by Paul Doherty of the San Francisco Exploratorium. In the Earth, earthquakes occur as slip occurs along a fault plane. The fault plane is not uniform in strength, so most of the energy is released from patches of the fault that are "stuck." These patches are called "asperities." In this model each piece of spaghetti acts as an asperity that must be broken for slip to occur. Sometime just one noodle breaks, somewhat analogous a small earthquake.